Novel polyolefin elastomer as well as preparation method and application thereof

Abstract

The invention provides a novel polyolefin elastomer and a preparation method and application thereof.The preparation method comprises the steps that ethylene, alpha-olefin and a condensing agent are refined, the refined reaction raw materials, hydrogen, nitrogen, a metallocene catalyst and an antistatic agent are subjected to a low-temperature polymerization reaction in a reactor, polyolefin elastomer powder is obtained, and the polyolefin elastomer powder is added into the reactor; polyolefin elastomer powder is sequentially subjected to degassing treatment and extrusion granulation treatment, the novel polyolefin elastomer is obtained, and in the polyolefin elastomer powder, the content of particles with the particle size D50 of 1 micrometer to 300 micrometers, the content of particles with the particle size D50 of 300 micrometers to 1000 micrometers, the content of particles with the particle size D50 of 1600 micrometers to 4000 micrometers are 0.1% to 0.3%, the content of particles with the particle size D50 of 3.0% to 9.6% and the content of particles with the particle size D50 of 33.4% to 58.9% respectively. The polyolefin elastomer is excellent in performance, bonding blocks are avoided in the preparation process, the production efficiency and quality are improved, and the industrial application prospect is excellent.

Description

Technical Field

[0001] The present application relates to the technical field of polyolefin elastomers, and in particular to a novel polyolefin elastomer and a preparation method and application thereof. Background Art

[0002] Polyolefin elastomer (POE) refers to a random copolymer obtained by polymerization of ethylene and α-olefins (1-butene, 1-hexene, 1-octene, etc.), with a comonomer content of 20-45% and a density of 0.860-0.890 g / cm 3 , polymer crystallinity <20%. Polyolefin elastomers have excellent water resistance, air permeability, aging resistance, corrosion resistance and heat resistance, and can be widely used in automotive plastic modification, photovoltaic encapsulation film, foamed shoe materials, packaging, household appliances, wires and cables, medical equipment, hot melt adhesives and other fields.

[0003] Since there are many technical difficulties in the production of polyolefin elastomers, solution polymerization processes are used both at home and abroad. Generally, there are three processes for the polymerization of ethylene and α-olefins: gas phase polymerization, slurry polymerization and solution polymerization. With the increase of the insertion rate of α-olefins, the polymer transitions from linear low-density polyethylene to polyolefin plastomers and polyolefin elastomers, the degree of branching of the molecular structure increases, and the density, crystallinity, softening point and melting point gradually decrease. When the insertion rate of α-olefins increases to 10% to 20%, the polymer concentration is too high, which will lead to excessive viscosity of the polymer, and it is difficult for the polymer to flow in a slurry reactor in a granular form to achieve homogeneous polymerization. In addition, low-melting-point polymers are easily swollen by solvents and agglomerated and adhered, which will become sticky and block pipelines, and there will be problems of blocking the kettle and hanging on the wall, so it is impossible to use the gas phase polymerization process for production. Therefore, in recent years, China has increased the development of solution-based polyolefin elastomer polymerization processes, but no polyolefin elastomer products have been developed on industrial devices of gas-phase fluidized bed processes. Compared with the gas phase polymerization process, the solution polymerization process overcomes the problem of low melting point and easy softening and clogging of polyolefin elastomers. However, the solution polymerization process requires the use of a large amount of organic solvents, and the separation and recovery of solvents consumes a lot of energy and is costly. In addition, as the concentration of polymer in the solvent increases, the resistance to mass transfer and heat transfer increases, which can easily cause scaling or even clogging in the reactor. Based on the above problems, in the prior art, a Chinese patent document with the authorization announcement number CN103221439B discloses a polyethylene polymerization in a gas phase reactor, and the product density range is 0.900g / cm 3 Up to 0.912g / cm 3 According to density, the product is actually classified as ultra-low density polyethylene, which is much higher than the range of polyolefin elastomers.

[0004] A Chinese patent document with the authorization announcement number CN105199031B discloses a method and device for olefin polymerization. The method comprises: introducing liquid material and catalyst into a first reactor, the olefin in the liquid material contacts with the catalyst to undergo polymerization reaction to form polyolefin; leading the liquid material and polyolefin from the discharge port of the first reactor to the second reactor, and at the same time, introducing the catalyst, gas material and liquid material into the second reactor; maintaining a dense phase fluidized bed inside the second reactor, the gas material, liquid material and catalyst contact to generate polyolefin; leading the unreacted gas material from the outlet of the second reactor, compressing, condensing and separating the gas and liquid, the liquid material obtained by gas-liquid separation is transported to the first reactor to form a circulation loop, and the remaining liquid material and gas material are transported to the second reactor to form a circulation loop; and the polyolefin is discharged continuously or intermittently from the second reactor. The addition of a first reactor with a stirred tank makes the product density higher than 0.90g / cm 3 Moreover, the series connection of the two reactors is conducive to the production of polyolefin products with wide distribution and improves the stability of reactor operation.

[0005] The Chinese patent document with the authorization announcement number CN108948248B discloses a method and device for producing polyolefin elastomers by gas phase method and the application of polyolefin elastomers. The method comprises the following steps: reacting in a reactor with polyethylene particles as a seed bed, introducing a raw material mixed gas including ethylene, hydrogen and nitrogen into the reactor, causing the polyethylene particles in the seed bed to flow and reach a fluidized state, then adding a catalyst into the reactor and introducing atomized droplet-shaped comonomers to react, wherein the comonomers are long-chain olefins with 6 to 18 carbon atoms, and the prepared polymer product has a density of 0.865 g / cm 3 Up to 0.910g / cm 3 , the long-chain olefin content is 6wt% to 40wt%. The purpose of the invention of this patent is to solve the problem of uneven distribution of liquid long-chain α-olefins with high comonomer content in the gas phase seed bed and poor copolymerization performance in the preparation process of polyolefin elastomers. The invention method and device of this patent must atomize the comonomer, and require a test device that has undergone structural modification, specifically a reactor with a special structural form. The polymerization temperature used is generally higher than the melting point of the product, and there is a risk of polymer stickiness blocking the reactor and pipeline, and a series of problems such as blockage and agglomeration that may occur in the system after polymerization are not considered.

[0006] Based on this, in the face of the problem that polyolefin elastomers in the prior art have polymer sticky blocks in the polymerization process, it is urgent to provide a new polyolefin elastomer and a preparation method thereof to improve the above problem. Summary of the invention

[0007] The main purpose of the present invention is to provide a novel polyolefin elastomer and a preparation method and application thereof, so as to solve the technical problem of the existence of polymer sticky blocks in the polymerization process of polyolefin elastomer in the prior art.

[0008] In order to achieve the above-mentioned object, according to one aspect of the present invention, a method for preparing a novel polyolefin elastomer is provided, the method comprising: step S1, refining ethylene, α-olefin and condensing agent to obtain refined reaction raw materials; step S2, subjecting the refined reaction raw materials, hydrogen, nitrogen, metallocene catalyst and antistatic agent to low-temperature polymerization in a reactor to obtain polyolefin elastomer powder; step S3, sequentially subjecting the polyolefin elastomer powder to degassing treatment and extrusion granulation treatment to obtain a novel polyolefin elastomer; wherein, in the polyolefin elastomer powder, the content of particles with a powder particle size D50 of 1 μm to 300 μm is 0.1% to 0.3%, the content of particles with a powder particle size D50 of 300 μm to 1000 μm is 3.0% to 9.6%, and the content of particles with a powder particle size D50 of 1600 μm to 4000 μm is 33.4% to 58.9%.

[0009] Furthermore, in step S1, the refining treatment includes: refining ethylene, α-olefin and condensing agent in a fixed bed reactor, so that the mass percentage of water in each reaction raw material after the refining treatment is independently 0 to 1 μg / g, the mass percentage of oxygen is independently 0 to 0.5 μg / g, and the volume percentage of the sum of carbon monoxide and carbon dioxide is independently 0 to 0.5 μg / g.

[0010] Furthermore, the active component of the metallocene catalyst is selected from one or more of zirconocene chloride, methylaluminoxane, butylaluminoxane and hexylaluminoxane, the particle size D50 of the metallocene catalyst is 45 μm to 54 μm, and the yield of the metallocene catalyst is 6000 g product / g catalyst to 15000 g product / g catalyst.

[0011] Furthermore, in step S2, the low-temperature polymerization reaction is carried out in a gas-phase fluidized bed reactor, and the gas-phase fluidization rate is 0.3 m / s to 0.8 m / s, and more preferably 0.40 m / s to 0.70 m / s; the bed pressure difference of the gas-phase fluidized bed reactor is preferably 10 kPa to 80 kPa, and more preferably 20 kPa to 45 kPa; the temperature of the low-temperature polymerization reaction is preferably 35°C to 65°C, the reaction pressure is 1.5 MPa to 3.0 MPa, and the reaction time is 7h to 12h.

[0012] Furthermore, in step S3, the degassing treatment includes primary degassing treatment and secondary degassing treatment, the degassing amount of the primary degassing treatment is 30 to 60 times the volume of the polyolefin elastomer powder, the primary degassing treatment temperature is 35°C to 55°C, the degassing amount of the secondary degassing treatment is 60 to 120 times the volume of the polyolefin elastomer powder, the secondary degassing treatment temperature is 45°C to 65°C, and the secondary degassing treatment time is 12h to 15h; preferably, during the extrusion granulation process, additives are added to the polyolefin elastomer powder, the additives include talcum powder and antioxidants, the amount of the additives added is 80ppm to 350ppm, wherein the amount of talcum powder added is 0 to 100ppm, and the pelletizing water temperature of the extrusion granulation is 13°C to 45°C.

[0013] Furthermore, when the gas phase fluidized bed reactor is in a polymerization equilibrium state, the molar percentage of ethylene is 30% to 40%, the molar percentage of α-olefin is 1.0% to 8.5%, the molar percentage of hydrogen is 0.005% to 0.06%, the molar percentage of the condensing agent is 0.5% to 5% and the remainder is nitrogen; preferably, the α-olefin is 1-butene and / or 1-hexene, and the condensing agent is selected from one or more of propane, pentane, cyclopentane, hexane and cyclohexane, and more preferably one or more of propane, pentane and / or cyclohexane.

[0014] Furthermore, the amount of the antistatic agent added is 0.002wt% to 0.005wt% of ethylene; the antistatic agent includes polysulfonated betaine, alkylbenzene sulfonic acid, α-olefin homopolymer and organic solvent, and the weight percentage of each component in the antistatic agent is: 2% to 5% of polysulfonated betaine, 4% to 10% of alkylbenzene sulfonic acid, 10% to 15% of α-olefin homopolymer and 71% to 81% of organic solvent.

[0015] In order to achieve the above object, according to one aspect of the present invention, a novel polyolefin elastomer is provided. The novel polyolefin elastomer is obtained by the preparation method of the novel polyolefin elastomer.

[0016] Furthermore, the density of the polyolefin elastomer is 0.870 g / cm 3 Up to 0.890g / cm 3 , the melt mass flow rate is 0.8 g / 10 min to 18 g / 10 min, and the volatile matter content is 30 ppm to 150 ppm.

[0017] According to another aspect of the present invention, there is provided a novel polyolefin elastomer for use in the fields of photovoltaic encapsulation film, automotive plastic modification, wire and cable, and film packaging. The novel polyolefin elastomer is the novel polyolefin elastomer described above.

[0018] The polyolefin elastomer obtained by applying the technical solution of the present invention has relatively excellent performance, reduces the problem of sticky blocks in the preparation process, improves the efficiency and quality of the production process, and has broad industrial application prospects. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application is clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0020] According to the background technology part of the present invention, the technical problem of polymer sticking blocks exists in the prior art polyolefin elastomer in the polymerization process. Based on this, the present invention provides a preparation method of a novel polyolefin elastomer, which comprises: step S1, ethylene, α-olefin and condensing agent are subjected to refining treatment to obtain the reaction raw materials after refining treatment; step S2, the reaction raw materials after refining treatment, hydrogen, nitrogen, metallocene catalyst and antistatic agent are subjected to low-temperature polymerization reaction in a reactor to obtain polyolefin elastomer powder; step S3, the polyolefin elastomer powder is subjected to degassing treatment and extrusion granulation treatment in sequence to obtain a novel polyolefin elastomer; wherein, in the polyolefin elastomer powder, the content of particles with a powder particle size D50 of 1 μm to 300 μm is 0.1% to 0.3%, the content of particles with a powder particle size D50 of 300 μm to 1000 μm is 3.0% to 9.6%, and the content of particles with a powder particle size D50 of 1600 μm to 4000 μm is 33.4% to 58.9%.

[0021] Based on the technical problem of the formation of sticky blocks in the polyolefin elastomer in the prior art, the present invention refines ethylene, α-olefin and condensing agent before entering the reactor. The purpose of refining is to reduce the influence of the materials on the activity of the catalyst. The refined materials, hydrogen, nitrogen, metallocene catalyst and antistatic agent are subjected to low-temperature polymerization in the reactor to obtain polyolefin elastomer powder. Degassing and extrusion granulation are performed again to reduce the temperature during the processing and prevent the materials from softening and clogging in the pipeline, and finally obtain a new polyolefin elastomer product. In particular, in the polyolefin elastomer powder, the content of particles with a powder particle size D50 of 1 μm to 300 μm is 0.1% to 0.3%, the content of particles with a powder particle size D50 of 300 μm to 1000 μm is 3.0% to 9.6%, and the content of particles with a powder particle size D50 of 1600 μm to 4000 μm is 33.4% to 58.9%.

[0022] The above-mentioned gas-phase fluidized bed process in the present invention does not require a major transformation of the production equipment. Compared with the solution polymerization process, it has the characteristics of short operation process, low production cost, low product odor, etc. The production of polyolefin elastomers by this method has a better industrial application prospect. Moreover, in the gas-phase fluidized bed process of a single reactor, a large-particle-size, high-activity metallocene catalyst is used, and by optimizing the polymerization reaction temperature, regulating the pressure in the reactor, the molar percentage of α-olefin and ethylene, and the gas-phase fluidization rate at the bottom of the reactor, injecting an antistatic agent, preventing and controlling polymerization stickiness, and reducing the generation of polymer fine powder, the problem of softening, agglomeration, and fouling blockage of polyolefin elastomers is effectively prevented, and the technical difficulties in the production of polyolefin elastomers in the gas-phase polymerization process are eliminated.

[0023] In a preferred embodiment, in step S1, the refining treatment includes: refining ethylene, α-olefin and condensing agent in a fixed bed reactor, so that the mass percentage of water in the reaction raw materials after the refining treatment is independently 0 to 1 μg / g, the mass percentage of oxygen is independently 0 to 0.5 μg / g, and the volume percentage of the sum of carbon monoxide and carbon dioxide is independently 0 to 0.5 μg / g, so as to further reduce the influence of the materials on the catalyst activity and minimize the phenomenon of product agglomeration.

[0024] In order to further improve the performance of the new polyolefin elastomer, the active component of the metallocene catalyst is preferably selected from one or more of zirconocene chloride, methylaluminoxane, butylaluminoxane and hexylaluminoxane, the particle size D50 of the metallocene catalyst is 45μm to 54μm, and the yield of the metallocene catalyst is 6000g product / g catalyst to 15000g product / g catalyst.

[0025] In a preferred embodiment, in step S2, the low-temperature polymerization reaction is carried out in a gas-phase fluidized bed reactor, and the gas-phase fluidization rate is 0.3 m / s to 0.8 m / s, more preferably 0.40 m / s to 0.70 m / s. Thus, the material in the gas-phase reactor is in a fluidized state, a homogeneous reaction is achieved under the action of the catalyst, and the generation of fine powder in the polymerization system is suppressed by a lower gas-phase fluidization rate.

[0026] In a preferred embodiment, the bed pressure difference of the gas phase fluidized bed reactor is further preferably 10 kPa to 80 kPa, more preferably 20 kPa to 45 kPa; the temperature of the low temperature polymerization reaction is 35°C to 65°C, the reaction pressure is 1.5 MPa to 3.0 MPa, and the reaction time is 7h to 12h. Too low polymerization pressure or polymerization temperature is not conducive to the release of catalyst activity, nor is it conducive to the improvement of the insertion rate of α-olefin in the polyolefin elastomer; too high polymerization pressure increases the fine powder content in the polyolefin elastomer powder, and the fine powder enters the reactor to soften, scale and clog; too high polymerization temperature will make the polymer sticky and clogged in the reactor.

[0027] In order to further remove light components, small molecules, volatiles, etc. in the polyolefin elastomer powder, low temperature control is used to prevent the polyolefin elastomer powder from softening and clogging in the pipeline, and the degassing effect of the powder is improved by increasing the degassing amount. Preferably, in step S3, the degassing treatment includes a primary degassing treatment and a secondary degassing treatment, the degassing amount of the primary degassing treatment is 30 to 60 times the volume of the polyolefin elastomer powder, the primary degassing treatment temperature is 35°C to 55°C, the degassing amount of the secondary degassing treatment is 60 to 120 times the volume of the polyolefin elastomer powder, the secondary degassing treatment temperature is 45°C to 65°C, and the secondary degassing treatment time is 12h to 15h.

[0028] In a preferred embodiment, during the extrusion granulation process, additives are added to the polyolefin elastomer powder, the additives include talcum powder and antioxidants, and more preferably the antioxidants include model 1076 antioxidants and 1010 antioxidants, the amount of additives added is 80ppm to 350ppm, wherein the amount of talcum powder added is 0 to 100ppm, and the pelletizing water temperature of the extrusion granulation is 13°C to 45°C. The addition of a small amount of talcum powder can reduce the adhesion between product particles and prevent the product from agglomerating during storage and transportation; the number of sticky particles of the polyolefin elastomer pellets can be controlled by a low pelletizing water temperature to meet the particle appearance requirements.

[0029] In order to further adjust the molar percentage of α-olefin and ethylene to improve the insertion rate of α-olefin in the polyolefin elastomer, the melt mass flow rate of the polyolefin elastomer powder is adjusted by adjusting the molar percentage of hydrogen and ethylene, and the heat withdrawal effect generated by polymerization in the reactor is improved by the flow of the condensing agent in the polymerization system. When the gas phase fluidized bed reactor is in a state of polymerization equilibrium, the molar percentage of ethylene in the reactor is preferably 30% to 40%, the molar percentage of α-olefin is 1.0% to 8.5%, the molar percentage of hydrogen is 0.005% to 0.06%, the molar percentage of the condensing agent is 0.5% to 5% and the remainder is nitrogen. More preferably, the α-olefin is 1-butene and / or 1-hexene, and the condensing agent is selected from one or more of propane, pentane, cyclopentane, hexane and cyclohexane, and more preferably one or more of propane, pentane and or cyclohexane.

[0030] In a preferred embodiment, the amount of antistatic agent added is 0.002wt% to 0.005wt% of ethylene; the antistatic agent includes polysulfonated betaine, alkylbenzene sulfonic acid, α-olefin homopolymer and organic solvent, and the weight percentage of each component in the antistatic agent is: 2% to 5% polysulfonated betaine, 4% to 10% alkylbenzene sulfonic acid, 10% to 15% α-olefin homopolymer and 71% to 81% organic solvent. Polysulfonated betaine forms a uniform conductive layer on the surface of the polymer, so that the static electricity generated by the polymer powder is quickly dissipated and transferred; alkylbenzene sulfonic acid is an anionic surfactant, and a small amount of its addition can promote the formation of a thin layer that is easy to conduct electricity on the surface of the polymer powder, and synergistically reduce the accumulation of static electricity with polysulfonated betaine.

[0031] The present invention also provides a novel polyolefin elastomer, which is obtained by the preparation method of the novel polyolefin elastomer. The density of the polyolefin elastomer is 0.870 g / cm 3 Up to 0.890g / cm 3 , the melt mass flow rate is 0.8 g / 10 min to 18 g / 10 min, and the volatile matter content is 30 ppm to 150 ppm.

[0032] On the other hand, the present invention also provides a novel polyolefin elastomer for use in the fields of photovoltaic encapsulation film, automotive plastic modification, wire and cable, and film packaging. The novel polyolefin elastomer is the novel polyolefin elastomer mentioned above.

[0033] The present application is further described in detail below in conjunction with specific embodiments. These embodiments should not be construed as limiting the scope of protection claimed in the present application.

[0034] Example 1 Ethylene, α-olefin (1-butene) and a condensing agent (cyclohexane) are subjected to refining treatment in a fixed bed reactor to obtain a refined reaction raw material; wherein, in the refined reaction raw material, the mass percentage of water is independently 0.7 μg / g, the mass percentage of oxygen is independently 0.3 μg / g, and the volume percentage of the sum of carbon monoxide and carbon dioxide is independently 0.3 μg / g.

[0035] The refined reaction raw materials, hydrogen, nitrogen, metallocene catalyst and antistatic agent are taken to a gas phase fluidized bed reactor for low temperature polymerization to obtain polyolefin elastomer powder. Wherein, when the gas phase fluidized bed reactor is in a polymerization equilibrium state, the molar percentage of ethylene is 39.3%, the molar percentage of α-olefin is 6.7%, the molar percentage of hydrogen is 0.0071%, the molar percentage of condensing agent is 1.3% and the balance is nitrogen. Wherein, the active components of the metallocene catalyst are zirconocene chloride and butylaluminoxane, the particle size D50 of the metallocene catalyst is 48μm, and the yield of the metallocene catalyst is 11000g product / g catalyst. The gas phase fluidization rate is 0.58 m / s, the bed pressure difference of the gas phase fluidized bed reactor is 23.5 kPa, the temperature of the low-temperature polymerization reaction is 62°C, the reaction pressure is 1.55 MPa, the reaction time is 7.5 h, and the amount of antistatic agent added accounts for 0.0022 wt% of ethylene; the antistatic agent includes polysulfonate betaine, alkylbenzene sulfonic acid, α-olefin homopolymer and organic solvent. By weight percentage, the antistatic agent includes the following components: 2.8% of polysulfonate betaine, 4.4% of alkylbenzene sulfonic acid, 12% of α-olefin homopolymer and 80.8% of organic solvent cyclohexane.

[0036] Finally, the polyolefin elastomer powder is subjected to degassing treatment and extrusion granulation treatment in sequence to obtain a novel polyolefin elastomer; wherein, in the polyolefin elastomer powder, the content of particles with a particle size D50 of 1 μm to 300 μm is 0.1%, the content of particles with a particle size D50 of 300 μm to 1000 μm is 3.8%, and the content of particles with a particle size D50 of 1600 μm to 4000 μm is 58.0%. The degassing treatment includes primary degassing treatment and secondary degassing treatment, the degassing amount of the primary degassing treatment is 33 times the volume of the polyolefin elastomer powder, and the primary degassing treatment temperature is 45°C; the degassing amount of the secondary degassing treatment is 65 times the volume of the polyolefin elastomer powder, the secondary degassing treatment temperature is 50°C, and the secondary degassing treatment time is 12.0h. During the extrusion granulation process, additives are added to the polyolefin elastomer powder. The additives include talcum powder and antioxidants. The antioxidant model is 1076, and the amount of additives added is 100 ppm. Among them, the amount of talcum powder added is 0 ppm. The pelletizing water temperature of the extrusion granulation is 42°C, and the appearance of the product particles is normal.

[0037] Finally, the density of the new polyolefin elastomer product is 0.8848 g / cm 3 , melt mass flow rate 1.06g / 10min, volatile matter 41ppm.

[0038] Example 2 The only difference from Example 1 is that the condensing agent is pentane, the molar percentage of ethylene in the gas phase fluidized bed reactor is 37.6%, the molar percentage of α-olefin is 4.6%, the molar percentage of hydrogen is 0.033%, the molar percentage of the condensing agent is 5.3%, the metallocene catalyst yield is 12500g product / g catalyst, and the bed pressure difference of the gas phase fluidized bed reactor is 28.2kPa. In the polyolefin elastomer powder, the content of particles with a particle size D50 of 1μm to 300μm is 0.12%, the content of particles with a particle size D50 of 300μm to 1000μm is 4.5%, and the content of particles with a particle size D50 of 1600μm to 4000μm is 52.2%.

[0039] Finally, the density of the new polyolefin elastomer product is 0.8854 g / cm 3 , melt mass flow rate 5.1g / 10min, volatile matter 69ppm.

[0040] Example 3 The only difference from Example 1 is that the condensing agent is pentane, the fluidization rate of the gas phase fluidized bed is 0.63 m / s, the polymerization temperature is 58°C, the molar percentage of ethylene in the gas phase fluidized bed reactor is 35.6%, the molar percentage of α-olefin is 3.6%, the molar percentage of hydrogen is 0.047%, the molar percentage of the condensing agent is 2.1%, the metallocene catalyst yield is 14600 g product / g catalyst, and the bed pressure difference of the gas phase fluidized bed reactor is 42.6 kPa. In the polyolefin elastomer powder, the content of particles with a particle size D50 of 1 μm to 300 μm is 0.2%, the content of particles with a particle size D50 of 300 μm to 1000 μm is 6.7%, and the content of particles with a particle size D50 of 1600 μm to 4000 μm is 44.3%. During the extrusion granulation process, the pelletizing water temperature of the extrusion granulation is 29°C.

[0041] Finally, the density of the new polyolefin elastomer product is 0.8850 g / cm 3 , melt mass flow rate 13.6g / 10min, volatile matter 100ppm.

[0042] Example 4 The only difference from Example 1 is that the α-olefin is 1-hexene, the condensing agent is propane, the active components of the metallocene catalyst are zirconocene chloride and hexylaluminoxane, the particle size D50 of the metallocene catalyst is 52 μm, and the antistatic agent includes the following components: 4% of polysulfonated betaine, 8.9% of alkylbenzene sulfonic acid, 12% of α-olefin homopolymer and 75.1% of organic solvent heptane. The fluidization rate of the gas phase fluidized bed is 0.42 m / s, the polymerization temperature is 55°C, the reaction pressure is 2.15 MPa, the reaction time is 9.0 h, the amount of antistatic agent added is 0.0048 wt% of ethylene, the molar percentage of ethylene in the gas phase fluidized bed reactor is 33.9%, the molar percentage of α-olefin is 2.2%, the molar percentage of hydrogen is 0.0056%, the molar percentage of condensing agent is 4.1%, the metallocene catalyst yield is 6400 g product / g catalyst, and the bed pressure difference of the gas phase fluidized bed reactor is 26 kPa. In the polyolefin elastomer powder, the content of particles with a powder particle size D50 of 1 μm to 300 μm is 0.15%, the content of particles with a powder particle size D50 of 300 μm to 1000 μm is 3.0%, and the content of particles with a powder particle size D50 of 1600 μm to 4000 μm is 50.0%. The degassing amount of the polyolefin elastomer powder in the primary degassing treatment is 50 times the volume of the polyolefin elastomer powder, and the primary degassing treatment temperature is 55°C; the degassing amount of the secondary degassing treatment is 110 times the volume of the polyolefin elastomer powder, and the secondary degassing treatment temperature is 63°C, and the secondary degassing treatment time is 15.0h. During the extrusion granulation process, the pelletizing water temperature of the extrusion granulation is 22°C.

[0043] Finally, the density of the new polyolefin elastomer product is 0.8855 g / cm 3 , melt mass flow rate 0.98g / 10min, volatile matter 112ppm.

[0044] Example 5 The only difference from Example 4 is that the molar percentage of ethylene in the gas-phase fluidized bed reactor is 31.9%, the molar percentage of α-olefin is 1.2%, the molar percentage of hydrogen is 0.03%, the molar percentage of the condensing agent is 4.1%, the metallocene catalyst yield is 8900 g product / g catalyst, and the bed pressure difference of the gas-phase fluidized bed reactor is 33.5 kPa.

[0045] Finally, the density of the new polyolefin elastomer product is 0.8855 g / cm 3 , melt mass flow rate 4.8g / 10min, volatile matter 125ppm.

[0046] Example 6 The only difference from Example 1 is that the condensing agent is propane, and in the reaction raw materials after the refined treatment, the mass percentage of water is independently 0.3 μg / g, the mass percentage of oxygen is independently 0.1 μg / g, and the volume percentage of the sum of carbon monoxide and carbon dioxide is independently 0.1 μg / g. The active components of the metallocene catalyst are zirconocene chloride and hexylaluminoxane, the particle size D50 of the metallocene catalyst is 52 μm, the antistatic agent comprises the following components: 5% of polysulfonated betaine, 8.9% of alkylbenzene sulfonic acid, 14.5% of α-olefin homopolymer and 71.6% of organic solvent heptane, the fluidization rate of the gas phase fluidized bed is 0.67 m / s, the polymerization temperature is 42° C., the reaction pressure is 3.0 MPa, the reaction time is 12.0 h, the amount of the antistatic agent added accounts for 0.0033 wt% of ethylene, the molar percentage of ethylene in the gas phase fluidized bed reactor is 35.2%, the molar percentage of α-olefin is 7.2%, the molar percentage of hydrogen is 0.031%, the condensing agent is propane, and its molar percentage is 4.1%, the metallocene catalyst yield is 7000 g product / g catalyst, and the bed pressure difference of the gas phase fluidized bed reactor is 32.2 kPa. In the polyolefin elastomer powder, the content of particles with a particle size D50 of 1μm to 300μm is 0.3%, the content of particles with a particle size D50 of 300μm to 1000μm is 9.6%, and the content of particles with a particle size D50 of 1600μm to 4000μm is 33.4%. The degassing amount of the polyolefin elastomer powder in the primary degassing treatment is 60 times the volume of the polyolefin elastomer powder, and the primary degassing treatment temperature is 35°C; the degassing amount of the secondary degassing treatment is 120 times the volume of the polyolefin elastomer powder, and the secondary degassing treatment temperature is 48°C, and the secondary degassing treatment time is 12.0h. During the extrusion granulation process, the pelletizing water temperature of the extrusion granulation is 13°C.

[0047] Finally, the density of the new polyolefin elastomer product is 0.8735 g / cm 3 , melt mass flow rate 4.87g / 10min, volatile matter 110ppm.

[0048] Example 7 The only difference from Example 6 is that the polymerization reaction temperature is 38° C., the molar percentage of ethylene in the gas-phase fluidized bed reactor is 36.0%, the molar percentage of α-olefin is 8.2%, the molar percentage of hydrogen is 0.057%, the molar percentage of the condensing agent is 1.7%, the metallocene catalyst yield is 9300 g product / g catalyst, and the bed pressure difference of the gas-phase fluidized bed reactor is 41.3 kPa.

[0049] Finally, the density of the new polyolefin elastomer product is 0.8742 g / cm 3, melt mass flow rate 14.2g / 10min, volatile matter 147ppm.

[0050] Comparative Example 1 The difference with embodiment 1 is only that: the catalyzer adopted is a general catalyst, the active component of this catalyzer is a titanium-containing organic metal mixture, the particle diameter D50 is 37 μ m, and the antistatic agent is a mixture containing quaternary ammonium salt and an organic solvent, and the commercially available trade mark is AS1200. The fluidization rate of the gas-phase fluidized bed is 0.72 m / s, the polymerization temperature is 85 ℃, and the reaction pressure is 2.15 MPa. In the gas-phase fluidized bed reactor, the mole percentage of ethene is 37.8%, the mole percentage of alpha-olefins is 2.2%, the mole percentage of hydrogen is 0.055%, the mole percentage of condensing agent is 1.7%, and the bed pressure difference of the gas-phase fluidized bed reactor is 17.5 kPa, and the add-on of the antistatic agent accounts for 0.0033wt% of ethene. In the process of lowering the polymerization temperature to 75°C and increasing the molar concentration of 1-butene to 3.2%, the reactor bed pressure difference quickly rose to 142 kPa, the distribution plates in the reactor were blocked, and the hopper at the bottom of the reactor discharged belt-like blocks, and the polymerization reaction was forced to stop. In the polyolefin elastomer powder, the content of particles with a particle size D50 of 1 μm to 300 μm was 5.5%, the content of particles with a particle size D50 of 300 μm to 1000 μm was 35.0%, and the content of particles with a particle size D50 of 1600 μm to 4000 μm was 18.2%. Finally, the density of the obtained linear low-density polyethylene product was 0.9193 g / cm 3 , melt mass flow rate 1.0g / 10min, volatile matter 349ppm.

[0051] Comparative Example 2 The difference from Example 1 is that the catalyst used is a general catalyst, the active component of the catalyst is a compound composed of vanadium and metallocene, the particle size D50 is 30 μm, and the antistatic agent is a mixture containing quaternary ammonium salt, alkylbenzene sulfonic acid and organic solvent, and the commercially available brand is Statsafe 6000. The fluidization rate of the gas-phase fluidized bed is 0.55 m / s, the polymerization temperature is 66° C., the reaction pressure is 2.15 MPa, the molar percentage of ethylene in the gas-phase fluidized bed reactor is 34.3%, the molar percentage of α-olefin is 3.4%, the molar percentage of hydrogen is 0.031%, the condensing agent is propane, and its molar percentage is 4.1%, the bed pressure difference of the gas-phase fluidized bed reactor is 37.1 kPa, and the amount of the antistatic agent added accounts for 0.0055wt% of ethylene. The reactor bed pressure difference slowly increased, and the reactor wall temperature monitoring showed a high alarm. Analysis showed that the polymer in the reactor was sticky and agglomerated and the wall was crusted. In order to ensure safe production, the polymerization reaction was forced to stop. In the polyolefin elastomer powder, the content of particles with a particle size D50 of 1μm to 300μm was 7.5%, the content of particles with a particle size D50 of 300μm to 1000μm was 16.0%, and the content of particles with a particle size D50 of 1600μm to 4000μm was 30.0%.

[0052] Comparative Example 3 The difference from Example 1 is that ethylene, α-olefin, hydrogen, nitrogen and condensing agent are not refined. The amount of antistatic agent added is 0.008wt% of ethylene, the metallocene catalyst yield is 4400g product / g catalyst, and the harmful substances in the reaction raw materials that are not refined and treated greatly reduce the catalyst yield. In the polyolefin elastomer powder, the content of particles with a particle size D50 of 1μm to 300μm is 2.2%, and the content of particles with a particle size D50 of 300μm to 1000μm is 10.2%. The primary degassing temperature of the powder degassing treatment is 60℃, and the secondary degassing temperature is 60℃. After the polymerization reaction is carried out for 30 hours, the pipeline from the secondary degassing bin to the extrusion granulator is blocked, and the air delivery system loses the function of conveying the polyolefin elastomer powder. The pressure of the airflow in the pipeline continues to increase, and the polymerization reaction is forced to stop. After shutdown and maintenance, it is verified that the metal pipeline with a diameter of 30cm is blocked, and the blockage is a sticky polymer.

[0053] Comparative Example 4 The only difference from Example 1 is that the polymerization reaction temperature is 35°C, the pressure is 1.2 MPa, the amount of antistatic agent added is 0.004wt% of ethylene, the metallocene catalyst yield is 1500g product / g catalyst, and the process parameters such as temperature and pressure are too low, resulting in a catalyst yield that is lower than expected. Too low a polymerization temperature requires an increase in the amount of heat withdrawal in the reactor, resulting in increased energy consumption in the production of polyolefin elastomers.

[0054] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects: From the test results of the embodiments and comparative examples, it can be found that the types of catalysts and antistatic agents, the indicators of raw materials after refining treatment, the polymerization temperature, polymerization pressure, fluidizing gas velocity, raw material composition in the reactor, the degassing amount in the degassing bin, degassing temperature control and other factors are necessary conditions for preparing polyolefin elastomer products by gas phase fluidized bed process. The effective combination of various process methods provided by the present invention can realize the efficient and stable production of qualified polyolefin elastomer products by gas phase polyethylene device.

[0055] The above-mentioned gas-phase fluidized bed process in the present invention does not require a major transformation of the production equipment. Compared with the solution polymerization process, it has the characteristics of short operation process, low production cost, low product odor, etc. The production of polyolefin elastomers by this method has a better industrial application prospect. Moreover, in the gas-phase fluidized bed process of a single reactor, a large-particle-size, high-activity metallocene catalyst is used, and by optimizing the polymerization reaction temperature, regulating the pressure in the reactor, the molar percentage of α-olefin and ethylene, and the gas-phase fluidization rate at the bottom of the reactor, injecting an antistatic agent, preventing and controlling polymerization stickiness, and reducing the generation of polymer fine powder, the problem of softening, agglomeration, and fouling blockage of polyolefin elastomers is effectively prevented, and the technical difficulties in the production of polyolefin elastomers in the gas-phase polymerization process are eliminated.

[0056] Although this specification includes many specific implementation details, these should not be interpreted as limiting the scope of any invention or the scope of protection claimed, but are mainly used to describe the features of the specific embodiments of specific inventions. Certain features described in multiple embodiments in this specification may also be implemented in combination in a single embodiment. On the other hand, the various features described in a single embodiment may also be implemented separately in multiple embodiments or in any suitable sub-combination. In addition, although the features may work as above in certain combinations and even initially claim protection, one or more features from the claimed combination may be removed from the combination in some cases, and the claimed combination may point to a sub-combination or a variation of a sub-combination.

[0057] Thus, particular embodiments of the subject matter have been described. Other embodiments are within the scope of the following claims. In some cases, the actions recited in the claims can be performed in a different order and still achieve desirable results.

[0058] It should be noted that, in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0059] The above is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A method for preparing a novel polyolefin elastomer, characterized in that: The preparation method comprises: Step S1, refining ethylene, α-olefin and condensing agent to obtain refined reaction raw materials; Step S2, subjecting the refined reaction raw materials, hydrogen, nitrogen, metallocene catalyst and antistatic agent to a low-temperature polymerization reaction in a reactor to obtain a polyolefin elastomer powder; Step S3, sequentially subjecting the polyolefin elastomer powder to degassing treatment and extrusion granulation treatment to obtain a novel polyolefin elastomer; wherein, In the polyolefin elastomer powder, the content of particles with a powder particle size D50 of 1μm to 300μm is 0.1% to 0.3%, the content of particles with a powder particle size D50 of 300μm to 1000μm is 3.0% to 9.6%, and the content of particles with a powder particle size D50 of 1600μm to 4000μm is 33.4% to 58.9%.

2. The method for preparing the novel polyolefin elastomer according to claim 1, characterized in that: In step S1, the refining treatment includes: refining ethylene, α-olefin and condensing agent in a fixed bed reactor, so that the mass percentage of water in each reaction raw material after the refining treatment is independently 0 to 1 μg / g, the mass percentage of oxygen is independently 0 to 0.5 μg / g, and the volume percentage of the sum of carbon monoxide and carbon dioxide is independently 0 to 0.5 μg / g.

3. The method for preparing the novel polyolefin elastomer according to claim 1 or 2, characterized in that: The active component of the metallocene catalyst is selected from one or more of zirconocene chloride, methylaluminoxane, butylaluminoxane and hexylaluminoxane, the particle size D50 of the metallocene catalyst is 45 μm to 54 μm, and the yield of the metallocene catalyst is 6000 g product / g catalyst to 15000 g product / g catalyst.

4. The method for preparing the novel polyolefin elastomer according to claim 3, characterized in that: In step S2, the low-temperature polymerization reaction is carried out in a gas-phase fluidized bed reactor, and the gas-phase fluidization rate is 0.3 m / s to 0.8 m / s; and / or, The bed pressure difference of the gas phase fluidized bed reactor is 10 kPa to 80 kPa; and / or, The temperature of the low-temperature polymerization reaction is 35° C. to 65° C., the reaction pressure is 1.5 MPa to 3.0 MPa, and the reaction time is 7 h to 12 h.

5. The method for preparing the novel polyolefin elastomer according to claim 1, 2 or 4, characterized in that: In step S3, the degassing treatment includes a primary degassing treatment and a secondary degassing treatment, the degassing amount of the primary degassing treatment is 30 to 60 times the volume of the polyolefin elastomer powder, the primary degassing treatment temperature is 35° C. to 55° C., the degassing amount of the secondary degassing treatment is 60 to 120 times the volume of the polyolefin elastomer powder, the secondary degassing treatment temperature is 45° C. to 65° C., and the secondary degassing treatment time is 12h to 15h; and / or, During the extrusion granulation process, additives are added to the polyolefin elastomer powder, the additives include talcum powder and antioxidants, the amount of additives added is 80ppm to 350ppm, wherein the amount of talcum powder added is 0 to 100ppm, and the pelletizing water temperature of the extrusion granulation is 13°C to 45°C.

6. The method for preparing the novel polyolefin elastomer according to claim 5, characterized in that: When the polymerization reaction in the gas phase fluidized bed reactor is in equilibrium, the molar percentage of ethylene is 30% to 40%, the molar percentage of α-olefin is 1.0% to 8.5%, the molar percentage of hydrogen is 0.005% to 0.06%, the molar percentage of condensing agent is 0.5% to 5% and the balance is nitrogen; and / or, The α-olefin is 1-butene and / or 1-hexene, and the condensing agent is selected from one or more of propane, pentane, cyclopentane, hexane and cyclohexane.

7. The method for preparing the novel polyolefin elastomer according to claim 1, 2, 4 or 6, characterized in that: The amount of the antistatic agent added is 0.002wt% to 0.005wt% of ethylene; the antistatic agent includes polysulfonated betaine, alkylbenzene sulfonic acid, α-olefin homopolymer and organic solvent, and the weight percentage of each component in the antistatic agent is: 2% to 5% of polysulfonated betaine, 4% to 10% of alkylbenzene sulfonic acid, 10% to 15% of α-olefin homopolymer and 71% to 81% of organic solvent.

8. A novel polyolefin elastomer, characterized in that: The novel polyolefin elastomer is prepared by the method for preparing the novel polyolefin elastomer according to any one of claims 1 to 7.

9. The novel polyolefin elastomer according to claim 8, characterized in that The density of polyolefin elastomer is 0.870g / cm 3 Up to 0.890g / cm 3 , the melt mass flow rate is 0.8 g / 10 min to 18 g / 10 min, and the volatile matter content is 30 ppm to 150 ppm.

10. Application of a novel polyolefin elastomer in the fields of photovoltaic encapsulation film, automotive plastic modification, wire and cable, and film packaging, characterized in that: The novel polyolefin elastomer is the novel polyolefin elastomer according to claim 8 or 9.