A method for green and efficient synthesis of high molecular weight olefin functional polymers

Abstract

The application provides a method for synthesizing high-molecular-weight olefin functional polymer, which comprises the following steps: (1) adding a functional monomer and a solvent into a polymerization reactor, and sufficiently replacing the atmosphere in the reactor with a protective gas atmosphere; (2) feeding low-carbon olefins into the reactor, and then increasing the temperature and pressure to reach the reaction temperature and pressure; (3) feeding an initiator into the polymerization reactor to perform a polymerization reaction, and continuously feeding low-carbon olefins to maintain the pressure during the reaction, so as to obtain an olefin functional copolymer.

Description

Technical Field

[0001] This invention relates to the field of organic polymerization technology, and more specifically to a method for synthesizing high molecular weight ethylene-maleic anhydride alternating copolymers using a low-temperature initiator. Background Technology

[0002] Against the backdrop of the booming development of modern materials science, high molecular weight ethylene-maleic anhydride alternating copolymers have become a focus of attention in scientific research and industry. With technological innovation in industries such as electronics, automobiles, and coatings, the demand for high-performance materials is exploding. In the electronics field, as chip integration continues to increase, the requirements for the insulation, heat resistance, and chemical stability of packaging materials are extremely stringent; the automotive industry, in order to achieve energy conservation and emission reduction, urgently needs lightweight and high-strength materials. Ethylene-maleic anhydride alternating copolymers, with their flexibility and stability of ethylene segments and the polarity and reactivity of maleic anhydride groups, have shown great potential in these emerging application scenarios. Meanwhile, traditional materials, such as glass fibers, suffer from poor interfacial compatibility when preparing composite materials due to their weak polarity, failing to meet the demands of high-performance materials. Ethylene-maleic anhydride alternating copolymers precisely compensate for this deficiency, and their unique structure provides a new solution for improving the overall performance of materials. Furthermore, in-depth research into the polymerization reaction mechanism and the continuous emergence of new catalysts and initiators have laid a solid theoretical and technical foundation for the research and development of this copolymer.

[0003] However, synthesizing high molecular weight ethylene-maleic anhydride alternating copolymers faces numerous challenges. Controlling the polymerization reaction is difficult; factors such as reaction temperature, pressure, monomer ratio, and reaction time significantly affect the copolymer's molecular weight and structure, requiring precise control of the initiator type and dosage. Separation and purification are complex; the high viscosity of the copolymer solution makes traditional separation methods inefficient and prone to damaging the copolymer structure, and residual impurities can also affect performance. Furthermore, production costs are high; specialized catalysts, initiators, and equipment increase costs, and the demanding reaction conditions consume significant amounts of energy. Reducing costs in large-scale production is a key challenge for achieving industrialization.

[0004] Therefore, there is an urgent need in this field to develop a green, efficient, mild reaction condition, and low production cost method for preparing high molecular weight ethylene-maleic anhydride alternating copolymers. Summary of the Invention

[0005] The first aspect of the present invention provides a method for synthesizing high molecular weight olefin functional polymers, the method comprising the following steps: (1) Add the primer containing the functional monomer and the first solvent to the polymerization reactor and fully replace the atmosphere in the reactor with a protective gas atmosphere; (2) After the low-carbon olefins are introduced into the reactor, the temperature and pressure are increased to reach the reaction temperature and reaction pressure; (3) The feed liquid including the initiator and the second solvent is fed into the polymerization reactor to carry out the polymerization reaction. During the reaction, low carbon olefins are continuously introduced to maintain the pressure, and olefin functional copolymers are obtained. The mass ratio of the first solvent to the functional monomer in the primer is 2 to 9 / 1; the mass ratio of the second solvent to the initiator in the feed solution is 5 to 10 / 1. The polymerization reaction in the polymerization reactor is carried out in one step. The olefin functional copolymers described herein have a weight-average molecular weight of at least 200,000 Daltons and are tested using gel permeation chromatography according to ASTM D6474 standard.

[0006] A second aspect of the present invention provides high molecular weight olefin functional polymers prepared by the method of the present invention. Detailed Implementation

[0007] The inventors of this application discovered that by using a specific feeding method with a single, continuous initiator and employing a heterogeneous polymerization method, combined with a specific low-temperature initiator, olefin-maleic anhydride alternating copolymers with a weight-average molecular weight of 20W-78W can be successfully prepared under relatively mild reaction temperatures (30-70℃) and suitable pressures (4-8MPa). Based on this discovery, the present invention was completed.

[0008] The "range" disclosed herein is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, it is expected that ranges of 60-110 and 80-120 are also expected. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0009] Unless otherwise specified in this application, all embodiments and preferred embodiments mentioned herein can be combined to form new technical solutions.

[0010] Unless otherwise specified, all technical features and preferred features mentioned herein can be combined to form new technical solutions.

[0011] In this application, unless otherwise specified, the terms "comprising" and "including" as used herein are open-ended or closed-ended. For example, "comprising" and "including" may mean that other components not listed may also be included, or that only the listed components may be included.

[0012] In the description of this article, it should be noted that, unless otherwise stated, "above" and "below" include the number itself, and "several" in "one or more" means two or more.

[0013] In this description, unless otherwise stated, the term "or" is inclusive. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, the condition "A or B" is satisfied by any of the following conditions: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0014] Unless otherwise specified, percentages (%) or parts refer to weight percentages or parts by weight of the composition.

[0015] Unless otherwise stated herein, the sum of the contents of the components in the composition is 100%.

[0016] Unless otherwise stated herein, the sum of the parts of each component in the composition may be 100 parts by weight.

[0017] In this document, unless otherwise stated, “combination of” means a multi-component mixture of the elements, such as two, three, four, and up to the maximum possible multi-component mixture.

[0018] Unless otherwise specified, the term "a" as used in this specification means "at least one".

[0019] In this paper, unless otherwise stated, all reactions were carried out at room temperature and pressure.

[0020] The first aspect of this application provides a method for synthesizing high molecular weight olefin functional polymers, the method comprising the following steps: (1) Add the primer containing the functional monomer and the first solvent to the polymerization reactor, and fully replace the atmosphere inside the reactor with a protective gas atmosphere; (2) After the low-carbon olefins are introduced into the reactor, the temperature and pressure are increased to reach the reaction temperature and reaction pressure; (3) The feed liquid including the initiator and the second solvent is fed into the polymerization reactor to carry out the polymerization reaction. During the reaction, low carbon olefins are continuously introduced to maintain the pressure, and olefin functional copolymers are obtained. The mass ratio of the first solvent to the functional monomer in the primer is 2 to 9 / 1; the mass ratio of the second solvent to the initiator in the feed solution is 5 to 10 / 1. The polymerization reaction in the polymerization reactor is carried out in one step. The olefin functional copolymers described herein have a weight-average molecular weight of at least 200,000 Daltons and are tested using gel permeation chromatography according to ASTM D6474 standard.

[0021] In this application, "one-time reaction" means that the raw materials undergo a continuous polymerization reaction in the polymerization reactor until the final olefin functional polymer is formed. That is, during the reaction, the raw materials and intermediate products remain in the polymerization reactor until the final olefin functional polymer is formed. During the reaction, the raw materials and intermediate products do not leave the polymerization reactor, nor are they subjected to any processing steps.

[0022] In this application, the term "olefin functional polymer" refers to a polymer generated by heterogeneous polymerization of low-carbon olefins and acid anhydride functional monomers, especially an alternating copolymer in which the monomer units of the low-carbon olefins and acid anhydride functional monomers are arranged alternately (or identically) on the main chain of the generated copolymer.

[0023] In this invention, functional monomers and solvents are prepared as a pretreatment solution and added to the polymerization reactor to create a high-concentration environment. Then, initiator feed solution is fed into the reactor. By adjusting the monomer concentration in the pretreatment solution and the feed flow rate, the free radical concentration can be precisely controlled, avoiding instantaneous excessive concentrations that could lead to explosive polymerization or an excessively wide molecular weight distribution. This achieves controllable synthesis within the molecular weight range of 20W-78W. Specifically, pre-adding the functional monomers and a portion of the solvent into the reactor allows for the pre-formation of a high-concentration monomer solution. Continuous addition of the initiator solution then enables a large amount of maleic anhydride monomer to form long chains (whether this should be ethylene and maleic anhydride forming long-chain alternating copolymers), preventing chain termination due to insufficient monomer. Simultaneously, using a specific solvent dosage range allows the precipitation polymerization reaction to proceed smoothly with high yield and high conversion rate.

[0024] In this invention, the functional monomer may be an acid anhydride monomer, including but not limited to maleic anhydride, itaconic anhydride, acetic anhydride, tung oil anhydride, phthalic anhydride, etc.; preferably, the functional monomer includes maleic anhydride monomer.

[0025] In this invention, low-carbon olefins refer to olefins having 2-5 carbon atoms. Preferably, the low-carbon olefins include at least one olefin selected from the group consisting of ethylene, propylene, butene, and butadiene.

[0026] In this invention, the solvent includes one or a combination of at least two of alkane compounds, organic alkanoates, or aromatic compounds. Preferably, the alkane compounds include one or a combination of at least two of cyclohexane, n-pentane, n-heptane, n-octane, or n-decane. The organic alkanoates include one or a combination of at least two of ethyl acetate, isoamyl acetate, or butyl acetate. The aromatic compounds include one or a combination of at least two of benzene, toluene, ethylbenzene, or xylene. The first solvent used for the primer and the second solvent used for the feed liquid may be the same or different. In one specific embodiment, the first solvent and the second solvent each include at least one solvent selected from the group consisting of n-heptane, isoamyl acetate, butyl acetate, toluene, and xylene.

[0027] In this invention, the initiator comprises azo compounds and / or peroxide compounds. Examples of azo compounds include azobisisobutyronitrile, azobisisovalerate, azobisisoheptanenitrile, azobiscyclohexylformitrile, or azobisisobutyric acid. Examples of peroxide compounds include benzoyl peroxide, dodecyl peroxide, dicumyl peroxide, diisopropyl peroxide, or diisohexyl peroxide. Preferably, the initiator comprises at least one initiator selected from the group consisting of azobisisoheptanenitrile (ABVN), diisopropyl peroxide (IPP), and diisohexyl peroxide (EHP).

[0028] In this invention, the protective gas can be nitrogen and inert gases, including but not limited to argon, helium, etc.

[0029] In this invention, the prepared solid-phase olefin functional polymer is preferably a copolymer of alternating ethylene and maleic anhydride, with a weight-average molecular weight (Mw) of 20W-78W and a maleic anhydride (MAH) content >70%. The weight-average molecular weight is tested using the standard test method ASTM D6474 of gel permeation chromatography.

[0030] In this invention, the initiator is fed in step (3) by continuous pumping, and low-carbon olefins are continuously introduced to maintain the system pressure. During the reaction, the continuous pumping of the initiator, the continuous introduction of ethylene to maintain the pressure, and the regulation of the pumping order of monomers and initiators can precisely control the reaction and avoid the risk of runaway.

[0031] In this invention, the total amount of the pretreatment liquid and the feed liquid is 40%-70% of the reactor volume, preferably 50%-70%, and the molar ratio of the initiator and functional monomer is 0.003-0.015, preferably 0.004-0.008. The mass ratio of solvent to functional monomer in the pretreatment liquid is 2-9 / 1, preferably 2.3-6:1; the mass ratio of solvent to initiator in the feed liquid is 5-10 / 1.

[0032] This invention utilizes reaction conditions of 30-70℃ low temperature and 4-8MPa low pressure, significantly reducing energy consumption and aligning with the principles of energy conservation and emission reduction. The mild reaction conditions lower equipment requirements and maintenance costs, and reduce the use of additives, thus lowering raw material costs. In this invention, the polymerization reaction temperature is 30-70℃, preferably 40-50℃; the polymerization reaction pressure is 4-8MPa, preferably 5-7MPa; and the polymerization reaction time is 4-15 hours, preferably 6-10 hours. The low-temperature initiator used in this invention offers significant advantages in this process. Compared to traditional initiators, the low-temperature initiator can function efficiently within the low-temperature range of 30-70℃, preferably 40-60℃. The lower polymerization reaction temperature effectively inhibits the rapid decomposition of the initiator, ensuring that the concentrations of monomer free radicals and initiator free radicals within the system are within a reasonable and stable range, thereby maintaining a high degree of polymerization and providing a strong guarantee for the synthesis of high molecular weight products. In addition, low-temperature initiators can reduce side reactions such as chain transfer and chain termination caused by high temperatures, making the polymer molecular chain structure more regular, further improving the quality and performance of the product, and optimizing the overall quality of the product while controlling the molecular weight of the product.

[0033] The method for synthesizing high molecular weight olefin functional polymers may further include step (4): the system after the polymerization reaction in step (3) is first subjected to gas-solid-liquid separation to recover low carbon olefins, and the remaining material is discharged and then subjected to solid-liquid separation.

[0034] In this invention, the low-carbon olefins recovered in step (4) can be returned to step (2) for recycling after being pressurized. The remaining material after recovering the low-carbon olefins is discharged in a solid-liquid manner. The solid-liquid separation method can be any solid-liquid separation method commonly used in the art, including but not limited to decantation, filtration, or centrifugation. The filtration includes but is not limited to gravity filtration, vacuum filtration, or pressure filtration. Filtration can be carried out using filters, including but not limited to atmospheric pressure filters, vacuum filters, or pressure filters.

[0035] In this invention, the solid product obtained from solid-liquid separation in step (4) is sequentially washed and dried to obtain an olefin functional polymer. Washing and drying methods commonly used in the art can be employed, including but not limited to vacuum drying, spray drying, or fluidized bed drying. Preferably, the washing is performed using the same solvent as in step (1).

[0036] In a preferred embodiment of the present invention, the method for synthesizing high molecular weight olefin functional polymers includes the following steps: (1) Add the base liquid, which includes maleic anhydride monomer and a first solvent, to the polymerization reactor and fully replace the atmosphere in the reactor with a nitrogen atmosphere, wherein the first solvent includes at least one solvent selected from the group consisting of n-heptane, isoamyl acetate, butyl acetate, toluene, and xylene. (2) After ethylene is introduced into the reactor, the temperature and pressure are increased to reach a reaction temperature of 30-70℃ and a reaction pressure of 4-8MPa; (3) The feed liquid including the initiator and the second solvent is fed into the polymerization reactor to carry out the polymerization reaction. The reaction time is 4-15h. During the reaction, ethylene is continuously introduced to maintain the pressure. The initiator includes at least one initiator selected from the group consisting of azobisisobutyronitrile (ABVN), diisopropyl peroxide (IPP), and diisohexyl peroxide (EHP). The second solvent includes at least one solvent selected from the group consisting of n-heptane, isoamyl acetate, butyl acetate, toluene, and xylene. (4) The system after the polymerization reaction in step (3) is first subjected to gas-solid-liquid separation to recover ethylene. After the remaining material is discharged, solid-liquid separation is performed to obtain high molecular weight ethylene-maleic anhydride alternating copolymer.

[0037] Another aspect of this application provides a high molecular weight olefin functional polymer prepared using the method described above. Preferably, the high molecular weight olefin functional polymer is an ethylene-maleic anhydride alternating copolymer with a weight-average molecular weight (Mw) of 20W-78W.

[0038] The method for synthesizing high molecular weight ethylene-maleic anhydride alternating copolymers provided by this invention is based on a common free radical mechanism. Therefore, the process is simple, the reaction conditions are mild, it is easy to separate and purify, the raw materials can be recycled, energy consumption is saved, the cost is low, the economic benefits are high, and it is conducive to industrial production. It can be widely used in plastic modification, adhesives, coatings, electronics, automobiles and other fields.

[0039] Compared with the prior art, the method of the present invention for synthesizing high molecular weight ethylene-maleic anhydride alternating copolymers has many outstanding advantages: 1. The present invention employs a feeding sequence in which the functional monomer is first dissolved in a base solvent, and then the initiator is fed in. By adjusting the feeding rate and the ratio of monomer to initiator, the desired high molecular weight olefin functional polymer can be prepared.

[0040] 2. The heterogeneous polymerization method eliminates the need for additional stabilizers or catalysts, reducing the introduction of metal impurities and simplifying product separation and purification. Furthermore, this polymerization method maintains a high monomer concentration in the reaction system, improving raw material utilization and further enhancing the copolymer's performance.

[0041] 3. A low-temperature initiator is used, which can effectively initiate the polymerization reaction at a lower temperature of 30-70℃ compared to traditional initiators. This not only reduces reaction energy consumption but also reduces the adverse effects of high temperatures on the copolymer structure and properties, helping to accurately control the molecular weight of the copolymer within the target range of 20W-78W, while suppressing unnecessary side reactions.

[0042] 4. The reaction conditions were optimized to conduct the reaction at a pressure of 4-8 MPa and a temperature of 30-70°C. These conditions ensured efficient reaction while avoiding the problems of high equipment requirements and safety risks associated with high temperature and high pressure. Mild reaction conditions are beneficial for large-scale industrial production and reduce production costs.

[0043] Unless otherwise specified, all raw materials used in this application are commercially available or prepared according to conventional methods in the art. Unless otherwise defined or stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of skill in the art. Furthermore, any methods and materials similar to or equivalent to those described herein may be applied to the methods of this invention. Other aspects of this invention will be apparent to those skilled in the art from the disclosure herein.

[0044] Example

[0045] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Experimental methods in the following embodiments, unless specific conditions are specified, are generally determined according to national standards. If no corresponding national standard exists, then common international standards, conventional conditions, or conditions recommended by the manufacturer are followed. Unless otherwise stated, all parts are parts by weight, all percentages are weight percentages, and the molecular weight of the polymer is the weight-average molecular weight.

[0046] Raw material sources and preparation

[0047] Main reagents for the experiment

[0048] Main instruments for the experiment

[0049] Gas chromatography test conditions

[0050] The methods and / or standards used for testing each parameter are as follows: Conversion rate of maleic anhydride: The conversion rate is calculated by the ratio of the mass difference between the added maleic anhydride and the free maleic anhydride after the reaction to the original input amount. Specifically, MAH conversion rate = 100 - filtrate mass × maleic anhydride content in filtrate / maleic anhydride feed amount / maleic anhydride purity - filter cake mass × filter cake maleic anhydride content / maleic anhydride feed amount / maleic anhydride purity. Polymer yield: Calculated by the mass ratio of maleic anhydride copolymer units to all added monomers in the alternating copolymer. The mass of the MAH copolymer units is estimated by the residual maleic anhydride in the filtrate and filter cake after solid-liquid separation at the end of the reaction. Polymer yield = 100 - mass of filtrate × anhydride value of filtrate / maleic anhydride feed amount - mass of filter cake × maleic anhydride content of filter cake / maleic anhydride feed amount / maleic anhydride purity; The content of maleic anhydride in the filtrate and filter cake was tested by gas chromatography. The test procedure is as follows: 1. Preparation of standard solution: Weigh 0.1000 g of superior grade maleic anhydride standard, dissolve it in acetonitrile, and make up to 100 mL to prepare a 1000 μg / mL standard stock solution; 2. Sample pretreatment: For organic solvent samples, take an appropriate amount of sample, dilute it with acetonitrile to the concentration range of the standard curve, filter it through a 0.22 μm filter membrane, and it is ready for testing; 3. Start the gas chromatograph, set the above gas chromatography test conditions, and wait for the instrument baseline to stabilize; inject the sample to be tested, and calculate the maleic anhydride content according to the sample peak area through the standard curve.

[0051] ; Anhydride value: The anhydride value was determined according to ISO 1390-4:1977 (Test methods for maleic anhydride for industrial use - Part 4: Determination of maleic anhydride content by titration). Polymer molecular weight: The weight-average molecular weight (Mw) and molecular weight distribution (expressed as polymer dispersibility index PDI) of the polymer were measured by gel permeation chromatography according to ASTM D6474.

[0052] Example 1

[0053] Prepare olefin functional polymers according to the following steps: (1) First, prepare a base solution by mixing 890g of maleic anhydride and 3560g of a mixture of isoamyl acetate and n-heptane (the ratio of isoamyl acetate to n-heptane is 2:1) and add it to the polymerization reactor. The concentration of maleic anhydride is 20wt%. (2) Perform nitrogen and ethylene purging operations on the high-pressure polymerization reactor in sequence, each purging five times; slowly raise the temperature, and when the predetermined reaction temperature of 70°C is reached, promptly pressurize to the reaction pressure of 4MPa; (3) Subsequently, 1550g of a feed solution prepared by azobisisobutyronitrile and isoamyl acetate-n-heptane mixed solvent (the ratio of isoamyl acetate to n-heptane is 2:1) was continuously pumped into the reactor by a transfer pump after preheating. The polymerization reaction was then started. Ethylene was continuously introduced during the reaction to maintain the pressure at 4MPa. The molar ratio of azobisisobutyronitrile to maleic anhydride was 0.008:1. The polymerization reaction temperature was 70℃, the pressure was 4MPa, and the feeding time was 6h. (4) After the reaction is completed, the system after the polymerization reaction in step (3) is filtered by a No. 4 sand core funnel. 2700g of filtrate and 3300g of filter cake are obtained by solid-liquid separation. The maleic anhydride content of the filtrate and filter cake is quantitatively analyzed by gas chromatography. The anhydride value of the filtrate is determined according to ISO 1390-4:1977 standard. The maleic anhydride content in the filtrate is 1.05%, the maleic anhydride content in the filter cake is 0.276%, and the anhydride value of the filtrate is 1.04. The conversion rate of maleic anhydride is calculated to be 95.77%, and the polymer yield is 95.82%. Ethylene is recovered. The discharged ethylene is pressurized and returned to step (2) for reuse. The obtained filter cake is washed and dried. The solvent used for washing is isoamyl acetate. The solid phase olefin functional polymer and liquid phase material are obtained by vacuum drying under negative pressure.

[0054] Example 2

[0055] Prepare olefin functional polymers according to the following steps: (1) Prepare a 30wt% maleic anhydride solution by mixing 890g of maleic anhydride and 2076g of butyl acetate solvent, and add the 30wt% maleic anhydride solution into the polymerization reactor. (2) Perform nitrogen and ethylene purging operations on the high-pressure polymerization reactor in sequence, each purging five times; slowly raise the temperature, and when the predetermined reaction temperature of 50°C is reached, promptly pressurize to the reaction pressure of 6MPa; (3) Subsequently, 1034g of a feed solution prepared from azobisisobutyronitrile and butyl acetate, wherein the concentration of azobisisobutyronitrile is 10wt%, was continuously pumped into the reactor under pressure after preheating, and the polymerization reaction was immediately started. Ethylene was continuously introduced during the reaction to maintain the pressure at 6MPa. The molar ratio of azobisisobutyronitrile to maleic anhydride was 0.0065:1, the polymerization reaction temperature was 50℃, the pressure was 6MPa, and the feeding time was 8h. (4) After the reaction is completed, the system after polymerization in step (3) is filtered by a No. 4 sand core funnel. 1900g of filtrate and 2100g of filter cake are obtained by solid-liquid separation. The maleic anhydride content of the filtrate and filter cake is quantitatively analyzed by gas chromatography. The anhydride value of the filtrate is determined according to ISO 1390-4:1977 standard. The maleic anhydride content in the filtrate is 1.01%, the maleic anhydride content in the filter cake is 0.264%, and the anhydride value of the filtrate is 1. The conversion rate of maleic anhydride is calculated to be 97.21%, and the polymer yield is 97.24%. Ethylene is recovered. The discharged ethylene is pressurized and returned to step (2) for reuse. The obtained filter cake is washed and dried. The solvent used for washing is isoamyl acetate. The solid phase olefin functional polymer and liquid phase material are obtained by vacuum drying under negative pressure.

[0056] Example 3

[0057] Prepare olefin functional polymers according to the following steps: (1) Prepare a 25wt% maleic anhydride solution by mixing 890g of maleic anhydride and 2670g of isoamyl acetate solvent, and add the 25wt% maleic anhydride solution into the polymerization reactor. (2) Perform nitrogen and ethylene purging operations on the high-pressure polymerization reactor in sequence, each purging five times; slowly raise the temperature, and when the predetermined reaction temperature of 40°C is reached, promptly pressurize to the reaction pressure of 8MPa; (3) Subsequently, 1440g of a feed solution prepared from azobisisobutyronitrile and isoamyl acetate, wherein the concentration of azobisisobutyronitrile is 10wt%, was continuously pumped into the reactor under pressure after preheating, and the polymerization reaction was immediately started. Ethylene was continuously introduced during the reaction to maintain the pressure at 8MPa. The molar ratio of azobisisobutyronitrile to maleic anhydride was 0.004:1. The polymerization reaction temperature was 40℃, the pressure was 8MPa, and the feeding time was 12h. (4) After the reaction is completed, the system after polymerization in step (3) is filtered by a No. 4 sand core funnel. 2000g of filtrate and 3000g of filter cake are obtained by solid-liquid separation. The maleic anhydride content of the filtrate and filter cake is quantitatively analyzed by gas chromatography. The anhydride value of the filtrate is determined according to ISO 1390-4:1977 standard. The maleic anhydride content in the filtrate is 3.24%, the maleic anhydride content in the filter cake is 1.134%, and the anhydride value of the filtrate is 6.48. The conversion rate of maleic anhydride is calculated to be 88.84%, and the polymer yield is 81.60%. Ethylene is recovered. The discharged ethylene is pressurized and returned to step (2) for reuse. The obtained filter cake is washed and dried. The solvent used for washing is isoamyl acetate. The solid phase olefin functional polymer and liquid phase material are obtained by vacuum drying under negative pressure.

[0058] Example 4

[0059] Prepare olefin functional polymers according to the following steps: (1) Prepare a 30wt% maleic anhydride solution by mixing 890g maleic anhydride and 2076g isoamyl acetate solvent, and add the 30wt% maleic anhydride solution into the polymerization reactor. (2) Perform nitrogen and ethylene purging operations on the high-pressure polymerization reactor in sequence, each purging five times; slowly raise the temperature, and when the predetermined reaction temperature of 60°C is reached, promptly pressurize to the reaction pressure of 7MPa; (3) Subsequently, 1034g of a feed solution prepared from azobisisobutyronitrile and isoamyl acetate, wherein the concentration of azobisisobutyronitrile is 10wt%, was continuously pumped into the reactor under pressure after preheating, and the polymerization reaction was started. Ethylene was continuously introduced during the reaction to maintain the pressure at 7MPa. The molar ratio of azobisisobutyronitrile to maleic anhydride was 0.004:1. The polymerization reaction temperature was 60℃, the pressure was 7MPa, and the feeding time was 10h. (4) After the reaction is completed, the system after polymerization in step (3) is filtered by a No. 4 sand core funnel. 1800g of filtrate and 2200g of filter cake are obtained by solid-liquid separation. The maleic anhydride content of the filtrate and filter cake is quantitatively analyzed by gas chromatography. The anhydride value of the filtrate is determined according to ISO 1390-4:1977 standard. The maleic anhydride content in the filtrate is 2.85%, the maleic anhydride content in the filter cake is 1.025%, and the anhydride value of the filtrate is 6.24. The conversion rate of maleic anhydride is calculated to be 91.66%, and the polymer yield is 84.83%. Ethylene is recovered. The discharged ethylene is pressurized and returned to step (2) for reuse. The obtained filter cake is washed and dried. The solvent used for washing is isoamyl acetate. The solid phase olefin functional polymer and liquid phase material are obtained by vacuum drying under negative pressure.

[0060] Example 5

[0061] Prepare olefin functional polymers according to the following steps: (1) Prepare a 20wt% maleic anhydride solution by mixing 890g maleic anhydride and 3560g butyl acetate solvent, and add the 20wt% maleic anhydride solution into the polymerization reactor. (2) Perform nitrogen and ethylene purging operations on the high-pressure polymerization reactor in sequence, each purging five times; slowly raise the temperature, and when the predetermined reaction temperature of 45°C is reached, promptly pressurize to the reaction pressure of 6.5 MPa; (3) Subsequently, 1550g of a feed solution prepared from azobisisobutyronitrile and butyl acetate, wherein the concentration of azobisisobutyronitrile is 10wt%, was continuously pumped into the reactor under pressure after preheating, and the polymerization reaction was started. Ethylene was continuously introduced during the reaction to maintain the pressure at 6.5MPa. The molar ratio of azobisisobutyronitrile to maleic anhydride was 0.0035:1. The polymerization reaction temperature was 45℃, the pressure was 6.5MPa, and the feeding time was 12h. (4) After the reaction is completed, the system after the polymerization reaction in step (3) is filtered by a No. 4 sand core funnel. After solid-liquid separation, 2300g of filtrate and 3700g of filter cake are obtained. The maleic anhydride content of the filtrate and filter cake is quantitatively analyzed by gas chromatography. The anhydride value of the filtrate is determined according to ISO 1390-4:1977 standard. The maleic anhydride content in the filtrate is 2.88%, the maleic anhydride content in the filter cake is 1.089%, and the anhydride value of the filtrate is 6.33. The conversion rate of maleic anhydride is calculated to be 87.97%, and the polymer yield is 79.09%. Ethylene is recovered. The discharged ethylene is pressurized and returned to step (2) for reuse. The obtained filter cake is washed and dried. The solvent used for washing is isoamyl acetate. After vacuum drying under negative pressure, solid-phase olefin functional polymer and liquid-phase material are obtained.

[0062] Example 6

[0063] Prepare olefin functional polymers according to the following steps: (1) Prepare a 15wt% maleic anhydride solution by mixing 890g of maleic anhydride and 5034g of toluene solvent, and add the 15wt% maleic anhydride solution into the polymerization reactor. (2) Perform nitrogen and ethylene purging operations on the high-pressure polymerization reactor in sequence, each purging five times; slowly raise the temperature, and when the predetermined reaction temperature of 40°C is reached, promptly pressurize to the reaction pressure of 7MPa; (3) Subsequently, 1076g of a feed solution prepared from diisopropyl peroxide and toluene, wherein the diisopropyl peroxide is 10wt%, was continuously pumped into the reactor under pressure after preheating, and the polymerization reaction was immediately started. Ethylene was continuously introduced during the reaction to maintain the pressure at 7MPa. The molar ratio of diisopropyl peroxide to maleic anhydride was 0.004:1. The polymerization reaction temperature was 40℃, the pressure was 7MPa, and the feeding time was 10h. (4) After the reaction is completed, the system after polymerization in step (3) is filtered by a No. 4 sand core funnel. 2500g of filtrate and 4500g of filter cake are obtained by solid-liquid separation. The maleic anhydride content of the filtrate and filter cake is quantitatively analyzed by gas chromatography. The anhydride value of the filtrate is determined according to ISO 1390-4:1977 standard. The maleic anhydride content in the filtrate is 6.33%, the maleic anhydride content in the filter cake is 2.880%, and the anhydride value of the filtrate is 8.31. The conversion rate of maleic anhydride is calculated to be 67.49%, and the polymer yield is 62.02%. Ethylene is recovered. The discharged ethylene is pressurized and returned to step (2) for reuse. The obtained filter cake is washed and dried. The solvent used for washing is isoamyl acetate. The solid phase olefin functional polymer and liquid phase material are obtained by vacuum drying under negative pressure.

[0064] Example 7

[0065] Prepare olefin functional polymers according to the following steps: (1) Prepare a 20wt% maleic anhydride solution by mixing 890g of maleic anhydride and 3560g of xylene solvent, and add the 20wt% maleic anhydride solution into the polymerization reactor. (2) Perform nitrogen and ethylene purging operations on the high-pressure polymerization reactor in sequence, each purging five times; slowly raise the temperature, and when the predetermined reaction temperature of 30°C is reached, promptly pressurize to the reaction pressure of 7MPa; (3) Subsequently, 1550g of a feed solution prepared from dihexyl peroxide and xylene, wherein diisopropyl peroxide is 10wt%, was preheated and then pumped steadily into the reactor under pressure by a transfer pump, and the polymerization reaction was immediately started. Ethylene was continuously introduced during the reaction to maintain the pressure at 7MPa. The molar ratio of dihexyl peroxide to maleic anhydride was 0.004:1. The polymerization reaction temperature was 30℃, the pressure was 7MPa, and the feeding time was 10h. (4) After the reaction is completed, the system after polymerization in step (3) is filtered by a No. 4 sand core funnel. 2100g of filtrate and 3900g of filter cake are obtained by solid-liquid separation. The maleic anhydride content of the filtrate and filter cake is quantitatively analyzed by gas chromatography. The anhydride value of the filtrate is determined according to ISO 1390-4:1977 standard. The maleic anhydride content in the filtrate is 8.25%, the maleic anhydride content in the filter cake is 2.879%, and the anhydride value of the filtrate is 8.24. The conversion rate of maleic anhydride is calculated to be 67.76%, and the polymer yield is 67.88%. Ethylene is recovered. The discharged ethylene is pressurized and returned to step (2) for reuse. The obtained filter cake is washed and dried. The solvent used for washing is isoamyl acetate. The solid phase olefin functional polymer and liquid phase material are obtained by vacuum drying under negative pressure.

[0066] Comparative Example 1

[0067] Prepare olefin functional polymers according to the following steps: (1) Add 1100g of butyl acetate solvent into the polymerization reactor; (2) Perform nitrogen and ethylene purging operations on the high-pressure polymerization reactor in sequence, each purging five times; slowly raise the temperature, and when the predetermined reaction temperature of 50°C is reached, promptly pressurize to the reaction pressure of 6MPa; (3) Subsequently, using a continuous pumping method, the monomer feed solution prepared by maleic anhydride and butyl acetate (including 890g of maleic anhydride and 2076g of butyl acetate, with a maleic anhydride concentration of 30wt%) and the initiator feed solution prepared by azobisisobutyronitrile and butyl acetate (with an azobisisobutyronitrile concentration of 10wt%) were preheated and then steadily injected into the reactor under pressure by a transfer pump, and the polymerization reaction was immediately started. During the reaction, ethylene was continuously introduced to maintain the pressure at 6MPa. The molar ratio of the initiator azobisisobutyronitrile to maleic anhydride was 0.0065:1, the polymerization reaction temperature was 50℃, the pressure was 6MPa, and the feeding time was 8h; (4) After the reaction is completed, the system after polymerization in step (3) is filtered by a No. 4 sand core funnel. 2900g of filtrate and 2200g of filter cake are obtained by solid-liquid separation. The maleic anhydride content of the filtrate and filter cake is quantitatively analyzed by gas chromatography. The anhydride value of the filtrate is determined according to ISO 1390-4:1977 standard. The maleic anhydride content in the filtrate is 13.21%, the maleic anhydride content in the filter cake is 3.875%, and the anhydride value of the filtrate is 9.42. The conversion rate of maleic anhydride is calculated to be 47.11%, and the polymer yield is 59.68%. Ethylene is recovered. The discharged ethylene is returned to step (2) for reuse after being pressurized. The obtained filter cake is washed and dried. The solvent used for washing is isoamyl acetate. The solid phase olefin functional polymer and liquid phase material are obtained by vacuum drying under negative pressure.

[0068] Comparative Example 2

[0069] Prepare olefin functional polymers according to the following steps: (1) Add 890g of maleic anhydride, 103.4g of azobisisoheptanenitrile and 3006.6g of butyl acetate into the polymerization reactor; (2) The high-pressure polymerization reactor was purged with nitrogen and ethylene in sequence, five times each; the temperature was slowly increased, and when the predetermined reaction temperature of 50°C was reached, the pressure was promptly increased to 6 MPa to start the reaction. The molar ratio of azobisisobutyronitrile to maleic anhydride was 0.0065:1, the polymerization reaction temperature was 50°C, the pressure was 6 MPa, and the reaction time was 8 h. (3) After the reaction is completed, the system after the polymerization reaction in step (2) is filtered by a No. 4 sand core funnel. After solid-liquid separation, 1700g of filtrate and 2300g of filter cake are obtained. The maleic anhydride content of the filtrate and filter cake is quantitatively analyzed by gas chromatography. The anhydride value of the filtrate is determined according to ISO 1390-4:1977 standard. The maleic anhydride content in the filtrate is 10.47%, the maleic anhydride content in the filter cake is 3.024%, and the anhydride value of the filtrate is 13.14. The conversion rate of maleic anhydride is calculated to be 72.05%, and the polymer yield is 67.05%. Ethylene is recovered. The discharged ethylene is pressurized and returned to step (2) for reuse. The obtained filter cake is washed and dried. The solvent used for washing is isoamyl acetate. After vacuum drying under negative pressure, solid-phase olefin functional polymer and liquid-phase material are obtained.

[0070] Comparative Example 3

[0071] Prepare olefin functional polymers according to the following steps: (1) Prepare a 50wt% maleic anhydride solution by mixing 1483g maleic anhydride and 1483g butyl acetate solvent, and add the 50wt% maleic anhydride solution into the polymerization reactor. (2) Perform nitrogen and ethylene purging operations on the high-pressure polymerization reactor in sequence, each purging five times; slowly raise the temperature, and when the predetermined reaction temperature of 50°C is reached, promptly pressurize to the reaction pressure of 6MPa; (3) Subsequently, 1034g of a feed solution prepared from azobisisobutyronitrile and butyl acetate, wherein the concentration of azobisisobutyronitrile is 10wt%, was continuously pumped into the reactor under pressure after preheating, and the polymerization reaction was immediately started. Ethylene was continuously introduced during the reaction to maintain the pressure at 6MPa. The molar ratio of azobisisobutyronitrile to maleic anhydride was 0.0065:1, the polymerization reaction temperature was 50℃, the pressure was 6MPa, and the feeding time was 8h. (4) After the reaction is completed, the system after polymerization in step (3) is filtered by a No. 4 sand core funnel. 2000g of filtrate and 2000g of filter cake are obtained by solid-liquid separation. The maleic anhydride content of the filtrate and filter cake is quantitatively analyzed by gas chromatography. The anhydride value of the filtrate is determined according to ISO 1390-4:1977 standard. The maleic anhydride content in the filtrate is 18.25%, the maleic anhydride content in the filter cake is 6.855%, and the anhydride value of the filtrate is 17.28. The conversion rate of maleic anhydride is calculated to be 65.97%, and the polymer yield is 67.40%. Ethylene is recovered. The discharged ethylene is pressurized and returned to step (2) for reuse. The obtained filter cake is washed and dried. The solvent used for washing is isoamyl acetate. The solid phase olefin functional polymer and liquid phase material are obtained by vacuum drying under negative pressure.

[0072] The anhydride values ​​and relative molecular masses of the olefin functional polymers obtained in Examples 1-7 and Comparative Examples 1-3, namely ethylene-maleic anhydride alternating copolymers, were tested, and the MAH conversion rate of the functional monomers and the polymer yield in each example and comparative example were calculated. The results are shown in Table 1. Table 1

[0073] Table 1 shows that high molecular weight ethylene-maleic anhydride copolymers can be synthesized using low-temperature initiators. By adjusting polymerization process parameters such as temperature, pressure, and reaction time, the conversion rate of functional monomers can reach over 95%, and the polymer yield can also reach over 95%. The anhydride value of the polymer is around 70%, and the weight-average molecular weight can be controlled within the range of 20-78 W. During polymerization, higher temperatures lead to faster initiator decomposition, lower monomer and initiator free radical ratios in the system, lower degree of polymerization, and lower product molecular weight. Higher polymerization pressure increases the proportion of monomer free radicals, resulting in a higher product molecular weight.

[0074] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the substantive technical content of the present invention. The substantive technical content of the present invention is broadly defined within the scope of the claims. Any technical entity or method completed by others that is completely identical to or an equivalent modification of the claims is considered to be covered within the scope of the claims.

[0075] All documents mentioned in this invention are incorporated herein by reference as if each document were individually incorporated by reference. Furthermore, it should be understood that after reading the foregoing description of this invention, those skilled in the art can make various alterations or modifications to this invention, and these equivalent forms also fall within the scope defined by the appended claims.

Claims

1. A method for synthesizing high molecular weight olefin functional polymers, the method comprising the following steps: (1) Add the primer containing the functional monomer and the first solvent to the polymerization reactor and fully replace the atmosphere in the reactor with a protective gas atmosphere; (2) After the low-carbon olefins are introduced into the reactor, the temperature and pressure are increased to reach the reaction temperature and reaction pressure; (3) The feed liquid including the initiator and the second solvent is fed into the polymerization reactor to carry out the polymerization reaction. During the reaction, low carbon olefins are continuously introduced to maintain the pressure, and olefin functional copolymers are obtained. The mass ratio of the first solvent to the functional monomer in the primer is 2 to 9 / 1; the mass ratio of the second solvent to the initiator in the feed solution is 5 to 10 / 1. The polymerization reaction in the polymerization reactor is carried out in one step. The olefin functional copolymers described herein have a weight-average molecular weight of at least 200,000 Daltons and are tested using gel permeation chromatography according to ASTM D6474 standard.

2. The method as described in claim 1, characterized in that, The functional monomer includes maleic anhydride monomer; and / or The low-carbon olefins include at least one olefin selected from the group consisting of ethylene, propylene, butene, and butadiene; and / or The first solvent and the second solvent each comprise at least one solvent selected from the group consisting of: n-heptane, isoamyl acetate, butyl acetate, toluene, and xylene; and / or The initiator comprises at least one initiator selected from the group consisting of azobisisobutyronitrile (ABVN), diisopropyl peroxide (IPP), and dihexyl peroxide (EHP); and / or The protective gas includes at least one gas selected from the group consisting of nitrogen, argon, and helium.

3. The method as described in claim 1 or 2, characterized in that, In step (3), the initiator is fed by continuous pumping.

4. The method as described in claim 1 or 2, characterized in that, The molar ratio of the initiator and functional monomer added is 0.003 to 0.015, preferably 0.004 to 0.008; and / or In step (1), the total feed amount is 40%-70% of the reactor volume, the mass ratio of solvent to functional monomer in the base liquid is 2~9 / 1, and the mass ratio of solvent to initiator in the feed liquid is 5~10 / 1.

5. The method as described in claim 1 or 2, characterized in that, The polymerization reaction is carried out at a temperature of 30-70°C; and / or The polymerization reaction is carried out at a pressure of 4 to 8 MPa; and / or The polymerization reaction takes 4 to 15 hours.

6. The method as described in claim 1 or 2, characterized in that, The method further includes first performing gas-solid-liquid separation on the system after the polymerization reaction in step (3) to recover low-carbon olefins, and then performing solid-liquid separation on the remaining material after discharge.

7. The method as described in claim 6, characterized in that, The recovered low-carbon olefins are returned to step (2) for recycling after being pressurized; and / or The remaining material after the recovery of low-carbon olefins is discharged in a solid-liquid manner.

8. The method as described in claim 6, characterized in that, The solid-liquid separation method includes any one or a combination of at least two of decantation, filtration, or centrifugation.

9. The method as described in claim 1 or 2, characterized in that, The high molecular weight olefin functional polymer is an alternating copolymer of ethylene and maleic anhydride, with a weight-average molecular weight (Mw) of 20W-78W and a maleic anhydride (MAH) content of >70%.

10. The high molecular weight olefin functional polymer prepared by the method according to any one of claims 1-9.

Images