EP0606285A1 - Activation d'un catalyseur dans la polymerisation de l'ethylene a haute temperature - Google Patents

Activation d'un catalyseur dans la polymerisation de l'ethylene a haute temperature

Info

Publication number
EP0606285A1
EP0606285A1 EP92920013A EP92920013A EP0606285A1 EP 0606285 A1 EP0606285 A1 EP 0606285A1 EP 92920013 A EP92920013 A EP 92920013A EP 92920013 A EP92920013 A EP 92920013A EP 0606285 A1 EP0606285 A1 EP 0606285A1
Authority
EP
European Patent Office
Prior art keywords
aluminum
ethylene
catalyst
alkyl
component
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP92920013A
Other languages
German (de)
English (en)
Inventor
Vaclav George Zboril
Stephen John Brown
Reginald Kurt Ungar
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nova Chemicals International SA
Original Assignee
DuPont Canada Inc
Nova Chemicals International SA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by DuPont Canada Inc, Nova Chemicals International SA filed Critical DuPont Canada Inc
Publication of EP0606285A1 publication Critical patent/EP0606285A1/fr
Withdrawn legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F10/00—Homopolymers and copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond
    • C08F10/02—Ethene
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F210/00—Copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond
    • C08F210/16—Copolymers of ethene with alpha-alkenes, e.g. EP rubbers

Definitions

  • the present invention relates to a process and catalyst for the preparation of polymers of ethylene, especially homopolymers of ethylene and copolymers of ethylene and higher alpha-olefins.
  • the invention relates to a solution polymerization process for the preparation of such polymers in which the process is operated at a temperature of at least 180°C, and the catalyst is activated with a alkoxy alkyl aluminum compound.
  • Polymers of ethylene for example, homopolymers of ethylene and copolymers of ethylene and higher alpha- olefins, are used in large volumes for a wide variety of end-uses, for example, in the form of film, fibres, moulded or thermoformed articles, pipe coatings and the like.
  • catalyst residue may contribute to the colour of the polymer obtained and to degradation of the polymer during or subsequent to processing of the polymer.
  • the amount of catalyst residue is related, at least in part, to the overall activity of the catalyst employed in' the polymerization step of the process as the higher the overall activity of the catalyst the less catalyst that is, in general, required to effect polymerization at an acceptable rate. Catalysts of relatively high overall activity are therefore preferred in solution polymerization processes.
  • Catalysts activated by siloxalanes are capable of polymerizing ethylene at very high temperatures.
  • the siloxalane residues from such catalysts tend to significantly adversely affect the performance of adsorbers used to purify solvent in the associated solvent recovery and recycle sections of the polymerization process.
  • the present invention provides in a solution process for the preparation of high molecular weight polymers of alpha-olefins selected from the group consisting of homopolymers of ethylene and copolymers of ethylene and C 3 -C 12 higher alpha-olefins, by polymerization of ethylene and/or mixtures of ethylene and C-.-C. j2 higher alpha-olefins in the presence of a catalytic amount of a titanium-containing coordination catalyst in an inert solvent at a temperature in excess of 105 ° C, the improvement characterized in that:
  • the present invention further provides a solution process for the preparation of high molecular weight polymers of alpha-olefins selected from the group consisting of homopolymers of ethylene and copolymers of ethylene and C 3 -C 12 higher alpha-olefins, said process comprising feeding monomer selected from the group consisting of ethylene and mixtures of ethylene and at least one C 3 -C 12 higher alpha-olefin, a coordination catalyst and inert hydrocarbon solvent to a reactor, polymerizing said monomer and recovering the polymer so obtained, characterized in that said monomer is polymerized at a temperature in the range of 180-320°C and said coordination catalyst having been formed from a first component and a second component, said first component containing titanium and second component being selected from the group consisting of alkoxy aluminum alkyl and mixtures of alkyl aluminum and alkoxyalkyl aluminum, said aluminum alkyl being of the formula AlR
  • n and said alkoxy alkyl aluminum being of the formula AIR ⁇ OR" ⁇ , in which each R, R' and R" may be the same or different and is independently selected from alkyl or aryl of 1-20 carbon atoms, X is halogen, n is 1-3 and is 0-2.
  • the second component is in the form of a mixture of trialkyl aluminum and an alcohol in which the amount of alcohol is less than the stoichio etric amount to form dialkyl alkoxy aluminum, especially in which the trialkyl aluminum is A1R 3 3 in which each R 3 is an alkyl group having 1-10 carbon atoms and the alcohol is of the formula R 4 0H in which R is alkyl or aryl of 1-20 carbon atoms, especially alkyl of 1-16 carbon atoms.
  • the first component is formed from:
  • the first component may be formed by rapidly admixing a solution of a titanium tetrahalide, optionally containing vanadium oxytrihalide, and with organoaluminum compound e.g. trialkyl aluminum or dialkyl aluminum halide, at a temperature of less than 30°C, and heating the resultant admixture to a temperature of 150-300°C for a period of 5 seconds to 60 minutes.
  • organoaluminum compound e.g. trialkyl aluminum or dialkyl aluminum halide
  • the forming of the first and second catalyst components and the admixing thereof are carried out in-line at a temperature of less than 30"C.
  • the present invention is directed to a process for the preparation of high molecular weight polymers of alpha-olefins, such polymers being intended for fabrication into articles by extrusion, injection moulding, thermoforming, rotational moulding and the like.
  • the polymers of alpha-olefins are homopolymers of ethylene and copolymers of ethylene and higher alpha-olefins i.e. alpha-olefins of the ethylene series, especially such higher alpha-olefins having 3 to 12 carbon atoms i.e. C 3 -C 12 alpha-olefins, examples of which are 1-butene, 1-hexene and 1-octene.
  • the preferred higher alpha-olefins have 4-10 carbon atoms.
  • cyclic endomethylenic dienes may be fed to the process with the ethylene or mixtures of ethylene and C 3 -C 12 alpha-olefin. Such polymers are known.
  • the monomer may be ethylene or mixtures of ethylene and at least one C 3 -C 12 higher alpha-olefin, preferably ethylene or mixtures of ethylene and at least one C 4 -C 10 higher alpha-olefin; it will be understood that the alpha- olefins are hydrocarbons.
  • the coordination catalyst is formed from two components viz. a first component and a second component.
  • the first component contains titanium or admixtures thereof with other transition metals in lower than maximum valency, and is an organometallic component of the type, typically used in solution polymerization processes.
  • the first component may be in a solid form. Examples of the first component have been given above.
  • the second component is a solution of an alkoxyalkyl aluminum or a mixture of aluminum alkyl and alkoxy alkyl aluminum in inert solvent; the ratio of aluminum alkyl to alkoxy aluminum alkyl in the mixture may be used in the control of the process.
  • the aluminum alkyl is of the formula AlR n X 3 .
  • n and the alkoxy aluminum alkyl is of the formula AIR ⁇ OR" ⁇ , in which each R, R' and R" is alkyl or aryl of 1-20 carbon atoms, X is halogen especially fluorine, chlorine or bromine, n is 1-3 and m is 2. The preferred halogen is chlorine.
  • the alkoxy aluminum alkyl may be prepared by admixing the corresponding alkyl aluminum with the corresponding alcohol, so as to form the alkoxy aluminum alkyl.
  • the alkyl aluminum is the same as the aluminum alkyl in the second component.
  • the preferred method of forming the second component is to add the alcohol to the alkyl aluminum in less than the stoichiometric amount required to convert all of the alkyl aluminum to alkoxy aluminum alkyl.
  • the mixing may be conveniently carried out in-line . at a temperature of less than 30°C, permitting reaction to occur for some minimum time. This time depends on the type and reactivity of the components used to prepare a particular catalyst. As exemplified hereinafter, feeding the alcohol directly to the reactor in the ' polymerization ' process is detrimental to the polymerization process.
  • the ratio of the alcohol to the alkyl aluminum used to achieve control of the polymerization process is in the range of 0.1-1 (alcohol:aluminum) .
  • concentration of the components of the solutions used in the preparation of the catalyst is not critical and is primarily governed by practical considerations. Concentrations of as low as 25 ppm, on a weight basis, may be used but higher concentrations, for example 100 ppm and above, are preferred.
  • the sequence of steps in the preparation of the catalyst is important in obtaining a catalyst with high activity.
  • the coordination catalyst described herein is used in the process of the invention without separation of any of the components of the catalyst. In particular, neither liquid nor solid fractions are separated from the catalyst before it is fed to the reactor. In addition, the catalyst and its components are not slurries. All the components are easy-to-handle, storage stable liquids.
  • the solvent used in the preparation of the coordination catalyst is an inert hydrocarbon, in particular a hydrocarbon that is inert with respect to the coordination catalyst.
  • solvents are known and include for example, hexane, heptane, octane, cyclohexane, methylcyclohexane and hydrogenated naphtha.
  • the solvent used in the preparation of the catalyst is preferably the same as that fed to the reactor for the polymerization process.
  • the first component of the catalyst described herein may be used, according to the process of the present invention, over the wide range of temperatures that may be used in an alpha-olefin polymerization process operated under solution conditions.
  • polymerization temperatures may be in the range of 105-320°C and especially in the range of 105-310°C.
  • the activator is particularly effective at temperatures of at 180"C, and thus the process of the invention is operated, at least in part, at such elevated temperatures.
  • the pressures used in the process of.the present invention are those known for solution polymerization processes, for example, pressures in the range of about 4-20 MPa.
  • the alpha- olefin monomers are polymerized in the reactor in the presence of the catalyst. Pressure and temperature are controlled so that the polymer formed remains in solution.
  • Small amounts of hydrogen for example 1-100 parts per million by weight, based on the total solution fed to the reactor may be added to the feed in order to improve control of the melt index and/or molecular weight distribution and thus aid in the production of a more uniform product, as is disclosed in Canadian Patent 703,704.
  • the solution passing from the polymerization reactor is normally treated to deactivate any catalyst remaining in the solution.
  • catalyst deactivators include fatty acids, alkaline earth metal salts of aliphatic carboxylic acids, alcohols and trialkanolamines, an example of which is triisopropanolamine.
  • the hydrocarbon solvent used for the deactivator is preferably the same as the solvent used in the polymerization process. If a different solvent is used, it must be compatible with the solvent used in the polymerization mixture and not cause adverse effects on the solvent recovery system associated with the polymerization process.
  • the solution containing polymer may be passed through a bed of activated alumina or bauxite which removes part or all of the deactivated catalyst residues and/or other impurities. It is, however, preferred that the process be operated without removal of deactivated catalyst residues.
  • the solvent may then be flashed off from the polymer, which subsequently may be extruded into water and cut into pellets or other suitable comminuted shapes.
  • the recovered polymer may then be treated with saturated steam at atmospheric pressure to, for example, reduce the amount of volatile materials and improve polymer colour. The treatment may be carried out for about 1 to 16 hours, following which the polymer may be dried and cooled with a stream of air for 1 to 4 hours.
  • Pigments, antioxidants, UV screeners, hindered a ine light stabilizers and other additives may be added to the polymer either before or after the polymer is initially formed into pellets or other comminuted shapes.
  • the antioxidant incorporated into polymer obtained from the process of the present invention may, in embodiments, be a single antioxidant e.g. a hindered phenolic antioxidant, or a mixture of antioxidants e.g. a hindered phenolic antioxidant combined with a secondary antioxidant e.g. a phosphite. Both types of antioxidant are known in the art.
  • the ratio of phenolic antioxidant to secondary antioxidant may be in the range of 0.1:1 to 5:1 with the total amount of antioxidant being in the range of 200 to 3000 ppm.
  • the process of the present invention may be used to prepare homopolymers of ethylene and copolymers of ethylene and higher alpha-olefins having densities in the range of, for example, about 0.900-0.970 g/cm 3 and especially 0.915-0.965 g/cm 3 ; the polymers of higher density, e.g. about 0.960 and above, being homopolymers.
  • Such polymers may have a melt index, as measured by the method of ASTM D-1238, condition E, in the range of, for example, about 0.1-200, and especially in the range of about 0.1-120 dg/min.
  • the polymers may be manufactured with narrow or broad molecular weight distribution.
  • the polymers may have a stress exponent, a measure of molecular weight distribution, in the range of about 1.1-2.5 and especially in the range of about 1.3-2.0.
  • the reactor was a 81 mL free-volume (regular internal shape, with the approximate dimensions of 15 x 90 mm) pressure vessel fitted with six regularly spaced internal baffles.
  • the vessel was fitted with a six blade turbine type impeller, a heating jacket, pressure and temperature controllers, three feed lines and a single outlet.
  • the feed lines were located on the top of the vessel, each at a radial distance of 40 mm from the axis, while the outlet line was axial with the agitator drive shaft.
  • the catalyst precursors and other reagents were prepared as solutions in cyclohexane which had been purified by passage through beds of activated alumina, molecular sieves and silica gel prior to being stripped with nitrogen.
  • Ethylene was metered into the reactor as a cyclohexane solution prepared by dissolving purified gaseous ethylene in purified solvent.
  • the feed rates of the catalyst components were adjusted to produce the desired conditions in the reactor.
  • the desired hold-up times in the catalyst lines were achieved by adjusting the length of the tubing through which the components were passed.
  • the hold-up time in the reactor was held constant by adjusting the solvent flow to the reactor such that the total flow remained constant.
  • the reactor pressure was maintained at 7.5 MPa and the temperature and flows were held constant during each experiment.
  • the initial (no conversion) monomer concentration in the reactor was 3-4 wt%.
  • a solution of deactivator viz. triisopropanolamine or nonanoic acid, in toluene or cyclohexane was injected into the reactor effluent at the reactor outlet line. The pressure of the stream was then reduced to about 110 kPa (Abs.) and the unreacted monomer was monitored by gas ehromatography.
  • Q is the fraction of ethylene (monomer) converted to polymer
  • HUT is the reactor hold-up time expressed in minutes
  • the catalyst concentration is the concentration in the reaction vessel expressed in mmol/1 and corrected for impurities.
  • the catalyst concentration is based on the sum of the transition metals.
  • the polymerization activity (Kp) was calculated.
  • the present invention is illustrated by the following examples. Unless stated to the contrary, in each example the solvent used was cyclohexane, the monomer was ethylene and the reactor hold-up time was held constant at 3.0 min.
  • Example I The catalyst was prepared by the in-line mixing at ambient temperature (approximately 30°C) of solutions of each of dibutyl magnesium, triethyl aluminum, tert butylchloride and titanium tetrachloride in cyclohexane, followed by the addition of further solution of triethyl aluminum in. cyclohexane.
  • the reactor polymerization was operated at a temperature of 230°C, as measured in the reactor.
  • the solution passing from the reactor was deactivated and the polymer recovered, as described above.
  • Catalyst activity (Kp) • was calculated and the results obtained are shown in Table 1.
  • the ratios reported for Cl/Mg and Al 2 /Mg are the optimized ratios required in order to obtain maximum catalyst activity at the indicated ratios of Mg/Ti and Al 1 /Mg.
  • the catalyst preparation was as above with the exception that one mole equivalent of tert butyl alcohol (per mole of Al 2 ) was added to the second aliquot of triethyl aluminum (thus forming the alkoxide) .
  • Runs 1, 2 and 3 illustrate that the ratios of the catalyst components for the alkoxide systems have significant effects on the increase in activity, which is expected to vary with the type and composition of the other catalyst components and the mode of operation of the process but nonetheless illustrates that increases in catalytic activity of greater than a factor of two are obtainable.
  • Run 2 illustrates that catalyst activity is sensitive to ratios of components, which may be used in the control of the process.
  • Runs 4, 5, 6 and 7 illustrate the use of alcohols other than tert butanol.
  • Run 8 illustrates the detrimental effect of the addition of the alcohol directly to the reactor, rather ' than to the second triethyl aluminum stream. This indicates that prior formation the alkoxydialkyl aluminum species is necessary.
  • Example II As a comparison with other known activators for high temperature polymerization processes, the procedure of Example I was repeated using the activators and reaction temperatures indicated in Table II. The results obtained were as follows.
  • This example shows the relative improvement in catalyst activity at the higher temperatures that is exhibited by t-butoxydiethyl aluminum compared with the other activators.
  • the catalyst was prepared from solutions of titanium tetrachloride, vanadium oxytrichlpride and diethylaluminum chloride in cyclohexane.
  • the admixed solutions were heat treated at 205-210°C for 110-120 seconds by admixing with hot cyclohexane solvent.
  • the activator was then added to activate the catalyst.
  • the polymerization reactor was run at the temperature indicated in Table 3.
  • the solution passing from the reactor was deactivated and the polymer recovered as described above.
  • This example illustrates improvements obtainable using t-butoxydiethyl aluminum as activator.
  • Example III In order to compare the use of alkoxydialkyl aluminum with other activators, the procedure of Example III was repeated using a reactor temperature of 130°C. The results were as follows. TABLE IV

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  • Chemical & Material Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Transition And Organic Metals Composition Catalysts For Addition Polymerization (AREA)

Abstract

Procédé pour la préparation de polymères à haut poids moléculaire des oléfines alpha sélectionnés dans le groupe comprenant les homopolymères et les copolymères d'éthylène et les oléfines alpha plus élevées C3-C12, par polymérisation de l'éthylène et/ou des mélanges d'éthylène et d'oléfines alpha plus élevées C3-C12 en présence d'une quantité catalytique d'un catalyseur de coordination contenant du titane dans un solvant inerte à une température dépassant 105 °C. L'amélioration du procédé se caractérise par le fait que: (a) le catalyseur est activé avec une solution d'alcoxyalkylaluminium dans un solvant inerte; et (b) le procédé est effectué au moins partiellement à une température d'au moins 180 °C. Selon un mode de réalisation, le catalyseur de coordination est formé à partir d'un premier composant et d'un second composant, le premier composant contenant du titane et le second composant étant sélectionné dans le groupe comprenant alcoxyaluminiumalkyle et des mélanges d'alkylaluminium et d'alcoxyalkylaluminium. L'aluminiumalkyle est de formule ARnX3-n et l'alcoxyalkylaluminium est de formule AR'mOR"3-m, dans lesquelles chacun des R, R' et R" peut être le même ou différent et est un alkyle ou un aryle avec 1 à 20 atomes de carbone, X est un halogène, n vaut 1 à 3 et m vaut 0 à 2.
EP92920013A 1991-10-03 1992-09-25 Activation d'un catalyseur dans la polymerisation de l'ethylene a haute temperature Withdrawn EP0606285A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
GB9121019 1991-10-03
GB919121019A GB9121019D0 (en) 1991-10-03 1991-10-03 Activation of catalyst in ethylene polymerization at high temperatures
PCT/CA1992/000419 WO1993007188A1 (fr) 1991-10-03 1992-09-25 Activation d'un catalyseur dans la polymerisation de l'ethylene a haute temperature

Publications (1)

Publication Number Publication Date
EP0606285A1 true EP0606285A1 (fr) 1994-07-20

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP92920013A Withdrawn EP0606285A1 (fr) 1991-10-03 1992-09-25 Activation d'un catalyseur dans la polymerisation de l'ethylene a haute temperature

Country Status (15)

Country Link
EP (1) EP0606285A1 (fr)
JP (1) JPH06511035A (fr)
KR (1) KR100245204B1 (fr)
CN (1) CN1033812C (fr)
AU (1) AU2585892A (fr)
BR (1) BR9206588A (fr)
CA (1) CA2119737C (fr)
GB (1) GB9121019D0 (fr)
IN (1) IN178304B (fr)
MX (1) MX9205650A (fr)
MY (1) MY111171A (fr)
RU (1) RU2119925C1 (fr)
TR (1) TR28911A (fr)
TW (1) TW206242B (fr)
WO (1) WO1993007188A1 (fr)

Families Citing this family (13)

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Publication number Priority date Publication date Assignee Title
US6506866B2 (en) 1994-11-17 2003-01-14 Dow Global Technologies Inc. Ethylene copolymer compositions
FR2741080B1 (fr) 1995-11-14 1998-09-18 Atochem Elf Sa Procede de polymerisation des olefines en presence d'un derive organique de l'aluminium
CA2234188C (fr) * 1998-04-07 2006-07-11 Nova Chemicals Ltd. Traitement thermique des catalyseurs ziegler-natta en vue d'accroitre l'activite dans la polymerisation en solution
AR018359A1 (es) 1998-05-18 2001-11-14 Dow Global Technologies Inc Articulo resistente al calor , configurado, irradiado y reticulado, libre de un agente de reticulacion de silano
DE10010811A1 (de) * 2000-03-08 2001-09-13 Basf Ag Verfahren zur Herstellung von Polymeren
US6391986B1 (en) 2000-12-05 2002-05-21 Union Carbide Chemicals & Plastics Technology Corporation Control of solution catalyst droplets
CA2347410C (fr) * 2001-05-11 2009-09-08 Nova Chemicals Corporation Procede de polymerisation en solution catalysee par une phosphinimine
MXPA04001928A (es) 2001-08-31 2004-07-23 Dow Global Technologies Inc Material de polietileno multimodal.
DE10360845A1 (de) 2003-12-20 2005-07-21 Corovin Gmbh Weiches Vlies auf Basis von Polyethylen
ES2496140T3 (es) * 2004-06-16 2014-09-18 Dow Global Technologies Llc Método para identificar cocatalizadores Ziegler-Natta
US9481748B2 (en) * 2014-08-12 2016-11-01 Nova Chemicals (International) S.A. Ziegler-Natta catalyst for high temperature polymerization
CA3007381A1 (fr) 2018-06-06 2019-12-06 Nova Chemicals Corporation Preparation de catalyseur ziegler-natta sans filtre hors ligne
CN114957530B (zh) * 2022-06-28 2023-09-29 杭州双安科技有限公司 一种乙烯和α-烯烃的溶液聚合方法

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US4342855A (en) * 1980-08-27 1982-08-03 Idemitsu Kosan Company Limited Process for the production of polyethylene
US4681924A (en) * 1982-12-29 1987-07-21 National Distillers And Chemical Corporation Catalyst systems for polymerizations at high temperatures
NL8700322A (nl) * 1987-02-11 1988-09-01 Stamicarbon Katalysatorsysteem voor (co)polymerisatie van etheen in solutie.

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9307188A1 *

Also Published As

Publication number Publication date
RU2119925C1 (ru) 1998-10-10
AU2585892A (en) 1993-05-03
TW206242B (fr) 1993-05-21
RU94021921A (ru) 1996-06-27
CA2119737C (fr) 2003-06-03
CN1033812C (zh) 1997-01-15
CN1070919A (zh) 1993-04-14
IN178304B (fr) 1997-03-22
CA2119737A1 (fr) 1993-04-15
JPH06511035A (ja) 1994-12-08
BR9206588A (pt) 1995-11-21
TR28911A (tr) 1997-07-17
GB9121019D0 (en) 1991-11-13
WO1993007188A1 (fr) 1993-04-15
MY111171A (en) 1999-09-30
KR100245204B1 (ko) 2000-02-15
MX9205650A (es) 1993-04-01

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