Polymer composition on the basis of polyolefins
(57) Abstract:Use thermovalve films. The inventive composition comprises, %: linear low density polyethylene (LLDPE) - 30 - 60, a crystalline copolymer of propylene with an alpha olefin 40 - 70. LLDPE has a melt index of 0.1 to 15 g / 10 minutes of the Second component of the composition is a copolymer of propylene with 8 - 20% of alpha-olefin selected from the group comprising ethylene, C4- C8-alpha-olefin or a mixture. Composition imanet a temperature of the welding 85 - 110oC. Composition obtained by copolymerization of alpha-olefins in the presence of a catalyst containing a compound of titanium on the active dihalogenide magnesium and alkylamine when the atomic ratio of aluminum: titanium from 1 to 1000. The process carried out at least in two stages: the 1st will copolymerize ethylene with C3- C12-alpha-olefin, and later on in the presence of the obtained polymer and catalyst for the copolymerization of propylene with C4- C8-alpha-olefin. 2 C. and 8 C.p. f-crystals, 3 tables. The present invention relates to compositions based on polyolefins suitable for receiving thermovalve films.Know the use of crystalline Mi olefin polymers, especially copolymers of 1-butylene, as materials having the ability to welding. These crystalline propylene copolymers produced by polymerization of propylene with small quantities of olefin comonomers in the presence of a stereospecific catalyst. The comonomers are statically distributed with the formed polymer and the melting point of this polymer is lower than the melting point of the crystalline propylene homopolymers.However, the introduction of comonomers in the polymer causes partial destruction of the crystalline structure, which includes the formation of relatively high amounts of the polymer fraction soluble in organic solvents, such as xylene or n-hexane. The presence of too high amounts of the above-mentioned soluble fraction is a significant disadvantage, because it makes these compositions unsuitable for some important applications, including use in the food industry. In particular, in accordance with the existing norms of the polymers used for materials associated with food, must have a content of fraction soluble in n-hexane at 50oC, not higher than 5.5 wt. and when used in prigotovlennyh compositions, which can be used, in particular, upon receipt thermovalve films with low temperature welding and low content of soluble fractions.The application for the European patent EP-A-0483523 describes the composition of the crystalline polymers of propylene containing (wt.):
A) 30-65% of a copolymer of propylene with C4-C8-olefin containing from 98 to 80% of propylene;
B) 35-70% of a copolymer of propylene with ethylene and optional C4-C8a-olefin in an amount of from 2 to 10% and the ethylene content in the copolymer is from 2 to 10% if C4-C8a-olefin is missing, and the ethylene content is from 0.5 to 5% if C4-C8a-olefin is present.These compositions have the temperature of the welding in the range of from 100 to 110oC and a content of fraction soluble in n-hexane at 50oC, less than 5.5 wt. usually about 3-5 wt%
It was unexpectedly discovered that by mixing certain amounts of linear low density polyethylene (LLDPE), having a relatively low melt index E (IRA) in accordance with ASTM-D-1238, with different types of crystalline copolymers of propylene get heat sealable polyolefin capitalthat is very unexpected, if we take into account that the achievements thus the content of soluble substances not only lower than the content of soluble substances in the crystalline copolymer (copolymer) of propylene, used (used) for songs, but significantly lower than the content of soluble substances, which can be calculated on the basis of the relative proportions of the crystalline copolymer (copolymer) of propylene and polyethylene LLDPE.In addition, the temperature of the beginning of the welding are low. They often significant and unpredictable below the temperatures at the beginning of welding crystalline copolymer (copolymer) of propylene, used (used) for composition. Therefore, the present invention provides a polyolefin composition comprising (wt.):
A) from 30 to 60%, preferably from 40 to 60% LLDPE with IRA from 0.1 to 15, preferably from 0.5 to 5;
B) from 40 to 70%, preferably from 0 to 60% of one or more crystalline copolymers of propylene with one or more comonomers selected from ethylene, C4-C8a olefins and mixtures thereof, so that the content of co monomer/comonomers (B) is from 5 to 20%, preferably from 8 to 15%
The content in the composition of this image is positive below 3 wt. When the content of LLDPE at least 40% of the value measured solubility of not more than 5.5 wt. As already mentioned, the content of soluble substances in the composition is lower than the content of soluble substances in the copolymer (copolymer) of propylene, used (used) as component (B). Temperatures start welding compositions of the present invention below 110oC, preferably not higher than 100oC, most preferably from 85 to 100oC.Under the temperature of beginning welding (THC) mean minimum temperature of welding in which the weld bead multilayer film with one layer of polypropylene and one of the compositions of the present invention is not disturbed in case of application to the film load 200, Items will be shown in the examples.As will be shown in the examples, beyond the limits defined above for the present invention, for example, using an LLDPE with a too high value of the IRA (for example in excess of the limits specified for (A), it is impossible to get a good balance of content of soluble substances and TNF. Density polyethylene LLDPE, which can be used as component (A) in the compositions of the present invention, preferably nah the hydrated polyethylene contains preferably from 3 to 20 wt. more preferably from 5 to 15% of one or more comonomers selected from C3-C12preferably C3-C8a-olefins. Examples of the above-mentioned comonomers are propylen, 1-butene, 1-penten, 1-hexene, 4-methyl-pentan and 1-octene. The preferred co monomer is 1-butene.LLDPE having the above characteristics and values of the IRA in certain higher limits are available commercially and can be obtained using the polymerization process described below.In addition to ethylene examples of preferred comonomers for the component (B) are 1-butylene, 1-penten, 1-hexene, 4-methyl-1-penten and 1-octene.Especially preferred of C4-C8a-olefin is 1-butylene.It is preferable to maintain the content of ethylene in (B) low, preferably from 0.5 to 6%, however, if (B) prepared from a mixture of a copolymer of propylene/ethylene copolymer of propylene and at least one C4-C8a-olefin, the ethylene content in the first copolymer can be high, for example, 10% Preferred components (B) are copolymers or mixtures of copolymers containing at least one C4-C8a-reprimere component (B) preferably varies from 2 to 20 wt%
Specific examples of preferred components (B) are:
copolymers of propylene with one or more C4-C8a-olefins in amounts from 5 to 20 wt%, preferably from 8 to 15%
copolymers of propylene with ethylene and one or more C4-C8a-olefins containing from 2 to 6 wt% of ethylene and from 3 to 14%, preferably from 6 to 9% above C4-C8a-olefins.Mixture (wt.):
(B1)30-65%, preferably 35 to 65%, more preferably 45 to 65% of a copolymer of propylene with C4-C8a-olefin containing from 98 to 80%, preferably from 95 to 85% of propylene,
(B2) 35 70%, preferably 35 to 65%, more preferably 35-55% of a copolymer of propylene with ethylene I. optional, C4-C8a-olefin in amounts from 2 to 10%, preferably from 3 to 6% and the content of ethylene in the copolymer is in the range from 5 to 10%, preferably from 7 to 9% when C4-C8a-olefin is missing, or 0.5 to 5%, preferably from 1 to 3% when C4-C8a-olefin is present, until the total content of comonomers in /B1/ + /B2/ not less than 5%, preferably not lower than 8%
Using the compounds (B1) + (B2) in the compositions of the present invention, the gain value THC, not one accepts isolani as component (B) in the compositions of the present invention, can be obtained by using a polymerization process based on the use of special catalysts of the Ziegler-Natta. These catalysts contain as an essential element of a solid catalytic component comprising a compound of titanium with communication titanium, halogen and an electron-donor compound, both deposited on activated magnesium halide and characterized by their ability to produce polypropylene with index isotacticity above 90%, preferably above 95%, the Catalysts with the above characteristics are well known in the patent literature. Especially suitable are catalysts described in U.S. patent N 4339054 and Heb. patent N 45977. Other examples of catalysts are described in U.S. patent N 4472524 and 4473660.Generally speaking, the solid catalyst components used in these catalysts contain as electron-donor compounds, compounds selected from ethers, ketones, lactones, compounds containing N atoms, P and/or S, and esters of mono - and dicarboxylic acids.Particularly suitable are the esters of phthalic acid, such as Diisobutyl, dioctyl and definiltely; esters of malonic acid, such as disatac diisobutylamine, ethylvinylbenzene and diphenylcarbonate, and esters salcinovic acids, such as mono - and diethylamine.Other particularly suitable electron donors are simple 1,3-diesters of the formula
< / BR>where
RI, RII-the same or different radicals, namely C1-18alkyl, C3-18cycloalkyl or C6-18aryl; RIIIor RIValso the same or different alkyl radicals with 1 to 4 carbon atoms.Ethers of this type are described in published application N 361493 on E. p. Examples representing these compounds, 2-methyl-2-isopropyl-1,3-dimethoxypropane, 2,2-Diisobutyl-1,3-dimethoxypropane and 2-isopropyl-2-cyclopentyl-1,3-dimethoxypropane.Catalytic components mentioned above, obtained using different methods.For example, the halide of magnesium (used in anhydrous form, containing less than 1% water), a compound of titanium and electron-donor compound can grind together in conditions when there is an active magnesium halide; then milled product is treated one or more times with an excess of TiCl4at a temperature of between 80 and 135oC and washed several times with a hydrocarbon (such as hexane) until the disappearance is everyt by known methods, and then enter into interaction with the excess TiCl4containing dissolved electron-donor compound. The temperature during this process also varies between 80 and 135oC. Processing TiCl4repeat (optional), then the solid is washed with hexane or other hydrocarbon solvent to remove traces of unreacted TiCl4.In the following way adduct MgCl2nROH (especially in the form of spheroidal particles), where n is usually a number from 1 to 3 and ROH ethanol, butanol or Isobutanol, enter into interaction with the excess TiCl4containing dissolved electron-donor compound. The temperature usually lies between 80 and 120oC. Then the solid is isolated and again enter into interaction with TiCl4, then separated and washed with a hydrocarbon until disappearance of the chlorine ions.In accordance with another method of the alcoholate and chloralkali magnesium (chloralkali prepared in a special way in accordance with the method described in U.S. patent N4220554) enter into interaction with the excess TiCl4containing dissolved electroni-donor compound, and the process is conducted in the conditions above.In solid kataliticheskoe electron-donor compound, which remains fixed on the solid (internal donor), usually varies from 5 to 20 mol% relative to the halide of magnesium.The titanium compounds which can be used to obtain a catalytic component, it halides and galogenangidridy. The preferred compound is titanium tetrachloride.Satisfactory results can be obtained also with trigliceride titanium, in particular TiCl3HR, TiCl3ARA and halogenoalkane, such as TiCl3OR, where R is the phenyl radical.The above reactions lead to the formation of activated magnesium halide. Besides those already mentioned, other known reactions leading to the formation of activated magnesium halide, in which the starting compound of magnesium do not use the halides and, for example, carboxylate magnesium.An activated form of magnesium halides in the solid catalytic components can be identified by the fact that in the x-ray spectrum of the catalyst component is no longer present, the maximum intensity reflection present in the spectrum of the unactivated magnesium halide ( with a specific surface area of less than 3 m2The preferred compound include magnesium halides is chloride. In the case of the most active forms of chloride Mg in the x-ray spectrum of the catalyst component is manifested halo on the place of reflection, which is present in the spectrum of non-activated chloride with 2,56 A.Alkylamine compounds that can be used as socialization include trialkyl aluminum, such as triethylaluminium, triisobutylaluminum, tri-n-butylamine, and linear or cyclic alkylamine compounds containing two or more atoms that are linked by O or N atoms or groups SO4and SO3.Examples of these are:
(C2H5)2Al-O-Al(C2H5)2< / BR>(C2H5)2Al-N-Al(C2H5)2< / BR>C6H5< / BR>(C2H5)2-Al-SO2-Al(CH)2< / BR>CH3< / BR>CH3(AlO-)nAl(CH3)2< / BR>sportsouth in such quantities, the ratio Al/Ti is from 1 to 1000.Electron-donor compounds that can be used as external donors ( in addition to alkylamino connection) include esters of aromatic acids, such as alkylbenzoates, and especially silicon compound containing at least one group Si OR/R is a hydrocarbon radical.2,2,6,6 tetramethylpiperidine and 2, 6 diisopropylamide.Examples of silicon compounds are (tert-butyl)2- Si(OCH3)2, (cyclohexyl)2Si(OCH3)2, (phenyl)2Si(OCH3)2.With success can be used as a simple 1,3-diesters having the formula described above. If the internal donor is one of these simple diesters, external donors can not be used.The polymerization process may be continuous or intermittent, flowing in known methods in the liquid phase in the presence or absence of an inert diluent, or in gas phase, or in a mixture of liquid gas. Preferably the implementation of its in the gas phase.The time and temperature of reaction at both stages are not decisive, but it is best if the temperature leih regulators, in particular hydrogen.The catalysts can be pre-entered in contact with small quantities of olefin (pre-polymerization). The preliminary polymerization improves the action of catalysts, and the morphology of the polymers.The preliminary polymerization is carried out maintaining the catalyst in suspension in a hydrocarbon solvent (such as hexane or heptane), and polymerization at a temperature from room temperature up to 60oC for a time sufficient to obtain the polymer in amounts of from half to three times the mass of the solid catalytic component. This can be carried out in liquid propylene in the temperature conditions mentioned above, obtaining the polymer in quantities that can go up to 1000 g per 1 g of the catalytic component.In cases where the catalytic component (B) is a mixture of copolymers, the mixture can be obtained directly in polymerization, preparing each copolymer on a separate sequential stages and completing each stage in the presence of polymer and catalyst of the preceding stage. For example, in the case when the component (B) is a mixture of copolymers (B1) and (B2) described above, the decree of the Le phase synthesis of the component (B) can be performed by a phase copolymerization of ethylene, so right in the synthesis of getting the component (A).In this way, the components (A) and (B) be the optimal mixture. Consequently, it is possible to obtain compositions of the present invention directly in the synthesis by a process comprising the polymerization of the monomers in the presence of stereospecific catalysts described above, and the polymerization carried out at least in two stages, receiving components (A) and (B) in different and successive stages and completing each stage in the presence of polymer and catalyst of the preceding stage. It is preferable to perform all stages of polymerization in the gas phase.Compositions of the present invention can also be obtained by mixing the components (A) and (B) synthesized separately.If the component (B) is a mixture of copolymers synthesized separately, they can be mixed with the component (A) separately or together.The mixture is prepared using known techniques, based on obtained directly in polymerization processes granules, powders or particles of polymers, which are pre-mixed in the solid state (for example by using a mixer Hensely-Lodige), and then passed through the extruder. Alternativefor, which provide a molten state all polymers, for example, at temperatures of from 170 to 250oC.The following examples illustrate but do not limit the present invention.Obtaining the component (B).1) General method of preparation of the catalyst
The solid catalytic component used in the examples was prepared as follows.In an inert atmosphere in a reactor equipped with a stirrer, enter 28.4 g MgCl2, a 49.5 g of anhydrous ethanol, 100 ml ROZOB/30 vaseline oil, 100 ml of silicone oil with a viscosity of 350, then the contents warm for up to 120oC to dissolve the MgCl2. Then the hot reaction mixture is transferred to a vessel with a capacity of 1500 ml equipped with a stirrer T-45 NUBtra Turrax, and in this vessel contains 150 ml of vaseline oil and 150 ml of silicone oil. Within 3 minutes to keep the temperature 120oC and a stirring speed of 3000 Rev/min the mixture is Then poured into a 2 liter vessel equipped with a stirrer and containing 1,000 ml of anhydrous n-heptane cooled to 0oC. the particles Obtained are separated by filtration, washed with 500 ml of n-hexane and gradually increase the temperature from 30 to 180oC in a stream of nitrogen over a period of time, Dostatok">25 g of the adduct containing a different number of moles of alcohol, specified below, is transferred into a reactor equipped with a stirrer and containing 625 ml of Ti Cl4at 0oC and stirring, bringing the temperature to 100oC for one hour when the temperature reaches 40oC add diisobutylphthalate in an amount such that the molar ratio of magnesium to phthalate was 8.The contents of the reactor are heated to 100oC for two hours under stirring, and then allowed to settle solid substance. Hot liquid is removed by means of a siphon. Add 550 ml of Ti Cl4and heat the mixture to 120oC for one hour under stirring. Stirring is stopped, the solid substance is allowed to settle, the hot liquid is removed by means of a siphon. The solid is washed 6 times with 200 ml of n-hexane, each time at 60oC, and then 3 times at room temperature.2) Polymerization.The polymerisation process is carried out continuously in the sequence of reactors equipped with a device for transferring a product from one reactor to another, directly following it.The gas phase is continuously analyzed for hydrogen and monomers are fed to maintain EA) - activator and dicyclohexylammonium electron donor in such amounts that the weight ratio of tea/silane is about 6.4 enter into contact with the solid catalytic component in the reactor at 0oC for about 15 min, so that the molar ratio of tea/Ti is equal to 80.Then the catalyst was transferred into another reactor containing an excess of liquid propylene, and conduct additional polymerization in the period from 3 to 5 minutes at a temperature in the range from 15 to 25oC.In the first and second experiments, the prepolymer is transferred into another reactor with the aim of polymerization of the monomers in the gas phase with the formation of component (B).In the third experience component (B2) are obtained in the first reactor in the gas phase, then after removal of unreacted monomers, the product of the reactor is injected into the second gas-phase reactor with the aim of polymerization of monomers with the formation of the component (B1). For the first experiment using a solid catalytic component obtained from the adduct MgCl22, THE IC2H5OH; for the second experiment the solid catalytic component obtained from the adduct MgCl21,1 C2H5OH; for the third experience of a solid catalytic component obtained the conditions shown in table. 1, the test results shown in the table. 2.As for the table. 2, then for some of the analyses used the following analytical methods.The ethylene content (C2).Determine by the method of IR-spectroscopy.Contents 1-butylene (C4).Determine by the method of IR-spectroscopy.The fraction soluble in hexane.Determine exposing the film product of a thickness of 100 microns extraction with hexane in an autoclave at 50oC for 2 h and Then hexane evaporated and determine the dry residue.The melt index.Determined in accordance with ASTM d 1238, condition L.The onset temperature welding (THC).Determine after the film is made in accordance with the following methods.The making of the film.Extrusion compositions at 200oC prepare various film thickness of 50 microns.Each film thus obtained, impose on polypropylene film with isotactic index 97 (in boiling n-heptane) and the rate of melt flow (P) in accordance with ASTM d 1238 L (4.5 g) 10 min. Thickness polypropylene film 560 m
Superimposed on each film is obtained thus glued film stretches to 6 times their length in both directions using tool to stretch the film TMLONG. The resulting film has a thickness of about 200 μm.This film makes samples of 5 x 10 cmThe definition of S. I. T.The test is carried out by applying thermovalve samples load of 200 gFor each test two of the above samples combine, turning to each other layers formed previously obtained copolymers. Then the samples welded along the side of 5 cm using a combination of laboratory welding machine SENTINEL Model 12-12 AS for 5 sec at a pressure of 1.2 ATM. The width of the weld 2,5 seeThe welding temperature increase to 2oC for each test sample.Then welded samples are cut into sections 2.5 x 10 cm and not welded side attached to the dynamometer.As stated previously, this is done to determine the minimum temperature welding in which the welding seam is not falling apart under the load 200, the Specified temperature is a temperature at which welding (THC).Mixing the propylene copolymers prepared in the above-described experiments with LLDPE, get polyolefin compositions of the present invention.Using a LODIGE mixer, conducting a first mechanical Chet mechanical mixture is kept for 10 minutes Thus obtained mechanical mixture granularit, passing through a single screw extruder at temperatures in the range from 190 to 210oC, with temperatures closer to the cylinder, and the temperature of the extruder crosshead 200oC. the Resulting granules are used to measure SIT and ability to extraction with n-hexane at 50oC in the films obtained by the above methods.Example 1. 50 wt. parts copolymer of propylene obtained in experiment 1, mixed with 50 wt. parts of polyethylene LLDPE brand NOYACOR United carbide Corporation (Union Carbide Corporation) density 0,9188 with JIREH 1 and containing 7.3 wt. 1-butylene. Properties of the thus obtained compositions are given in table. 3.Comparative example 1. 50 wt. parts of the same copolymer of propylene that in example 1, is mixed with 50 wt. parts of polyethylene LLDPE brand M 50026 SABIC LADENE density 0,9252 with MIE 55 and containing 6.7 wt. 1-butene.The properties of the compositions thus obtained are shown in table.3.Example 2. 50 wt. parts copolymer of propylene obtained in experiment 2 are mixed with 50 wt. including LLDPE used in example 1. The properties of the compositions thus obtained are shown in table. 3.
wt. parts of the LLDPE used in comparative example 1. Properties of the thus obtained compositions are given in table. 3
Example 3. 50 wt. parts of a copolymer of polypropylene obtained in experiment 3, is mixed with 50 wt. The LLDPE used in comparative example 1. Properties of the thus obtained compositions are given in table. 3.
C4/C4+ C20,173.The polymer discharged from the third gas-phase reactor, when the number of LLDPE reaches 30 wt. in relation to the total number is 0,9170, contents 1-butylene equal to 7.9 wt.The values of TNF and solubility in n-hexane at 50oC for polyolefin compositions obtained in this way are, respectively, 100oC and 4.6 wt. 1. Polymer composition on the basis of polyolefins, including linear low density polyethylene and a crystalline copolymer of propylene with an alpha olefin, wherein the linear low density polyethylene it contains linear low density polyethylene with a melt index of 0.1 to 15 g/10 min, and as a crystalline copolymer of propylene with an alpha olefin, the crystalline copolymer of propylene with 8 to 20 wt. alpha-olefin selected from the group comprising ethylene, WITH4- C8-alpha-olefin or a mixture, and the composition has a temperature of the welding from 85 to 110oWith the following ratio of components, wt.Linear low-density polyethylene 30 60
Crystalline copolymer of propylene with an alpha olefin 40 70
2. The composition according to p. 1, wherein the linear low density polyethylene contains a copolymer of ethylene containing from 3 to 20 wt. at least one alpha-olefin with 3 to 12 carbon atoms and having olyethylene low density component And it contains a copolymer of ethylene with 1-butylene.4. The composition according to p. 1, characterized in that as a crystalline copolymer of propylene with an alpha olefin contains a copolymer of propylene with co monomer selected from the group comprising ethylene, 1-butylene, 1-penten, 1-hexene, 4-methyl-1-penten and 1-octene.5. The composition according to p. 1, characterized in that as a crystalline copolymer of propylene with an alpha olefin contains a copolymer of propylene with at least one4WITH8-alpha-olefin, when the content comonomer alpha-olefin of 8 to 15 wt.6. The composition according to p. 1, characterized in that as a crystalline copolymer of propylene with an alpha olefin contains a copolymer of propylene with at least one4WITH8-alpha-olefin, the ethylene content of 2 to 6 wt. and one or more alpha-olefin of 6 to 9 wt.7. The composition according to p. 1, characterized in that as a crystalline copolymer of propylene with an alpha olefin contains a mixture of 30 to 65 wt. copolymer of propylene with4WITH8-alpha olefin, the propylene content of 80 to 98 wt. and 35 to 70 wt. copolymer of propylene with ethylene or ethylene and C1WITH8-alpha-olefin content of alpha-olefin of 2 to 10 wt. when the content is under one or more4WITH8-alpha-olefin with a total content of comonomers in a mixture of copolymers of at least 8 wt.8. The method of obtaining the polymer compositions based on polyolefins by copolymerization of alpha-olefins in the presence of a stereospecific catalyst containing a compound of titanium on the carrier from the active dihalogenide magnesium and the alkyl-aluminum as socializaton when the atomic ratio of aluminum to titanium of from 1 to 1000, and the process is carried out in at least two successive stages in the presence of, at a subsequent stage of the polymer and the catalyst of the preceding stage, wherein in the first stage, carry out the copolymerization of ethylene with C3- C12-alpha-olefin to obtain a linear low density polyethylene with a melt index of 0.1 to 15 g/10 min and subsequent copolymerization of propylene with an alpha olefin with obtaining a crystalline copolymer of propylene with 8 to 20 wt. alpha-olefin selected from the group comprising ethylene, WITH4WITH8-alpha-olefin or a mixture of the content of the crystalline propylene copolymer in the final product 40 to 70 wt.9. The method according to p. 1, wherein the process is carried out in the presence of an electron donor.