Method for the emulsion polymerization of olefins

0001The present invention relates to a process for the emulsion polymerization of one or more olefins by reacting a ligand of the general formulas Ia or Ib or a mixture of at least two of the ligands Ia or Ib<chemistry id="chem0001" num="0001"><img file="EP1527103B1_D0001.tif" /></chemistry>where each R represents one or more of the following radicals:<ul id="ul0001" list-style="none" compact="compact"><li>hydrogen</li><li>halogen</li><li>Nitrile</li></ul>C.₁-C₁₂-Alkyl groups, C₁-C₁₂Alkoxy groups, C₇-C₁₃Aralkyl groups, C₆-C₁₄Aryl groups, unsubstituted or substituted by: C₁-C₁₂-Alkyl groups, halogens, C₁-C₁₂Alkoxy groups, C₃-C₁₂Cycloalkyl groups, C₁-C₁₂-Thioethergruppen, optionally also present in the form of their salts carboxyl groups or sulfone groups, as well as amino groups with hydrogen and / or C.₁-C₁₂Alkyl residues Amino groups NO¹R², where R¹ and R² together or separately represent hydrogen, C₁-C₁₂-Alkyl groups, C₇-C₁₃Aralkyl radicals and C₆-C₁₄Aryl groups and in addition also a saturated or unsaturated 5- to 10-membered ring, unsubstituted or substituted by: C₁-C₁₂-Alkyl groups, halogens, C₁-C₁₂Alkoxy groups, C₃-C₁₂Cycloalkyl groups, C₁-C₁₂-Thioethergruppen, optionally also present in the form of their salts carboxyl groups or sulfone groups, as well as amino groups with hydrogen and / or C.₁-C₁₂Alkyl radicals and where identical or different compounds of the general formulas Ia and Ib optionally also by one or more C.₁-C₁₂Alkylene bridges, C₂-C₁₂ alkylated azo bridges or bridges of the general formula II<chemistry id="chem0002" num="0002"><img file="EP1527103B1_D0002.tif" /></chemistry>where Y is silicon or germanium and R³, R⁴ is hydrogen and / or C.₁-C₁₂-Alkyl, can be bridged with a phosphine compound PR₃', where R' is hydrogen, C₁-C₁₂-Alkyl groups, C₄-C₁₂Cycloalkyl groups, C₇-C₁₅Aralkyl groups or C₆-C₁₅-Aryl groups means or with a diphosphine compound R₂'PG-PR₂', where R' has the same meaning as for the phosphine compounds PR₃'and G for C₁-C₁₂-Alkyl groups, C₄-C₁₂Cycloalkyl groups, C₇-C₁₅Aralkyl groups or C₆-C₁₅Aryl groups, and with a metal compound of the general formula M (L²)₂ or M (L²)₂(L¹)_e.g., where the variables are defined as follows:<dl id="dl0001"><dt>M</dt><dd>a transition metal from Groups 7 to 10 of the Periodic Table of the Elements;</dd><dt>L¹</dt><dd>Phosphines (R⁵)_xPH_3-x or amines (R⁵)_xNH_3-x with the same or different radicals R⁵, Ether (R⁵)₂O, H₂O, alcohols (R⁵) OH, pyridine, pyridine derivatives of the formula C.₅H_5-x(R⁵)_xN, CO, C₁-C₁₂Alkyl nitriles, C₆-C₁₄Aryl nitriles or ethylenically unsaturated double bond systems, where x is an integer from 0 to 3,</dd><dt>R⁵</dt><dd>Hydrogen, C₁-C₂₀-Alkylgruppen, which in turn with O (C₁-C₆-Alkyl) or N (C₁-C₆-Alkyl)₂Groups can be substituted, C₃-C₁₂Cycloalkyl groups, C₇-C₁₃Aralkyl radicals and C₆-C₁₄Aryl groups,</dd><dt>L²</dt><dd>Halide ions R⁶_xNH_3-x, where x is an integer from 0 to 3 and R⁶C.₁-C₁₂-Alkyl means, and furthermore C₁-C₆Alkyl anions, allyl anions, benzyl anions or aryl anions, where L¹ and L² can be linked together by one or more covalent bonds,</dd><dt>e.g.</dt><dd>a number from 0 to 4,</dd></dl>and immediate use of the reaction product for the polymerization or copolymerization of olefins in water or in a solvent mixture which contains at least 50% by volume of water, in the presence of an emulsifier and optionally in the presence of an activator.

0002The complex formed in situ is not isolated or cleaned.

0003An activator such as, for example, olefin complexes of rhodium or nickel is optionally used for the process according to the invention.

0004Aqueous dispersions of polymers are used commercially in numerous very different applications. Examples include paper applications (coating and surface sizing), raw materials for paints and varnishes, raw materials for adhesives (including pressure sensitive adhesives), textile and leather applications, in construction chemistry, molded foams (mattresses, carpet backing coatings) and for medical and pharmaceutical products, for example as binders for preparations. A summary can be found in <nplcit id="ncit0001" npl-type="b"><text>D. Distler (Editor) "Aqueous polymer dispersions", Wiley-VCH Verlag, 1st edition, 1999</text></nplcit>.

0005Until now, it has been difficult to prepare aqueous dispersions of polyolefins. However, it would be desirable to be able to provide such aqueous dispersions of polyolefins because the monomers such as ethylene or propylene are very advantageous from an economic point of view.

0006The current processes for the production of such aqueous dispersions from the corresponding olefins either use free-radical high-pressure polymerization or else the production of secondary dispersions. These methods have disadvantages. The radical polymerization processes require extremely high pressures, they are limited on an industrial scale to ethylene and ethylene copolymers, and the equipment required is very expensive to purchase and maintain. Another possibility is to first polymerize ethylene in any process and then to produce a secondary dispersion, as in<patcit id="pcit0001" dnum="US5574091A"><text>US-A 5,574,091</text></patcit> described. This method is a multi-stage process and therefore very complex.

0007It is therefore desirable to polymerize 1-olefins such as ethylene or propylene under the conditions of the emulsion polymerization and to prepare the required dispersion in one step from the corresponding monomer. In addition, emulsion polymerization processes generally have the advantage that they provide polymers with high molar masses, the heat dissipation being well controlled due to the process. After all, reactions in aqueous systems are of general interest because water is a cheap and environmentally friendly solvent.

0008Processes previously described for the emulsion polymerization of 1-olefins such as ethylene or propylene are still to be improved. The problem generally lies in the catalyst required to polymerize these monomers.

0009With electrophilic transition metal compounds such as TiCl₄ (Ziegler-Natta catalyst) or metallocenes, olefins can be polymerized, as described, for example, by H.-H. Brintzinger et al. in Angew. Chem., Int. Ed. Engl. 1995, 34, 1143. However, both TiCl₄ as well as metallocenes are sensitive to moisture and are therefore not very suitable for the production of polyolefins in emulsion polymerization. The aluminum alkyls used as cocatalysts are also sensitive to moisture, so water must be carefully excluded as a catalyst poison.

0010There are few reports of transition metal catalyzed reactions of ethylene in an aqueous environment. So report<nplcit id="ncit0002" npl-type="s"><text>L. Wang et al. in J. Am. Chem. Soc. 1993, 115, 6999</text></nplcit> via a rhodium-catalyzed polymerization. At around one insertion / hour, however, the activity is far too low for technical applications.

0011The reaction of ethylene with nickel-P, O-chelate complexes appears much more promising, as is the case in the US documents <patcit id="pcit0002" dnum="US3635937A"><text>US-A 3,635,937</text></patcit> and <patcit id="pcit0003" dnum="US3686159A"><text>US-A 3,686,159</text></patcit> is described. Nothing is reported about the polymer analytical data. The reported activity for technical applications is still too low.

0012In <patcit id="pcit0004" dnum="EP0046331A"><text>EP-A 0 046 331</text></patcit> and <patcit id="pcit0005" dnum="EP0046328A"><text>EP-A 0 046 328</text></patcit> reports on the reaction of ethylene with Ni chelate complexes of the general formula A.<chemistry id="chem0003" num="0003"><img file="EP1527103B1_D0003.tif" /></chemistry>where R is the same or different organic substituents, one of which carries a sulfonyl group, and F is phosphorus, arsenic or nitrogen. Under the selected reaction conditions in solvents such as methanol or mixtures of methanol and a hydrocarbon, only oligomers were obtained which are unsuitable for the above-mentioned applications.

0013In <patcit id="pcit0006" dnum="US4698403A"><text>US-A 4,698,403</text></patcit> (Column 7, lines 13-18) and in <patcit id="pcit0007" dnum="US4716205A"><text>US-A 4,716,205</text></patcit> (Column 6, lines 59-64) it is shown that an excess of water over bidentate Ni chelate complexes acts as a catalyst poison, even if it is an SO₃^--Carry group.

0014It can be seen from the documents cited above that numerous Ni complexes are not polymerization-active in the presence of water.

0015On the other hand it is over <patcit id="pcit0008" dnum="WO9717380A"><text>WO 97/17380</text></patcit> known that palladium compounds of formula B,<chemistry id="chem0004" num="0004"><img file="EP1527103B1_D0004.tif" /></chemistry>Et = C₂H₅, Ph = phenyl in which R 'is, for example, isopropyl groups, or the analog nickel compounds can polymerize higher olefins such as 1-octene in an aqueous environment. Optionally, an emulsifier can be added to facilitate polymerization. However, it should be noted that the temperature should not exceed 40 ° C, otherwise the catalytic converter will be deactivated (p. 25, line 5 ff). However, higher reaction temperatures are generally desirable because this can increase the activity of a catalyst system. Another disadvantage of catalyst systems of the general formula B is that generally highly branched polymers are formed with ethylene (<nplcit id="ncit0003" npl-type="s"><text>LK Johnson J. Am. Chem. Soc. 1995, 117, 6414</text></nplcit>), which have so far been of less technical importance, and so-called "chain running" of the active complexes has to be observed with higher α-olefins. "Chain running" leads to a large number of 1, ω misinserts, and as a result, amorphous polymers are generally produced which are not very suitable as materials.

0016It is also known that complexes of the general formula C<chemistry id="chem0005" num="0005"><img file="EP1527103B1_D0005.tif" /></chemistry> (<patcit id="pcit0009" dnum="WO9842665A"><text>WO 98/42665</text></patcit>) with M = Ni or Pd and n neutral ligands L are polymerization-active in the presence of small amounts of water without the catalytic activity suffering (page 16, line 13). However, these amounts of water must not exceed 100 equivalents, based on the complex (page 16, lines 30-31). However, emulsion polymerization cannot be carried out under these conditions.

0017In addition, it is disclosed that complexes of the general formula D<chemistry id="chem0006" num="0006"><img file="EP1527103B1_D0006.tif" /></chemistry>with the same or different radicals R are able to polymerize ethylene in the presence of small amounts of water (<patcit id="pcit0010" dnum="WO9842664A"><text>WO 98/42664</text></patcit>, in particular page 17, line 14 ff). However, these amounts of water must not exceed 100 equivalents, based on the complex (page 17, lines 33-35). However, emulsion polymerization cannot be carried out under these conditions.

0018The production of aqueous dispersions using transition metal catalysts is also used in the <patcit id="pcit0011" dnum="EP1110977A"><text>EP-A 1110977</text></patcit> and <patcit id="pcit0012" dnum="WO0144325A"><text>where 01/44325</text></patcit> described.

0019Furthermore, in the two publications <patcit id="pcit0013" dnum="DE2923206A"><text>DE-A 2923206</text></patcit> and <patcit id="pcit0014" dnum="DE3345785A"><text>DE-A 3345785</text></patcit> Processes for the production of polyethylene each described, so-called in situ catalysts consisting of a nickel compound and a mixture of a quinoid compound and a tert. Phosphine can be used. However, it is not known from both documents that aqueous dispersions which contain polyethylene can also be produced therewith.

0020Because of the great commercial importance of polyolefins, the search for improved polymerization processes continues to be of great importance.

0021The object was therefore to provide an improved method which<ul id="ul0002" list-style="dash" compact="compact"><li>Polymerized olefins to polyolefins in the presence of large amounts of water,</li><li>delivers as few branched materials as possible with high molecular weights, and</li><li>allows this reaction to be carried out under technically reasonable conditions.</li></ul>

0022It has now been found that this problem is solved by the method defined at the outset.

0023Suitable olefins for polymerization are: ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene and 1-eicosen, but also branched olefins such as 4-methyl-1 -Pentene, vinylcyclohexene and vinylcyclohexane as well as styrene, para-methylstyrene and para-vinylpyridine, with ethylene and propylene being preferred. Ethylene is particularly preferred.

0024The copolymerization of two olefins is also possible with the process according to the invention, the comonomer being able to be selected from the following groups:<ul id="ul0003" list-style="dash" compact="compact"><li>1-olefins such as ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene and 1-eicosen, but also branched olefins such as 4-methyl-1-pentene, vinylcyclohexene and vinylcyclohexane and styrene, para-methylstyrene and para-vinylpyridine, with propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene being preferred;</li><li>internal olefins such as norbornene, norbornadiene or cis or trans-2-butene;</li><li>polar monomers such as acrylic acid, acrylic acid-C₁-C₈-alkyl ester, 2-hydroxyethyl acrylate, 3-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, methacrylic acid, methacrylic acid-C₁-C₈alkyl ester, C₁-C₆-Alkyl vinyl ether and vinyl acetate; preferred are acrylic acid, methyl acrylate, ethyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, ethyl vinyl ether and vinyl acetate.</li></ul>

0025The ratio of the two monomers can be chosen freely. However, it is preferred that the comonomer is used in proportions of 0.1 to 20 mol%, based on the main monomer. The radicals in the ligands of the general formulas I a and I b are defined as follows:<ul id="ul0004" list-style="none" compact="compact"><li>R is selected from one or more of the following radicals:<ul id="ul0005" list-style="dash"><li>hydrogen</li><li>Halogens, ie atoms of fluorine, chlorine, bromine, iodine, with fluorine, chlorine and bromine being preferred</li><li>Nitrile</li><li>C.₁-C₁₂-Alkyl groups such as methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, sec.-butyl, tert.-butyl, n-pentyl, iso-pentyl. sec.-pentyl, neo-pentyl, 1,2-dimethylpropyl, iso-amyl, n-hexyl, iso-hexyl, sec.-hexyl, n-heptyl, iso-heptyl, n-octyl, n-nonyl, n- Decyl and n-dodecyl; preferably C₁-C₆Alkyl such as methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, sec.-butyl, tert.-butyl, n-pentyl, iso-pentyl, sec.-pentyl, neo-pentyl, 1,2-dimethylpropyl, iso-amyl, n-hexyl, iso-hexyl, sec.-hexyl, particularly preferably C₁-C₄-Alkyl such as methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, sec-butyl and tert-butyl.</li><li>C.₁-C₁₂Alkoxy groups such as those for C₁-C₁₂Examples of alkyl groups listed, each provided with an oxygen atom at the end of the group (for example methoxy, ethoxy, n-propyloxy, iso-propyloxy, n-butyloxy)</li><li>C.₇-C₁₃Aralkyl groups such as C₇- to C₁₂-Phenylalkyl such as benzyl, 1-phenethyl, 2-phenethyl, 1-phenyl-propyl, 2-phenyl-propyl, 3-phenyl-propyl, neophyl (1-methyl-1-phenylethyl), 1-phenyl-butyl, 2- Phenyl-butyl, 3-phenyl-butyl and 4-phenyl-butyl, particularly preferably benzyl;</li><li>C.₆-C₁₄Aryl groups such as phenyl, 1-naphthyl, 2-naphthyl, 1-anthryl, 2-anthryl, 9-anthryl, 1-phenanthryl, 2-phenanthryl, 3-phenanthryl, 4-phenanthryl and 9-phenanthryl, preferably phenyl, 1-naphthyl and 2-naphthyl, particularly preferably phenyl.</li><li>Amino groups NO¹R², where R¹ and R² together or separately represent hydrogen, C₁-C₁₂-Alkyl groups, C₇-C₁₃Alkyl residues and C₆-C₁₄Aryl groups (each as defined above) and can also form a saturated or unsaturated 5- to 10-membered ring, preferred are the dimethylamino, the diethylamino, the diisopropylamino, the methylphenylamino group and the dimethylamino group. Examples of amino groups with saturated rings are the N-piperidyl group and the N-pyrrolidinyl group; Examples of amino groups with unsaturated rings are N-pyrryl group, the N-indolyl group and the N-carbazolyl group.</li></ul></li></ul>

0026The above radicals C₁-C₁₂-Alkyl groups, C₁-C₁₂Alkoxy groups, C₇-C₁₃Aralkyl groups, C₆-C₁₄Aryl groups and amino groups NO¹R² can each be unsubstituted on the quinoid backbone of the formulas Ia and Ib. You can also have one or more of the following substituents on your own molecular structure:<ul id="ul0006" list-style="dash"><li>Halogens</li><li>C.₁-C₁₂-Alkyl groups, C₁-C₁₂Alkoxy groups, amino groups with hydrogen and / or C.₁-C₁₂Alkyl groups as defined above in each case;</li><li>C.₃-C₁₂Cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, cycloundecyl and cyclododecyl; cyclopentyl, cyclohexyl and cycloheptyl are preferred;</li><li>C.₁-C₁₂-Thioether groups such as methyl mercaptyl, ethyl mercaptyl, n-propyl mercaptyl, iso-propyl mercaptyl, n-butyl mercaptyl, iso-butyl mercaptyl, tert-butyl mercaptyl, n-pentyl mercaptyl, iso-pentyl mercaptyl, neopentyl mercaptyl, n-hexyl mercaptyl;</li><li>Carboxyl groups optionally also in the form of their salts, preferably their alkali salts, in particular in the form of their lithium, sodium or potassium salts and their ammonium salts</li><li>Sulphone groups such as, if appropriate, also in the form of their salts, preferably their alkali metal salts, in particular in the form of their lithium, sodium or potassium salts and their ammonium salts.</li></ul>

0027Furthermore, it is also possible to use compounds of the general formulas Ia and Ib which are characterized by one or more C.₁-C₁₂Alkylene bridges, in particular by one or more C₂-C₁₀Alkylene bridges, particularly preferably by one or more C₃-C₈-Alkylene bridges, through one or more C₂-C₁₂alkylated azo bridges, in particular by one or more C.₄-C₁₀alkylated azo bridges are bridged together.

0028In addition, the same or different compounds of the general formulas Ia and Ib can also by bridges of the general formula II<chemistry id="chem0007" num="0007"><img file="EP1527103B1_D0007.tif" /></chemistry>where Y is silicon or germanium and R³ and R⁴ is hydrogen and / or C.₁-C₁₂-Alkyl bridged. Silicon-based bridges are preferably used for this.

0029Selected ligands of the general formula Ia, which are very particularly suitable, are below as formulas Ia₁ to Ia₁₇ pictured:<chemistry id="chem0008" num="0008"><img file="EP1527103B1_D0008.tif" /></chemistry><chemistry id="chem0009" num="0009"><img file="EP1527103B1_D0009.tif" /></chemistry><chemistry id="chem0010" num="0010"><img file="EP1527103B1_D0010.tif" /></chemistry><chemistry id="chem0011" num="0011"><img file="EP1527103B1_D0011.tif" /></chemistry><chemistry id="chem0012" num="0012"><img file="EP1527103B1_D0012.tif" /></chemistry><chemistry id="chem0013" num="0013"><img file="EP1527103B1_D0013.tif" /></chemistry><chemistry id="chem0014" num="0014"><img file="EP1527103B1_D0014.tif" /></chemistry>

0030Particularly suitable ligands which consist of several bridged compounds of the general formula Ia are shown below as formulas Ia_I. and Ia_II pictured.<chemistry id="chem0015" num="0015"><img file="EP1527103B1_D0015.tif" /></chemistry>

0031The synthesis of the ligands of the general formulas Ia and Ib is known per se. Synthesis instructions for such ligands can be found, inter alia, in<patcit id="pcit0015" dnum="DE2923206A"><text>DE-A 2923206</text></patcit>, of the <patcit id="pcit0016" dnum="EP046331A"><text>EP-A 046331</text></patcit>, of the <patcit id="pcit0017" dnum="EP046328A"><text>EP-A 046328</text></patcit> and the <patcit id="pcit0018" dnum="EP052929A"><text>EP-A 052929</text></patcit>.

0032The ligands Ia and Ib can be used in mixtures in ratios of 0: 100 to 100: 0 mol%. Preferred embodiments are 0: 100 mol%, 10: 90 mol%, 50: 50 mol%, 90: 10 mol% and 100: 0 mol%.

0033The ligands of the general formula Ia and Ib are PR with a phosphine compound₃'combined, where R' is hydrogen, C₁-C₁₂-Alkyl groups, C₄-C₁₂Cycloalkyl groups, C₇-C₁₅Aralkyl groups or C₆-C₁₅-Aryl groups means.

0034With regard to examples of particularly preferred substituents, we refer to our explanations for the radical R of the general formulas Ia and Ib.

0035Triphenylphosphine is used as a particularly preferred phosphine compound.

0036Instead of the phosphine compound PR₃'can also the diphosphine compound R₂'PG-PR₂'are used, where R' has the same meaning as for the phosphine compounds PR₃'and G for C₁-C₁₂-Alkyl groups, C₄-C₁₂Cycloalkyl groups, C₇-C₁₅Aralkyl groups or C₆-C₁₅Aryl groups.

0037Such phosphine compounds can be prepared by conventional syntheses in organic chemistry and are also commercially available.

0038The ligands of the general formula Ia to Ib are in addition to the phosphine compound also with one or more metal compounds of the formula M (L²)₂ or M (L²)₂(L¹)₂ united. The variables are defined as follows:<dl id="dl0002"><dt>L¹</dt><dd>is selected from phosphines of the formula (R⁵)_xPH_3-x or amines of the formula (R⁵)_xNH_3-x, where x is an integer between 0 and 3. But also ether (R⁵)₂O such as diethyl ether or tetrahydrofuran, H₂O, alcohols (R⁵) OH such as methanol or ethanol, pyridine, pyridine derivatives of the formula C.₅H_5-x(R⁵)_xN, such as, for example, 2-picoline, 3-picoline, 4-picoline, 2,3-lutidine, 2,4-lutidine, 2,5-lutidine, 2,6-lutidine or 3,5-lutidine, CO, C₁-C₁₂-Alkyl nitriles or C₆-C₁₄Aryl nitriles are suitable, such as acetonitrile, propionitrile, butyronitrile or benzonitrile. Furthermore, single or multiple ethylenically unsaturated double bond systems can serve as ligand, such as ethenyl, propenyl, cis-2-butenyl, trans-2-butenyl, cyclohexenyl or norbornanyl.</dd><dt>R⁵</dt><dd>is selected from hydrogen, C₁-C₂₀-Alkylgruppen, which in turn with O (C₁-C₆-Alkyl) or N (C₁-C₆-Alkyl)₂Groups can be substituted, C₃-C₁₂Cycloalkyl groups, C₇-C₁₃Aralkyl radicals and C₆-C₁₄Aryl groups, specific examples of these groups being found in the definition of the radical R.</dd><dt>L²</dt><dd>is selected from - halide ions such as fluoride, chloride, bromide or iodide, preference is given to chloride and bromide, - amines (R⁵)_xNH_3-x, where x is an integer between 0 and 3 and R is for C₁-C₁₂-Alkyl stands, - C₁-C₆-Alkyl anions such as Me-, (C₂H₅) -, (C₃H₇) -, (nC₄H₉) -, (tert.-C₄H₉) - or (C₆H₁₄); - allyl anions or methallyl anions, - benzyl anions or - aryl anions such as (C₆H₅) -; M is a transition metal from Groups 7 to 10 of the Periodic Table of the Elements; manganese, iron, cobalt, nickel or palladium are preferred and nickel is particularly preferred.</dd><dt>e.g.</dt><dd>is an integer from 0 to 4.</dd></dl>

0039In a particular embodiment, L¹ and L² linked together by one or more covalent bonds. Examples of such ligands are 1,5-cyclooctadienyl ligands ("COD"), 1,6-cyclodecenyl ligands or 1,5,9-all-trans-cyclododecatrienyl ligands.

0040In another special version, L¹ Tetramethylethylenediamine.

0041Very particularly preferred metal compounds are Ni (COD)₂ and Ni (CH₃)₂(TMEDA).

0042The conditions for reacting the ligand (s) of the formula Ia and Ib with the metal compound and the phosphine compound are not critical per se. Usually they are reacted at a temperature of 0 to 100 ° C in a solvent which can be selected from aliphatic or aromatic hydrocarbons such as n-heptane, toluene, ethylbenzene, ortho-xylene, meta-xylene or para-xylene. Chlorobenzene is also suitable as a solvent, as are ketones such as acetone, noncyclic or cyclic ethers such as diethyl ether, diisopropyl ether, 1,4-dioxane or tetrahydrofuran, water or alcohols such as methanol or ethanol. Ratios of 1: 1000 to 1000: 1 have proven to be the molar ratio of metal compound to phosphine compound, preferably 1:10 to 10: 1 and particularly preferably 1: 2 to 2: 1. The molar ratio of the ligand (s) Ia or Ib to the phosphine compound is likewise 1: 1000 to 1000: 1, preferably 1:10 to 10: 1, in particular 1: 2 to 2: 1.

0043It is possible to react the metal compound with the selected organic ligand and the phosphine compound outside the polymerization reactor and then to add the reaction solution to the polymerization reactor.

0044The reaction of metal compound, phosphine compound and ligand can also take place within the polymerization reactor, although it can be advantageous to add other substances such as further solvents, monomers to be polymerized and other auxiliaries such as activators or emulsifiers.

0045The choice of reaction conditions depends on the substances used. Particularly in the case of water-sensitive precursors, it has proven to be advantageous first to react the precursors outside the polymerization reactor and then to meter the reaction product into the polymerization reactor.

0046This procedure is also advantageous if the precursors do not completely dissolve in the solvent used, but the reaction product does.

0047The complexes formed in situ are not isolated and cleaned.

0048The complexes generated in situ are particularly suitable for use in the polymerization or copolymerization of olefins in water or in a solvent mixture which contains at least 50% by volume of water. The polymerization is optionally carried out in the presence of an activator and optionally in the presence of an emulsifier.

0049In addition, it is advisable to use an activator to increase the activity. The activator can be olefin complexes of rhodium or nickel.

0050Preferred nickel (olefin) commercially available from Aldrich_yComplexes are Ni (C₂H₄)₃, Ni (1,5-cyclooctadiene)₂ "Ni (COD)₂", Ni (1,6-cyclodecadiene)₂, or Ni (1,5,9-all-trans-cyclododecatriene)₂. Ni (COD) is particularly preferred₂.

0051Mixed ethylene / 1,3-dicarbonyl complexes of rhodium, for example rhodium acetylacetonate-ethylene Rh (acac) (CH₂= CH₂)₂, Rhodium Benzoylacetonate Ethylene Rh (C₆H₅-CO-CH-CO-CH₃) (CH₂= CH₂)₂ or Rh (C₆H₅-CO-CH-CO-C₆H₅) (CH₂= CH₂)₂. Rh (acac) (CH₂= CH₂)₂. This connection can be made according to the recipe by R. Cramer from Inorg. Synth. 1974, 15, 14 synthesize.

0052In some cases, activation by ethylene is successful. The ease of the activation reaction depends crucially on the nature of the ligand L.¹ from. It could be shown that in the event that L¹ for example a tetramethylethylenediamine ligand, no activator is required.

0053The polymerization of the 1-olefins by the process according to the invention can be carried out in a manner known per se.

0054The order in which the reagents are added during the polymerization is not critical. For example, gaseous monomer can first be pressed onto the solvent or liquid monomer can be metered in, and then the mixture of ligand, phosphine compound and metal compound is added. However, the mixture of ligand, phosphine compound and metal compound can also first be diluted with further solvent and then monomer added.

0055At the same time, if necessary, the activator is dissolved in a second portion of the same solvent or in acetone.

0056The actual polymerization usually takes place at a minimum pressure of 1 bar, below this pressure the polymerization rate is too slow. 2 bar are preferred and a minimum pressure of 10 bar is particularly preferred.

0057The maximum pressure is 4000 bar; at higher pressures, the demands on the material of the polymerization reactor are very high and the process becomes uneconomical. 100 bar are preferred and 50 bar are particularly preferred.

0058The polymerization temperature can be varied within a wide range. The minimum temperature to be mentioned is 10 ° C, since the rate of polymerization decreases at low temperatures. A minimum temperature of 40 ° C. is preferred and 65 ° C. is particularly preferred. The maximum sensible temperature is 350 ° C. and preferably 150 ° C., particularly preferably 100 ° C. Aromatic solvents such as benzene, toluene, ethylbenzene, ortho-xylene, meta-xylene and para-xylene and mixtures thereof are suitable as organic solvents. Cyclic ethers such as tetrahydrofuran and dioxane or acyclic ethers such as diethyl ether, di-<i>n</i>-butyl ether, di-isopropyl ether or 1,2-dimethoxyethane. Ketones such as acetone, methyl ethyl ketone or diisobutyl ketone are also suitable, as are amides such as dimethylformamide or dimethylacetamide. Mixtures of these solvents with one another are also suitable, as are mixtures of these solvents with water or alcohols such as methanol or ethanol.

0059Acetone and water and mixtures of acetone and water are preferred, the mixing ratio being arbitrary.

0060The amount of solvent is also not critical, but it must be ensured that the complex formed in situ and the activator can dissolve completely, otherwise loss of activity can be expected. If necessary, the dissolving process can be accelerated by ultrasound treatment.

0061The emulsifier, which is also to be added, can be dissolved in a third portion of the solvent or together with the ligand or the metal compound.

0062The amount of emulsifier is chosen so that the mass ratio between monomer and emulsifier is greater than 1, preferably greater than 10 and particularly preferably greater than 20. The less emulsifier that has to be used, the cheaper.

0063The ligands of the formula Ia and Ib can act as emulsifiers. However, the activity in the polymerization is significantly increased if an additional emulsifier is added. This emulsifier can be non-ionic or ionic in nature.

0064Common nonionic emulsifiers are, for example, ethoxylated mono-, di- and tri-alkylphenols (EO degree: 3 to 50, alkyl radical: C₄-C₁₂) and ethoxylated fatty alcohols (EO grade: 3 to 80; alkyl radical: C₈-C₃₆). Examples of this are the Lutensol^®Brands of BASF AG or Triton^®Brands of Union Carbide.

0065Typical anionic emulsifiers are, for example, alkali metal and ammonium salts of alkyl sulfates (alkyl radical: C₈ to C₁₂), of sulfuric acid half-esters of ethoxylated alkanols (EO grade: 4 to 30, alkyl residue: C₁₂-C₁₈) and ethoxylated alkylphenols (EO grade: 3 to 50, alkyl radical: C₄-C₁₂), of alkyl sulfonic acids (alkyl radical: C₁₂-C₁₈) and of alkylarylsulfonic acids (alkyl radical: C₉-C₁₈).

0066Suitable cationic emulsifiers are usually a C.₆-C₁₈Alkyl, aralkyl or heterocyclic radical having primary, secondary, tertiary or quaternary ammonium salts, alkanolammonium salts, pyridinium salts, imidazolinium salts, oxazolinium salts, morpholinium salts, thiazolinium salts and salts of amine oxides, quinolinium salts, isoquinonium salts and sulfonium salts. Examples include dodecylammonium acetate or the corresponding hydrochloride, the chlorides or acetates of the various 2- (N, N, N-trimethylammonium) ethyl paraffinic acid esters, N-cetylpyridinium chloride, N-laurylpyridinium sulfate and N-cetyl-N, N, N-trimethylammonium bromide, N- Dodecyl-N, N, N-trimethylammonium bromide, N, N-distearyl-N, N-dimethylammonium chloride and the gemini surfactant N, N '- (lauryldimethyl) ethylenediamine dibromide. Numerous other examples can be found in<nplcit id="ncit0004" npl-type="b"><text>H. Stache, Tensid-Taschenbuch, Carl-Hanser-Verlag, Munich, Vienna, 1981</text></nplcit> and in <nplcit id="ncit0005" npl-type="b"><text>McCutcheon's, Emulsifiers &amp; Detergents, MC Publishing Company, Glen Rock, 1989</text></nplcit>.

0067Stirred vessels and autoclaves and tubular reactors have proven to be useful as the polymerization reactor, and the tubular reactors can be designed as a loop reactor.

0068The monomer or monomers to be polymerized are mixed in the polymerization medium. Water or mixtures of water with the solvents listed above can be used as the polymerization medium. It should be noted that the proportion of water is at least 50% by volume, based on the total mixture, preferably at least 90% by volume and particularly preferably at least 95% by volume.

0069The solutions of the complex generated in situ, optionally the activator and optionally the emulsifier, are combined with the mixture of monomer and aqueous polymerization medium. The order in which the various components are added is in itself not critical. However, it is necessary for the components to be combined so quickly that there is no crystallization of difficultly soluble complex compounds which may occur as intermediates.

0070In principle, continuous and discontinuous processes are suitable as the polymerization process. Preference is given to semi-batch processes (semi-batch processes) in which, after all the components have been mixed, monomer or monomer mixtures are subsequently metered in during the polymerization.

0071Aqueous polymer dispersions are initially obtained by the process according to the invention.

0072The average particle diameters of the polymer particles in the dispersions produced according to the invention are between 10 and 1000 nm, preferably between 50 and 500 nm and particularly preferably between 70 and 350 nm. The distribution of the particle diameters can, but need not, be very uniform. For some applications, especially those with high solids (> 55%), broad or bimodal distributions are even preferred.

0073The aqueous dispersions prepared according to the invention can also be in the form of a mini emulsion, which means that the emulsified particles have a particle diameter of from 50 nm to 150 nm, in particular from 70 nm to 100 nm. To produce such a miniemulsion, the emulsified particles are subjected to strong shear. Such high shear can be achieved, among other things, by high pressure homogenization, by ultrasound or by jet dispersers. Ultrasound is preferred.

0074The polymers obtained by the process according to the invention have technically interesting properties. In the case of polyethylene, they can have a high degree of crystallinity, which can be demonstrated, for example, by the number of branches. Often less than 40 branches are found, preferably less than 20 branches per 1000 carbon atoms of the polymer and particularly preferably less than 10 branches, determined by¹H-NMR and ¹³C-NMR spectroscopy.

0075The molecular weight distributions of the polyolefins obtainable by the process according to the invention, ie the Q values ​​are between 1.0 and 50 and preferably between 1.5 and 10. The molecular weights of the polyolefins obtained are in the range from 1000 to 1,000,000, in particular in the range from 100,000 to 3,000 (Means of payment). &lt;

0076> An advantage of the dispersions prepared according to the invention, in addition to the low price due to the cheap monomers and processes, is that they are more weather-resistant than dispersions of polybutadiene or butadiene copolymers. Compared to dispersions of polymers with acrylates or methacrylates as the main monomer, the lower tendency to saponify is to be mentioned as advantageous. Another advantage is that most olefins are volatile and unpolymerized residual monomers can be easily removed. Finally, it is advantageous that no molecular weight regulators, such as, for example, tert-dodecyl mercaptan, have to be added during the polymerization, which on the one hand are difficult to separate, but on the other hand smell unpleasant. It is furthermore favorable that the aqueous dispersions obtained from the process according to the invention have relatively high solids contents of up to 20%.

0077The polymer particles as such can be obtained from the aqueous dispersions initially obtained by removing the water and, if appropriate, the organic solvent or solvents. Numerous common methods are suitable for removing the water and, if appropriate, the organic solvent or solvents, for example filtering, spray drying or evaporation. The polymers thus obtained have a good morphology and a high bulk density.

0078The particle size can be determined using light scattering methods. An overview can be found in<nplcit id="ncit0006" npl-type="b"><text>D. Distler (Editor) "Aqueous Polymer Dispersions", Wiley-VCH Verlag, 1st Edition, 1999, Chapter 4</text></nplcit>.

0079The dispersions prepared according to the invention can be used advantageously in numerous applications, such as paper applications such as paper coating or surface sizing, further paints and varnishes, construction chemicals, adhesive raw materials, molded foams, textile and leather applications, carpet backing coatings, mattresses or pharmaceutical applications.

0080Paper coating is the coating of the paper surface with aqueous pigmented dispersions. The dispersions prepared according to the invention are advantageous because of their low price. Surface sizing is the pigment-free application of hydrophobic substances. The polyolefin dispersions which have hitherto been difficult to access under economic conditions are particularly advantageous as a particularly hydrophobic substance. Another advantage is that during the production of the dispersions for paper coating or surface sizing according to the invention, no molecular weight regulators, such as, for example, tert-dodecyl mercaptan, have to be added, which are difficult to separate on the one hand, but smell unpleasant on the other.

0081The dispersions prepared according to the invention are particularly suitable in paints and varnishes because they are very cheap in terms of price. Aqueous polyethylene dispersions are particularly advantageous because they also have special UV stability. Furthermore, aqueous polyethylene dispersions are particularly suitable because they are resistant to basic chemicals that are common in construction chemistry.

0082In adhesives, in particular in adhesives for self-adhesive labels or foils and plasters, but also in construction adhesives or industrial adhesives, the dispersions produced according to the invention have economic advantages. They are particularly cheap in construction adhesives because they are resistant to basic chemicals that are common in construction chemicals.

0083In molded foams which can be produced from the dispersions produced according to the invention by processes known per se, such as the Dunlop process or the Talalay process, the low price of the dispersions according to the invention is again advantageous. Gelling agents, soaps, thickeners and vulcanizing pastes serve as further components. Molded foams are processed into mattresses, for example.

0084Textile and leather applications serve to preserve and finish textile or leather. Among the effects are the impregnation and the further finishing of the textiles. An advantage of the dispersions produced according to the invention as a constituent in textile and leather applications, in addition to the low price, is the absence of odors, since olefins as residual monomers can be easily removed.

0085Carpet back coatings are used to glue the carpet fibers on the back, and they also have the task of giving the carpet the necessary rigidity and evenly distributing additives such as flame retardants or antistatic agents. An advantage of the dispersions prepared according to the invention, in addition to the low price, is their insensitivity to the common additives. Polyethylene dispersions in particular have proven to be particularly inert chemically. Finally, it is advantageous that during the preparation of the dispersions for carpet backing coatings according to the invention, no molecular weight regulators, such as, for example, tert-dodecyl mercaptan, have to be added, which on the one hand are difficult to separate, but on the other hand smell unpleasant.

0086Pharmaceutical preparations are understood to mean dispersions as carriers of medicaments. Dispersions as carriers of medicines are known per se. An advantage of the dispersions produced according to the invention as carriers of medicaments is the economically favorable price and the resistance to body influences such as gastric juice or enzymes.

Working examples

0087General: Unless otherwise described, the syntheses were carried out using the Schlenk technique with exclusion of air and moisture.

0088The molecular weights of the polymers obtained were determined by GPC.

0089The following conditions were selected based on DIN 55672: solvent 1,2,4-trichlorobenzene, flow: 1 ml / min; Temperature 140 ° C. It was measured on a Waters 150C device that had been calibrated with polyethylene standards.

0090The solids content was determined by precipitating the polyethylene with methanol.

example 1

(starting from 2,3,5,6-tetrachloro-p-benzoquinone)

009164 mg (258 µmol) 2,3,5,6-tetrachloro-p-benzoquinone and 68 mg (258 µmol) triphenylphosphine were added in 1 ml methanol (dried and degassed), 4 ml toluene (dried and degassed) and 0.3 ml Hexadecane (degassed) solved. The solution thus obtained was stirred for 20 minutes, during which it turned orange. The solution was then placed in another Schlenck flask containing 79 mg (287 µmol; 1.11 eq) nickel (cyclooctadiene)₂ [Ni (cod)₂] contained.

0092In the meantime, a solution of 1 g sodium dodecyl sulfate [SDS] in 95 ml degassed and deionized water was prepared. 75 ml of this aqueous solution was added directly to the reactor, the other 20 ml were added to the catalyst mixture and subjected to ultrasound treatment (120 W, 2 minutes). The miniemulsion thus obtained was then added to the reactor using a Teflon cannula.

0093The reactor was then filled with ethylene, a constant ethylene pressure of 40 bar being set, and at the same time the interior of the reactor was heated to 70 ° C. with stirring (1000 rpm). After a reaction time of 2 hours, the polymerization was terminated by cooling and relaxing the ethylene.

0094The aqueous latex obtained had a solids content of 18% (determined by precipitation of 7.1 g of polyethylene with 40 ml of methanol from the latex). The polyethylene obtained had a molecular weight (number average) of 6200, the weight average was about 18000.

Example 2

(starting from 2,3,5,6-tetrachloro-p-benzoquinone)

009564 mg (258 µmol) 2,3,5,6-tetrachloro-p-benzoquinone and 68 mg (258 µmol) triphenylphosphine were added in 1 ml methanol (dried and degassed), 4 ml toluene (dried and degassed) and 0.3 ml Hexadecane (degassed) solved. The solution thus obtained was stirred for 20 minutes, during which it turned orange. The solution was then placed in another Schlenck flask containing 79 mg (287 µmol; 1.11 eq) nickel (cyclooctadiene)₂ [Ni (cod)₂] contained.

0096In the meantime, a solution of 1 g SDS in 95 ml degassed and deionized water was prepared. 75 ml of this aqueous solution was added directly to the reactor, the other 20 ml were added to the catalyst mixture and subjected to ultrasound treatment (120 W, 2 minutes). The miniemulsion thus obtained was then added to the reactor using a Teflon cannula.

0097The reactor was then filled with but-1-ene, a constant but-1-end pressure of 10 bar being set, and at the same time the interior of the reactor was heated to 70 ° C. with stirring (1000 rpm). After 30 minutes, the but-1-ene was replaced by ethylene, which was under a constant pressure of 40 bar.

0098After a further reaction time of 1.5 hours, the polymerization was terminated by cooling and relaxing the ethylene.

0099The aqueous latex obtained had a solids content of 8% (determined by precipitation of 13.01 g of the copolymer of ethylene and but-1-ene with methanol from the latex).

Example 3

(starting from 2,3,5,6-tetrabromo-p-benzoquinone)

010064 mg (258 µmol) 2,3,5,6-tetrabromo-p-benzoquinone and 68 mg (258 µmol) triphenylphosphine were added in 1 ml methanol (dried and degassed), 4 ml toluene (dried and degassed) and 0.3 ml Hexadecane (degassed) solved. The solution thus obtained was stirred for 20 minutes, during which it turned orange. The solution was then placed in another Schlenck flask containing 79 mg (267 µmol; 1.11 eq) Ni (cod)₂ contained.

0101In the meantime, a solution of 1 g SDS in 95 ml degassed and deionized water was prepared. 75 ml of this aqueous solution was added directly to the reactor, the other 20 ml were added to the catalyst mixture and subjected to ultrasound treatment (120 W; 2 minutes). The miniemulsion thus obtained was then added to the reactor using a Teflon cannula.

0102The reactor was then filled with ethylene, a constant ethylene pressure of 40 bar being set. and at the same time the inside of the reactor was heated to 40 ° C. with stirring (1000 rpm). After a reaction time of 2 hours, the polymerization was terminated by cooling and relaxing the ethylene.

0103The aqueous latex obtained had a solids content of 9% (determined by precipitation of 3.4 g of polyethylene with 40 ml of methanol from the latex).