DE1495173A1 - Process for the production of molding compounds from polypropylene and polyisobutylene - Google Patents

Description

Process for the production of molding compounds from polypropylene and polyisobutylene It is known that high molecular weight crystalline polypropylene can be obtained by polymerization of propylene using catalysts made from halogen compounds of titanium, such as titanium trichloride and alkyl aluminum halides, such as ethyl aluminum sesquichloride, at temperatures between room temperature and 160 0C and pressures up to about 100 Atmospheres in the presence or absence of liquid solvents or suspending agents polymerized. The process produces a polypropylene that is predominantly isotactic Structure and a proportion of over 80 percent by weight which is insoluble in boiling heptane having.

It is characterized by surface hardness, transparency, high tensile and strength Tear resistance and at temperatures above 0 ° C due to high impact and notched impact strength the end. At temperatures below 0 ° C, however, it becomes relatively brittle and embrittled At such temperatures it only has notched impact strengths that are common to many Areas of application are not sufficient.

To improve the notched impact strength of the polypropylene one can polypropylene, which generally has intrinsic viscosities from [#] = 0.5 to 15dl / g, add high molecular weight polyisobutylene. In practice mixtures were known which, in addition to polypropylene, up to about 30 percent by weight Contain polyisobutylene. The polyisobutylene used for this purpose generally has an intrinsic viscosity between 1.0 1, 0 and 4.0 dl / g. For the production However, these known molding compositions made of polypropylene and polyisobutylene are essentially three separate operations are required, namely the production of the Polypropylene and polyisobutylene by polymerizing and mixing them Polymerisate O When mixing, it is necessary to knead particularly intensively, otherwise products are obtained whose mechanical properties are due to Inhomogeneities leave something to be desired.

It is also known (French patent specification 1 234 905) that one can produce graft polymers from olefins such as ethylene and propylene, by using preformed vinyl polymers such as polyisobutylene, ethylene or propylene using catalysts made from halides of titanium and alkyl aluminum compounds grafts. From the same patent it is also known that block copolymers can be used can be prepared by relying on polyisobutylene using such catalysts obtained by polymerizing isobutylene in a hydrocarbon solvent without prior isolation and without destruction or re-addition of polymerization catalysts Ethylene is polymerized. However, this must be done in the manufacture of polyisobutylene isobutylene not consumed before using the Ziegler catalysts Polymerize Separate the ethylene from the reaction mixture.

This known method is also somewhat technically complex because it requires relatively long response times.

It has now been found that molding compositions from 99.5 to 70 percent by weight Polypropylene and 0.5 to 30 percent by weight polyisobutylene by polymerization of propylene and isobutylene in the presence of catalysts made from halogen compounds of titanium and alkyl aluminum halides under normal pressure and temperature conditions Surprisingly, particularly easy to prepare by using propylene and isobutylene polymerized in a mixture, the molar ratio of halogen to aluminum des alkyl aluminum halide fed to the polymerization vessel from 1.1: 1 to 1.9: 1 and the molar ratio of aluminum to titanium is from 10: 1 to 1: 3.

The new process can be carried out in the presence or absence of liquid solutions or suspending agents, such as aliphatic hydrocarbons, for example gasoline fractions, Heptane, cyclohexane, isooctane and liquid propylene. aside from that can in the polymerization, the usual regulators, such as organic phosphorus and Arsenic compounds and hydrogen are added. The ratio of propylene to isobutylene, the pressure and the temperature can be used during the polymerization within further limits can be varied. In general, however, the proportion of isobutylene should be at least 5 percent by volume in the mixture of propylene and isobutylene and not exceed 50 percent by volume. Preferably the volume ratio is from propylene to isobutylene in the polymerization between 10 and 30 Volume percent, the pressure between 2 and 30 ata and the temperature between 0 and 90 ° C.

The main halogen compounds of titanium are its chlorine and bromine compounds in question, which are also in the form of complex compounds with aluminum halides, such as aluminum chloride and aluminum bromide, as well as with antimony and silicon halides may exist. Examples of particularly suitable titanium halides are titanium trichloride and complex compounds of the general formula 3 TiCl3 # AlCl3. Are also suitable Titanium tetrabromide and titanium tetrachloride. Preferred alkyl aluminum halides are used those in question, the straight-chain or branched alkyl groups with 2 to 8 carbon atoms and contain chlorine or bromine atoms.

Furthermore, alkyl aluminum halides, the cycloalkyl radicals, aryl radicals, Aralkyl radicals or alkyl radicals containing more than 8 carbon atoms are suitable. Examples of suitable alkylaluminum compounds, either alone or as a mixture can be used with each other are diethyl aluminum chloride, ethyl aluminum dichloride, Ethy laluminum esquichloride, Isopropy laluminum dichloride, Dibutylaluminum chloride, Octyl aluminum dichloride, 2-ethylhexyl aluminum dichloride, dihexyl aluminum chloride, Diethyl aluminum bromide and hexyl aluminum dibromide. As alkyl aluminum halides become ethyl aluminum dichloride, diethyl aluminum chloride and ethyl aluminum sesquichloride or mixtures thereof are preferred. The molar ratio of halogen to aluminum in the alkyl aluminum halides or mixtures of these substances should be added when adding into the reaction vessel from 1.1: 1 to 1.9: 1, preferably from 1.3: 1 to 1.5: 1. Can spread in the polymerization vessel the interaction between Alkyl aluminum halide and the halides of titanium also have a different molar Set the ratio of halogen to aluminum.

In the polymerization catalysts, the molar ratio should be Aluminum to titanium from 10: 1 to 1: 3, preferably from 6: 1 to 1: 1. the Catalysts can be modified by adding substances that form complexes with them be. Inorganic salts such as sodium chloride, Sodium fluoride, sodium cyanide, calcium chloride and calcium fluoride. Suitable organic complexing agents are, for example, ethers such as diethyl ether, tetrahydrofuran, Dioxane and diethylene glycol diethyl ether and amino ethers, such as 3-methoxypropylamine. Such complexing agents are, if desired, between the catalysts in amounts about 5 and 50 percent by weight, based on the amount of catalysts, added.

In the process, the catalyst components can be added to the polymerization vessel be added before or during the polymerization. The catalyst components can also be mixed before adding to the polymerization vessel.

The polymerization mixture can be worked up in a customary manner be made. For example, if in a hydrocarbon exhaustion was polymerized, the catalyst by adding alcohols such as methanol and Ethanol, destroyed and the polymer would be practically completely precipitated. Even can the catalyst residues in the work-up in an Ublioher manner, for example by addition of inorganic ones or organic acids, such as hydrogen chloride, Phosphoric acid, oxalic acid, citric acid, alcohols such as methanol, methanol, butanol and carbonizers such as acetylacetone and diacetyldioxime are kept in solution. Catalyst residues can also be separated off by treating the polymers with phosphorus-containing compounds such as phosphorus trichloride and phosphorus pentachloride be made by, for example, the suspension of the polymer in a Hydrocarbons and methanol with the addition of up to 00 percent by weight of phosphorus trichloride, based on the amount of catalyst, stirred and then filtered off.

When performing the process in the absence of liquid solvents or diluents is carried out, one obtains in general 80 high yields that a separation of catalyst residues unnecessary.

In the process, homopolymers of propylene are obtained side by side and isobutylene, but surprisingly practically no copolymers Propylene and isobutylene.

If you work in the absence of regulators, you get a mixture of polyisobutylene with polypropylene having an intrinsic viscosity of [#] = 4 to 12 dl / g. The addition of hydrogen as a regulator during the polymerization gives a mixture of polyisobutylene with polypropylene, the intrinsic viscosity of which is im can generally be set between [#] = 0.5 and 4 dl / g.

The polyisobutylene, which in the process is mixed with polypropylene is obtained, has. generally a molecular weight of from 20,000 to 100,000 on, practically regardless of whether hydrogen was added during the polymerization became. Included are below the molecular weights of polyisobutylene 50,000 obtained when the temperature during the polymerization is above 50 ° C., and Molecular weights above 50,000 when the polymerization temperature falls below 5000, for example at OOC.

The molding compositions generally have a penetrometric measurement Melting point over 1600C. Their stiffness decreases compared to the stiffness (The torsional modulus measured at 200C serves as a measure) of the polypropylene for one Share of over 5 percent by weight of polyisobutylene from something, with the same time the notched impact strength (determined in accordance with DIN 53 453) increases. The molding compounds can the usual additives for polyolefins, such as fillers, stabilizers and parb pigments can be added. According to the procedure in a particularly simple and time-saving manner Molding compositions prepared in a conventional manner, which are then processed in the usual way Way can be granulated, are very homogeneous and are suitable for production molded articles such as household items, gears, films, fibers and coatings. Shaped structures produced therefrom have a shape even at low temperatures excellent impact strength. Those mentioned in the following examples Parts are parts by weight. The volume parts specified therein relate to them like the liter to the kilogram. The intrinsic viscosities given therein were determined at 13500 in decahydronaphthalene.

Example 1 In a stirred autoclave with a free volume of 10 000 parts by volume you put a mixture of 4,000 parts by volume Light petrol, 5 parts of a complex compound prepared in a customary manner general formula 3 TiCl3 Al0, 10 parts of diethyl aluminum chloride and 5 parts of ethyl aluminum sesquichloride before. 1,000 parts of isobutylene are then added under pressure and the mixture is pressed until the pressure is total of 15 atmospheres of propylene and polymerized with stirring for 10 hours 600C, the pressure in the autoclave being kept constant at 15 by forcing in propylene Atmospheres is maintained. The reaction mixture is then allowed to cool and added to 16,000 parts by volume of methanol, the polymer being precipitated. After this Separation and drying gives 3,010 parts of a flaky polymer mixture, that the intrinsic viscosity [#] = 12 dl / g and one insoluble in boiling heptane Has a proportion of 89 percent by weight. The molding compound contains 4.2 percent by weight Polyisobutylene with an intrinsic viscosity below 4 dl / g.

The molding compound is used in a commercially available screw shaft extruder thermally degraded with a particularly high-speed worm shaft at 250 ° C. Included a screw shaft extruder from Alpine is used, which is known as H 8 brought onto the market and the one at the end of the worm shaft has a conical gap which is set to a distance of 0.04 mm during dismantling. The extruder 1.5 kg of the molding compound are added per hour. A molding compound of intrinsic viscosity is obtained 3.2 dl / g, the torsional modulus 7-109 dyn / cm2 and the notched impact strength at 200C 13.8 kg # cm². Its notched impact strength is at -20 ° C 1.7 kg # cm / cm2.

Example 2 works as indicated in Example 1, but uses 8 parts of diethylaluminum chloride and 5 parts of ethylaluminum sequichloride as a catalyst This gives 2,400 parts of a molding compound containing 8.6 percent by weight of polyisobutylene in addition to polypropylene and which has the intrinsic viscosity P 11.1 dl / g and one has an insoluble fraction of 82 percent by weight in boiling heptane. That in it The polyisobutylene it contains has an intrinsic viscosity [#] below 4 dl / g.

After thermal degradation, as described in Example 1, the Molding compound has the intrinsic viscosity F'kJ = 3 dl / g, at 20 ° C the torsional modulus 5.109 dyn / cm2 and the notched impact strength 18.3 kg # cm / cm2. Your notched impact strength at -20 ° C is 1.7 kg # cm / cm2, its pehetrometrically measured melting point is 16,300.

EXAMPLE 3 The procedure described in Example 1 is followed, but the same is used as a catalyst 6 parts of diethyl aluminum chloride and 8 parts of ethyl aluminum sesquichloride. This gives 2,010 g of a molding compound which has an intrinsic viscosity [#] = 11.1 dl / g and an insoluble proportion in boiling heptane of 82 percent by weight. It contains 13 percent by weight polyisobutylene, which has an intrinsic viscosity below [#] = 3 dl / g.

After thermal degradation, as described in Example 1, the Molding compound has the intrinsic viscosity [#] = 3.5 dl / g, the one measured penetrometrically Melting point 163 ° C and at 20 ° C den Torsional modulus 3.8 # 109 dynes / cm2 and the notched lug strength 21.8 kg # cm / cm2. Their notched impact strength is at -20 ° C 2.0 kg # cm / cm2.

Polypropylene of intrinsic viscosity [#] = 3.2 dl / g has at 20 ° C the torsional modulus 7.2 # 109 dyn / cm2 and the notched impact strength 5.2 kg cm / cm2. At -20 ° C, its notched impact strength is only 1.5 kg # cm / cm2.

A conventionally prepared mixture of 13 parts of polyisobutylene an intrinsic viscosity below 3 dl / g and 87 parts of isotactic polypropylene the intrinsic viscosity [J = 3.4 dl / g has a torsional modulus of 5 to 6.0 # 109 at 2000 dyn / cm2 and the notched impact strength 9.5 kg # cm / cm2.

At -20 ° C, its notched impact strength is 2.0 kg # cm / cm2.

Example 4 500 parts of the polymer prepared according to Example 1 are in a stirred autoclave, the free volume of which is 10,000 parts by volume, with a mixture of 10 parts of diethyl aluminum chloride, 5 parts of ethyl aluminum sesquichloride and 150 parts of powdered polypropylene of intrinsic viscosity [#] = 4.5 dl / g and a mixture of 5 parts of a complex compound of the general formula 3 TiC13 A1C13 and 150 parts of powdered polypropylene of intrinsic viscosity [#] = 4.5 dl / g offset. 800 parts of isobutylene are added under pressure and the mixture is pressed Propylene to atmospheric total pressure then polymerizes for 12 hours at 60 ° C with stirring and keeps the pressure constant by injecting propylene. An additional 2,400 parts of a powdery one are obtained. Polymer, the intrinsic viscosity [#] = 6.2 in a mixture with the submitted polymer dl / g has.

The proportion of polyisobutylene in the molding composition obtained is 14 percent by weight.

After thermal degradation, as indicated in Example 1, is the intrinsic viscosity of the mold mass is 3.4 dl / g. It has the modulus of torsion at 20 ° C 3.8 # 109 dynes / cm2 and does not break in the notched impact strength test. Your notched impact strength at -20 ° C is 2.2 kg # cm / cm2.

Example 5 The procedure described in Example 3 is followed, but pressing half an atmosphere of hydrogen after adding the isobutylene.

This gives 3,200 parts of a molding compound, the intrinsic viscosity of which [#] = 2 dl / g and the fraction insoluble in boiling heptane of 78 Has weight percent. It contains 11.5 percent by weight polyisobutylene. Her Notched impact strength at 2000 is 1.8 kg. cm / cm2, its modulus of torsion at 200C 5.6 # 109 dynes / cm2.

Claims (1)

Method for the production of molding compounds from 99.5 up to 70 percent by weight of polypropylene and 0.5 to 30 percent by weight of polyisobutylene by polymerizing propylene and isobutylene in the presence of Kataiyeatoren from halogen compounds of titanium and alkylaluminium halides among the usual Pressure and temperature conditions, characterized in that propylene and isobutylene are polymerized in a mixture, the molar ratio of halogen to aluminum of the alkyl aluminum halide fed to the polymerization vessel from 1.1: 1 to 1.9: 1 and the molar ratio of aluminum to titanium is from 10: 1 to 1: 3.