DK162533B - FRACTIONABLE ELASTIC POLYPROPYLES AND PROCEDURES FOR ITS MANUFACTURING - Google Patents

Description

DK 162533 B

The present invention relates to a fractional elastic polypropylene and a process for its preparation.

Both crystalline and amorphous polypropylenes are well known products. Crystalline polypropylene is generally considered to be at least predominantly of the isotactic or syndiotactic structure, while amorphous polypropylene is considered to be at least predominantly of the atactic structure. US Patent Nos. 3,112,300 and 3,112,301 describe isotactic and predominantly isotactic polypropylene, respectively, while structural formulas for isotactic and syndiotactic polypropylene are found in United States Patent No. 3,511,824. "Atactic" polypropylene is defined as polypropylene in which the methyl substituents are randomly arranged above and below the backbone chain or the main chain of atoms, all of which are in the same plane.

Most of the technical qualities of polypropylene are highly crystalline and are, as is well known, used in the manufacture of plastic products. Amorphous polypropyls are also commercially available and are generally low-strength rubber materials. The amorphous polypropylenes are usually found as a small fraction of predominantly isotactic polypropylene and can be readily extracted. They are usually used as adhesives.

Rubber-like polypropylenes are also known, and it has been said that such products are formed directly by usual polymerization using special catalysts, by repeated extractions of usual polypropylene, by chemical treatment of crystalline polypropylene and by sequence polymerization processes. Examples of rubbery polypropylenes are found in United States Patent Nos. 3,329,741, 3,175,999, 3,511,824 and 3,784,502. However, such polypropylenes have not found appreciable use in products requiring an elastic polymer.

U.S. Patent No. 3,950,269 discloses the preparation of two separate polypropylenes, a hexane-soluble product and a hexane-insoluble product. Evaporation of a solution of the soluble product gives a rubbery product having a "major" melting point of approx. 70-85'C. The low melting point shows that the product cannot be elastomeric polypropylene which has a "major" melting point.

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2 tea point between 135 and 155 ° C. After extraction in boiling toluene, the hexane-insoluble product gives high crystalline polypropylene, as evidenced by its melting point of ca. 162 ° C. Thus, none of the products are elastic polypropylene.

Therefore, there is a need for a polypropylene which has practically useful elastic properties and can be prepared as a direct reaction product by a practicable process.

The present invention relates to a fractional elastic polypropylene which is characterized in that it has a logarithmic viscosity number of 1.5r * 9. exhibit no float limit, has a prolonged elongation of not more than 150%, an isotactic content of 55% by weight or less and a "major" melting point between ca. 135 and approx. 155 ° C and contains 10-80% by weight of a diethyl ether-soluble fraction having a logarithmic viscosity number greater than 1.50, which ether-soluble fraction has an isotactic crystalline content of between ca. 0.5 and approx. 5% by weight and exhibiting birefringence when a film formed therefrom is viewed under crossed Nicol prisms in a polarizing microscope at ca. 25 ° C.

The invention further relates to a process for preparing this fractionable resilient polypropylene which is characterized by contacting propyl with a catalyst which is the reaction product of a metal oxide and an organometallic compound of formula (RCH2) 4M wherein M is Zr. Ti or Hf, R is aryl, aralkyl, tert-alkyl or trialkylsilyl, wherein the alkyl groups contain 1-12 carbon atoms and the group RCH2 contains no hydrogen bonded to the carbon atom at the 3-position to M, or with products formed by hydrogenation of such catalysts, and the reaction is carried out in the presence of hydrogen.

The fractional product of the invention, which is the direct reaction product itself without the separation of any polypropylene components, is elastic and exhibits properties like a vulcanized rubber. This result is obtained without sequence polymerization, where reaction conditions or monomer ratios are varied during polymerization to produce alternating "blocks" in the polymer structure.

By "fractional" is meant that the product is non-homogeneous 3

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and thereby essentially consisting of two or more fractions which are readily separable by extraction with solvents such as diethyl ether and hexane. Thus, the product consists essentially of 10-80% by weight (preferably 40-75% by weight) of a diethyl ether-soluble fraction and varying amounts of other fractions, typically between about 10% by weight. 10 and approx. 35% by weight of a fraction soluble in boiling hexane, but insoluble in boiling diethyl ether, and between ca. 10 and approx. 55% by weight of a fraction insoluble in boiling hexane.

The diethyl ether-soluble or ether-soluble content as used herein for polypropylene is determined in boiling diethyl ether by the method described below in the "Methods of Analysis" section.

The measure of elasticity used in the description of the polypropylenes of the invention is the permanent deformation defined as the elongation remaining in a compression molded sample body after being stretched at a rate of 51 cm / min. to a 300% extension at 22-24 * c and then immediately allowed to recover at the same rate until it has an O voltage. It is expressed as a percentage of the original length or distance between fixed points. The polypropylenes of the invention have a permanent elongation of at most 150% and preferably at most 100%, and some samples have a permanent elongation of 75% or less.

The polypropylenes of the invention are characterized in that they do not exhibit a flow limit. By "flow limit" is meant here that in the test according to ASTM method D412, performed for fracture at 51 cro / min. and 25 ° C, is a voltage (or extension value), at which time the voltage (force) required to further increase the extension decreases.

All tensile and tension / elongation measurements discussed below, including the examples, are performed on straight or dumbbell-shaped test bodies 0.64 cm wide and 0.045-0.20 cm thick, according to ASTM] Method D 412 , with the exception that where averaged, two samples of the product have been examined.

The drawing shows a voltage / extension (hysteria- 4

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se) curve for a typical polymer according to the invention, namely that described in Example 1, compared to a previously known highly isotactic polypropylene sold by Hercules Inc., under the designation nPro-fax®6523n (isotactic content 94%). The polymer of Example 1 has a permanent elongation of 93% at a stretching rate of 51 cm / min. and relaxation at the same rate, and it shows no floating point. The known isotactic polypropylene has a permanent elongation of 300% (ie shows no recovery) and shows a floating point at an elongation of approx. 15% at a stretching rate of 0.5 cm / min. and a recovery rate of 51 cm / min.

The polypropylenes of the invention have a logarithmic viscosity number of 1.5-9, preferably 3-8, and the diethyl ether soluble fraction has a logarithmic viscosity number of more than 1.5 and preferably more than 2.5. The logarithmic viscosity number (inherent viscosityL is measured in the decahydronaphthalene at 135 ° C according to the method described in the section "Analytical Methods". It is expressed in dl / g. The polypropylenes of the invention become increasingly elastic with increasing content and increasing logarithmic A birefringence is clearly visible when a film formed by pressing a sample of the ether-soluble fraction between microscope slides is viewed under crossed Nicol prisms in a yarm step polarizing microscope at When the temperature is raised, the birefringence disappears in the region of the melting point of the film. The birefringence is also clearly visible when a film formed by the ether-soluble fraction is pressed or stretched between crossed polarizing foils at a temperature of ca. 25 ° C.

The polypropylenes have an isotactic content of 55% or less and preferably between about 10%. 25 and approx. 45%. By "isotactic content" is meant the amount of polymerized propylene units present in chain segments in which five successive polymerized propylene units have identical steric configuration. Thus, a polypropylene in which 45% of the polymerized propylene units are found in segments of five or more successive polymerized propylene units, all having the same steric configuration, will have an isotactic content of 45%. The isotactic content as discussed herein can be measured 13 directly by C-nuclear magnetic resonance (NMR1 by known methods,

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a particularly suitable one will be described in the section "Analysis Methods". At a given isotactic content, the polymers of the invention are highly elastic, as evidenced by their persistent elongation and absence of floating point.

The polypropylenes also have syndiotactic content, by which is meant the portion of the polymerized propylene where the methyl groups lie alternately above and below the plane of the main chain. The syndiotactic content can also be measured directly by C-NMR.

The polypropylenes have a tensile strength in the range of approx. 28 2 to about 175 kg / cm as determined by ASTM Method D 412, while the ether-soluble fractions have tensile strengths of between ca. 7 and ca.

2 42 kg / cm.

The polypropylenes have a "major" melting point between ca.

135 and approx. 155 ° C, determined by the method described in more detail in the "Methods of Analysis".

The diethyl ether soluble fractions of the aforementioned novel elastic polypropylenes possess properties which clearly distinguish them from solvent-extracted fractions of known polypropylenes. Thus, e.g. relatively wide molecular weight distributions as indicated by the relatively high values of the ratio M ^ i ^ where Mw is the weight average molecular weight and Mr is the number average molecular weight, see Billmeyer, "Textbook of Polymer Science", page 6-7 (interscience /

Wiley, 1962) .. The ratio Μ ^ ΐϊ will be referred to as dispersity.

It is determined by gel permeation chromatography (GPC).

The diethyl ether-soluble fractions also have relatively high logarithmic viscosity ratios relative to the corresponding undiluted polymers, the ratio of the logarithmic viscosity number of the ether-soluble fraction to the logarithmic viscosity number of the undiluted polymer generally being within the range of 0.5-0, ft. .

Furthermore, the diethyl ether-soluble fractions have isotactic crystalline content of between ca. 0.5 and approx. 5% by weight. The crystalline content is strongly suggested by the birefringence and is detected by and determined from the heat of fusion (<Δ ^) and C-NMR, the latter data showing that the crystallinity of these fractions is iso-tactical. The method for determining the above-mentioned properties will be discussed in the "Methods of Analysis" section.

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The foregoing regarding properties of the ether-soluble fractions is particularly true for the ether-soluble fractions of undiluted polymers which are isolated from the polymerization mixture by methods which do not include heat melting or extrusion. Generally, such polypropylenes, as isolated from the reaction, exhibit a higher percentage of ether extractable components, i.e. between approx. 30 and approx. 80% than after hot melting, extrusion or other fabrication methods. The decrease is believed to be due to an interaction between the ether-soluble fraction and stronger crystalline components of the product.

The high molecular weight diethyl ether soluble component is the key factor contributing to the resilient properties of the polymers of the invention, and in this respect, these polymers differ from the prior art, where the elastomeric properties are limited to the hexane soluble fraction. The ether-soluble fraction of the polymers of the invention is highly elastic but generally has low tensile strength, but it can be combined with more crystalline polypropylenes (i.e., with higher isotactic content) to provide elastomeric materials with greatly improved tensile strength. It is believed that the isotactic units of the more crystalline polypropylene co-crystallize with the isotactic units of the ether-soluble component to form a cross-linked elastomeric network.

The polypropyls of the invention may be prepared by polymerization of propylene in the presence of a catalyst which is the reaction product between an organometallic compound and a partially hydrated surface of a metal oxide such as A 2 O 2, TiO 2, s - + - ° 2 or MgO or physical mixtures thereof. The organometallic compounds have the formula (RCH.2I_4M, where M is Ti, Zr or Hf, R is aryl, aralkyl, tert-alkyl, for example trialkylmethyl, or trialkylsilyl, and the group RCH to M. The alkyl groups mentioned may contain from 1 to 12 carbon atoms.

Typically, the two catalyst components are reacted in the ratio 0f01-1.0 mmol of organometallic compound one for each gram of metal oxide, and the preferred catalysts are those obtained by reaction of organo-zirconium compounds (RCH₂-Zr, especially tetraneophylzirconium (TN In the approximate ratio of 0.1-1.0 mmol of the organozirconium compound per gram of aluminum

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oxide. Such catalysts and their preparation are described in U.S. Patent No. 3,932,307. Preferably, the hydroxylated alumina is prepared by allowing "fumed" alumina to equilibrate and thereby absorb atmospheric humidity and then heat to 120-500 ° C for a period of between 1 minute and 10 hours in a stream of nitrogen. Suitable catalysts also include the reaction products of other organometallic compounds as set forth above with said metal oxides, and these catalysts are prepared in the same manner as the preferred "neophylzirconium aluminate-on-alumina" catalyst described above. Examples of useful organometallic compounds are tetraneopentyl zirconium, tetrabenzyl titanium, tetrabenzyl zirconium, tetraneopentylhafnium, tetrabenzylhafnium, tetrakis (trimethylsilylmethyl) zirconium, tetraneophyltitanium and tetraneopentyl titanium.

Also suitable catalysts are those obtained by hydrogenation of the above-mentioned reaction products of organometallic compounds and metal oxides according to the method described in U.S. Patent No. 3,950,269.

In the polymerization process itself, the catalyst, usually in the form of a suspension in a hydrocarbon such as cyclohexane (about 25-50 ml hydrocarbon per gram of metal oxide 1) is contacted with liquid propylene or dissolved in a suitable solvent such as hexane or cyclohexane. these types of medium used, the catalyst can also be prepared by bringing the components together in the presence of the monomer (s), preferably the reaction medium is liquid propylene and the reaction comprises forming a slurry of polypropylene in the liquid monomer. in an amount equal to 1 gram atom of zirconium, hafnium or titanium in the catalyst for every 2 (X) .000-2,000,000 grams of propylene.

The reaction can be carried out at atmospheric pressure or at elevated 2 pressures of up to 350 kg / cm and both portionwise and continuous polymerization can be used. The usual reaction time for batch execution is between about 10 minutes and approx. 1 hour. Reaction temperatures are between ca. 0 and approx. 175 ° C, preferably between 25 and 100 ° C.

It has been found that the presence of hydrogen in the reaction medium not only reduces the logarithmic viscosity number of the polymers of the invention, but also increases the amount of the

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diethyl ether-soluble fraction, and the polypropylenes of the invention are therefore usually prepared in the presence of hydrogen gas.

Using a "neophyl zirconium aluminate-on-alumina" catalyst at 50 ° C, a partial hydrogen pressure of approx. 1.4 kg / cm 2 result in a product containing at least 35% ether soluble fraction having a logarithmic viscosity number of at least 1.50 and usually of 2 or more. As the amount of hydrogen is increased, the amount of ether-soluble fraction increases, usually without appreciable decrease in the logarithmic viscosity of this fraction.

The ratio of zirconia to metal oxide in the catalyst sys tern affects the amount of ether soluble fraction obtained both in the presence and absence of hydrogen. Thus, with "neophyl zirconium aluminate-on-alumina" catalysts, a zirconium-alumina ratio of approx. 0.6 mmol of tetraneophylzirconium <pr. grams of alumina usually yield a polymer containing approx. 30% by weight of the soluble fraction and as the zirconium / alumina ratio decreases, the amount of the ether soluble fraction will be increased.

The logarithmic viscosity number of the polypropylenes and the amount of ether-soluble fraction can also be controlled through the reaction temperature, the logarithmic viscosity number decreasing and the amount of ether-soluble fraction increasing as the reaction temperature is increased, especially at temperatures above ca. 50 ° C.

The persistent elongation of the polypropylene will generally decrease as the content and logarithmic viscosity number of the ether-soluble fraction are increased, and the polymers will have particularly low "tensile set" values when the logarithmic viscosity number of the ether-soluble fraction is 2.5 or higher. . In the examples given below, methods for preparing such polymers will be illustrated.

Although the order in which propylene, hydrogen and catalyst are added to the reaction zone is usually of no particular importance, it is found that when M is Hf, the amount of ether-soluble polymer will be increased if the catalyst is allowed to come into contact. with hydrogen for at least about 5 minutes before introducing the propylene.

After venting excess propylene, the polypropylene can be isolated by conventional methods. When the reaction medium is liquid propylene, hot grinding, extraction / extrusion can be used

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or steam evaporation to remove all residual unreacted propylene and all volatile solvent which formed part of the catalyst slurry. Alternatively, the product mixture may be swelled to a gel by the addition of a liquid hydrocarbon such as cyclohexane, and the polypropylene may be precipitated and converted into a solid which can be filtered off by the addition of a liquid such as acetone and the polypropylene isolated by filtration. When the reaction medium is a liquid such as cyclohexane, the polypropylene can be isolated by precipitation with acetone followed by a filtration.

As previously mentioned, the method of isolation used may affect the amount of diethyl ether-soluble fraction found in the recovered polymer.

The polypropylenes of the invention can be prepared in good yields, especially using "neophyl zirconium aluminate-on-alumina" catalysts, with the yields being between about 10%.

30,000 and 1,000,000 grams of polymer per gram atom of zirconium and usually is at least approx. 200,000 grams of polymer per gram atom of zirconium.

The ether-soluble fraction can be separated by extraction with boiling diethyl ether.

The polypropylenes of the invention also comprise polymers containing small amounts of units derived from α-olefins other than propylene, e.g. up to approx. 10 mol% of the undivided polymer. Such α-olefins can be incorporated into the polymers by copolymerization without altering the essential properties described herein. Examples of such α-olefins are ethylene, 1-butene, 1-pentene and 1-hexene.

The polypropylenes of the invention can be prepared in the same way as conventional elastomers. Thus, if desired, the product can be mixed with such additives as carbon black, mineral fillers, oils and pigments. The polypropylenes are excellent general-purpose thermoplastic elastomers with properties that make them suitable for use in films (including heat-shrinkable films), filaments, fibers and films with elastomeric properties, as well as coatings on fabrics, wires and cables, heat-melt adhesives and injection molds, extruded objects such as tires and hoses.

Also oriented articles such as uniaxially oriented bands and uniaxially or biaxially oriented films can be made.

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of the polypropylenes. The uniaxially oriented films exhibit excellent elastic return at later elongation, and the biaxially oriented films are particularly valuable for packaging applications as they combine low shrinkage stress desirable for heat shrinkable wrap with high extensibility desirable for stretch wrapping. Biaxially oriented films can be prepared by known methods, e.g. the film is simultaneously stretched (usually 400-700%) in two directions, followed by a gradual lifting of the tension. The film can be heated up to approx. 125 ° C during the stretch, in which case it cools while still under tension.

The polymers of the invention do not require the addition of extractable plasticizers to achieve high flexibility and are therefore particularly useful for extruded flexible tubing used in contact with such liquids as milk, blood and parenteral boxes. Such hoses can be prepared by known methods such as melt extrusion at temperatures between about 200 and approx. 250 ° C in an extruder containing a polyethylene screwdriver and a nozzle tube mandrel for tubing manufacture. The hose is extruded into a vacuum box filled with water to cool the product and maintain its dimensions.

Products of the type described above can be made directly from the polypropylenes of the invention. For some applications, the polymers may be subjected to thermal and mechanical treatment such as shear for use in products requiring lower molecular weights and narrower molecular weight distributions. A particularly important advantage of the present invention is that it provides an elastomeric polypropylene which is manufactured directly and thus does not need to be separated into its components in order to be used in the manufacture of such products.

The properties used to characterize the products in the present case are determined as follows:

Solubility

The solvent is heated to boil in a round bottomed glass flask. The vapors rise through the outer zone in a vertical cylindrical

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π chamber and cool in a reflux condenser. The condensate drips into a fiber or glass thimble and with a sintered glass filter disc at the bottom, suspended in the center of the vertical cylinder. The thimble contains a sample (1-2 g), of the polypropylene having an average particle size of no more than approx. 3 mm. The wall of the thimble is surrounded and heated by the hot solvent vapor so that the real extraction is performed at or near the boiling temperature of the solvent. The extraction is continued until no loss of more than 0.01 g occurs during an overnight extraction period or at least 15 hours. The entire operation is carried out in an atmosphere of nitrogen and solvent vapor. The portion of the sample extracted is the soluble portion.

At 25 ° C, 0.0275 g of the polypropylene sample is added to 50 ml of decahydronaphthalene containing 0.1 g / liter of BHT (2,6-di-tert-butyl 1-4-methylphenol) 1 to give a weight / volume. concentration of 0.05% at 135 ° C, at which temperature the sample is dissolved under nitrogen by stirring with a magnetic stirrer for 2 hours. The solution is poured through a filter rod into a Cannon-Ubbelohde - viscometer, in which its expiration time is measured at 135 ° C and compared with the solvent expiration time alone.

(t \ in | L T = solution expiration time 7inh) = _2 Two = solvent expiration time t 'C C = concentration (0.05 g / dl) iS2 £ §3Sti§lS „iSÉii2iå 13

This is determined by C-NMR spectra as follows: 1 C-NMR spectra are obtained at 137 ° C with a Bruker WH-90 NMR spectrometer operating at 22.63 MHz following the Fourier transform method. . For typical experiments, 10,000 "scans" are taken and the radio frequency pulse is set to give a pitch angle of 60 °. The samples are used as solutions of 0.2 g polymer in a mixture of 1 ml o-dichlorobenzene and 1 ml dideuterotetrachloroethane containing 0.05% (w / v 1 BHT as stabilizer and tetramethylsilane as 13 12

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reference. The C NMR isotactic content is the area of the mmmm pentad peak at ca. 21.7 ppm divided by the entire area of the 13 C-methyl resonance (see Zambelli et al., Macromolecules, 6, 925, 1973). The syndiotactic content is similarly determined from the peak at ca. 20.2 ppm.

Kr stall stallinity at C C NMR

When a sample of polypropylene is examined by C-NMR as described above and then re-examined after the solution has cooled to ambient temperature, a decrease in the height and area of the mmmm pentad peak may occur if a sufficiently long crystallization is obtained. isotactic sequence. This 13 difference is a measure of the polymer's C "stiffness" and corresponds to the isotactic "pentads" that have been immobilized.

The observed percent of pentad isotactic content in the hot and cold polymer solution can be denoted by 13 H and C, respectively, and then the percent C stiffness can be calculated from the equation "13 H1% C strength = -1

100-C

where (100-H1 / (100-C) is used to bring the absolute values of the non-isotactic pentads in H and C to the same level.

13

The percent C-isotactic stiffness corresponds to the crystallinity measured by "differential scanning" calorimetry (see below).

13

The percent C isotactic crystallinity can be obtained from Equation 13 13% C isotactic crystallinity = 0.625 x (% C isotactic stiffness) where the factor 0.625 is the slope of a straight line obtained by depositing 2Ahf (see below 1 against the percent C-isotactic stiffness for a variety of polypropylenes including "Pro-fax 6523".

The melting points listed here are major melting points determined by "differential scanning" calorimetry (dsc). A 10-20 mg sample is heated from -40 ° C to 200 ° C at 20 ° C. min., cooled from 200 ° C

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13 to -40 ° C at 5 ° C per day. and heated again from -40 ° C to 200 ° C at 10 ° C per minute. minute. The major melting point is taken from the heat flow / temperature curve obtained by the reheat operation and is the temperature of the endothermic main peak on it. The melting points of ether-soluble fractions are determined by the first heating.

All of the ether-soluble fractions in the following examples have similar thermal history (70 ° C / 4 hours for removal of volatiles followed by storage at room temperature).

For further information, see Ke, "Newer Methods of Polymer Characterization," page 350 (Interscience, 1964).

5 £ Zstallinitet_bestemt_yed_fusionsvarme

The fusion heat (Ah ^) is calculated from the area enclosed by the dsc melting point, the "start" and "stop" temperatures, i.e. the lower and upper boundary, which determines the part of the curve to be used for calculating the area, is visually selected as deviations of the curve from the baseline. The equation used is Ahj = area / Km, where K is an adjustment constant that is assumed to be independent of temperature and is determined using indium which has a known transition heat and m is the mass of the sample. The values are given as calories per day. grams, see above, pages 357-369.

The weight fraction of crystalline polymer, X, can be determined from the equationAh ^ = XcAhQ, where Ah ^ is the fusion heat per minute. grams of polymer, and AhQ is the fusion heat per grams of pure crystal, see also Mark and Tobolsky, "Polymer Science and Materials", page 180 (Interscience / Wiley, 1971). For polypropylene, a value of Ah of 50 calories per day has been proposed. grams, and X,

U U

expressed as a percentage, corresponds to Ahf / 50 x 100 or 2Ahf.

Double refraction is a well-known optical phenomenon due to differences in the refractive index of light which are polarized to correspond to the differences in polarizability in different directions in an anisotropic material. It can be observed in detail under a polarizing microscope and more simply as a multicolor spectral pattern when a film is stretched between two crossed polarizing

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14 sheets and considered through the sheets. Both methods are used in the following examples. For more information, see e.g. Battista, "Fundamentals of High Polymers", pages 97-98 (Reinhold, 1958)., Seymour, "Introduction of Polymer Chemistry", pages 284-285 (MaGraw-Hill 1971)., And Tanford "Physical Chemistry of Macromolecules", pp. 116-118 (Wiley, 1961).

The following examples, in which all percentages are by weight, unless otherwise stated, are intended to further illustrate the invention.

In each example, oxygen and water are excluded from the polymerization and from all previous steps. Furthermore, all materials used are of high purity, the catalyst slurries are prepared under nitrogen, and all transfers are carried out under nitrogen.

Unless otherwise stated, in each example, the alumina support is prepared by allowing "fumed" alumina to settle to an equilibrium with the humidity of the atmosphere, after which the product obtained is heated for 4 hours to 400 ° C in a stream of nitrogen and then cooled under nitrogen.

Eksemgel_l

A 1 liter stainless steel autoclave equipped with a stirrer is heated to 150 ° C for 2 hours while being evacuated, and after disruption of the vacuum source, nitrogen is allowed in the autoclave to a pressure of 21 kg / cm and the system is allowed to cool to room temperature.

A slurry of catalyst is prepared by stirring 1 g of alumina (AlgOg) in 40 ml of cyclohexane for 14 hours, then adding a solution of 0.36 mmol of tetraneophyl zirconium in 2.0 ml of toluene and stirring is continued for 1 hour. The slurry is then transferred with a syringe to a 75 ml stainless steel cylinder designed to inject its nitrogen pressure into the autoclave used for the polymerization.

Cyclohexane (450 ml) is passed through a layer of acidic Woelm alumina into a glass container and then under nitrogen pressure into the autoclave which has been deaerated to atmospheric pressure and is under vacuum.

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Rinse with nitrogen. The autoclave is evacuated to a pressure of approx. 50 ram for 1 minute and refill 126 g of propylene with stirring at 500 rpm (pressure 6.3 kg / cin at 22 ° C), and hydrogen is injected to a total pressure 2 2 of 8.0 kg / cm (a partial pressure of hydrogen of 1.8 kg / cm). The solution is heated to 50 ° C and the catalyst slurry is injected, raising the temperature to 70 ° C over approx. 5 minutes. The system is then kept at 50-52 ° C for 1 hour from the time it first reaches 50 ° C (total pressure 6.8-14 kg / cm²), then the autoclave is de-aerated, cooled and opened. , are divided into three approximately equal parts, each of which is stirred in a blender with about 700 ml of acetone. The resulting solids are separated by filtration, combined and stirred in a blender with about 700 ml of acetone containing 0.3 g " Irganox® 1010 "antioxidant (tetrakis - [methylene-3 (31,5-di-tert-butyl-4L-hydroxyphenyl 11 propionate] -methane)). After filtration, air drying and drying in a vacuum oven at 70-80 For 4 hours, 102.4 g of polypropylene are obtained as a curvature-like solid. A test film pressed at 225 ° C is non-sticky and moderately strong, as well as stretchable and elastic. The logarithmic viscosity number of the polymer is 5.5. and the isotactic content, determined by 1 C-NMR, is 37%, m.p. 151 ° C.

The product contains 46.5% diethyl ether soluble fraction having a logarithmic viscosity number of 3.1 and the birefringence is clearly visible when one of this fraction formed is stretched between crossed polarizing films at room temperature. The ratio of the logarithmic viscosity numbers of the ether-soluble fraction to the undiluted polymer is 0.56 and no reduction of syndiotactic "pentads" by C-NMR is observed. An isotactic 13 crystallinity of 2% is determined by C-NMR and the melting point and Ahf are 58 ° C and 1.6 cal / g, respectively. The dispersion equals 7.6. Double refraction is also clearly visible when a film is viewed under crossed Nicol prisms in a hot-step polarization microscope at approx. 25 ° C. When the temperature is raised by 10 ° C per day. minute, the birefringence disappears at approx. 78 ° C.

A 0.76 mm thick film of the total polymer is prepared by hot compression molding of a sample of the product at 180 ° C. When samples of this film are stretched at 51 cm / min. and immediately after being allowed to recover at the same rate to zero voltage, they show one

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16 average permanent extension of 93%. Another sample of this film shows in a stress-strain test for fracture a tensile strength of 68 kg / cm at an extension of 620%. No flow limit is observed in these provisions.

Eksempel_2

A 1 liter stainless steel autoclave equipped with a stirrer is heated to 150 ° C for 2 hours while being evacuated, then the vacuum sensor is disconnected, the propylene enters the autoclave to a pressure 2 of 3.5 kg / cm and the system is allowed to cool to room temperature.

A slurry of a benzylhafnium aluminate catalyst on alumina is prepared by stirring 1 g of alumina, a solution of 0.29 mmol of tetrabenzylhafnium in 3.0 ml of toluene and 40 ml of cyclohexane for 17 hours.

The autoclave is vented to remove excess propylene and evacuated at approx. 50 mn for 1 minute, then cool in ice / methanol. Stirring at 200 rpm is started and 168 g of propylene are added to the autoclave. The stirring speed is increased to 500 rpm, the system is heated to 25 ° C (pressure 10.8 kg / cm 2) and hydrogen is released into the autoclave to a hydrogen partial pressure of 1.8 kg / cm (total pressure 2 12.6 kg / cm) _. The catalyst slurry is then injected as in Example 1, and the system is heated to 75 ° C for 35 minutes, and then to 72-77 ° C for 1 hour at autogenous pressure (28.0-30.5 kg / cm 2). the autoclave is vented and cooled.

The product is stirred with 300 ml of cyclohexane in a blender to convert it to a gel, then 1 liter of acetone is added, the mixture is stirred for approx. 1 minute and the product is separated by filtration. The product is then stirred in a mixer with 1 liter of fresh acetone containing 0.3 g of "Irganox® 1010" antioxidant, after which it is separated by filtration, air dried and dried in a vacuum oven at 70-80 ° C for 4 hours, , 9 g of solid polypropylene. The logarithmic viscosity number of this product is 13 8.2, the isotactic content after C-NMR is 45% and the melting point is 154 ° C.

By extraction with diethyl ether, the product thus obtained is found to contain an ether soluble fraction which constitutes 39.1% of the total polymer and has a logarithmic viscosity number.

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17 at 4.7. The ratio of the logarithmic viscosity numbers of the ether-soluble fraction to the total polymer is 0.57. Double refraction is clearly visible when a film of this fraction is stretched between crossed polarizing foils at room temperature. An iso-tactical crystallinity of 1% is found by C-NMR and a melting point of 57 ° C and one of 1.5 cal / g is found. No reduction of syndiotactic "pentads" is observed at 13 C NMR and the dispersion is 5.1. The birefringence is also clearly visible when a film is viewed under crossed Nicol prisms in a hot-step polarization microscope at ca. 25 ° C. When the temperature is raised by 10 ° C / min, the birefringence disappears at approx. 98 ° C.

A 0.45 mm thick film of the total polymer is prepared by hot compression molding a sample of the product at 180 ° C.

When samples of this film are stretched at 51 cm / min. and immediately allowed to recover at the same rate of 0 voltage, they show an average lasting extension of 106%. Other samples of this film show in stress-strain experiments for fractures an average tensile tensile strength of 160 kg / cm at an extension of 510%. No flow limit is observed by these provisions.

example ^

A 1 liter stainless steel autoclave equipped with a stirrer is heated to 150 ° C for 2 hours while being evacuated. The vacuum generator is switched off, the propylene is brought into the autoclave to a pressure of 3.5 kg / cm and the system is allowed to cool to room temperature.

A catalyst slurry is prepared by stirring 1.0 g of alumina, a solution of 0.3 mmol of tetraneopentyl2irconium in 4.0 ml of toluene and 40 ml of cyclohexane for 16 hours.

The autoclave is deaerated to remove excess propylene, then evacuated to ca. 50 mm for 1 minute and cool in ice. Stirring at 200 rpm is started and 168 g of propylene are added to the autoclave. The stirring speed is increased to 500 rpm, the system is heated to 27 ° C (pressure 11.5 kg / cm 2) and hydrogen is introduced into the autoclave to a 2 2 hydrogen partial pressure of 1.8 kg / cm (total pressure 13.3 kg / cm), after which catalyst The slurry is injected as in Example 1. The system is heated to 50 ° C over 16 minutes and then heated to 50-54 ° C for 1 hour at autogenous pressure (18.9-21.0 kg / cm 2}, after which the autoclave is deaerated. and cool.

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18

The product is stirred with 400 ml of cyclohexane in a blender to convert it to a gel, and then 1 liter of acetone is added. 1 minute and the product is separated by filtration. The product is then stirred in a mixer with 1 liter of fresh acetone containing 0.3 g of "Irganox 1010" antioxidant, filtered off and air dried in a vacuum oven at 70-80 ° C for 4 hours to give 81.7 g of solid polypropylene. The logarithmic viscosity number for this product is 5.4, the isotactic content after 1 C NMR is 40% and the melting point is 150 ° C.

By extraction with diethyl ether, this product is found to contain an ether-soluble fraction which constitutes 50.8% of the total polymer and has a logarithmic viscosity number of 4.8. The ratio of the logarithmic viscosity numbers of the ether-soluble fraction to the total polymer is 0.89. Double refraction is clearly visible when a film formed by this fraction is stretched between crossed polarizing films at room temperature. The melting point is 73 ° C, ΔΙι ^ 1.3 cal / g and the dispersion 4.6.

A 0.73 mm thick film of the total polymer is prepared by hot compression molding of a sample of the product at 180 ° C.

When samples of this film are stretched at 51 cm / min and are immediately allowed to recover at the same rate to zero voltage, they show an average lasting elongation of 54%. Other samples of this film show in stress-strain samples for fractures a tensile strength of 105 2 kg / cm at an extension of 730%. No such flow limit is observed in these provisions.

Example gel 4 A ^ Polymer bond position

A slurry of 19 g of activated alumina in 487 ml of cyclohexane is placed in a dry glass flask under a nitrogen atmosphere.

A solution of 4.8 mmol of tetraneophyl zirconium in 24 ml of toluene is added with stirring, the flask is closed and the catalyst slurry is stirred overnight with a magnetic stirrer.

A 19 liter dry reactor is flushed with propylene to remove nitrogen and then charged with 3,300 g of propylene. After heating to 25 ° C, hydrogen is added to increase the reactor pressure by 6.3 kg / cm and the catalyst slurry is injected as

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19 of Example 1 with 500 rpm stirring. The reactor temperature rises to 35 ° C with the catalyst addition and heat is added to raise the reactor temperature to 40 ° C. The reactor temperature during the 1 hour reaction period is 40-64 ° C and the pressure is 16.4-22.7 kg / cm. During the reaction, the temperature is kept within the specified range by the discharge of gas from the reactor and additional hydrogen is injected to replace the loss on the vent.

The polypropylene product obtained is ground on a 2-roller rubber mill at temperatures up to 120 ° C to remove solvent. At this point, stabilizers (0.2% of the condensation product of 3 moles of 3-methyl-6-tert.butyl-phenol with 1 mole of crotonaldehyde ("Tropanol® CA") and 0.5% dilaurylthio dipropionate ("Cyanox®") are also added). LTD. 1948 g of stabilized polypropylene are obtained and this product is treated on a 2-roller rubber mill at 180 ° C for 5 minutes to remove traces of solvent. The logarithmic viscosity number of the product is 3.3, the isotactic content 36 % and the melting point 146 ° C.

On extraction of a sample of the product of 200 g of boiling diethyl ether, it is found to have an ether-soluble fraction which constitutes 66% of the undivided polymer and has a logarithmic viscosity number of 1.9. The ratio of the logarithmic viscosity numbers of the ether-soluble fraction to the undiluted polymer is 0.58. Double refraction is clearly visible when a film formed by this fraction is stretched between crossed polarizing films at room temperature. This fraction has an isotactic crystallinity of 3%, determined by C-NMR, a melting point of 57 ° C and a Λ h 2 of 1.6 cal / g. No decrease of syndiotactic 13 "pentads" is observed by C-NMR and the dispersion equals 10.6. The birefringence is also clearly visible when a film of the ether-soluble fraction is viewed under crossed Nicol prisms in a hot-step polarization microscope at ca. 25 ° C. When the temperature is raised by 10 ° C / min. the double refraction disappears at approx. 52 ° C.

A 0.78 mm thick film of the total polymer shows an average residual elongation of 85%, the average tensile strength for fracture is 65 kg / cm at an elongation of 725% and no flow limit is observed.

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20

A 2.0 mm thick film of the same polymer is uniaxially stretched under ASTM conditions at 23 ° C to 700% at 51 cm / min and allowed to recover at the same rate to 0 voltage. The sample then has a length of 330% of the original, giving a stretch ratio of 2.3. The stretched sample shows a tensile strength to fracture of 154 kg / cm at an elongation of 180% at 51 cm / min, and it immediately returns completely from this stress, showing very high elasticity. No flow limit is observed.

§In-iIiiSi £ iS§ £ iiiiS2_22wZE £ 2Y £ I22

From the product prepared in the manner described above, films of various thicknesses are prepared by compression molding at 225 ° C followed by a rapid quench in water of 5-10 ° C. The elastic behavior is measured by stretching / recovery tests, where 0.056-0.011 mm thick films are extended to 100, 200 and 300% of their original length, after which the tension is removed and the films are allowed to relax for 1 hour. The degree to which they are recovered is measured and the results are given in the following table, where "recovery", expressed in%, is defined as 100 x (length at max, stretch - length at relaxation1 (length at max. Stretch - original) length1

Extension Recovery 100% 9.2% 200% 91% 300% 88.5%

A heat shrinkable is produced by biaxial orientation carried out as follows: A 0.76 mm thick film is heated to 125 ° C for 2 minutes, stretched four times simultaneously in mutually perpendicular directions at 125 ° C and a stretching rate of 10,000% / min. , is allowed to cure for 5 minutes at the stretching temperature of 125 ° C - cool and remove from the extruder, then relax 2 to (3.75X). The film shrinkage is then measured at various temperatures which give the results given below.

21 DK 162533 B

Shrinkage temperature Shrinkage Shrinkage voltage X

7 5 ° C 9% 1.7 kg / cm2 100 ° C 26% 2.4 kg / cm2 125 ° C 54% 3.9 kg / cm2 K ASTM D-2838-69

Eksemgel_5

A 0.00125 M solution of tetraneophyl zirconium in cyclohexane is prepared and a suspension of an active supported catalyst consisting of neophyl zirconium aluminate on alumina is continuously prepared by this solution of tetra-neophyl zirconium at a rate of 294 cm / h. solution of 0.0374 g of alumina per ml of mineral oil at a rate of 1.4 g A ^ O ^ / h is fed into a stainless steel autoclave with stirrer and a capacity of 961 cm 2, diluting with 161 cc hexane of 51 ° C. The alumina is pretreated by drying in a stream of nitrogen at 1000 ° C for 6 hours and partially rehydrating by touching with an atmosphere of 50% relative humidity at 23 ° C for 16 hours and then re-drying by heating to 400 ° C. 4 hours in a stream of nitrogen. After a stay in the autoclave of approx. 117 minutes to allow the reactions between tetraneophyl zirconium and the activated alumina to form neophyl zirconium aluminate, the catalyst suspension 3 is continuously fed to a 253 cm 3 stainless steel autoclave at the same rate and diluted there with 158 cm cyclohexane per minute. hour. After a residence time of 25 minutes in this autoclave, the diluted catalyst suspension is continuously fed to a 253 cm 253 cm stainless steel polymerization container maintained at 130 kg / cm 2 and 85 ° C, where the catalyst suspension is brought into contact with propylene. The propylene is supplied at a rate of 386 g / h by introducing it into a stream of cyclohexane which is fed at a rate of 592 cm / h. An additional cyclohexane stream of 250 cm / h is fed as a stirrer to the stirrer, and the product stream is withdrawn at the same rate as the total feed, so that the nominal residence time in the reactor becomes approx. 7.6 minutes. The product mixture passes to a chamber where the catalyst is deactivated by the addition of one

22 DK 162533 B

0.00836 M solution of isopropanol in cyclohexane at a rate 3 of 523 cm / h.

The polypropylene solution is discharged continuously through a regulated pressure reducing valve to a product receiver maintained at 50 ° C and the polymer product is isolated by acetone treatment. The precipitated polymer is ground in a Waring mixer in the presence of acetone, after which the curved polymers are air dried in a fume cupboard and then dried by hot grinding. 12 g of product per hour.

This product has a logarithmic viscosity of 3.0, an isotactic content of 44% and a melting point of 150 ° C.

A 0.76 mm thick film of the total polymer is prepared by hot compression molding of a sample of the product at 180 ° C. When samples of this film are stretched at 51 cm / min. and are immediately allowed to recover at the same rate for 0 voltage, they show an average lasting extension of 89%. Another sample of this film shows a tensile strength of 106 kg / cm at a stress-strain test at an extension of 780%. No such flow limit is observed in these provisions.

The combined polymer is extracted with boiling diethyl ether and the ether-soluble fraction is then extracted with boiling hexane to give the following fraction% of undivided%

Fraction Polymer Inh Isotactic Mp.

Ether soluble 47 2.4 14 56 ° C

Hexane Soluble 23 3.8 47 111 ° C

Hexane Insoluble 30 3.3 65 155 ° C

Total polymer 3.0 44 150 ° C

A birefringence is clearly visible when a film made of the ether-soluble fraction is stretched between crossed polarizing films at room temperature. An isotactic crystallinity of 1% is determined by C-NMR, and an Al₂ of 2.7 cal / g is observed.

No reduction of syndiotactic "pentads" was observed at 13 C NMR, and the dispersion equals 7.6. The birefringence is also clearly visible when a film is viewed under crossed Nical prizes in a hot-step polarization microscope at approx. 25 C. When tempera

23 DK 162533 B

the trip is increased by 10 ° C / min. the double refraction disappears at approx. 60 ° C. The ratio of the logarithmic viscosity numbers of the ether-soluble fraction to the total polymer is 0.80.

Example_6 A ^ Polymer Formation

A 3.8 liter stainless steel autoclave equipped with a stirrer is heated to 150 ° C for 2 hours while being evacuated. Then the vacuum generator is switched off, the propylene is brought into the autoclave 2 to a pressure of 3.5 kg / cm and the system is allowed to cool to room temperature.

A catalyst slurry is prepared by stirring 5.7 grams of alumina and 188 ml of cyclohexane for 18 hours, then adding a solution of 1.43 mmol of tetraneophylzirconium in 7.2 ml of toluene and stirring for an additional 1 1/2 hours.

The autoclave is deaerated to remove excess propylene, evacuated to ca. 50 mm for 1 minute and cool to below 0 ° C. Then stirring at 500 rpm is started and the autoclave is charged with 795 g of propylene. The system is heated to 25 ° C (pressure 9.1 kg / cm 2) and hydrogen 2 is fed into the autoclave to a hydrogen partial pressure of 2.1 kg / cm 2.

2

Internal pressure continues to rise to 12.9 kg / cm. The catalyst slurry is injected as in Example 1 and the system heats to 35 ° C over 14 minutes and then to 35-51 ° C for 1 hour at autogenous pressure (17.1-19.6 kg / cm). , after which the autoclave of air is cooled and cooled. The product is added to 1 liter of cyclohexane and the mixture is allowed to stand overnight, then 1 liter of acetone is added, the mixture is stirred in a mixer and the product is separated by filtration. This treatment with acetone is repeated. Finally, the product is placed in a mixer with 1 liter of fresh acetone containing 1.5 g of "Irganox-1010" antioxidant and the mixture is allowed to stand overnight with stirring. Then, the solid is separated by filtration, air dried and dried in a vacuum oven at 70-80 ° C for 4 hours to give 247.3 g of solid polypropylene having a logarithmic viscosity of 5.4, an isotactic content of 36% and a mp 144 ° C.

By extraction with boiling diethyl ether, this product is found to contain an ether-soluble fraction which constitutes 74.5% of the undiluted polymer and has a logarithmic viscosity number of 4.6.

24 DK 162533 B

The portion of the polymer which is insoluble in diethyl ether is extracted with boiling hexane to give a hexane-soluble fraction which constitutes 11.4% of the total polymer and has a logarithmic viscosity number of 4.6. The hexane-insoluble fraction makes up 14.1% of the total polymer and has a logarithmic viscosity number of 6.1.

When one of the ether-soluble fraction formed films is stretched between crossed polarizing films at room temperature, a birefringence is clearly visible. An isotactic crystallinity of 1% is determined by C-NMR, and a melting point of 60 ° C and a Z 1 h, of 1.5 cal / g are found. No decrease * 13 of syndiotactic "pentads" is observed by C-NMR, and the dispersion equals 6.2. The ratio of the logarithmic viscosity numbers of the ether-soluble fraction to the undiluted polymer is 0.85. The birefringence is also clearly visible when a film is viewed under crossed Nicol prisms in a hot-step polarization microscope at about, 25 ° C. When the temperature is increased by 10 ° C / min, the birefringence disappears at approx. 88 ° C.

A 0.78 mm thick film of the total polymer is prepared by hot compression molding a sample of the product at 180 ° C. When samples of this film are stretched at 51 cm / min. to an extension of 300% and immediately allowed "zero-voltage" at zero voltage to zero voltage, they show an average "tensile set" of 41%. Other samples of this film show in stress-strain tests for fractures, an average tensile strength of 62 kg / cm at an extension of 725% No flow limit is observed by these provisions.

Example-7

This example illustrates the reduction of the percentage of ether soluble fraction and of the logarithmic viscosity of this fraction when an elastomeric polypropylene of the invention is obtained.

A 1 liter stainless steel autoclave equipped with a stirrer is heated to 150 ° C with 500 ml of cyclohexane for 10 minutes, then the cyclohexane is removed at 90 ° C under vacuum and the autoclave flushed with nitrogen at 150 ° C for 4 hours. While rinsing is continued, a slurry of 1.0 g of alumina is introduced into 40 ml of cyclohexane. Then 8 ml of hydrogen is introduced at 350 kg / cm, the autoclave is cooled to 8 ° C and 200 g of propylene is added from a tarred cycle.

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cylinder. The autoclave is heated to 20 ° C and a solution of 0/5 mmol of tetraneophyl zirconium is introduced into 5 ml of toluene under nitrogen pressure as in Example 1 while stirring at 500 rpm. The temperature is increased to 24 ° C immediately and to 28 ° C in approx. 15 minutes and then drops to 23 ° C after 1 hour when excess propylene is de-aerated. The obtained gel is cut into small pieces and heated to 70 ° C under vacuum to remove all volatiles. 55.5 g of elastomeric polypropylene are thus obtained.

At this point, the product has a logarithmic viscosity of 8.2, an isotactic content of 25% and a melting point of 144 ° C, and it contains 57% of diethyl ether soluble fraction having a logarithmic viscosity of 6.4, a dispersion of 13.9, a melting point of 51 ° C and a Δ h ^ of 1.6 cal / g. Double refraction is clearly visible when one of the ether-soluble fraction prepared film is viewed under crossed NicO1 prisms in a hot-step polarization microscope at ca. 25 ° C. When the temperature is increased by 10 ° C / min. the double refraction disappears at approx. 85 ° C.

Of the product described above, 53 gm is ground by ...................

180 ° C for 10 minutes with 0.265 g of "Cyanox LTDP" and 0.32 g of "Topanol CA" as antioxidants. The milled product has a viscosity of 7.5 and contains 22% ether-soluble fraction having a logarithmic viscosity number of 9.1, a dispersion of 3.6, a melting point of 49 ° C and a Δ h / g. A film of the milled product having a thickness of 0.19-0.20 cm compression molded at 180 ° C and samples of this film stretched at 51 cm / min to a 300% extension and immediately allowed to recover at the same rate to zero voltage, and they show an average lasting elongation of 39%. Other samples of this foil show, for stress / strain tests, fractures, an average tensile strength of 105 kg / cm at an extension of 910%. No flow limit is observed in these provisions.

Example Gel 8 In the autoclave used in Example 7, preconditioned as described in Example 7, a slurry of 2 g of alumina is introduced into 80 ml of cyclohexane, then the autoclave is closed and 2 pressurized with ethylene to a total pressure of 4.55 kg / cm . Total pressure

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The reaction mixture is then brought to 6.3 kg / cm with hydrogen, the vessel is cooled and 168 g of propylene are introduced. While the system is stirred at 500 rpm, the temperature rises to 50 ° C and 4 ml of a solution of 0.4 mmol of tetraneophyl zirconium in toluene is introduced with nitrogen. This causes an instantaneous temperature increase to 95 ° C and the polymerization is allowed to proceed for 1 hour while the temperature gradually drops to 54 ° C. Excess propylene is de-aerated at the polymerization temperature and the product is freed from volatiles by rinsing with nitrogen and evacuating at 70 ° C / 0.2 mm. There is thus obtained 146 g of an elastomeric polypropylene / ethylene copolymer containing 6 mole% (4 wt%) units derived from ethylene. After isolation, this product shows a logarithmic viscosity of 5.9, an ether solubility of 64%, a melting point of 142 ° C and a glass transition s temp (T) of -21 ° C. The logarithmic viscosity number of the ether-soluble fraction is 3.35. Of this product, 143 grams are milled at 150 ° C for 10 minutes with 0.72 g of "Cyanox. LTDP" and 0.36 g of "Topanol CA" as antioxidants, and then compression molded a film of the ground product with a thickness of 0f20 cm at 150 ° C. When samples of this film are stretched at 51 cm / min. to an extension of 300% and recovering at the same rate to zero voltage, they show an average "tensile set" of 87%. Other samples of this foil show, for stress / strain tests, a mean tensile strength of 4 "9kg / cm2 at an elongation of 900%. No flow limit is observed.

13

The total ethylene content is determined by C-NMR, see Tanaka and Hatada, j. Polym. Sci., Polym. Chem. Ed., 11, 2057 (19731, and Tg is determined from the dsc curve, see Ke, as previously mentioned, page 350).

Claims (13)

1. Fractional elastic polypropylene, characterized in that it has a logarithmic viscosity of 1.5-9, exhibits no flow limit, has a permanent elongation of not more than 150%, an isotactic content of 55% by weight or less, and a "major" "melting point between ca. 135 and approx. 155 ° C and contains 10-80% by weight of a diethyl ether-soluble fraction having a logarithmic viscosity number greater than 1.50, which ether-soluble fraction has an isotactic crystalline content of between ca. 0.5 and approx. 5% by weight and exhibiting birefringence when a film formed therefrom is viewed under crossed Nicol prisms in a polarizing microscope at ca. 25'C. Fractional elastic polypropylene according to claim 1, characterized in that it contains 30-80% by weight of the diethyl ether-soluble fraction. Polypropylene according to claim 1 or 2, characterized in that it has a permanent extension of not more than 100%. Polypropylene according to claim 1 or 2, characterized in that it has a logarithmic viscosity number of 2-8. Polypropylene according to claim 1, characterized in that it contains between approx. 40 and about 75% by weight of said ether-soluble fraction. Polypropylene according to claim 1, characterized in that it has a logarithmic viscosity number of 3-8, a continuous elongation of not more than 100% and contains between about 10% and 10%. 40 and approx. 75% by weight of a diethyl ether soluble fraction having a logarithmic viscosity number greater than 2.5. Polypropylene according to claim 1, characterized in that it is in the form of a film. Polypropylene film according to claim 7, characterized in that it is oriented. Polypropylene according to claim 1 / characterized in that it is in the form of an extruded tube. 28 DK 162533 B Polypropylene according to claim 1, characterized in that it contains up to 10 mol% of polymerized α-monoolefin units different from propylene. Process for preparing an elastic polypropylene, characterized in that propylene is contacted with a catalyst which is the reaction product of a metal oxide and an organometallic compound of formula (RCH2) -4M wherein M is Zr, Ti or Hf. 'R is aryl', aralkyl, tert-alkyl 'or trialkylsilyl, wherein the' Vlkyl groups contain 1-12 carbon atoms and the group RCH2 contains no hydrogen bonded to the carbon atom at the β-position to M or with products formed at hydrogenation of such catalysts and the reaction being carried out in the presence of hydrogen. A process according to claim 11, characterized in that a catalyst of the formula is set wherein M is Zr, Process according to claim 11, characterized in that the catalyst is neophyl zirconium aluminate on alumina.