Process for post-treatment of vinyl polymers and vinyl polymers obtained thereby

Abstract

The invention relates to a post-treatment method of a vinyl polymer and the vinyl polymer obtained by the method. According to the post-treatment method disclosed by the invention, the post-treatment method comprising a washing step and an adsorption step is adopted, so that the ash content in the vinyl polymer can be effectively reduced in a simple manner.

Description

Technical Field

[0001] The present invention relates to a post-treatment method of a vinyl polymer and a vinyl polymer obtained by the method, and more particularly to a post-treatment method of a vinyl polymer crude material from solution polymerization and a vinyl polymer with a low ash content obtained by the method. Background Art

[0002] Polyolefin materials play an irreplaceable role in improving people's production and living standards and promoting the development of new technologies. Polyethylene materials are the largest variety of polyolefin materials and are widely used due to their good mechanical properties, chemical stability, superior processing performance, reusability and low cost.

[0003] In addition to its advantages of high quality and low price, polyethylene also benefits from the continuous development of olefin polymerization catalysts. The unique physical and chemical properties of branched polyethylene make it valuable for application in many fields, such as replacing rubber, and can be used in inner tubes, soles, medical rubber plugs, lubricant modifiers, etc.; in the application of resin modification, it can be used as a toughening agent, modifier, etc.; due to its unique branched or hyperbranched structure, it can also realize its application value in the replacement of POE.

[0004] In particular, low-ash branched polyethylene has better film-forming properties, light transmittance and smoothness than ordinary polyethylene, and has become a research hotspot. As the high cleanliness requirements of polyethylene products have become a research hotspot and market difficulty, we urgently need to reduce the ash content in polyethylene products through a new high-efficiency, low-cost and low-energy technology.

[0005] Chinese patent CN1 05504124A discloses a method of three reactors in series, wherein the polymerization solution is flashed, centrifugally dried and degassed to obtain a low-ash high-density polyethylene resin for forming a wet-process lithium-ion battery separator. In this method, the low ash content is derived from the use of a high-activity catalyst system, so this method is limited to the occasion of a high-activity catalyst system, the cost is high, and it is not conducive to industrial promotion.

[0006] Chinese patent CN106554434A discloses a post-treatment process for vinyl copolymers based on solution polymerization, in which the polymerization reaction of the vinyl polymer solution is terminated without using a deactivator, and then the polymer solution is subjected to steps such as polymer separation to obtain a polymer, and the liquid phase containing the co-catalyst is sent to a liquid return tank and then circulated back to the polymerization kettle. When the polymerization initiation conditions are met again, it can continue to initiate the polymerization reaction as an active component. The post-treatment method of the invention is to reuse the co-catalyst to make full use of it. However, there is no specific step for processing and purifying the polymer.

[0007] As mentioned above, the post-processing steps of polyethylene in the prior art are complicated, costly, and the actual treatment effect is not satisfactory. In the face of this situation, a treatment process is needed that can effectively post-treat vinyl polymers through simple steps and sufficiently reduce the ash content of the obtained vinyl polymer product. Summary of the invention

[0008] The inventors of the present invention have conducted intensive studies and have found that the ash content of a vinyl polymer crude material that has completed polymerization can be effectively reduced in a simple manner by combining a washing step and an adsorption step.

[0009] Specifically, the present invention relates to the following technical solutions.

[0010] A post-treatment method for a vinyl polymer, which is carried out according to method 1 or method 2,

[0011] Method 1 includes the following steps:

[0012] A) a washing step, in which the crude vinyl polymer material is washed with a washing liquid, and

[0013] B) an adsorption step, wherein an adsorbent is brought into contact with the material that has completed the washing step to perform adsorption;

[0014] Method 2 includes the following steps:

[0015] A') an adsorption step, wherein an adsorbent is brought into contact with the vinyl polymer crude material to effect adsorption, and

[0016] B') A washing step, wherein the material after the adsorption step is washed with a washing liquid.

[0017] A post-treatment device for vinyl polymers comprises a washing unit and an adsorption unit, wherein the washing unit and the adsorption unit are connected via a pipeline, wherein:

[0018] When the washing unit is located upstream of the adsorption unit, a vinyl polymer raw material inlet and a washing liquid inlet are provided in the washing unit, and a washing finished material inlet and an adsorbent inlet are provided in the adsorption unit; or,

[0019] When the adsorption unit is located upstream of the washing unit, a vinyl polymer coarse material inlet and an adsorbent inlet are arranged in the adsorption unit, and an adsorption finished material inlet and a washing liquid inlet are arranged in the washing unit.

[0020] Vinyl polymer product, wherein the ash content is less than 80 ppm (e.g., the aluminum content is less than 70 ppm and the nickel content is less than 10 ppm).

[0021] Technical Effects

[0022] The post-treatment method of the vinyl polymer of the present invention can effectively reduce the ash content in the vinyl polymer crude material with simple steps, which not only improves the manufacturing efficiency of the vinyl polymer product, but also greatly reduces the manufacturing cost of the low-ash vinyl polymer.

[0023] In addition, the post-processing device of the present invention can effectively remove the ash component in the vinyl polymer raw material. Moreover, the post-processing device of the present invention has a simple structure and convenient pipeline arrangement, and can conveniently improve the existing whole set of equipment for preparing vinyl polymer. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 . Flowchart of one embodiment of the present invention.

[0025] Figure 2 . Flowchart of another embodiment of the present invention.

[0026] Figure 3 . Flowchart of another embodiment of the present invention. DETAILED DESCRIPTION

[0027] The specific embodiments of the present invention are described in detail below, but it should be pointed out that the protection scope of the present invention is not limited by these specific embodiments, but is determined by the claims in the appendix.

[0028] In the context of this specification, except for the contents explicitly described, any matters or items not mentioned are directly applicable to those known in the art without any changes. Moreover, any embodiment described herein can be freely combined with one or more other embodiments described herein, and the technical solutions or technical ideas formed thereby are regarded as part of the original disclosure or original record of the present invention, and should not be regarded as new contents not disclosed or anticipated herein, unless a person skilled in the art considers that the combination is obviously unreasonable.

[0029] Unless otherwise specified, all percentages, parts, ratios, etc. mentioned in this specification are based on weight, unless the weight basis does not conform to the common understanding of those skilled in the art.

[0030] The specific embodiments of the present invention are described in detail below. However, it should be noted that the protection scope of the present invention is not limited by these specific embodiments, but is determined by the appended claims.

[0031] In the context of the present invention, unless otherwise specified, the physical properties of a substance (such as boiling point) are measured at normal temperature (25° C.) and normal pressure (101325 Pa).

[0032] [Post-treatment method of vinyl polymer]

[0033] In the present invention, the vinyl polymer includes ethylene homopolymer, copolymer of ethylene and other comonomers, which can be in the form of branched polyethylene, high molecular weight polyethylene, ultra-high molecular weight polyethylene. In the present invention, the vinyl polymer is sometimes also referred to as polyethylene for short.

[0034] In the present invention, the vinyl polymer crude material refers to a material that has completed the polymerization reaction but has not been subjected to post-treatment. Here, the completion of the polymerization reaction refers to the situation where the catalyst used in the polymerization reaction is deactivated / quenched and the polymerization reaction is terminated. Therefore, the water or acid aqueous solution or water vapor, etc. added to deactivate / quench the catalyst is not a washing of the vinyl polymer crude material. In the present invention, as the post-treatment proceeds, the impurities in the vinyl polymer crude material are gradually removed. Therefore, after going through each step in the post-treatment method, the impurity content in the vinyl polymer material is different. However, for convenience, the vinyl polymer material in the post-treatment process is collectively referred to as vinyl polymer crude material.

[0035] In the present invention, the vinyl polymer crude material comes from the discharge of the polymerization reactor of ethylene and optional co-olefin monomers. In the present invention, the polymerization reaction mode of ethylene and optional co-olefin monomers is not particularly limited, and can be solution polymerization, slurry polymerization, gas phase polymerization. Among them, solution polymerization is preferred, in which case the vinyl polymer crude material is dissolved in a polymerization solvent, and the polymerization solvent can be an organic solvent described below in the present invention.

[0036] In the present invention, when the polymerization is carried out by slurry polymerization or gas phase polymerization, the crude vinyl polymer material discharged from the polymerization reactor is preferably dissolved by an organic solvent before the post-treatment of the present invention. That is, in the post-treatment method of the present invention, the crude vinyl polymer material used as the treatment feed is preferably in the form of a solution. In this case, the starting material for the post-treatment method of the present invention is an organic solution containing the crude vinyl polymer material. In the present invention, the organic solvent is not particularly limited as long as it can dissolve the vinyl polymer. It can be a polymerization solvent commonly used in polyethylene polymerization reactions, for example, including but not limited to C 4-10 Alkanes (such as butane, pentane, hexane, heptane, octane, nonane or decane, etc.), halogenated C 1-10 Alkanes (e.g., dichloromethane), aromatic hydrocarbon solvents (e.g., toluene and xylene), ether solvents (e.g., diethyl ether or tetrahydrofuran), ester solvents (e.g., ethyl acetate), and ketone solvents (e.g., acetone), etc. Among them, hexane, isopropane, etc. are preferably used as the organic solvent.

[0037] In the present invention, the comonomer that can be copolymerized with ethylene is selected from α-olefins, diolefins, cyclic olefins and other ethylenically unsaturated compounds. The α-olefin can be C3-C 10 As the α-olefins, for example, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 4-methyl-1-pentene, 4-methyl-1-hexene, 1-octene, 1-decene, 1-undecene, 1-dodecene and styrene can be mentioned. As the cyclic olefins, for example, 1-cyclopentene, ethylidene norbornene and norbornene can be mentioned. As the dienes, for example, 1,4-butadiene, 2,5-pentadiene, 1,5-hexadiene, vinyl norbornene, norbornene and 1,7-octadiene can be mentioned. As the other ethylenically unsaturated compounds, for example, vinyl acetate and (meth)acrylate can be mentioned. Among them, the comonomer is preferably C3-C 10 The α-olefin is more preferably at least one selected from 1-butene, 1-hexene, 4-methyl-1-pentene, and 1-octene, and further preferably at least one selected from 1-butene, 1-hexene, and 1-octene.

[0038] The post-treatment method of the vinyl polymer of the present invention is a post-treatment method in the process of manufacturing the vinyl polymer, and more specifically, it is a method of post-treating the product after the polymerization reaction is completed and the vinyl polymer reaction product is obtained.

[0039] The present invention provides a post-treatment method for a vinyl polymer, which is carried out according to Mode 1 or Mode 2.

[0040] Method 1 includes the following steps:

[0041] A) a washing step, in which the crude vinyl polymer material is washed with a washing liquid, and

[0042] B) an adsorption step, wherein an adsorbent is brought into contact with the material that has completed the washing step to perform adsorption;

[0043] Method 2 includes the following steps:

[0044] A') an adsorption step, wherein an adsorbent is brought into contact with the vinyl polymer crude material to effect adsorption, and

[0045] B') A washing step, wherein the material after the adsorption step is washed with a washing liquid.

[0046] In one embodiment of the present invention, the washing liquid used in the washing step can be an aqueous solvent that is immiscible with the polymerization solvent used in the polymerization reaction or the organic solvent for dissolving the crude material, and is preferably selected from water and an alcohol-containing aqueous solution. The alcohol is a C1-6 lower alcohol, such as methanol, ethanol, propanol, isopropanol, butanol, etc. More preferably, the washing liquid is deionized water.

[0047] In one embodiment of the present invention, the washing step is performed in steps. The stepwise step means that the washing liquid is added twice or more for washing (it can be evenly divided into 2-6 times, preferably evenly divided into 2 times, 3 times or 4 times for washing), and liquid separation is performed between the two washings.

[0048] In one embodiment of the present invention, in the washing step, stirring is preferably performed to fully wash the surface. At this time, the stirring method can be performed in a manner known in the art, including but not limited to stirring methods such as stirring paddles.

[0049] In one embodiment of the present invention, in the washing step, a post-washing separation is further performed after washing to separate the washing liquid and the organic solution. The separation method can be conventional in the art to separate the washing liquid and the organic solution, for example, liquid separation to remove the aqueous phase and retain the organic phase.

[0050] In one embodiment of the present invention, in the washing step, the amount of the washing liquid is 10 to 1000 parts by mass, preferably 20 to 800 parts by mass, and more preferably 50 to 500 parts by mass, relative to the vinyl polymer crude material. When the amount of the washing liquid is too small, sufficient washing cannot be performed, and as a result, the ash content in the vinyl polymer product cannot be effectively reduced. When the amount of the washing liquid is too large, not only the separation of the washing liquid and the organic solvent is affected, but also energy consumption is increased.

[0051] In one embodiment of the present invention, the washing step may be performed for 3 minutes to 4 hours, preferably 5 minutes to 2 hours, and more preferably 5 minutes to 1 hour.

[0052] In one embodiment of the present invention, the temperature of the washing step is not particularly limited, and can be 0-100° C., or can be room temperature or the temperature of the material to be treated.

[0053] In one embodiment of the present invention, the adsorbent used in the adsorption step can be any porous solid having adsorption capacity, and can be at least one selected from organic porous solids and inorganic porous solids.

[0054] Specifically, the organic porous solid includes, for example, olefin homopolymers or copolymers, polyvinyl alcohol or its copolymers, cyclodextrin, (co)polyester, (co)polyamide, vinyl chloride homopolymers or copolymers, acrylate homopolymers or copolymers, methacrylate homopolymers or copolymers, styrene homopolymers or copolymers, and the like, and at least one of the partially cross-linked forms of these homopolymers or copolymers, among which partially cross-linked (for example, a cross-linking degree of at least 2% but less than 100%) styrene polymers are preferred.

[0055] As the inorganic porous solid, for example, refractory oxides of metals of Group II A, IIIA, IVA or IVB of the periodic table (such as silicon dioxide (also known as silicon oxide or silica gel), aluminum oxide, magnesium oxide, titanium oxide, zirconium oxide or thorium oxide, etc.), or any refractory composite oxides of these metals (such as silicon aluminum oxide, magnesium aluminum oxide, titanium silicon oxide, titanium magnesium oxide and titanium aluminum oxide, etc.), as well as clay, molecular sieves (such as ZSM-5 and MCM-41), mica, montmorillonite, bentonite and diatomaceous earth, etc. As the inorganic porous solid, oxides generated by high-temperature hydrolysis of gaseous metal halides or gaseous silicon compounds can also be cited.

[0056] As the inorganic porous solid, silicon dioxide, aluminum oxide, magnesium oxide, silicon aluminum oxide, magnesium aluminum oxide, titanium silicon oxide, titanium dioxide, molecular sieves, and montmorillonite are preferred, and aluminum oxide, silicon dioxide, and molecular sieves are particularly preferred.

[0057] In one embodiment of the present invention, in the adsorption step, stirring is preferably performed to allow the adsorbent to fully contact the material to be adsorbed. At this time, the stirring method can be carried out in a manner known in the art, including but not limited to stirring methods such as stirring paddles.

[0058] In one embodiment of the present invention, in the adsorption step, after the adsorption is completed, a post-adsorption separation is performed, wherein the adsorbent and the organic solution are separated. The separation method can be conventional in the art to separate the adsorbent solid from the organic solution, for example, by filtration separation.

[0059] In one embodiment of the present invention, in the adsorption step, the amount of the adsorbent is 0.5-15 parts by mass, preferably 1-10 parts by mass, and more preferably 3-8 parts by mass, relative to the crude vinyl polymer material. When the amount of the adsorbent is too small, sufficient adsorption cannot be performed, the purification effect of the crude vinyl polymer material is poor, and the ash content in the vinyl polymer product cannot be effectively reduced. When the amount of the adsorbent is too much, not only the separation of the adsorbent and the organic solvent is affected, but also too much adsorbent will cause unnecessary adsorption of the organic solution, affecting the final yield of the vinyl polymer, and also resulting in increased energy consumption.

[0060] In one embodiment of the present invention, the adsorption step may last for 5 minutes to 2 hours, preferably 5 minutes to 1 hour, and more preferably 10 to 30 minutes.

[0061] In one embodiment of the present invention, the temperature of the adsorption step is 60-300° C., preferably 80-250° C., and more preferably 120-180° C. If the adsorption temperature is too low, sufficient adsorption cannot be performed, resulting in excessive ash residue; however, if the adsorption temperature is too high, the yield of the final vinyl polymer will be affected.

[0062] In the present invention, post-processing can be performed according to method 1 or method 2.

[0063] In one embodiment of the present invention, in the case of mode 1, it sequentially includes A) a washing step, in which the organic solution containing the crude vinyl polymer material is washed with a washing liquid, and B) an adsorption step, in which an adsorbent is brought into contact with the organic solution containing the crude vinyl polymer material to perform adsorption.

[0064] In one embodiment of the present invention, in the case of method 1, it sequentially includes A) a washing step, in which an organic solution containing a crude vinyl polymer material is washed with a washing liquid, and then the washing liquid is separated from the organic solution containing the crude vinyl polymer material, and B) an adsorption step, in which an adsorbent is brought into contact with the organic solution containing the crude vinyl polymer material for adsorption.

[0065] In one embodiment of the present invention, in the case of method 1, it sequentially includes A) a washing step, in which the organic solution containing the crude vinyl polymer material is washed with a washing liquid, and B) an adsorption step, in which an adsorbent is brought into contact with the organic solution containing the crude vinyl polymer material to perform adsorption, and then the adsorbent and the organic solution containing the crude vinyl polymer material are separated.

[0066] In one embodiment of the present invention, in the case of method 1, it includes in sequence A) a washing step, in which an organic solution containing a crude vinyl polymer material is washed with a washing liquid, and then the washing liquid is separated from the organic solution containing the crude vinyl polymer material, and B) an adsorption step, in which an adsorbent is brought into contact with the organic solution containing the crude vinyl polymer material, adsorption is performed, and then the adsorbent and the organic solution containing the crude vinyl polymer material are separated.

[0067] In one embodiment of the present invention, in the case of mode 2, it sequentially includes A′) an adsorption step, in which the adsorbent is brought into contact with an organic solution containing a vinyl polymer crude material to perform adsorption, and B′) a washing step, in which the organic solution containing the vinyl polymer crude material is washed with a washing liquid.

[0068] In one embodiment of the present invention, in the case of mode 2, it sequentially includes A′) an adsorption step, in which an adsorbent is contacted with an organic solution containing a crude vinyl polymer material to perform adsorption, and then the adsorbent and the organic solution containing the crude vinyl polymer material are separated, and B′) a washing step, in which the organic solution containing the crude vinyl polymer material is washed using a washing liquid.

[0069] In one embodiment of the present invention, in the case of mode 2, it sequentially includes A′) an adsorption step, in which an adsorbent is brought into contact with an organic solution containing a crude vinyl polymer material to perform adsorption, and B′) a washing step, in which a washing liquid is used to wash the organic solution containing the crude vinyl polymer material, and then the washing liquid is separated from the organic solution containing the crude vinyl polymer material.

[0070] In one embodiment of the present invention, in the case of method 2, it sequentially includes A′) an adsorption step, wherein an adsorbent is contacted with an organic solution containing a crude vinyl polymer material to perform adsorption, and then the adsorbent and the organic solution containing the crude vinyl polymer material are separated, and B′) a washing step, wherein the organic solution containing the crude vinyl polymer material is washed with a washing liquid, and then the washing liquid is separated from the organic solution containing the crude vinyl polymer material.

[0071] In the present invention, the post-treatment method of the vinyl polymer is preferably carried out according to the second embodiment.

[0072] In the present invention, an organic solution containing a vinyl polymer is obtained by a post-treatment method of the vinyl polymer. The vinyl polymer can be obtained from the organic solution containing the vinyl polymer by performing a separation step in a conventional manner in the art. For example, the vinyl polymer can be obtained by removing the solvent by drying, flash separation, etc.; or the organic solution containing the vinyl polymer is added to a poor solvent for the vinyl polymer to precipitate the vinyl polymer.

[0073] Therefore, in one embodiment of the present invention, in the post-treatment method of the vinyl polymer of the present invention, after the vinyl polymer crude material is treated according to method 1 or method 2, a separation step is further performed to obtain a vinyl polymer product.

[0074] In an exemplary embodiment of the present invention, a nickel-based catalyst represented by the following formula (1) is used as a main catalyst, one or more selected from aluminoxane, modified aluminoxane, alkyl aluminum, alkyl aluminum hydrolyzate, alkyl aluminum halide, borofluorane, alkyl boron and alkyl boron ammonium salt are used as co-catalysts, and hexane is used as a polymerization solvent to carry out solution polymerization of ethylene to prepare branched polyethylene.

[0075]

[0076] In formula (1), R1 and R2 are hydrogen, C 1-4 Straight or branched hydrocarbon group (preferably C 1-4 Straight or branched alkyl), they may also form a ring with each other (preferably a 5-6 membered ring). 12 Selected from hydrogen, C 1-4 Straight or branched hydrocarbon group (preferably C 1-4 (a) a straight chain or branched chain alkyl group; and (b) a halogen group.

[0077] The obtained polymerization solution containing branched polyethylene crude material is subjected to the above-mentioned post-treatment method of the present invention, and the above-mentioned washing step and adsorption step are carried out in sequence; or the above-mentioned adsorption step and washing step are carried out in sequence to obtain a purified polymerization solution containing branched polyethylene, and after drying and separation, branched polyethylene can be obtained. The ash content of the branched polyethylene is measured to be less than 80ppm (for example, the aluminum content is less than 70ppm, and the nickel content is less than 10ppm), preferably less than 70ppm (for example, the aluminum content is less than 65ppm, and the nickel content is less than 5ppm), and more preferably less than 60ppm (for example, the aluminum content is less than 55ppm, and the nickel content is less than 4.5ppm).

[0078] The present invention Figure 1 In the method, the discharge from the polymerization reactor (reactor) is first introduced into a washing step for washing, and then the washed material is introduced into an adsorption step for adsorption and post-treatment.

[0079] The present invention Figure 2 In the method, the discharge from the polymerization reactor (reactor) is first introduced into an adsorption step for adsorption, and then the adsorbed material is introduced into a washing step for washing and post-treatment.

[0080] The present invention Figure 3 In the method, the discharge from the polymerization reactor (reactor) is first introduced into a washing step for washing, wherein the washing is performed twice, and then the washed material is introduced into an adsorption step for adsorption and post-treatment.

[0081] [Post-treatment device for vinyl polymer]

[0082] The post-treatment device of the vinyl polymer of the present invention comprises a washing unit and an adsorption unit, wherein the washing unit and the adsorption unit are connected by a pipeline, wherein:

[0083] When the washing unit is located upstream of the adsorption unit, a vinyl polymer raw material inlet and a washing liquid inlet are provided in the washing unit, and a washing finished material inlet and an adsorbent inlet are provided in the adsorption unit; or,

[0084] When the adsorption unit is located upstream of the washing unit, a vinyl polymer coarse material inlet and an adsorbent inlet are arranged in the adsorption unit, and an adsorption finished material inlet and a washing liquid inlet are arranged in the washing unit.

[0085] In the present invention, the post-treatment device for the vinyl polymer receives the output from the polymerization reactor.

[0086] In the present invention, the polymerization reactor may be a conventional polymerization reactor in the art, for example, a solution polymerization reactor, a slurry polymerization reactor, a gas phase polymerization reactor, preferably a solution polymerization reactor. When the polymerization reactor is a slurry polymerization reactor or a gas phase polymerization reactor, it is preferred that an organic solvent is used to dissolve the discharge of the polymerization reactor, and the organic solvent may be the organic solvent described above in the present invention. That is, in the present invention, the vinyl polymer crude material fed to the post-processing device is preferably in the form of a solution. At this time, the starting material fed to the post-processing device of the present invention is an organic solution containing the vinyl polymer crude material.

[0087] In one embodiment of the present invention, in the post-processing device of the present invention, at least one of an agitator and a post-washing separator is provided in the washing unit.

[0088] In one embodiment of the present invention, in the post-processing device of the present invention, a stirrer is provided in the washing unit to stir the material therein.

[0089] In one embodiment of the present invention, in the post-treatment device of the present invention, a post-washing separator is further provided in the washing unit to separate the washing liquid and the organic solution. The post-washing separator can be any separator that can separate the aqueous phase and the organic phase.

[0090] In one embodiment of the present invention, in the post-processing device of the present invention, the washing unit may include more than two washing tanks connected in series to wash the material more than twice, for example, it may include 2-6, preferably 2, 3 or 4 washing tanks.

[0091] In one embodiment of the present invention, in the post-processing device of the present invention, when the washing unit includes two or more washing tanks connected in series, at least one of an agitator and a post-washing separator may be provided in each washing tank.

[0092] In one embodiment of the present invention, in the post-treatment device of the present invention, at least one of a stirrer and a post-adsorption separator is provided in the adsorption unit.

[0093] In one embodiment of the present invention, in the post-processing device of the present invention, an agitator is provided in the adsorption unit to agitate the material therein.

[0094] In one embodiment of the present invention, in the post-treatment device of the present invention, a post-adsorption separator is further provided in the adsorption unit to separate the adsorbent and the organic solution. The post-adsorption separator can be any separator that can separate the solid phase and the liquid phase.

[0095] In one embodiment of the present invention, the washing unit is located upstream of the adsorption unit, an inlet for an organic solution containing a vinyl polymer crude material and an inlet for a washing liquid are provided in the washing unit, a discharge port of the washing unit is connected to an inlet of the adsorption unit through a pipeline, and the adsorption unit has an adsorbent inlet and a discharge port. The discharge port of the adsorption unit is connected to an evaporator, etc., to remove the organic solvent and obtain the vinyl polymer.

[0096] In one embodiment of the present invention, the adsorption unit is located upstream of the washing unit, an inlet for an organic solution containing a vinyl polymer crude material and an adsorbent inlet are provided in the adsorption unit, a discharge port of the adsorption unit is connected to the inlet of the washing unit through a pipeline, and a washing liquid inlet and a discharge port are provided in the washing unit. The discharge port of the washing unit is connected to an evaporator, etc., to remove the organic solvent and obtain the vinyl polymer.

[0097] The present invention Figure 1 In the process, the discharge from the polymerization reactor (reactor) is first introduced into a washing unit (washing kettle) for washing, and then the washed material is introduced into an adsorption unit (adsorption kettle) for adsorption and post-treatment.

[0098] The present invention Figure 2 In the process, the discharge from the polymerization reactor (reactor) is first introduced into an adsorption unit (adsorption kettle) for adsorption, and then the adsorbed material is introduced into a washing unit (washing kettle) for washing and post-treatment.

[0099] The present invention Figure 3 In the method, the discharge from the polymerization reactor (reactor) is first introduced into a washing unit (which includes two washing kettles connected in series) for washing, and then the washed material is introduced into an adsorption unit (adsorption kettle) for adsorption and post-treatment.

[0100] [Vinyl polymer products]

[0101] By means of the post-treatment method of the vinyl polymer of the present invention, the ash content of the obtained vinyl polymer product is sufficiently reduced.

[0102] In the present invention, the ash content in the vinyl polymer product is expressed by the content of metal elements (Al, Ni, etc.) therein.

[0103] By using the post-treatment method of the vinyl polymer of the present invention, the ash content of the obtained vinyl polymer product is lower than 80 ppm (for example, the aluminum content is lower than 70 ppm, and the nickel content is lower than 10 ppm), preferably lower than 70 ppm (for example, the aluminum content is lower than 65 ppm, and the nickel content is lower than 5 ppm), and more preferably lower than 60 ppm (for example, the aluminum content is lower than 55 ppm, and the nickel content is lower than 4.5 ppm).

[0104] Example

[0105] The present invention is further described in detail below using examples, but the present invention is not limited to these examples.

[0106] Ash content determination method:

[0107] The contents of aluminum, nickel and other elements in polyethylene were determined by ICP-AES method.

[0108] The α-diimine nickel catalyst used in the embodiment is a catalyst shown in the following formula:

[0109]

[0110] Example 1

[0111] In this embodiment, α-diimine nickel catalyst and ethylaluminum dichloride are used as co-catalysts, and hexane is used as the polymerization solution to produce branched polyethylene by solution polymerization. The polymerization reaction is carried out at 10 kg of ethylene pressure and 60° C. for 0.5 hour. 5% hydrochloric acid is added to the polymerization reactor to acidify ethanol and terminate the reaction.

[0112] The hexane solution containing 10 g of branched polyethylene crude material discharged from the reactor was washed three times with 3 liters of deionized water at room temperature, and the washing water was removed by liquid separation. The single washing time was 5 minutes. Then, 60 g of Al2O3 (alumina for chromatography) was added to the obtained hexane solution containing branched polyethylene crude material for adsorption at an adsorption temperature of 150°C for 10 minutes, and filtered to obtain a hexane solution containing branched polyethylene. Then, the hexane was dried to obtain low-ash branched polyethylene.

[0113] The obtained low-ash branched polyethylene had an Al content of 35 ppm and a Ni content of 3.6 ppm.

[0114] Example 2

[0115] In this embodiment, α-diimine nickel catalyst and ethylaluminum dichloride are used as co-catalysts, and hexane is used as the polymerization solution to produce branched polyethylene by solution polymerization. The polymerization reaction is carried out at 10 kg of ethylene pressure and 60° C. for 0.5 h. 5% hydrochloric acid is added to the polymerization reactor to acidify ethanol and terminate the reaction.

[0116] 60 g of Al2O3 (alumina for chromatography) was added to the above hexane solution containing 10 g of branched polyethylene crude material discharged from the reactor for adsorption at an adsorption temperature of 150°C for 10 minutes, filtered, and the obtained hexane solution containing branched polyethylene crude material was washed three times with 3 liters of deionized water at room temperature, and the washing water was removed by liquid separation, and the single washing time was 5 minutes. A hexane solution containing branched polyethylene was obtained, and then the hexane was dried to obtain low-ash branched polyethylene.

[0117] The obtained low-ash branched polyethylene had an Al content of 31 ppm and a Ni content of 2.9 ppm.

[0118] Example 3

[0119] In this embodiment, α-diimine nickel catalyst and ethylaluminum dichloride are used as co-catalysts, and hexane is used as the polymerization solution to produce branched polyethylene by solution polymerization. The polymerization reaction is carried out at 10 kg of ethylene pressure and 60° C. for 0.5 h. 5% hydrochloric acid is added to the polymerization reactor to acidify ethanol and terminate the reaction.

[0120] The hexane solution containing 10 g of branched polyethylene crude material discharged from the reactor was washed once with 3 liters of deionized water at room temperature, and the washing water was removed by liquid separation. The washing time was 5 minutes, and then 60 g of Al2O3 (alumina for chromatography) was added to the obtained hexane solution containing branched polyethylene crude material for adsorption at an adsorption temperature of 150°C for 10 minutes, and filtered to obtain a hexane solution containing branched polyethylene. Then, the hexane was dried to obtain low-ash branched polyethylene.

[0121] The obtained low-ash branched polyethylene had an Al content of 50 ppm and a Ni content of 4.3 ppm.

[0122] Example 4

[0123] In this embodiment, α-diimine nickel catalyst and ethylaluminum dichloride are used as co-catalysts, and hexane is used as the polymerization solution to produce branched polyethylene by solution polymerization. The polymerization reaction is carried out at 10 kg of ethylene pressure and 60° C. for 0.5 h. 5% hydrochloric acid is added to the polymerization reactor to acidify ethanol and terminate the reaction.

[0124] 60 g of Al2O3 (alumina for chromatography) was added to the above hexane solution containing 10 g of branched polyethylene crude material discharged from the reactor for adsorption at an adsorption temperature of 150°C for 10 minutes, filtered, and the obtained hexane solution containing branched polyethylene crude material was washed once with 3 liters of deionized water at room temperature, and the washing water was removed by liquid separation for 5 minutes. A hexane solution containing branched polyethylene was obtained, and then the hexane was dried to obtain low-ash branched polyethylene.

[0125] The obtained low-ash branched polyethylene had an Al content of 48 ppm and a Ni content of 3.8 ppm.

[0126] Example 5

[0127] In this embodiment, α-diimine nickel catalyst and ethylaluminum dichloride are used as co-catalysts, and hexane is used as the polymerization solution to produce branched polyethylene by solution polymerization. The polymerization reaction is carried out at 10 kg of ethylene pressure and 60° C. for 0.5 h. 5% hydrochloric acid is added to the polymerization reactor to acidify ethanol and terminate the reaction.

[0128] The hexane solution containing 10 g of branched polyethylene crude material discharged from the reactor was washed once with 3 liters of deionized water at room temperature, and the washing water was removed by liquid separation. The washing time was 5 minutes, and then 60 g of Al2O3 (alumina for chromatography) was added to the obtained hexane solution containing branched polyethylene crude material for adsorption at an adsorption temperature of 100°C for 10 minutes, and filtered to obtain a hexane solution containing branched polyethylene. Then, the hexane was dried to obtain low-ash branched polyethylene.

[0129] The obtained low-ash branched polyethylene had an Al content of 60 ppm and a Ni content of 4.3 ppm.

[0130] Example 6

[0131] In this embodiment, α-diimine nickel catalyst and ethylaluminum dichloride are used as co-catalysts, and hexane is used as the polymerization solution to produce branched polyethylene by solution polymerization. The polymerization reaction is carried out at 10 kg of ethylene pressure and 60° C. for 0.5 h. 5% hydrochloric acid is added to the polymerization reactor to acidify ethanol and terminate the reaction.

[0132] 60 g of Al2O3 (alumina for chromatography) was added to the hexane solution containing the branched polyethylene crude material discharged from the reactor for adsorption at an adsorption temperature of 100° C. for 10 minutes, and then filtered. The obtained hexane solution containing the branched polyethylene crude material was washed once with 3 liters of deionized water at room temperature, and the washing water was removed by liquid separation for 5 minutes. A hexane solution containing branched polyethylene was obtained, and then the hexane was dried to obtain low-ash branched polyethylene.

[0133] The obtained low-ash branched polyethylene had an Al content of 55 ppm and a Ni content of 4.2 ppm.

[0134] Comparative Example 1

[0135] Branched polyethylene was produced by solution polymerization using α-diimine nickel catalyst and ethylaluminum dichloride as co-catalyst and hexane as polymerization solution. The polymerization reaction was carried out at 10 kg ethylene pressure and 60° C. for 0.5 h. 5% hydrochloric acid was added to the polymerization reactor to acidify ethanol and terminate the reaction.

[0136] The hexane solution containing 10 g of the branched polyethylene crude material discharged from the reactor was washed three times with 3 liters of deionized water at room temperature, and the washing water was removed by liquid separation. The single washing time was 5 minutes. The obtained hexane solution containing the branched polyethylene was then dried to remove the hexane to obtain the branched polyethylene.

[0137] The Al content of the obtained branched polyethylene was 224 ppm and the Ni content was 24.4 ppm.

[0138] Comparative Example 2

[0139] Branched polyethylene was produced by solution polymerization using α-diimine nickel catalyst and ethylaluminum dichloride as co-catalyst and hexane as polymerization solution. The polymerization reaction was carried out at 10 kg ethylene pressure and 60° C. for 0.5 h. 5% hydrochloric acid was added to the polymerization reactor to acidify ethanol and terminate the reaction.

[0140] 60 g of Al2O3 (alumina for chromatography) was added to the hexane solution containing 10 g of branched polyethylene crude material discharged from the reactor for adsorption at an adsorption temperature of 150° C. for 10 minutes, and then filtered. The obtained hexane solution containing branched polyethylene was then dried to remove hexane to obtain branched polyethylene.

[0141] The Al content of the obtained branched polyethylene was 192 ppm and the Ni content was 16.3 ppm.

[0142] Comparative Example 3

[0143] Branched polyethylene was produced by solution polymerization using α-diimine nickel catalyst and ethylaluminum dichloride as co-catalyst and hexane as polymerization solution. The polymerization reaction was carried out at 10 kg ethylene pressure and 60° C. for 0.5 h. 5% hydrochloric acid was added to the polymerization reactor to acidify ethanol and terminate the reaction.

[0144] The hexane solution containing 10 g of the branched polyethylene crude material discharged from the reactor was washed once with 3 liters of deionized water at room temperature, and the washing water was removed by liquid separation. The washing time was 5 minutes. The obtained hexane solution containing the branched polyethylene was then dried to remove the hexane to obtain the branched polyethylene.

[0145] The Al content of the obtained branched polyethylene was 280 ppm and the Ni content was 28.6 ppm.

[0146] Comparative Example 4

[0147] In this embodiment, α-diimine nickel catalyst and ethylaluminum dichloride are used as co-catalysts, and hexane is used as the polymerization solution to produce branched polyethylene by solution polymerization. The polymerization reaction is carried out at 10 kg of ethylene pressure and 60° C. for 0.5 h. 5% hydrochloric acid is added to the polymerization reactor to acidify ethanol and terminate the reaction.

[0148] 60 g of Al2O3 (alumina for chromatography) was added to the hexane solution containing 10 g of branched polyethylene crude material discharged from the reactor for adsorption at an adsorption temperature of 100° C. for 10 minutes, and then filtered. The obtained hexane solution containing branched polyethylene was then dried to remove hexane to obtain branched polyethylene.

[0149] The Al content of the obtained branched polyethylene was 219 ppm and the Ni content was 19 ppm.

[0150] It can be seen from the above data that the post-treatment method of the present invention can significantly reduce the ash content in polyethylene with simple steps and at a low cost.

[0151] Industrial Applicability

[0152] The method of the present invention can realize post-treatment of vinyl polymer crude material in a simple manner to effectively reduce the ash content therein. In addition, the device of the present invention has a simple structure and convenient pipeline arrangement, and can be conveniently applied to existing vinyl polymer preparation complete sets of equipment.

Claims

1. A post-treatment method for a vinyl polymer, which is carried out according to method 1 or method 2, Method 1 includes the following steps: A) a washing step, in which the crude vinyl polymer material is washed with a washing liquid, and B) an adsorption step, wherein an adsorbent is brought into contact with the material that has completed the washing step to perform adsorption; Method 2 includes the following steps: A') an adsorption step, wherein an adsorbent is brought into contact with the vinyl polymer crude material to effect adsorption, and B') A washing step, wherein the material after the adsorption step is washed with a washing liquid.

2. The method according to claim 1, wherein: The washing liquid is water or an alcohol-containing aqueous solution, preferably deionized water.

3. The method according to claim 1 or 2, wherein: In the washing step, the washing liquid is added twice or more for washing (it can be evenly added for 2-6 times, preferably evenly added for 2, 3 or 4 times for washing). Preferably, stirring is performed during the washing step.

4. The method according to any one of claims 1 to 3, wherein: The amount of the washing liquid is 10 parts by mass to 1000 parts by mass, preferably 20 parts by mass to 800 parts by mass, and more preferably 50 parts by mass to 500 parts by mass, relative to the vinyl polymer crude material.

5. The method according to any one of claims 1 to 4, wherein: The adsorbent in the adsorption step is selected from at least one of an organic porous solid and an inorganic porous solid, As the organic porous solid, it is preferably selected from at least one of olefin homopolymers or copolymers, polyvinyl alcohol or its copolymers, cyclodextrin, (co)polyester, (co)polyamide, vinyl chloride homopolymers or copolymers, acrylate homopolymers or copolymers, methacrylate homopolymers or copolymers, styrene homopolymers or copolymers, and partially crosslinked forms of these homopolymers or copolymers, wherein at least one partially crosslinked (crosslinking degree of at least 2% but less than 100%) styrene polymer is preferred, As the inorganic porous solid, it is preferably selected from refractory oxides of metals of Groups IIA, IIIA, IVA or IVB of the periodic table (such as silicon dioxide (also known as silicon oxide or silica gel), aluminum oxide, magnesium oxide, titanium oxide, zirconium oxide or thorium oxide, etc.), or any refractory composite oxides of these metals (such as silicon aluminum oxide, magnesium aluminum oxide, titanium silicon oxide, titanium magnesium oxide and titanium aluminum oxide), as well as clay, molecular sieves (such as ZSM-5 and MCM-41), mica, montmorillonite, bentonite and diatomaceous earth, and at least one of oxides generated by high-temperature hydrolysis of gaseous metal halides or gaseous silicon compounds. It is further preferably selected from at least one of silicon dioxide, aluminum oxide, magnesium oxide, silicon aluminum oxide, magnesium aluminum oxide, titanium silicon oxide, titanium dioxide, molecular sieves and montmorillonite, and particularly preferably selected from at least one of aluminum oxide, silicon dioxide and molecular sieves.

6. The method according to any one of claims 1 to 5, wherein: The amount of the adsorbent is 0.5 to 15 parts by mass, preferably 1 to 10 parts by mass, and more preferably 3 to 8 parts by mass, based on the vinyl polymer crude material.

7. The method according to any one of claims 1 to 6, wherein: The time of the washing step is 3 minutes to 4 hours, preferably 5 minutes to 2 hours, more preferably 5 minutes to 1 hour; the temperature of the washing step is 0-100°C.

8. The method according to any one of claims 1 to 7, wherein: The time of the adsorption step is 5 minutes to 2 hours, preferably 5 minutes to 1 hour, more preferably 10 to 30 minutes; the temperature of the adsorption step is 60 to 300°C, preferably 80 to 250°C, more preferably 120 to 180°C.

9. The method according to any one of claims 1 to 8, wherein: The washing step further comprises a post-washing separation step, wherein the washing liquid is separated from the organic solution, preferably by liquid separation.

10. The method according to any one of claims 1 to 9, wherein: The adsorption step further comprises a post-adsorption separation step, wherein the adsorbent is separated from the organic solution, preferably by filtration.

11. The method according to any one of claims 1 to 10, wherein: In case of method 1, The method comprises: sequentially comprising: A) a washing step, in which an organic solution containing a crude vinyl polymer material is washed with a washing liquid, and B) an adsorption step, in which an adsorbent is brought into contact with the organic solution containing the crude vinyl polymer material to perform adsorption; or The method comprises: sequentially comprising: A) a washing step, wherein an organic solution containing a crude vinyl polymer material is washed with a washing liquid, and then the washing liquid is separated from the organic solution containing the crude vinyl polymer material, and B) an adsorption step, wherein an adsorbent is contacted with the organic solution containing the crude vinyl polymer material to perform adsorption; or The method comprises: sequentially comprising: A) a washing step, in which an organic solution containing a crude vinyl polymer material is washed with a washing liquid, and B) an adsorption step, in which an adsorbent is brought into contact with the organic solution containing the crude vinyl polymer material, adsorption is performed, and then the adsorbent and the organic solution containing the crude vinyl polymer material are separated; or The method comprises: sequentially comprising: A) a washing step, wherein an organic solution containing a crude vinyl polymer material is washed with a washing liquid, and then the washing liquid is separated from the organic solution containing the crude vinyl polymer material, and B) an adsorption step, wherein an adsorbent is contacted with the organic solution containing the crude vinyl polymer material, adsorption is performed, and then the adsorbent and the organic solution containing the crude vinyl polymer material are separated; In case of method 2, The method comprises A') an adsorption step, wherein an adsorbent is contacted with an organic solution containing a vinyl polymer crude material to perform adsorption, and B') a washing step, wherein the organic solution containing the vinyl polymer crude material is washed with a washing liquid; or The method comprises: sequentially comprising: A′) an adsorption step, wherein an adsorbent is contacted with an organic solution containing a crude vinyl polymer material, adsorption is performed, and then the adsorbent and the organic solution containing the crude vinyl polymer material are separated, and B′) a washing step, wherein the organic solution containing the crude vinyl polymer material is washed with a washing liquid; or The method comprises A′) an adsorption step, wherein an adsorbent is brought into contact with an organic solution containing a crude vinyl polymer material to perform adsorption, and B′) a washing step, wherein the organic solution containing the crude vinyl polymer material is washed with a washing liquid, and then the washing liquid is separated from the organic solution containing the crude vinyl polymer material; or The method comprises, in sequence, A′) an adsorption step, wherein an adsorbent is brought into contact with an organic solution containing a crude vinyl polymer material, adsorption is carried out, and then the adsorbent and the organic solution containing the crude vinyl polymer material are separated, and B′) a washing step, wherein the organic solution containing the crude vinyl polymer material is washed with a washing liquid, and then the washing liquid is separated from the organic solution containing the crude vinyl polymer material.

12. The method according to any one of claims 1 to 11, wherein: After the vinyl polymer crude material is treated according to method 1 or method 2, a separation step is further performed to obtain a vinyl polymer product.

13. The method according to any one of claims 1 to 12, wherein: The vinyl polymer crude material is obtained from solution polymerization.

14. A post-treatment device for vinyl polymers, comprising a washing unit and an adsorption unit, wherein the washing unit and the adsorption unit are connected via a pipeline, wherein: When the washing unit is located upstream of the adsorption unit, a vinyl polymer raw material inlet and a washing liquid inlet are provided in the washing unit, and a washing finished material inlet and an adsorbent inlet are provided in the adsorption unit; or, When the adsorption unit is located upstream of the washing unit, a vinyl polymer coarse material inlet and an adsorbent inlet are arranged in the adsorption unit, and an adsorption finished material inlet and a washing liquid inlet are arranged in the washing unit.

15. The post-processing device for vinyl polymer according to claim 14, wherein: The washing unit is provided with at least one of an agitator and a post-washing separator.

16. The post-processing device for vinyl polymer according to claim 14 or 15, wherein: The adsorption unit is provided with at least one of an agitator and a post-adsorption separator.

17. The post-processing device for vinyl polymer according to any one of claims 14 to 16, wherein: The washing unit comprises two or more washing tanks connected in series, for example, 2-6, preferably 2, 3 or 4 washing tanks.

18. A vinyl polymer obtained by the post-treatment method of a vinyl polymer according to any one of claims 1 to 13, wherein the ash content is less than 80 ppm (e.g., the aluminum content is less than 70 ppm, the nickel content is less than 10 ppm).

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