• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    abstract patent of invention: "process for the preparation of homopolymers or copolymers of ethylene in a tubular reactor with at least two reaction zones having different concentrations of chain transfer agent". the present invention relates to a process for the preparation of homopolymers or copolymers of ethylene in the presence of free radical polymerization initiator and at least one chain transfer agent at pressures in the range of 110 mpa and 350 mpa and temperatures in the range 100 ° c to 350 ° c in a tubular reactor with at least two reaction zones having different concentrations of the chain transfer agent, where the concentration of the chain transfer agent in the first reaction zone is less than 70% of concentration of the chain transfer agent in the reaction zone zone with the highest concentration of the chain transfer agent, homopolymers or copolymers of ethylene obtainable by such a process, the use of homopolymers or copolymers of ethylene for the extrusion coating and a extrusion coating process for a substrate selected from the group consisting of paper, cardboard, polymer film and metal, with such homopolymers and copolymers of ethylene.
    公开号:BR112013022111B1
    申请号:R112013022111-9
    申请日:2012-03-01
    公开日:2020-03-10
    发明作者:Iakovos Vittorias；Barbara Gall；Sebastian Weiand；Andrei Gonioukh；Stephan Schmitz；Klaus Berhalter；Gerd Mannebach；Markus Busch；Thomas Herrmann
    申请人:Basell Polyolefine Gmbh；
    IPC主号:
    专利说明:

    Invention Patent Descriptive Report for "PROCESS TO PREPARE ETHYLENE HOMOPOLYMER OR COPOLYMER IN THE PRESENCE OF A FREE RADICAL POLYMERIZATION INITIATOR AND AT LEAST ONE CHAIN TRANSFER AGENT IN A TUBULAR REACTOR, HOMOPOLYMER OR COPOLYMERAL TYPE OF USING ETHYLENE TYPE OF TYPE, THERE IS A TYPE OF ETHYLENE TYPE OF USE, AND SUBSTRATE EXTRUSION COATING PROCESS ".
    Description [001] The present invention relates to a process for the preparation of homopolymers or copolymers of ethylene in the presence of a free radical polymerization initiator and at least one chain transfer agent at pressures in the range of 110 MPa to 350 MPa and temperatures in the range of 100 ° C to 350 ° C in a tubular reactor with at least two reaction zones having different concentrations of the chain transfer agent, where the concentration of the chain transfer agent in the first reaction zone is lower than 70% of the concentration of the chain transfer agent in the reaction zone with the highest concentration of the chain transfer agent, and also refers to the homopolymers or copolymers of ethylene that can be obtained by such a process, with the use of homopolymers or copolymers of ethylene for extrusion coating, and a process for extrusion coating of a substrate selected from the gas group consisting of paper, cardboard, polymeric film and metal with such homopolymers or copolymers of ethylene. [002] Polyethylene is the most widely used commercial polymer. It can be prepared by a couple of different processes. Polymerization in the presence of free radical initiators at high pressures was the first method discovered to obtain polyethylene and remains a highly valued process with high commercial relevance for the preparation of low density polyethylene (LDPE). LDPE is a versatile polymer that can be used in a variety of applications, such as film, coating, molding, and wire and cable insulation. Consequently, there is still demand to optimize the processes for their preparation.
    [003] Common reactors for preparing high pressure LDPE polymers are tubular reactors or agitated autoclave reactors. The advantages of polymerization in a tubular reactor are those in which superior modifications can be obtained in the polymerization process, the process is easier to scale and it is consequently possible to build installations "on a world scale" and polymerization is, in general, more economical because of lower specific consumption by utility companies such as electricity and cooling water. However, LDPE polymers prepared in a high pressure tubular reactor have certain disadvantages for some applications. Compared to similar melt flow rate (MFR) and density LDPE polymers prepared in a high pressure autoclave LDPE reactor, LDPE polymers prepared in a tubular reactor generally have a molecular weight distribution more limited and a smaller amount of long chain branching (LCB).
    [004] An example for an application, in which the LDPE prepared in a tubular reactor is inferior to the LDPE prepared in an autoclave reactor, is the extrusion coating. In this process, the molten LDPE is extruded through a slit mold and melted into a film, which is then coated on a substrate such as paper, cardboard, a polymeric film such as a polyethylene terephthalate (PET) film or a film biaxially oriented polypropylene (BOPP), or a metal such as aluminum foil. For good processing capacity, LDPE must show a stable network, that is, the melted film outside the mold must not oscillate, and a low internal narrowing is required, that is, the ratio of the film width over the mold width should not be too low. In addition, high processing temperatures of up to 350 ° C are required for the post-treatment of the polymer film produced in order to improve its adhesion properties on substrates such as metal, paper or cardboard. In order to meet these requirements, a certain range of molecular weight distribution and a relatively high level of LCB in polymer chains with a higher molecular weight are advantageous.
    [005] To extend the molecular weight distribution of ethylene copolymers obtained through free radical polymerization in a tubular reactor with multiple reaction zones, EP 1 589 043 A2 describes a process with little or no injection of chain transfer in a downstream reaction zone. WO 2004/108271 A1 discloses a process for the polymerization of ethylene in a tubular reactor with multiple reaction zones, in which streams of different concentrations of chain transfer agent are fed into the reactor at different positions and the current rich in agent transfer zone is fed to a reaction zone upstream of a reaction zone downstream that receives the current poor in transfer agent. The obtained ethylene polymers are, however, not entirely suitable for extrusion coating on substrates such as metal, paper or cardboard.
    [006] Thus, the objective of the present invention was to overcome the disadvantages of the present LDPE polymers prepared by polymerization in a tubular reactor and to provide the possibility of preparing LDPE polymers in a tubular reactor that are suitable for extrusion coating applications and which have a broader molecular weight distribution and an increased level of LCB in the polymer chains, with a higher molecular weight than the common LDPE polymers prepared in a high pressure tubular reactor.
    [007] We observed that this objective is achieved by a process for the preparation of homopolymers and copolymers of ethylene in the presence of a free radical polymerization initiator and at least one chain transfer agent at pressures in the range of 110 MPa to 350 MPa and temperatures in the range of 100 ° C to 350 ° C in a tubular reactor with at least two reaction zones having different concentrations of chain transfer agent, where the concentration of chain transfer agent in the first reaction zone is lower than 70% of the concentration of the chain transfer agent in the reaction zone with the highest concentration of the chain transfer agent.
    [008] Furthermore, we observe that the homopolymers or copolymers of ethylene that can be obtained by such a process use the homopolymers or copolymers of ethylene for the extrusion coating, and a process for the extrusion coating of a substrate selected from the group consisting of paper, cardboard, polymeric film and metal, with such homopolymers or copolymers of ethylene.
    [009] The aspects and advantages of the present invention can be better understood through the following description and the accompanying drawings where Figures 1 and 3 show schematic configurations of tubular polymerization reactors that can be used in the process of the present invention. Figure 2 represents the configuration of a prior art tubular polymerization reactor. Figure 4 illustrates the temperature profile along the tubular reactor for the examples of the present application and Figure 5 represents the molecular weight distributions of the obtained polymers.
    [0010] The process of the invention can be used both for the homopolymerization of ethylene and for the copolymerization of ethylene with one or more other monomers, provided that these monomers are copolymerized by free radical with ethylene under high pressure. Examples of suitable copolymerizable monomers are C3-C8 α, β-unsaturated carboxylic acids, in particular maleic acid, fumaric acid, itaconic acid, acrylic acid, methacrylic acid and chromatic acid, derivatives of C3-C8 α, β- carboxylic acids unsaturated, for example, unsaturated C3-C15 carboxylic esters, in particular the esters of 1-Ce alkanols, or anhydrides, in particular methyl methacrylate, ethyl methacrylate, n-butyl methacrylate or tert-butyl methacrylate, acrylate methyl, ethyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, tert-butyl acrylate, methacrylic anhydride, maleic anhydride or itaconic anhydride, and 1-olefins such as propene, 1-butene, 1- pentene, 1-hexene, 1-octene or 1-decene. In addition, vinyl carboxylates, particularly preferable vinyl acetate, can be used as comonomers. Propene, 1-hexene, acrylic acid, n-butyl acrylate, tert-butyl, 2-ethylhexyl acrylate, vinyl acetate or vinyl propionate are in particular advantageously used as a comonomer.
    [0011] In the case of copolymerization, the proportion of comonomer or comonomers in the reaction mixture is 1 to 45% by weight, preferably 3 to 30% by weight, based on the amount of monomers, that is, the sum of ethylene and other monomers. Depending on the type of comonomer, it may be preferable to feed the comonomers at a plurality of different points in the reactor.
    [0012] For the purposes of the present invention, polymers are all substances that are prepared with at least two monomer units. They are preferably LDPE polymers with an average molecular weight Mn of more than 20000 g / mol. However, the method of the invention can also be advantageously employed in the preparation of oligomers, waxes and polymers having a molecular weight Mn less than 20000 g / mol.
    [0013] Possible initiators for initiating free radical polymerization in the respective reaction zones are, for example, oxygen, air, azo compounds or peroxide polymerization initiators. The process is especially suitable for polymerizations using oxygen, fed in the form of pure O2 or as air. In the case of starting polymerization with oxygen, the initiator is usually first mixed with the ethylene feed and then fed into the reactor. In the preferred embodiments for the process, such a stream comprising monomer and oxygen is not only fed at the beginning of the tubular reactor, but also at one or more points along the reactor which creates two or more reaction zones. The start using organic peroxides or azo compounds, also represents a preferred embodiment of the process of the invention. Examples of suitable organic peroxides are peroxide esters, peroxide ketones, peroxide ketones and peroxycarbonates, for example, di (2-ethylexyl) peroxydicarbonate, dici-clohexyl peroxydicarbonate, diacetyl peroxydicarbonate, tertiary-peroxyisopropylcarbonate, tertiary-peroxycarbonate, tertiary-peroxycarbonate. di-tert-butyl, di-tert-amyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-di-tert-butylperoxyethane, tert-butyl cumyl peroxide, 2,5-dimethyl-2 , 5-di (tert-butylperoxy) hex-3-yn, 1,3-diisopropyl mono-droperoxide or tert-butyl hydroperoxide, didecanoyl peroxide, 2,5-dimethyl-2,5-di (2 tert-butyl-ethylexanoylperoxy) hexane, p -oxy-2-ethylexanoate, dibenzoyl peroxide, tert-butyl peroxy-2-tert-butyl peroxyethylacetate, tert-butyl peroxyethylisobutyrate, 3-peroxy-butyl, peroxy-3-butyl, peroxide Tert-butyl 5,5-trimethylexanoate, 1,1-di (tert-butylperoxy) -3,3,5-trimethylcyclohexane, 1.1- di (tert-butylperoxy) cyclohexane, tert-butyl peroxyacetate, peroxine cumyl decanoate, tert-amyl peroxinodecanoate, tert-butyl peroxy-pivalate, tert-butyl peroxineodecanoate, tert-butyl permaleate, tert-butyl peroxypivalate, tert-butyl peroxyisononanoate, diisopropylbenzene hydroxide; less, tert-butyl peroxybenzoate, methyl isobutyl hydroperoxide ketone, 3,6,9-triethyl-3,6,9-trimethyl-triperoxyclononane and 2.2-di (tert-butylperoxy) -butane. Azoalkanes (diazenes), azodi-carboxylic esters, azodicarboxylic dinitriles such as azobisisobutyronitrile and hydrocarbons that break down into free radicals and are referred to as CC inhibitors, for example, derivatives of 1,2-diphenyl-1,2-dimethylethane and derivatives of 1,1 , 2,2-tetramethylethane, are also suitable. It is possible to use individual primers or preferably mixtures of several primers. A wide range of initiators, in particular peroxides, is commercially available, for example, Akzo Nobel products offered under the trade names Trigonox® or Perkadox®.
    [0014] In a preferred embodiment of the process of the invention, peroxide polymerization initiators having a relatively high decomposition temperature are used. Suitable peroxide polymerization inhibitors include, for example, 1,1-di (tert-butylperoxy) cyclohexane, 2,2-di (tert-butylperoxy) butane, peroxy-3,5,5-trimethylexanoate butyl, tert-butyl peroxybenzoate, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane, tert-butyl cumyl peroxide, di-tert-butyl peroxide and 2,5-dimethyl-2,5 -di (tert-butylperoxy) hex-3 -ine, and particular preference is given to the use of di-tert-butyl peroxide or 3,6,9-triethyl-3,6,9-trimethyl-triperoxycyclononane.
    [0015] The initiators can be used individually or as a mixture in concentrations of 0.1 to 50 mol / t of the produced polyethylene, in particular from 0.2 to 20 mol / t, in each reaction zone.
    In a preferred embodiment of the present invention the free radical polymerization initiator, which is fed into a reaction zone, is a mixture of at least two different azo compounds or organic peroxides. If such initiator mixtures are used, it is preferable that they are fed to all reaction zones. There is no limit to the number of different initiators in such a mixture, however, preferably, the mixtures are composed of two to six and in particular four or five different initiators. Particular preference is given to the use of mixtures of initiators that have different decomposition temperatures. [0016] It is often advantageous to use the initiators in the dissolved state. Examples of suitable solvents are ketones and aliphatic hydrocarbons, in particular octane, decane and isododecane and also other saturated C8-C25 hydrocarbons. The solutions comprise the initiators or initiator mixtures in proportions of 2 to 65% by weight, preferably from 5 to 40% by weight and particularly preferably from 10 to 30% by weight.
    [0017] The process of the present invention is carried out in the presence of at least one chain transfer agent. Chain transfer agents, which are often also called modifiers, are commonly added to radical polymerization to alter the molecular weight of the polymers to be prepared. Examples of suitable modifiers are hydrogen, aliphatic and olefinic hydrocarbons, for example, propane, butane, pentane, he-xane, cyclohexane, propene, 1-pentene or 1-hexene, ketones such as acetone, ethyl ethyl ketone (2-butanone) , methyl isobutyl ketone, methyl isoamyl ketone, diethyl ketone or diamyl ketone, aldehydes such as formaldehyde, acetaldehyde or propionaldehyde and saturated aliphatic alcohols such as methanol, ethanol, propanol, isopropanol or butanol. Particular preference is given to the use of saturated aliphatic aldehydes, in particular propionaldehyde, or a 1-olefins such as propene or 1 hexene, or hydrocarbons such as propane.
    [0018] The reaction mixture generally comprises polyethylene in an amount in the range of 0 to 45% by weight, based on the total monomer-polymer mixture, preferably from 0 to 35% by weight. [0019] The process of the invention is carried out at pressures from 110 MPa to 350 MPa, with pressures of 160 MPa and 340 MPa being preferred and pressures from 200 MPa to 330 MPa being particularly preferred. Temperatures are in the range of 100 ° C to 350 ° C, preferably from 120 ° C to 340 ° C and most particularly preferable from 150 ° C to 320 ° C.
    [0020] The process of the present invention can be carried out with all types of tubular reactors suitable for high pressure polymerization having at least two reaction zones, preferably 2 to 6 reaction zones and more preferably 2 to 5 zones reaction. The number of reaction zones is determined by the number of feed points for the initiator. Such a feed point can be an injection point for a solution of azo compounds and organic peroxides or a cold ethylene side feed comprising oxygen or another free radical polymerization initiator. In all these cases a new initiator is added to the reactor, where it decomposes into free radicals and initiates another polymerization. The heat generated from the reaction raises the temperature of the reaction mixture, since more heat is generated than can be removed through the walls of the tubular reactor. The rise in temperature increases the rate of decomposition of the free radical initiators and accelerates polymerization until essentially all of the free radical initiator is consumed. After that, no other heat is generated and the temperature decreases again, since the temperature of the reactor walls is lower than that of the reaction mixture. Consequently, the part of the tubular reactor downstream of an initiator supply point where the temperature rises is the reaction zone, while the part after that, where the temperature decreases again, is predominantly a cooling zone. .
    [0021] The amount and nature of free radical initiators added determine how much the temperature rises and consequently allows to adjust this value. Normally, the temperature rise is adjusted to be in the range of 70 ° C to 170 ° C in the first reaction zone and from 50 ° C to 130 ° C for subsequent reaction zones, depending on product specifications and the configuration of the reactor.
    [0022] Suitable tubular reactors are basically tubes with long thick walls, which are generally about 0.5 km to 4 km, preferably from 0.75 km to 3 km and especially from 1 km to 2.5 km from length. The inner diameter of the tubes is generally in the range of about 30 mm to 120 mm and preferably 40 mm to 90 mm. Such tubular reactors preferably have a length to diameter ratio greater than 1000, preferably from 10,000 to 40,000 and in particular from 25,000 to 35,000.
    [0023] A typical configuration for a tubular reactor LDPE installation consists essentially of a group of two compressors, a primary and a high pressure compressor, a tubular polymerization reactor and at least two separators to separate the monomer mixture -polymer that leaves the tubular reactor, in which in a first separator, the high pressure separator, the non-polymerized components of the reaction mixture separate from the reaction mixture are recycled to the ethylene supply between the primary compressor and the high pressure compressor pressure, and the nonpolymerized components of the reaction mixture separated from the reaction mixture in a second separator, the low pressure separator, are added to the new ethylene stream before being fed to the primary compressor. Typically, the separation of the polymer obtained from the non-polymerized components of the reaction mixture occurs in the high pressure stage at a pressure of 10 to 50 MPa, and in the low pressure stage at a pressure of 0.1 to 10 MPa. Such a high pressure polymerization unit usually also includes mechanisms such as extruders and granulators for granulating the obtained polymer. The supply of monomer to the tubular reactor can be carried out only at the beginning of the reactor or only partially at the beginning with the other part fed through one or more side feed inlets.
    [0024] According to the present invention, polymerization is carried out in a tubular reactor with at least two reaction zones having different concentrations of at least one chain transfer agent, in which the concentration of the chain transfer agent in the first zone reaction time is less than 70% of the concentration of the chain transfer agent in the reaction zone with the highest concentration of the chain transfer agent. Preferably, the concentration of the chain transfer agent in the first reaction zone is not more than 50%, and more preferably not more than 30% of the concentration of the chain transfer agent in the reaction zone with the highest concentration of the chain transfer agent. In an especially preferred embodiment of the present invention, polymerization in the first reaction zone is carried out in the absence of the chain transfer agent. In another especially preferred embodiment, no new chain transfer agent is added to the first reaction zone. In another preferred embodiment of the present invention, a certain amount of new chain transfer agent is fed into the first reaction zone, preferably less than 70% by weight, more preferable not more than 40% by weight, and especially not more than 20% by weight of the total amount of new chain transfer agent fed, in order to adjust the properties of the high molecular weight fraction according to the desired properties of the product. [0025] Since common chain transfer agents such as propionaldehyde or propene are not completely consumed when the reaction mixture leaves the tubular reactor, a major proportion of the added chain transfer agent is recycled in the compressor along with the non-ethylene. reacted. This occurs mainly through the high pressure circuit of ethylene separated from the reaction mixture in the high pressure separator. In order to have a lower chain transfer agent concentration in the first reaction zone, it is therefore not only necessary not to have any new chain transfer agent added to that reaction zone, but also not to feed the recycled ethylene in the first reaction zone. reaction or at least feed a single reduced amount of recycled ethylene and especially recycled ethylene through the high pressure circuit.
    [0026] This can, for example, be achieved by feeding at least a part of the non-polymerized components recycled from the reaction mixture into the tubular reactor downstream of the first reaction zone. In an embodiment of the present invention a new monomer stream, that is, new ethylene or a mixture of new ethylene and one or more new comonomers, which contains no or only a small amount of chain transfer agent , is fed into the first reaction zone and the stream of non-polymerized components recycled from the reaction mixture, predominantly ethylene, and optionally another new monomer is fed into a reaction zone, further downstream, that is, the tubular reactor a downstream of the first reaction zone. Consequently, the recycled chain transfer agent is prevented from being present in the first reaction zone. Preferably, the ratio of the new monomer feed to the tubular reactor inlet, that is, the first reaction zone, for the total monomer feed, that is, the sum of the new monomer and recycled monomer feeds, is 1 : 100 to 1: 1, more preferably from 1:20 to 3: 4 and especially from 1: 5 to 1: 2, based on the weights of the monomers fed.
    [0027] It is possible to supply the entire part of the tubular reactor, which, when compared to the common configuration of LDPE production in a tubular reactor, forms the first reaction zone, only with the new monomer. However, as a consequence of the lower amount of ethylene fed, the residence time of the reaction mixture in this part of the reactor is dramatically increased. It is also possible to divide the part of the tubular reactor, which normally forms the first reaction zone, into two zones, that is, to add somewhere in the middle of the part of the tubular reactor, which normally forms the first reaction zone, an inlet for the recycling stream and an additional supply point for the initiator. Consequently, an additional reaction zone is created.
    [0028] In another preferred embodiment of the present invention, the positions where the high pressure and low pressure recycling currents are fed into the reactor are separated and the high pressure recycling current is not fed or is only partially in the first reaction zone. Thus, the non-polymerized recycled components of the reaction mixture fed into the tubular reactor downstream of the first reaction zone, reach at least in part the high pressure recycling line. Preferably, the non-polymerized components of the reaction mixture recirculated to the tubular reactor in the low pressure recycling line are fed into the first polymerization zone of the tubular reactor.
    [0029] Through polymerization in the absence of chain transfer agent or at least in the presence of a low concentration it is possible to obtain a significant amount of polymer chains of high or ultra high molecular weight in the first reaction zone. These polymer chains are then present in the subsequent reaction zones, where the long chain branched polymer chains are produced by grafting growth chains or fragments of chains previously obtained on the previously obtained main chains. If high or ultra-high molecular weight chains or fragments are present over the entire length of the tubular reactor, the probability of producing a high proportion of long chain branched high molecular polymer chains is much higher than if the polymer chains high and ultra high molecular weight are only produced in the final reaction zone.
    [0030] Figure 1 shows a typical configuration for a suitable tubular polymerization reactor without, however, restricting the invention in the embodiments described herein.
    [0031] A portion of the new ethylene, which is generally under a pressure of 1.7 MPa, is first compressed to a pressure of about 30 MPa by means of a primary compressor 1 and then compressed to the reaction pressure of about 300 MPa, using a high pressure compressor 2. Optionally, a small amount of new chain transfer agent (CTA) can be added to this new ethylene stream. The reaction mixture that leaves the high pressure compressor 2 is fed to the preheater 3, where the reaction mixture is preheated to the starting temperature of the reaction around 120 ° C to 220 ° C, and then transported to the tubular reactor 4. Optionally, the comonomer can be added between primary compressor 1 and high pressure compressor 2.
    [0032] The tubular reactor 4 is basically a long, thick-walled tube with cooling liners to remove the heat released from the reaction from the reaction mixture via a coolant circuit (not shown).
    [0033] The tubular reactor 4 shown in Figure 1 has four primer injection points from 5a to 5d for the supply of initiators or mixtures of initiators from I1 to I4 in the reactor, which are arranged in a way that the four zones of the tubular reactor from one of these four primer injection points to the next or from the last of these primer injection points to the end of the reactor are approximately the same length. The feed point for recycled ethylene 6 and another primer injection point 7 for feeding an additional primer or mixture of primers I5 are located in a position between the primer injection points 5a and 5b, i.e. it is, between the first and the second of the primer injection points equidistant from 5th to 5th. Consequently, the configuration represented in Figure 1 has five reaction zones with two of them being positioned in the part of the tubular reactor between the primer injection points 5a and 5b.
    [0034] The reaction mixture leaves the tubular reactor 4 through a high pressure lowering valve 8 and passes through a post reactor cooler 9. Then the resulting polymer is extracted by separating unreacted ethylene and other compounds from low molecular weight (monomers, oligomers, polymers, additives, solvents, etc.) by means of a high pressure separator 10 and a low pressure separator 11, discharged and granulated by means of an extruder and granulator 12.
    [0035] The ethylene that is extracted by vaporization in the high pressure separator 10 is fed back to the reactor 4 in the high pressure circuit 13 around 30 MPa. Figure 1 shows a purification stage consisting of a heat exchanger 14 and a separator 15. However, it is also possible to use a plurality of purification stages. The high pressure circuit 13 generally separates the waxes and also recycles most of the uneaten chain transfer agent.
    [0036] The ethylene that was extracted by vaporization in the low pressure separator 11, which still comprises, inter alia, most of the low molecular weight products of polymerization (oligomers) and the solvent, is prepared in the low pressure circuit 16 at a pressure of about 0.1 to 0.5 MPa in a plurality of separators with a heat exchanger being located between each of the separators. Figure 1 shows two stages of purification consisting of heat exchangers 17 and 19 and separators 18 and 20. However, it is also possible to use only one of the stages of purification or preferably more than two stages of purification. The low pressure circuit 16 generally separates oil and waxes.
    [0037] The ethylene recycled in the low pressure circuit 16 is fed to a primary compressor 21, combined with the ethylene recycled in the high pressure circuit 13, further compressed at the reaction pressure of about 300 MPa using a high pressure compressor main pressure 22 and then fed through the cooler 23 to the tubular reactor at the feed point 6. The remainder of the new ethylene and the chain transfer agent to adjust the properties of the resulting polymer are also fed into the primary compressor 21. In addition in addition, the comonomer can be added between the primary primary compressor 21 and the primary high pressure compressor 22.
    [0038] The configuration shown in Figure 1 has the specific characteristic that requires two groups of compressors instead of one as in the common configuration for the production of LDPE in a tubular reactor. Starting from a configuration with a side feed of ethylene, it is, however, possible to arrive at a configuration of a tubular polymerization reactor suitable for carrying out the process of the present invention without the need to significantly change the arrangement.
    [0039] Figure 2 represents the configuration of a tubular polymerization reactor with a lateral supply of ethylene according to the prior art. New ethylene is fed into the recycled ethylene that leaves a 100 vaporization gas compressor. The mixture is partially fed to a primary compressor 101, compressed to a pressure of about 30 MPa and then further compressed to a reaction pressure of about 300 MPa, using a 102 high pressure compressor. Air as the oxygen source, or alternatively pure O2, and the chain transfer agent (CTA) are added to the primary compressor 101. In addition, the comonomer can be added between the primary compressor 101 and high pressure compressor 102. The reaction mixture leaving the high pressure compressor 102 is fed to a preheater 103, where the reaction mixture is preheated to the starting temperature of the reaction of about 120 ° C to 220 ° C, and is then transported to the tubular reactor 104, which is equipped with cooling coatings to remove the heat released from the reaction of the reaction mixture via u m coolant circuit (not shown).
    [0040] The other part of the mixture of new ethylene and recycled ethylene leaving the vaporization gas compressor 100 is fed first to a second primary compressor 121, compressed at a pressure of about 30 MPa and then further compressed to the reaction pressure using a second high pressure compressor 122. Air as an oxygen source, or alternatively pure O2, is fed into the second primary compressor 121 and the comonomer can be added between the second primary compressor 121 and the second high compressor pressure 122. In addition, an additional amount of new chain transfer agent can also be fed into the second primary compressor 121. Preferably, the added amount of new chain transfer agent is fed in equal amounts to the primary compressor 101 and the second primary compressor 121 or the total amount of the new chain transfer agent is fed into the buy primary absorber 101.
    [0041] The reaction mixture that leaves the second high pressure compressor 122 is fed as a cold mixture through the refrigerator 123 in the tubular reactor 104 at point 106. The temperature of this side current is controlled by the controller 123 so that the temperature of the Combined main and secondary currents are preferably in the range of 160 ° C to 220 ° C, more preferably from 170 ° C to 200 ° C, and especially from 180 ° C to 190 ° C. The supply of additional oxygen begins another polymerization downstream of point 106, thus creating a second reaction zone. There may also be additional points along the tubular reactor where the cold reaction mixture is fed. Preferably the number of secondary feeds to the reactor is 1 to 4 and in particular 1 or 2 and most preferably 1.
    [0042] The reaction mixture leaves the tubular reactor 104 through a high pressure lowering valve 108 and passes through a post reactor cooler 109. Then, the resulting polymer is separated from unreacted ethylene and other low weight compounds molecular by means of a high pressure separator 110 and a low pressure separator 111, discharged and granulated by means of an extruder and granulator 112.
    [0043] The ethylene that was extracted by vaporization in the high pressure separator 110 is fed back to the tubular reactor 104 in the high pressure circuit 113 around 30 MPa. It is first released from other constituents in at least one purification stage and then added to the monomer stream at the inlet end of the tubular reactor 104 between the primary compressor 101 and the high pressure compressor 102, and on the flow side. monomer feed between the primary compressor 121 and the high pressure compressor 122. Figure 2 shows a purification stage consisting of a heat exchanger 114 and a separator 115. However, it is also possible to use a plurality of purification stages. [0044] The ethylene that was extracted by vaporization in the low pressure separator 111, which still comprises, inter alia, the main part of the low molecular weight products of polymerization (oligomers) and the solvent of the initiators, is prepared in the low circuit pressure 116 at a pressure of about 0.1 to 0.5 MPa in a plurality of separators with a heat exchanger being located between each of the separators, and then fed into the vaporization compressor 100. Figure 2 shows two stages of purification consisting of heat exchangers 117 and 119 and separators 118 and 120. However, it is also possible to use only one of the purification stages or preferably more than two purification stages. [0045] Figure 3 shows a modification of the configuration shown in Figure 2 that is suitable for carrying out the process of the present invention. In this modification, the mixture that was compressed in the primary compressor 121 is no longer fed into the high pressure compressor 122 and then at point 106, but combined with the mixture that leaves the other primary compressor 101 and fed through the high pressure compressor. pressure 102 at the inlet of the tubular reactor 104. Instead, the recycled ethylene in the high pressure circuit 113 is combined with air as an oxygen source, or alternatively with pure O2, with the chain transfer agent to adjust the polymer properties resultant and optionally comonomer and this mixture is fed to the high pressure compressor 122 to enter the tubular reactor 104 at the feed point 106. Optionally, a small amount of new chain transfer agent (CTA) can be additionally fed into the primary compressor 101 and in the second primary compressor 121. In addition, a portion of the recycled ethylene in the high pressure circuit 113 may optionally finally be fed through a valve 124 for the mixture to enter the high pressure compressor 102.
    [0046] The configuration shown in Figure 3 allows the exclusion of recycled ethylene in the high pressure circuit 113, which contains most of the recycled chain transfer agent, from entering the first polymerization zone. Only new ethylene and ethylene recycled in the low pressure circuit 116, which contains none or only a small concentration of chain transfer agent, are fed into the first polymerization zone, as long as not a part of the ethylene recycled in the circuit is deliberately high pressure valve 113 is also fed to the inlet of the tubular reactor 104 through valve 124.
    [0047] Instead of using oxygen to initiate the polymerization reaction, it is also possible in a variation of the configuration shown in Figure 3 to use organic peroxides or mixtures of organic peroxides. Such a feed of organic peroxides or mixtures of organic peroxides can replace the oxygen feed of the recycled ethylene in the high pressure circuit 113 upstream of the high pressure compressor 122. The organic peroxide or organic peroxide mixture is then injected at one or more primer injection points upstream or downstream of the 106 point of supply in the reactor. However, it is also possible to replace both the oxygen supply in recycled ethylene in the high pressure circuit 113 and the oxygen supply in primary compressors 101 and 121 with organic feed peroxides or mixtures of organic peroxides in the reactor.
    [0048] The present invention also relates to ethylene copolymers that can be obtained by the process described above. These homopolymers and copolymers of ethylene have a significantly increased molecular weight distribution compared to LDPE normally obtained from free radical polymerization in tubular reactors. They, however, also differ from LDPE obtained from free radical polymerization in autoclave reactors in that they do not have a very high amount of long chain branches. Due to their molecular structure, they are therefore particularly suitable for use in extrusion coating processes. They have superior melting stability during processing, that is, high mesh stability and low internal narrowing, and superior adhesion potential on the substrate such as paper, cardboard, polymeric film or metal. Consequently, the present invention also relates to the use of ethylene copolymers for the extrusion coating and for a process for the extrusion coating of a substrate selected from the group consisting of paper, cardboard, polymeric film and metal, with these copolymers of ethylene.
    [0049] The invention is illustrated below with the aid of examples, without being limited by them.
    Examples Comparative Example A
    [0050] The simulation of a common homopolymerization of ethylene in a high pressure tubular reactor was performed using the PREDICI commercial polymerization modeling software by Dr. Michael Wulkow Computing in Technology GmbH (CiT), Rastede, Germany. The kinetic data for homopolymerization of ethylene were taken from M. Busch, Macromol. Theory Simul. 2001, 10, 408 - 429.
    [0051] The reactor was adopted to have four initiator injection points and to be of a similar design to that illustrated in Figure 1, however, without the primary compressor 1 and the high pressure compressor 2 and the reaction mixture that leaves the compressor high pressure 22 being fed to the preheater 3. Thus, all new ethylene was assumed to be fed into the primary compressor 21 and no initiator I5 fed to point 7. The reactor was adopted to have a total length of 2000 m and a 76 mm diameter. The calculation was performed based on the following assumptions: - ethylene production from the high pressure compressor 117 metric tons / h; - supply of propionaldehyde as a chain transfer agent to the high-pressure compressor 1.5 kg per ton of LDPE produced; - ethylene supply temperature at the 157 ° C reactor inlet; - pressure at the 280 MPa reactor inlet; - feed of 0.3754 g / s of tert-butyl peroxy-3,5,5-trimethylexanoate (TBPIN), 0.3610 g / s of di-tert-butyl peroxide (DTBP), 0.1506 g / s of tert-butyl peroxineodecanoate (TBPND) and 0.3447 g / s of tert-butyl peroxypivalate (TBPP) at the reactor inlet; - feeding of 0.0476 g / s of tert-butyl peroxy-3,5,5-trimethylexanoate (TBPIN) and 0.3547 g / s of di-tert-butyl peroxide (DTBP) in a position of 640 ma downstream of the reactor inlet; - feeding of 0.0521 g / s of tert-butyl peroxy-3,5,5-trimethylexanoate (TBPIN) and 0.2951 g / s of di-tert-butyl peroxide (DTBP) in a position of 1200 ma downstream of the reactor inlet, and - feeding 0.2779 g / s of di-tert-butyl peroxide (DTBP) at a position of 1760 m downstream of the reactor inlet. [0052] The temperature profile calculated along the tubular reactor is shown in Figure 4 and Figure 5 represents the obtained molecular weight distribution. The resulting data on the molecular weight distribution and on the long and short chain branch, expressed as number of branches per 1000 carbon atoms, of the LDPE obtained and of the ethylene conversion, are provided in Table 1.
    Example 1 [0053] The simulation of Comparative Example A was repeated adopting a reactor of the same size, however, with a configuration as shown in Figure 1. The new ethylene feed is divided with only a part of the new ethylene fed at the reactor inlet and most of the new ethylene fed together with the recycled ethylene at a position 160 m downstream of the reactor inlet. The calculation was performed based on the assumptions of Comparative Example A except that - the supply of new ethylene at the reactor inlet is 11.7 metric tons / h and the temperature of this current is 157 ° C; - the ethylene production of the main high pressure compressor is 105.3 metric tons / h and the temperature of the current fed to the reactor is also 157 ° C; - propionaldehyde as a chain transfer agent is only added to the ethylene in the stream fed to the reactor in the 160 m position downstream of the reactor with the same amount as in Comparative Example A; - the initiator feed at the reactor inlet is 0.0360 g / s of di-tert-butyl peroxide (DTBP); - the initiator feed at the 160 m position downstream of the reactor inlet is 0.3750 g / s of tert-butyl peroxy-3,5,5-trimethylexanoate (TBPIN), 0.3600 g / s of peroxide di-tert-butyl (DTBP); 0.1506 g / s tert-butyl peroxineodecanoate (TBPND) and 0.3447 g / s tert-butyl peroxypivalate (TBPP); and - the initiator feeds at positions 640 m, 1200 m and 1760 m downstream from the reactor inlet are the same as in Comparative Example A.
    [0054] The temperature profile calculated along the tubular reactor is shown in Figure 4 and Figure 5 represents the obtained molecular weight distribution. The data obtained on the molecular weight distribution and on the long and short chain branch, expressed as number of branches per 1000 carbon atoms, of the LDPE obtained and of the ethylene conversion, are provided in Table 1.
    Example 2 [0055] The simulation of Example 1 was repeated except that - the supply of new ethylene at the reactor inlet is 23.4 metric tons / h; - the ethylene production of the main high pressure compressor is 93.6 metric tons / h and the temperature of the current fed to the reactor is also 157 ° C; - the initiator feed at the reactor inlet is 0.0720 g / s of di-tert-butyl peroxide (DTBP); and - the initiator feeds at positions 160 m, 640 m, 1200 m and 1760 m downstream from the reactor inlet are the same as in Example 1.
    [0056] The temperature profile calculated along the tubular reactor is shown in Figure 4 and Figure 5 represents the obtained molecular weight distribution. The data obtained on the molecular weight distribution and on the long and short chain branch, expressed as the number of branches per 1000 carbon atoms, the LDPE obtained and the ethylene conversion, are provided in Table 1.
    Table 1 [0057] The comparison of Examples and 2 with Comparative Example A shows that, through the polymerization of pure ethylene without chain transfer agent in the first reaction zone, the polydispersity of the LDPE obtained, here quantified as Mw / Mn and as Mz / Mw, it is intensified and the LCB concentration is preserved. The polymeric structure is closer to the structure of an autoclave LDPE product, so the processing properties for the extrusion coating will be enhanced.
    权利要求:
    Claims (5)
    [1]
    1. Process for preparing ethylene homopolymer or copolymer in the presence of a free radical polymerization initiator and at least one chain transfer agent selected from the group consisting of aliphatic and olefinic hydrocarbons, ketones, aldehydes and saturated aliphatic alcohols pressures in the range of 110 MPa and 350 MPa and temperatures in the range of 100 ° C to 350 ° C in a tubular reactor with at least two reaction zones having different concentrations of the chain transfer agent, characterized by the fact that the components do not polymerized from the reaction mixture exiting the reactor are separated from the polymer obtained and the non-polymerized components of the reaction mixture are recirculated to the tubular reactor, in which only fresh monomer and no recycled non-polymerized components of the reaction mixture are fed to the first reaction zone. polymerization and non-polymerized components recycled from the reaction mixture and the optional additional fresh monomer are fed to a reaction zone further downstream and where no fresh chain transfer agent is added to the first reaction zone and polymerization in the first reaction zone is carried out in the absence of the transfer agent jail.
    [2]
    2. Process according to claim 1, characterized by the fact that the proportion of the fresh monomer feed in the first reaction zone to the total monomer feed is in the range of 1: 100 to 1: 1 based on the weights of the monomers fed.
    [3]
    3. Ethylene homopolymer or copolymer, characterized by the fact that it is obtainable by a process as defined in claim 1 or 2.
    [4]
    4. Use of an ethylene homopolymer or copolymer as defined in claim 4, characterized by the fact that it is for coating by extrusion.
    [5]
    5. Process for extrusion coating a substrate selected from the group consisting of paper, cardboard, polymeric film and metal, characterized by the fact that it is with an ethylene homopolymer or copolymer as defined in claim 3.
    类似技术:
    公开号 | 公开日 | 专利标题
    BR112013022111B1|2020-03-10|PROCESS TO PREPARE ETHYLENE HOMOPOLYMER OR COPOLYMER IN THE PRESENCE OF A FREE RADICAL POLYMERIZATION INITIATOR AND AT LEAST ONE CHAIN TRANSFER AGENT IN A TUBULAR REACTOR, HOMOPOLYMER OR ETHYLENE COPOLYMER REALLY PROCESSABLE FOR YOUR PROCESS, AS A PROCESS THAT IS REALLY PROCESSY
    EP2655444B1|2015-03-18|Process for the preparation of ethylene copolymers in the presence of free-radical polymerization initiator by copolymerizing ethylene, a bi- or multifunctional comonomer and optionally further comonomers
    KR20180025967A|2018-03-09|High Pressure Polymerization of Ethylenically Unsaturated Monomer in Tubular Reactor
    CN102282180B|2013-11-20|Method for ethylene polymerization in a tubular reactor with reduced output
    KR101708136B1|2017-02-17|Process for copolymerizing ethylene and esters of vinyl alcohol
    KR101747575B1|2017-06-14|Process for separating vinyl esters from a gas stream comprising ethylene and vinyl esters
    TW201136958A|2011-11-01|Modification of polyethylene pipe to improve sag resistance
    RU2701923C2|2019-10-02|Device for polymerisation of olefins and method of polymerisation of olefins
    CN109715674B|2021-03-16|Process for preparing polyethylene
    EP3299397A1|2018-03-28|Method for separating hydrocarbons from polymer
    KR20100058508A|2010-06-03|Process for the olefin polymerization using multiple loop reactors
    WO2021257286A1|2021-12-23|Process for reducing ethylene volatiles during ldpe polymerization
    CN111363222A|2020-07-03|Polymer composition, preparation method, application and synthesis device thereof
    BR112015013417B1|2021-10-26|PROCESS FOR COPOLYMERIZATION OF ETHYLENE AND VINYL ALCOHOL ESTERS
    同族专利:
    公开号 | 公开日
    RU2013144352A|2015-04-10|
    EP2681250B1|2015-04-15|
    KR102040337B1|2019-11-04|
    US20130333832A1|2013-12-19|
    WO2012117039A1|2012-09-07|
    EP2681250B2|2018-11-14|
    CN103403040B|2015-11-25|
    EP2681250A1|2014-01-08|
    KR20140044781A|2014-04-15|
    RU2572821C2|2016-01-20|
    CN103403040A|2013-11-20|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    BE607527A†|1960-08-29|1900-01-01|
    DE1908962C3|1969-02-22|1980-04-30|Basf Ag, 6700 Ludwigshafen|Process for the continuous production of ethylene homopolymers|
    BE778690A|1971-02-03|1972-05-16|Snam Progetti|HIGH PRESSURE OLEFINS POLYMERIZATION PROCESS IN TUBULAR REACTORS|
    GB1419012A†|1973-03-29|1975-12-24|Ici Ltd|Production of polyethylene|
    EP0928797B3|1998-01-12|2012-01-11|Dow Global Technologies LLC|Medium density ethylene polymers, a process to prepare these polymers and use of carbonyl group containing chain transfer agents in this process|
    AT271075T|2000-03-16|2004-07-15|Basell Polyolefine Gmbh|METHOD FOR PRODUCING POLYETHYLENE|
    DE10128221A1|2001-06-11|2002-12-19|Basell Polyolefine Gmbh|Preparation of ethylene homo- and copolymers by radical polymerization in the presence of molecular weight regulator and chain starter with increased heat transfer efficiency and yield by temperature control|
    US7745550B2|2001-12-19|2010-06-29|Exxonmobil Chemical Patents Inc.|Tubular polymerization reactors and polymers made therein|
    US6673878B2|2001-12-19|2004-01-06|Exxonmobil Chemical Patents Inc.|Tubular polymerization reactors and polymers made therein|
    EP1589043A3|2003-08-11|2006-02-15|ExxonMobil Chemical Patents Inc.|Polymers of ethylene and, optionally, copolymerizable esters, films using such polymers and stretch hood packaging processes using such films|
    GB0318757D0|2003-08-11|2003-09-10|Exxonmobil Chem Patents Inc|Polymers of ethylene and, optionally, copolymerizable esters, films using such polymers and stretch hood packaging processes using such films|
    DE10351262A1|2003-10-31|2005-06-02|Basell Polyolefine Gmbh|Continuous production of polyethylene by high-pressure polymerization uses free radical initiator as solution in isoparaffin of given boiling range, which is separated in low pressure cycle and re-used for dissolving initiator|
    WO2006049783A1|2004-11-02|2006-05-11|Dow Global Technologies Inc.|Process for producing low density polyethylene compositions and polymers produced therefrom|
    ES2421584T3|2005-03-09|2013-09-04|Saudi Basic Ind Corp|A process for the preparation of an ethylene copolymer in a tubular reactor|
    KR20110084905A|2008-10-07|2011-07-26|다우 글로벌 테크놀로지스 엘엘씨|High pressure low density polyethylene resins with improved optical properties produced through the use of highly active chain transfer agents|IN2014CN02739A|2011-10-19|2015-07-03|Dow Global Technologies Llc|
    JP6002017B2|2012-12-03|2016-10-05|住友化学株式会社|Method for producing methacrylic polymer composition|
    RU2674968C1|2013-12-19|2018-12-13|Базелл Полиолефин Гмбх|Separator with integrated bursting discs for separation of components of reaction mixture obtained by high-pressure polymerisation of ethylenically unsaturated monomers|
    KR102240585B1|2013-12-19|2021-04-16|다우 글로벌 테크놀로지스 엘엘씨|Tubular low density ethylene-based polymers with improved balance of extractables and melt elasticity|
    JP6609254B2|2013-12-26|2019-11-20|ダウグローバルテクノロジーズエルエルシー|Method for improving reactor stability for the preparation of ethylene-based polymers using asymmetric polyenes|
    ES2717973T3|2013-12-26|2019-06-26|Dow Global Technologies Llc|Procedures for forming polymers based on ethylene using asymmetric polyenes|
    SG11201705241QA|2014-12-30|2017-07-28|Dow Global Technologies Llc|Process to control output and quality of ethylene-based polymer formed by high pressure free radical polymerization|
    EP3072567B1|2015-03-27|2017-12-20|Borealis AG|Process for separating hydrocarbons from polymer|
    BR112017027866A2|2015-06-25|2018-08-28|Dow Global Technologies Llc|ethylene-based polymers with low hexane extractables|
    BR112017027794A2|2015-06-25|2018-08-28|Dow Global Technologies Llc|ethylene-based polymers with low hexane extractables and low densities|
    ES2774813T3|2015-06-25|2020-07-22|Dow Global Technologies Llc|Improved process to prepare high G'-wide and high MWD ethylene-based tubular polymers|
    ES2786677T3|2015-06-25|2020-10-13|Dow Global Technologies Llc|Process for forming ethylene-based polymers|
    US10400046B2|2015-06-25|2019-09-03|Joseph J. Matsko|Portable powered paint system|
    KR101983521B1|2015-09-11|2019-05-28|엑손모빌 케미칼 패턴츠 인코포레이티드|High Pressure Polyethylene Product Cooling|
    WO2017058570A1|2015-09-28|2017-04-06|Dow Global Technologies Llc|Process for producing ethylene-based polymers with reduced gel counts and low reactor fouling|
    EP3168239A1|2015-11-10|2017-05-17|Dow Global Technologies LLC|High pressure free radical polymerizations|
    EP3168237A1|2015-11-10|2017-05-17|Dow Global Technologies LLC|High pressure, free radical polymerizations to produce ethylene-based polymers|
    EP3168238A1|2015-11-10|2017-05-17|Dow Global Technologies LLC|Ethylene-based polymers formed by high pressure free radical polymerizations|
    WO2017106940A1|2015-12-22|2017-06-29|Braskem S.A.|Device for injecting a polymerization initiator in a tubular reactor, tubular reactor for continuous polymerization of olefins, and process for producing ethylene copolymers and polymers|
    CN108602043B|2016-02-26|2021-05-14|埃克森美孚化学专利公司|Apparatus and process for high pressure polymerization of ethylene|
    US10835882B2|2016-02-26|2020-11-17|Exxonmobil Chemical Patents Inc.|Apparatus and process for high pressure polymerization of ethylene|
    BR112018069870A2|2016-04-22|2019-01-29|Dow Global Technologies Llc|method for producing low volatile tubular low density ethylene based polymers for clean extrusion coating processing|
    EP3260472A1|2016-06-24|2017-12-27|Dow Global Technologies LLC|Ethylene-based polymers formed by high pressure free radical polymerizations|
    EP3260473A1|2016-06-24|2017-12-27|Dow Global Technologies LLC|High pressure, free radical polymerizations to produce ethylene-based polymers|
    CN109715674B|2016-10-04|2021-03-16|阿克苏诺贝尔化学品国际有限公司|Process for preparing polyethylene|
    WO2020159204A1|2019-02-01|2020-08-06|에스케이이노베이션 주식회사|Method for producing ethylene-carboxylic acid copolymer|
    法律状态:
    2018-04-03| B06F| Objections, documents and/or translations needed after an examination request according [chapter 6.6 patent gazette]|
    2019-08-27| B06U| Preliminary requirement: requests with searches performed by other patent offices: procedure suspended [chapter 6.21 patent gazette]|
    2020-01-21| B09A| Decision: intention to grant [chapter 9.1 patent gazette]|
    2020-03-10| B16A| Patent or certificate of addition of invention granted|Free format text: PRAZO DE VALIDADE: 20 (VINTE) ANOS CONTADOS A PARTIR DE 01/03/2012, OBSERVADAS AS CONDICOES LEGAIS. |
    优先权:
    申请号 | 申请日 | 专利标题
    EP11001770.4|2011-03-03|
    EP11001770|2011-03-03|
    PCT/EP2012/053484|WO2012117039A1|2011-03-03|2012-03-01|Process for preparing ethylene homopolymers or copolymers in a tubular reactor with at least two reaction zones having different concentrations of chain transfer agent|
    [返回顶部]