DE2844312A1 - PROCESS FOR THE PRODUCTION OF POWDERY AETHYLENE COPOLYMERISATES - Google Patents

Description

PATENT LAWYERS

WUESTHOFF - ν. PECHMAIN - BEHRENS - GOET2

PROFESSIONAL REPRESENTATIVES BEFORE THE EUROPEAN PATENT OFFICE MANDATAIRES AGREiS PRES l'OFFICE EUROPEEN DES BREVETS DR.-ING. FRANZ WUESTHOFF DR. PHIL. FREDA \ PUESTHOFF (1927-I9J6) DIPL.-ING. GERHARD PULS (19J2-I971) DIPL.-CHEM. DR. E. BARBER OF PECHMANN

DR.-ING. THREE YEARS

TO / / O Λ DIPL.-ING .; DIFL £ «Ql * $ oty .- <tP (4 qfjPERT GOETZ

D-8000 MUNICH SCHWEIGERSTRASSE

TELEroN. · (0S9) 66 20 ji telegram! protectpatent telex: 524070

1A-51 408

Patent application dunp ;

Applicant;

s.a.

Tour NEPTUNE La Defense 1, 20, place de Seine 92400 Courbevoie, France

Title:

Process for the production of powdery ethylene copolymers

909816/0923

DR -ING. FRANZ WÜESTHOFF

PATENTANWÄLTE _db .phil.f «bda tuesthoff ( ₉₇ «

WUESTHOFF-v. PECHMANN-BEHRENS-GOETZ _DIP u- ™ gg * ehard puls (x _9ii -., _7. )

DIPL.-CHEM. DR. E. BARBER OF PECHMANN PROFESSIONAL REPRESENTATIVES BEFORE THE EUROPEAN PATENT OFFICE DR.-ING. DIETER BEHRElO Q / / O 1 O

MANDATAiRES AGREES PRES l / OFFICE BUROPEEN DES BREVETS DIPL.-ING.J DI PL.-WIRTSCH.-ING. RU PERT GOETZ

■ s

D-8000 MUNICH 90 SCHWEIGERSTRASSE 2

phone: (089) 6620 ji Telegram: protectpatent telex: 524070

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Note: NAPHTACHIMIE S.A.

description

The invention relates to a method for fluidized bed polymerization of ethylene together with a C-, to Gg e ^ -Qlefrn to copolymers with a density or specific Weight from 0.900 to 0.945 g / ml, which is up to 33% by weight Containing units of C to Gg ^ -olefin.

It is known to polymerize mixtures of ethylene and butene-1 in a bed of particles which are swirled by the rising monomer mixture; the polymerization takes place in the presence of a catalyst which consists of a chromium compound which is deposited on a granular support material, generally silica or silica-based. With the help of this shipping but apparently no copolymers are obtained that more than. Contains 5 to 6% by weight of butene-1 units. In addition, the copolymers prepared in this way have a broad molecular weight distribution generally above 6 and a low melt index in the range from 0.1 to 0.2. The melt index is determined in accordance with the American standard ASTM D 1238 under a load of 2.16 kg, and the molecular weight distribution is the ratio of the weight average molecular weight Mw to the number average molecular weight Mn if the molecular weight is determined after separation of the polymer by means of gel penetration chromatography _f .

909816/0923

Attempts have also been made to produce copolymers with a higher melt index by polymerizing in the presence was carried out by catalysts, which at the same time a chromium compound and a compound of the tetravalent Titans included. The combination of these two compounds has both catalytic properties but different Having nature probably leads to the simultaneous formation of two types of polymers: The properties of the copolymers fluctuate depending on the residence time of the copolymer in the reactor due to the different The rate at which the two catalytic compounds are exhausted. In addition, the The melt index of the copolymers prepared in this way is below 2, and the molecular weight distribution is still broader than in the case of the copolymers prepared as described above.

A process has now been developed that enables the production of Ethylene copolymer powder allows up to 33 wt .- $ Contain units of a higher ^ -olefin and which have a molecular weight distribution in the range from 2 to 11 as well have a melt index in the range from 0.1 to 30.

The invention thus provides a process for the production of powdered copolymers from ethylene and a higher diolefin - with 3 to 6 carbon atoms such as propylene or butene-1, which contain 1 to 33 wt .- $ units of this higher diolefin and a density of 0.900 to 0.945 g / ml, a molecular weight distribution in the range from 2 to 11 and a melt index of 0.1 to 30 at 190 ^° C. below 2.16 kg, at which a gas mixture consisting of the olefins which polymerizes are to be, and optionally hydrogen, polymerized and passed from bottom to top through a fluidized bed of the copolymers being formed; the process is characterized in that the copolymerization is carried out in the presence of a Ka.talysatorsystems which

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is composed of

1. a cocatalyst in the form of at least one organometallic Compound of a metal of groups II and III of the periodic table and

2. a solid compound of titanium, magnesium and a halogen as a catalyst, which by reaction at -20 to + 15O ⁰ C, preferably at 60 to 90 ⁰ C, of

a) one or more compounds of tetravalent titanium of the general formula TiX ₄ _ _n (OR) _n , in which X is a chlorine or bromine atom, R is a C ₂ to Cg alkyl group and η is any number from 0 to 4 means with

b) an alkyl halide of the formula RX, in which R and X have the meaning given under a), and

c) a magnesium orga.ni see compound of the general compound RMgX, an organomagnesium compound of the formula MgR ₂ or metallic magnesium has been obtained, the components mentioned under a.) to c) were used in such a molar ratio that

0.1 ύ TiX _4-11 (OR) ₁₁ AMgX = 0.33 and -

1 = RX / RMgX S 2,

if a magnesium or ganic connection of general Formula RMgX has been used as component c,

0.1 = TiX ₄ _ _n (OR) _n / MgR ₂ = 0.33 and

2 S RX / MgR ₂ = 4,

if an organomagnesium compound of the general formula MgR _{2 has been used} as component c, and

0.1 - TiX ₄ _ _n (0R) _n / Mg = 0.33 and

0.5 = RX / Mg = 10, preferably 1.5 = RX / Mg = 4,

if ο metallic magnesium has been used as a component.

When carrying out the process according to the invention, the catalyst can either be fed directly into the polymerization kettle be introduced or in the first

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Polymerization kettles if several are connected in series Polymerization kettles are used.

The catalyst can also be put into the polymerization kettle * be introduced in the form of a prepolymer, which by prior polymerization of one or more olefins in an inert liquid, for example an aliphatic hydrocarbon, and in the presence of a halogenated one Titanium and magnesium compounds, as indicated above, and in the presence of a Cokata.lysators, for example one organoaluminum compound. The prepolymerization is after the formation of a small amount Polymer which is usually 1 to 500 g / mg atom of titanium of the catalyst has been obtained. After the prepolymerisa.t with entrapped halogenated titanium and magnesium compounds from the liquid medium in which it is has been produced, has been separated, it can be used directly as a solid with catalytic activity. Advantageously, however, the prepolymer is first one or more times with a solvent, for example an aliphatic hydrocarbon, extracted so that im Porosity is created inside the granulated prepolymer particles. This porosity favors the access of the Olefins to the catalytically active sites.

The copolymer present in the polymerization vessel or reactor is replaced by an ascending stream of carrier gas swirled; this carrier gas stream contains the olefins that are to be polymerized, as well as optionally hydrogen, its proportion making up to 70 vol .- $ of the gas mixture can. "The gas mixture is advantageously composed of the gas mixture that comes from the polymerization kettle exits and is returned to the polymerization, as well as from an amount of olefins which are polymerized should and which are newly introduced into the reaction cycle,

* or fluidized bed reactor

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The upward flow velocity of the Gas mixture that is necessary to keep the copolymer present in the boiler in the fluidized bed in relation to the physical parameters of the copolymer and the gas mixture. These parameters include especially the dimensions of the copolymer particles, the density of the copolymer and its specific weight and the viscosity and density of the gas mixture itself. The most common rates of climb are in the A few decimeters per second.

The temperature in the reaction vessel is set so that that the polymerization proceeds quickly, but should not be too close to the temperature at which agglomerates form that would interfere with or stop the polymerization.

The composition of the circulating in the polymerization kettle Gas mixture is then determined which comonomers are used and what proportion of comonomers in the Copolymer is desired. The total pressure in the polymerization kettles is generally in the range from 1 to 40 bar. The inventive method can also be used in Pressures below 1 bar or at pressures above 40 bar can be carried out.

The gas mixture with the catalyst present in the polymerization kettle is only available for a limited period Length of time in contact that is generally less than some Tenths of a second. For this reason, only a part of the olefins introduced into the boiler is polymerized here and as a result, the gas mixture, which from the Exits the boiler, can be returned to it. In order to prevent the gas mixture from particles of the polymer or entrains the catalyst from the polymerization kettle, this is, for example, in its upper part combined a so-called calming zone, which has a larger cross-section than the polymerization kettle himself. In this space is the rate of rise of the gas mixture less than in the polymerization kettle, so that

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at least some of the entrained polymer or catalyst particles can fall back into the polymerization kettle. The particles entrained by the gas mixture can can also be separated in a cyclone and returned to the boiler, preferably in its lower part. There During the polymerization of the olefins heat is generated, this heat must be dissipated so that it can be in the boiler or in the boilers a constant temperature is maintained. The heat is preferably dissipated in such a way that the gas mixture, which is brought into circulation, passes through a heat exchanger arranged outside the reactor.

According to the invention, the polymerization of the olefins can also be carried out in a plurality of fluidized bed reactors arranged one behind the other be performed. In this case, only part of the polymerization takes place in each reactor or vessel and the polymer being formed is fed from the first to the last reactor. According to a modified one Embodiment can have several reactors or boilers in parallel are switched, so that the polymer just created in a boiler is fed into two or more post-reactors will.

The polymer obtained as the end product is removed from the polymerization kettle with the help of various mechanical or pneumatically operated devices. In the case of a discharge device, the lower part of the reactor or boiler provided with a closable opening which is in communication with a chamber in which a smaller one There is pressure than in the boiler itself. The discharge device is opened for a predetermined period of time and dispensed the desired amount of polymer into the chamber. After closing the discharge device needs the chamber which has received the polymer can only be brought into contact with the environment in order to keep the polymer finally to be discharged and to isolate.

The method according to the invention is preferably carried out under essentially constant, constant operating conditions

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conditions in the polymerization kettle or in the polymerization kettles executed. These constant conditions are achieved in practice that one in each reactor or boiler circulates a gas mixture with essentially constant properties, the main part of which is discharged the recirculated gas mixture exists.

The cocatalysts used according to the invention preferably consist of at least one organoaluminum compound of the general formula AlR ¹ Y (3-x)> in which R ^{1 is} an alkyl group having 1 to 12 carbon atoms, preferably 6 to 10 carbon atoms, Y is a hydrogen atom or a Halogen atom, for example a chlorine or bromine atom, and x is any number from 1 to 3.

The catalysts and cocatalysts are advantageously used in amounts such that the atomic ratio from metals of groups II and III in the cocatalysts to titanium in catalyst 1 to 50. The cocatalysts can be introduced into the polymerization kettle in a number of ways. The organoaluminum Cocatalysts, which are generally liquid under normal temperature and pressure conditions, can directly introduced into the boiler in the liquid state or evaporated beforehand. The cocatalysts can also initially brought into contact with the catalyst or with the prepolymer and then fed into the reactor.

The copolymers produced according to the invention have a density of 0.900 to 0.945 g / ml, a molecular weight Weight distribution in the range from 2 to 11 and the melt index can assume numerical values from 0.1 to 30.

The properties of these copolymers vary, in particular as a function of their unit content of the higher t * -olefin. In general it can be said that the The higher the content of units of the ot-olefin, the lower the density of the copolymers. For example

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the density of copolymers * is about 1 to 7% by weight of propylene or 1-butene units, for example. From 0.945 to 0.950 g / ml and its melting temperature is in the range of about 130 to 12O ⁰ C. These copolymers are partially soluble in boiling cyclohexane, and this soluble portion can include up to 40 wt -. Constitute ° / o of the copolymer. If the copolymers contain about 7 to 35% by weight of propylene or 1-butene units, their density is in the range from 0.930 to 0.900 g / ml and their melting temperature in the range from about 120 to 100 C. The boiling point The cyclohexane-soluble fraction of these copolymers is relatively high and is generally 40 to 80 wt . The melt index of the copolymers is higher, the greater the proportion of units of the higher cX -olefin. Furthermore, with a given content of units of the higher ^ -olefin, the melt index of the copolymer can be increased by increasing the hydrogen content of the gas mixture. the

Molecular weight distribution of the copolymers can be determined by the selection of the catalyst (s) used in the preparation of the catalyst used titanium compound (s) and by selecting the cocatalyst can be modified or influenced. Catalysts based on titanium compounds with alkoxy groups lead to copolymers with a narrower molecular weight distribution than catalysts which were made from only titanium halides.

With the aid of the method according to the invention, copolymers can thus be produced directly and in the form of powders produce, the content of units of a higher "^ -olefin can amount to up to 33 wt .- $ and their properties, namely density, melting temperature, molecular weight distribution and melt index, within very wide Areas can be varied. Such a wide range of copolymers can be obtained with the aid of the previously known Do not produce the fluidized bed polymerisation process. It must also be pointed out that the copolymerization of cx-oiefinen in an inert Liquid, such as n-heptane, and in the presence of the

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according to the intended catalyst systems also not to one such a range of copolymers leads. Difficulties arise in practice in this liquid phase polymerization on, which are based mainly on the high viscosity of the polymerization medium and on it. That the polymer of the inert liquid must be separated.

The copolymers prepared according to the invention are suitable are particularly good for the production of moldings by means of rotation processes. In this procedure, the polymer powder placed in a rotating mold which is heated to a temperature above the melting temperature of the polymer is. The polymer powder melts and spreads over the inner surface of the mold. The desired body then becomes demolded after cooling and opening the mold. In the previously known procedures, this had to be obtained in the form of granules Copolymer must first be comminuted or ground in an expensive manner before it is introduced into the rotatable mold could be. The copolymers produced according to the invention are also suitable for coating substrates, for example plastic films, fabrics or foils Paper or cardboard, due to their relatively low melting temperature and their good adhesion properties.

example 1

a) Preparation of a catalyst

In a 1 1 glass flask equipped with mechanical stirrer, and heating or cooling apparatus were presented successively at 25 ⁰ C, 500 ml n-heptane, 9.6 g of magnesium powder (0.40 gram-atom), 1.2 g. Iodine. The flask contents were heated with stirring at 8O ⁰ C; then added: 9.1 g of titanium tetrachloride (48 mmol), 13.7 g of tetrapropyl titanate (48 mmol) and 74.5 g of butyl chloride (0.805 mol) over 4 hours.

The obtained precipitate became 3 times with settling washed in between with 200 ml of n-heptane. After this

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28A4312

The catalyst thus obtained was dried analyzed: it contained 8% by weight of titanium.

b) Production of a prepolymer

Equipped in a 5 liter stainless steel boiler with a mechanical stirrer and a heating or cooling jacket, were presented: 1 1 n-heptane, 2.1 g catalyst, prepared according to a), and 1.3 g of tri-n-octylaluminum.

The kettle contents were heated with stirring to 70 ⁰ G. Then hydrogen was introduced up to a relative pressure of 1 bar and then ethylene in an amount of 100 g / h. After 2 1/2 hours of polymerization, 250 g of prepolymer were isolated and suspended in a solution of 2.6 g of tri-n-octylaluminum in 500 ml of n-heptane. The n-heptane was then evaporated.

c) fluidized bed polymerization

100 g of polyethylene powder prepared beforehand were introduced into a fluidized bed reactor with a diameter of 15 cm and swirled with the aid of a gas stream of 65 ° C., the rate of which was 20 cm / s, calculated for the empty reactor. The gas stream was a mixture of 40 vol. -Fo ethylene, propylene and 40 vol .- # 20 # .- Yol hydrogen. The prepolymer prepared according to b) was added in proportions of 5 g every 12 minutes, and it was observed that about 800 g of polymer were formed per hour. Periodically, part of the polymer was withdrawn from the reactor and only about 2 kg of polymer was left in it. After 3 hours of polymerization, a sample of the polymer was taken in the form of a white, non-sticky powder. The physical properties of this polymer are listed in Table 1 below.

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Examples 2 to 7

The procedure was as in Example 1, but the composition of the gas mixture changed during the polymerization. The respective composition of the gas mixture and the properties of the polymer powders obtained are also listed in Table 1.

Examples 8-10

The procedure was again as in Example 1, however with a gas mixture which contained B.uten-1 instead of propylene »The composition of the gas mixture and the properties of the polymers obtained are listed in Table 2.

Examples 11-13

a) The procedure was as in Example 1a) with the modification that the catalyst, starting from 18.2 g (96 mmol) of titanium tetrachloride, was ^{prepared at 80 0} G (instead of starting from a mixture of 9.1 g of titanium tetrachloride and 13 , 7 g tetrapropyl titanate and temperature 7O ⁰ C). The finished catalyst contained 8.7 wt .- ^ Tita.n.

b) · The prepolymer was prepared analogously to Example 1 b), starting from 1.9 g of the above catalyst.

c) The polymerization was carried out under the conditions in Example 1 c) specified conditions. The composition of the gas mixture and the properties of the polymers obtained are listed in Table 3 below.

In Tables 1 to 3:

IF ₂ de * ¹ melt index of the polymer, measured under a load of 2.16 kg, in accordance with the ASTM D 1238 standard; fo Gz and fo G. denote the weight fraction of propylene units and 1-butene units in the polymer, determined by IR spectrometry;

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RP is the flexural strength, determined according to the French standard BNMP 40-422 A;

exe means the molecular weight distribution, i.e. the ratio Mw / Mn from weight average molecular weight Mw to number average molecular weight Mn, where the Molecular weights determined in each case after fractionation of the polymer by means of gel permeation chromatography have been.

../Tables

909816/0923

Example composition of the gas mixture

Table 1

Polymerization properties of the polymer speed

1 ^C 2 ^H 4 C ₅ H ₆ H ₂ 800 2 15th density RP Melting OC 2 J O Ci. 600 7th . 15th temp. ⁰ C 3 40 40 20th 1000 0.5 15th 0.915 160 111-120 3.0 34 34 32 0.915 170 108-122 2.5 co
O 4th 45 45 10 900 20th 15th 0.915 155 107-120 2.3 (O OO
-> * 5 28 30th 42 900 1.2 20th 0.913 - - 2.9 σ> ο 6th 38 48 14th 750 2 5.3 0> 908 135 106 3.1 CD 7th 800 10 1.6 Ν » 55 21st 24 0.935 345 121 3 52 4th 44 0.954 570 125 3.6

ro oo,

Table 2

Example Composition Polymerization properties of the polymer of the gas mixture speed by volume g / h

C ₂ H ₄ ° 4 ^H 8 H ₂ 8th 66 6th 28 9 62 20th 18th 10 51 33 16

density

RP melting temp. ⁰ C

2 0.943 485 1.5 7 0.925 280 5.7 15.5 0.911 165

126 1.22 122

11
12th
13th

C ₂ H ₄

3. 32
5 35
6 38

density

RP

Melting temp. ⁰ C

1 , 7 1.7 0 , 951 2 , 5 3 0 , 946 4th 4.5 0 , 940

3.5

3.5

Table 3 '

Example Composition Polymerization Properties of the Polymerization of the Gas Mixture Velocity YoI .-? O g / h

125 124 123

Claims (4)

Patent claims 1, a process for the production of powdery copolymers from ethylene and a C- * to Cg (fs. -Olefin, such as propylene or butene-1, which contain 1 to 33% by weight of units of the C ^ to Cg oC olefin, a Density of 0.900 to 0.945 g / ml, a molecular weight distribution of 2 to 11 and a melt index of 0.1 to 30 at 190 ° C under a load of 2.16 kg, in which a gas mixture containing the olefins which are polymerized should and optionally contain hydrogen is passed from bottom to top through a fluidized bed of the copolymer being formed, thereby ge ke nn ζ eic hn et. that the polymerization is carried out in the presence of a catalyst system; this consists of A. at least one organometallic compound of a metal of groups II and III of the periodic table as a cocatalyst as well B. a catalyst in the form of a solid compound of titanium. Magnesium and a halogen, which by reaction at -20 to + 150 C °, preferably at 60 to 90 ⁰ C of 909816/0923 1A-51 408 a) one or more compounds of tetravalent titanium of the general formula TiX ^ (OR), in which X is a chlorine or bromine atom, R stands for an alkyl group having 2 to 8 carbon atoms and η means an integer or fraction from 0 to 4, with b) an alkyl halide of the general formula RX, in ·. the R and X correspond to the definition given under a) and c) an organomagnesium compound of the general formula RMgX, an organomagnesium compound of the general formula MgRp or with metallic Magnesium has been obtained, the various compounds being used in such molar ratios that when using an organomagnesium compound RMgX applies: 0.1 ^ TiX ₄ _ _n (OR) _n ^ RMgX ^ 0.33 and 1 ^ RX / RMgX £ 2 if an organomagnesium compound of the formula MgR ^ is used: 0.1 ^ TiX ₄ _ _n (0R) _n / MgR ₂ = 0.33 and 2 = RX / MgR ₂ = 4 and when using metallic magnesium, the following applies: 0.1 = TiX ₄ _ _n (OR) _n / Mg ^ 0.33 and 0.5 ^ "RX / Mg ^ 10 or preferably 1.5 ^ RX / Mg ^ 4. 909816/0923 1A-51 2. The method according to claim 1, characterized in that one is in the presence of a catalyst works obtained from titanium tetrachloride. 3. The method according to claim 1, characterized in that one is in the presence of a catalyst works based on titanium tetrachloride and tetrapropyl titanate used together, has been received. 4. The method according to any one of claims 1 to 3, characterized in that one works in the presence of a cocatalyst which consists of at least one organoaluminum compound of the general formula AlR ¹ ^ Y / -, _v \, in which R 'is an alkyl group with 1 is up to 12 carbon atoms and preferably 6 to 8 carbon atoms, Y is a hydrogen atom or a halogen atom such as chlorine or bromine, and χ is an integer or fractional number from 1 to 3. 9038-16 / 0923