CS197263B2 - Method for treatment of vinylic polymers - Google Patents

Description

THE CZECHOSLOVAK SOCIALIST REPUBLIC (19) DESCRIPTION OF THE INVENTION 197263 (11) (B2) (51) Int. Cl.1 * 3 C 08 F 2/34 (22) Registered 15 01 76 Wi (21) (PV 276-76) (40) Published 31 07 79 OFFICE AND DISCOVERY OFFICE (45) Released 15 02 83 Í721

The inventor JEZL JAMES LOUIS, ST. CHARLES and PETERS EDWIN FRANCIS, WINFIELD (S.A.) (73) '

Patent holder of STANDARD OIL COMPANY, CHICAGO (Sp. A. J (54 J Vinyl polymer processing method 1)

BACKGROUND OF THE INVENTION The present invention relates to a novel method for efficiently delivering heat to solid polymer particles which leave the reactor working vapor phase, so that the polymer melts to an elevated temperature sufficient to effectively melt the molten polymer through a series of melt end stages. More particularly, the present invention relates to a novel process for treating solid polymer particles leaving a polymerization reactor operating in a steam stage, wherein the process utilizes a post-polymerization reactor downstream of the reactor, into which solid polymer particles are prepared without substantial pressure drop and where the monomer monomer is added and allowed to proceed. the polymerization essentially under adiabaitic conditions such that the solid particles of the polymer are raised and melted to form a melt for further processing.

According to the present invention, the process of treating the vinyl polymers produced by vapor phase polymerization in the polymerization zone from at least one vinyl monomer in the vapor phase consists in dissolving the solid polymer together with the off-gases from the poly-metering zone into the post-polymerization zone where additional polymer is introduced, substantially adiabatic polymerization, optionally with the addition of additional heat 2, and the molten polymer is removed from the post-polymerization zone.

Thus, according to the present invention, the solid particles of the polymer removed from the vapor-phase reactor without substantially decreasing the pressure are sufficiently high and melt in the post-polymerization zone, where substantially adiabatic polymerization of the monomer vapor from the reactor and additionally added monomer may result in a linear heating associated with increasing the formation of a melt capable of flowing. In addition, the molten polymer is then treated with the catalyst-decomposing agent and other additives, such as stabilizers and dyeing, then degassed, whereby the molten product is cooled and processed into a commercial particle size product.

One of the problems of monomer polymerization in solution or suspension is the manufacturing cost. The polymerization of the monomer carried out in the feed phase can be considerably more economical if some of the problems associated with the polymerization in the vapor state can be solved. In this process a high yield cocatalyst is used, i.e. the polymer produced is processed from which there is no need to remove catalyst residues. The solid polymer particles are removed from the reactor and then, after decomposition of the 197263 197263 catalyst and cocatalyst, the additive is molten after being added to a product that is commercially suitable. Advantageous storage of the necessary heat can be achieved if the solid polymer particles are melted directly after leaving the reactor without intermediate cooling and then all the final processing of the molten polymer is carried out. However, the melting of the polymer from the reactor by external heat transfer is insufficient, that both the solid polymer particles and the molten polymer have low thermal conductivity and low heat transfer rates.

The present inventors have now found that supplying an important portion of the additional heat required to increase the temperature of the solids of the polymer leaving the reactor by virtue of the polymer's melting point substantially adiabatic polymerization in the poatpolymerization zone is an extremely efficient method of preparing the molten polymer that is suitable. final melt production. The additional advantage obtained by melting the polymer downstream of the reactor is to improve the purity of the final product, since the postpolymerization melts the polymer in particular, even before the catalyst decomposition. An important economic benefit is achieved by saving energy, raw materials and basic equipment.

Fig. 1 shows a flow diagram of an embodiment of the invention.

FIG. 2 shows a longitudinal view of the post-polymerization zone (melting member).

The process of the present invention utilizes a downstream reactor adiabatic polymerization in which it utilizes variable amounts of heat from the polymerization to assist in melting the polymer and increasing the temperature of its solid particles leaving the vapor phase reactor. The polymer enters the post-polymerization zone together with the gases leaving the reactor. In this zone, polymerization is carried out in the presence of additionally added monomer under substantially adiabatic conditions. The temperature in the post-polymerization zone increases depending on the polymerized monomer, the extent of polymerization that takes place in the polymerization zone and the heat supplied from the outside. The polymer melts and the temperature increases until it is sufficient to successfully transport the polymer in the molten state at a number of final polymerization stages. As used herein, the term "reactor" means a reactor or process in which the monomer or monomers are treated in a vapor or gas.

In Fig. 1, the solid polymer particles are removed without substantially reducing the pressure from the reactor 101 to the post-polymerization zone, into the container for the protruding polymer 103, together with some of the gases that have escaped from the reactor. The monomer from these gases and the mono-mer added via line 113 are further polymerized in the zone because the particles contain a certain amount of still active catalyst and, if used, also a cocatalyst. This additional polymerization is carried out essentially under adiabatic conditions and it allows extremely excellent heat transfer of the reinforcing polymer as the heat from the polymerization is essentially uniformly produced by the polymer particles in the individual polymerization sites. Depending on the rate of removal of polymer from the reactor, the rate of addition of the monomer through the conduit 113, the amount of still active catalyst and the like, the heat of the polymerization contributes to a greater or lesser degree, or even the polymerization is quite sufficient. . The additional heat is usually supplied by the heater 148 to increase the temperature range of the molten polymer in the container for the protruding polymer 103 so that the molten polymer can be efficiently transferred to other end stages.

In addition to the efficient process of increasing the polymerization temperature in the container for the protruding polymer 103, the polymer melt is substantially ameliorated with the monomer and optionally also with the amount of coolant (in the reactor using the coolant) and hydrogen, after being transported by the melt pump. The previous degassing in the melt tank for the protruding polymer 103 provides a pure polymer that contains less catalyst residue from the resulting decomposition catalyst and optionally absorbed coolant.

The polymer is then readily pumped to ISO, where the catalyst decomposition agent, usually water, is added through conduit 107. Subsequently, additives, such as stabilizers and colorants, can be added, separately or mixed, via line 109. These additives are mixed with the molten polymer in the mixer 111. However, the additives can also be added downstream of the degassing stage. In a preferred embodiment, both the catalyst decomposing agent and the additives may be added together, suspended in an inert volatile substance such as hexane and the like. In this case, the substances are mixed with the expanded polymer prior to the degassing step.

Thereafter, the molten polymer is preferably heated in a heat exchanger 146 and passed to the diclining tower 119, which is preferably adapted to be polymyticized through a standard nozzle at the densification tower 119. Thin strands of the expanded polymer formed at the nozzle falling in and out they evacuate the vacuum they move. Volatiles, such as catalyst product, optionally hydrogen, monomer, and the like, are removed by conduit 115. Optionally, a purification line can be connected to the degassing tower 119 to purify volatile matter through conduit 115, using steam, nitrogen or other inert substances. Advantageous effect using this procedure 197263

After the polymerization of ethylene with hydrogen, the substantial amount of ethane produced by hydrogenation of the ethylene during polymerization is fed from the polymer-mixed reactor 101 and suctioned off in this degassing stage.

The molten polymer 152 at the bottom of the degassing tower 119 is then discharged via line 121 through pump 117 for cooling and pelletizing or similar processing to a commercial product. Using the invention for the final processing of polyethylene, the melt temperature is approximately above 129 ° C at the bottom of the polymer exit container 103, above about 149 ° C in the catalyst decomposition region and up to 288 ° C degassing In the present invention, for use in the final processing of polypropylene, the melt temperature is about 166 ° C at the bottom of the polymer exit container 103, above about 177 ° C in the decomposition region of the catalyst and up to 288 ° C. The various polymers will be different temperatures will depend on the melt temperature or the softening temperature, the viscosity of the molten polymer, and the exact nature of the melting steps that are known to those skilled in the art.

Fig. 2 shows the solid and molten polymer layers in the polymer exit vessel 203.

The process described herein may be used in the polymerization of polymerizable monomers that are polymerizable under the softening temperature of their polymers. These include ethylene, propylene, 4-methyl-1-pentene, 1-butene, vinyl chloride, butadiene, styrene mixtures of these monomers. It is particularly preferably used to polymerize ethylene and propylene.

According to the invention, a monomer corresponding to the monomer introduced into the main polymerization zone, which is selected from the group of the above-mentioned monomers, is used as an additional mono-mer.

Catalysts which are most preferred in the process of the invention are those that are very active and provide high yields per catalyst. For the polymerization of olefins, this group includes some cocatalysts which consist of the organometallic compounds of the group Ia, IIa and the lilaperiodic system and the catalysts of the compounds of the transition elements. The yococatalysts are particularly preferred aluminum-alkyl compounds and include trialkylaluminums and alkylaluminum halides such as dialkylaluminum chloride. The precursor metal catalysts may be those containing IV compounds. or V. groups of the periodic system, such as titanium and vanadium compounds, of compound VI. groups of the periodic system, such as chromium oxides and molybdenum, or the transition metal compounds may be deposited on magnesium oxide on alumina, silica, or mixtures thereof. Preferred catalysts and cocatalysts are those which yield high yields, such high yields providing catalysts and cocatalysts whose residues do not need to be removed from the products produced by the process. Preferred catalysts and cocatalysts for ethylene propolymerization are the trialkylaluminum as a cocatalyst, with a catalyst which is a titanium compound deposited on a magnesium base or a oxide of alumina, silica or mixtures thereof. For the polymerization of propylene, it is preferable to use dialkylaluminum chloride as the cocatalyst and use of active titanium trichloride as catalyst. However, the process and apparatus described herein are not limited by the catalysts, except that the process must be carried out with catalysts which yield a high yield (based on catalyst). While the invention is described in the context of the specific examples set forth below, it is to be understood that these examples are provided for illustrative purposes only. Possible modifications, variations and variations apparent to those skilled in the art are also within the scope of the appended invention. Přikladl

The titanium tetrachloride catalyst is suspended in isopentane at a concentration of 30 mg / liter and pumped continuously to the horizontal reactor operating in the vapor phase, with a mixed bed, at a rate of 300 ml / h. Triethyl aluminum is diluted with isopentane to a concentration of 1000 mg / liter and is continuously pumped at a rate that maintains the desired weight ratio of triethylaluminum to catalyst 3: 1 to 15: 1. Ethylene is continuously fed at such a rate that the polymerization maintained a pressure of 2.2 MPa. A continuous 9.4 L / h stream of gas was removed from the reactor for gas chromatographic analysis. The hydrogen concentration in the reactor was maintained at 34% molecular weight by the occasional introduction of hydrogen, a control of the molecular weight of the polymer. The temperature of the polymer bed in the reactor was maintained at 71 ° C by continuously spraying the iso-pentane onto the polymer bed stirred at an appropriate speed of 30 rpm. Evaporated isopentane is condensed and recirculated. The uncondensed gas (4.5-10 ° C) is recirculated continuously back to the bottom of the stirred polymer bed. The height of the polymer gel is maintained by opening the opening in the containment overflow. The polymer flows through the thin-film into a melting cell which is maintained at 177 to 204 ° C by heat from polymerization and the heat supplied by the external electric heating. The molten polymer falls to the bottom and is passed through a horizontal pipe with a diameter of 1.9 cm and a length of 122 cm at 197263 204-260 ° C under pressure in the reactor. Water is continuously injected into the polymer melt, between the melter and the mixer decomposition of the catalyst at a rate of 10 ml / h. The polymer melt is extruded from the mixer for the catalyst decomposition through a 9.5 mm hole and passed through a water bath and then cut into pieces. The polymer is produced at a rate of 0.45 to 1.35 kg / h with a yield of 100,000 grams of polymer per gram of catalyst. The physical properties of the polymer coming from the melt cell are shown in Table 1. Table 2 shows some properties of the polymer from the reactor.

Conditions: 71 ° C, 2.2 MPa, 34 mole% hydrogen, triethyl aluminum / catalyst weight ratio = 13: 1 to 15: 1, 1. weight ratio of triethylaluminum and catalyst = 2.6: 1 to 3.75: 1.

General Properties Experiment A Experiment B1) Non-annealed Density, g / cm3 0.961 0.959 Annealed Melt Density, g / cm3 0.977 0.977 Viscosity Limit Number, dl / g 1.87 2.29 Melt Index, MFi, g / 10 min. 0.92 0.44 Melt Index, MF 10, g / 10 min. 38 24 Ratio, MFio / MFl 41.4 54.5 Hexane Extractable Component,% wt. 0.47 0.41 Dry volatile component,% wt. 0.20 0.28 Stiffness, MPa 1160.0 1120.0 Molecular Weight Parameters, GPU Molecular Weight Distribution, Mw / Mn 7.6 10.5

Tensile properties

Intermediate Deformation Tensile Strength, MPa at 5.2 cm / min 3.18 3.22 Tensile Strength, MPa at 5.2 cm / min Permanent Deformation Extension, 2.38 1.97% at 5 , 2 cm / min 10 11 Elongation limit,% at 5.2 cm / min 1200 689 Impact resistance Impact strength, J / cm2 13.6 18.5 Impact resistance, Izod, J / cm 12.7 13.5 Thermal properties Vicat softening temperature, ° C, embrittlement temperature, ° C TABLE 2 130 127. Conditions: 71 ° C, 2.2 MPa, 34 mol% hydrogen, mass ratio of triethylaluminum ε i catalyst = = 13: 1 to 14: 1. Experiment A Experiment B Fraction number 5R 8R 10R Total polymer produced, g 3628 5509 6637 1952 Bulk density, g / cm3 0.35 0.37 0.37 0.41 Melt index, MF 10, g / 10 min. 28.7 38.7 48.2 - Melt Index, MFi, g / 10 min. Flow Rate Ratio, 0.89 1.0 1.3 - MFio / MFl 32.3 38.7 37.1 - 19 7.2 83 A d d e 2

A mixed-bed horizontal carbon steel reactor with a diameter of about 61 cm and a length of 92 cm, which is equipped for recirculating gas and where it is also possible to recirculate the cooling liquid, is used for continuous polymerization of ethylene and propyl. A temperature of 83 ° C is maintained at one end of the reactor, a temperature of 77 ° C in the middle of the reactor and a temperature of 83 ° C, near where the outlet overflow is located. The total reactor pressure was 2.9 MPa. The batch was charged with 9.3 kg / hr of ethylene and 0.13 kg / hr of propylene. The recirculated gas has a velocity of 0.065 Nm 3 / min isopentane, as recirculating coolant is introduced at a rate of 1.3 liters per minute. As the catalyst, titanium is added in an amount of 0.3 g / h as a suspension in iso-pentane. The suspension is introduced at a rate of about 13.5 liters per hour. Triethylaluminum as cocatalyst is added in the form of a solution in isopentane at a rate of 35 ml / h by concentrating 0.025 g of triethylaluminum per milliliter.

The gases from the reactor are continuously analyzed, with the following typical values: 10 hydrogen mol% ethane 0.3 mol% propylene 1.1 mol% isopentane 1 mol% ethylene 60.6 mol%.

The product melt index is approximately 0.58 g for 10 minutes. Example 3

Ethylene is polymerized in the same manner as described in Example 1. 2.0 wt. % of chromium oxide on silica (WRGrace 952 SiO 2. The catalyst is calcined at 631 ° C with dry oxygen for 12 hours. The catalyst is continuously fed with the catalyst, triisobutylaluminum and ethylene at 99 ° C and 2.2 MPa. The mole ratio of triisobutylaluminum to chromium trioxide is 3: 1. The polymer yield per gcatalyst is 4600 g. The polymer is continuously removed in the form of a melt. has the following physical properties: TABLE 3

Fraction MFi index g / l-O min. Melting index MFio g / 10 min. Flow Rate Ratio MFI / MFi Extractable Ratio,% wt. Volatile% w / w wt. Molecular Weight Distribution Mw / Mn 5 0.20 22.2 111 1.5 0.65 14.7 6 0.12 16.6 138 1.6 0.87 17.0 7 0.12 20.2 168 1, 8 0.98 15.4 Example 4

Propylene is polymerized in substantially the same manner as described in Example 1. The recirculated gas and coolant are propylene. The temperature in the melt cell is 177 ° C, and is operated at 204 ° C in the catalyst degradation section. The catalyst used is titanium tetrachloride (33 mg), together with the cocatalyst, diethylaluminum chloride (77 mg). The molar ratio of aluminum to titanium is 3: 1. The catalyst and cocatalyst are fed to the reactor every 30 minutes. The reactor temperature was maintained at 71 ° C while maintaining the reactor pressure at 2.2 MPa by adjusting the temperature of the recirculated coolant to about 49 ° C. The polymer was removed from the reactor in the form of a melt, and the polymer had a melt flow rate of 16.4 g per 10 minutes at 230 ° C under a load of 2.060 g. Extractable with n-hexane 4.0% by weight Example 5

Ethylene is polymerized in the same manner as described in Example 1, except that two sequesterators are used which are maintained at different temperatures. One reaction section is operated at 71 ° C while the other reaction section is operated at 99-110 ° C. This is achieved by varying the amount of isopentane, such as the coolant added to each section. A titanium compound is used as the catalyst, and triethyl aluminum is added as the cocatalyst, with a cocatalyst to catalyst weight ratio of 3: 1. to 2.1 MPa and hydrogen concentration to 40 mole%. The yield was 62,000 g of polymer per g of catalyst used. The measurements were performed on a melt index of 5.5, a flow rate ratio of MIO / MFi of about 40, and a spiral flow of 45.8 cm. The polymer produced under uniform temperature conditions exhibited the same melt index, a melt flow rate ratio MF 10 / Mf 1 of about 34 and a helical flux of about 40, 7 cm.

Claims (2)

197263 11 12 Spiral Flow is an empirical method of blending the ease of processability of a polymer, and is based on measuring the flow length in a special form under specific temperature and pressure conditions. Longer spiral flow indicates easier workability. The abbreviation "MF" refers to the polymer flow rate determined by the American Test Method ASTM D 1238-73, Flow Rates SUBJECT What is claimed is: 1. A process for the treatment of vinyl polymers produced by polymerization in a vapor phase in a polymerization zone from at least one vapor phase monomer, characterized in that the solid polymer is discharged with the off-gases from the polymerization strand into postpolymerization zone, where additional monomer is introduced into the basically adiabatic polymerization, optionally with the addition of additional heat and melting of Thermoplastics Extrusion Plastomer. MFi refers to the flow rate according to the procedure labeled "Condition E". MFiose is determined according to the procedure labeled "Condition F". The flow rate velocity rate expressed as MF 10 / MFi is an indicator of molecular weight distribution, with the higher ratio showing wider distribution and vice versa. The inventive polymer is removed from the postpolymerization band. 2. The process of claim 1 wherein the additional monomer is an monomer corresponding to the monomer introduced into the main polymerization zone selected from the group consisting of ethylene, propylene, 1-butene, vinyl chloride, 4-methyl-1. -pentene, butadiene and Styrene. 1 sheet of drawings severografia, n. P., Plant 7, Most