Post-treatment method for solution polymerization of cycloolefin copolymer

Abstract

The invention provides a post-treatment method for solution polymerization of a cycloolefin copolymer. The post-treatment method for solution polymerization of the cycloolefin copolymer comprises the following steps: adding a terminating agent and a poor solvent A into a cycloolefin copolymer solution subjected to solution polymerization, and carrying out a termination reaction to obtain a reaction solution; and dropwise adding the reaction liquid into a poor solvent B, stirring for precipitation, separating, and drying to finish post-treatment. The post-treatment method of the cycloolefin copolymer obtained through solution polymerization is designed, the use amount of a solvent in the post-treatment process is small, catalyst metal impurities and volatile substances in the cycloolefin copolymer solution are removed at the same time, the post-treatment method is simple and convenient, the impurity removal efficiency is high, and the use amount of the solvent is small.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer post-processing, and in particular relates to a method for post-processing a cycloolefin copolymer solution polymerization. Background Art

[0002] Cyclic olefin copolymer (COC) is a type of non-crystalline polymer formed by copolymerization of cyclic olefins and α-olefins. It has excellent properties such as high transparency, low birefringence, high glass transition temperature, high chemical resistance, high dimensional stability, and low water absorption. It has been used in medical equipment, optical lenses, and food packaging. In addition to polymers, cyclic olefin copolymer solutions also contain impurities such as solvents, catalysts, and unreacted monomers. The presence of catalysts affects the dielectric properties of polymers, induces oxidative degradation of polymers at high temperatures, and causes yellowing; the presence of solvents and monomers affects the haze of polymers and the surface flatness of parts, which will also limit their application in the medical field. Therefore, after solution polymerization, the catalyst, solvent, and monomer need to be removed. Generally, the methods for removing metal impurities include catalyst precipitation, extraction washing, and adsorption. The methods for removing solvents and monomers are multi-stage flash devolatilization. These methods often have complicated steps and expensive equipment, and cannot remove metal impurities and volatile substances at the same time.

[0003] JPH06100668A discloses a method for purifying cycloolefin copolymers, which uses an aqueous solution of organic acid or inorganic acid to extract the polymer solution to remove metal impurities, but the method produces a large amount of acidic wastewater and requires equipment and pipelines to resist acid corrosion. JP6050951B2 discloses a method for refining a polymer solution, which uses inorganic adsorbents such as molecular sieves, silica gel and alumina to adsorb metal impurities, but the impurity removal efficiency of the method is not high, and the residual metal impurities are still higher than 10ppm. CN1662561A discloses a method for removing volatiles from olefin solution polymers, which uses a two-stage flash devolatilization and a one-stage extrusion devolatilization method to remove volatiles, but the method has complex equipment, a long process, and cannot remove catalyst metals. US5128446A discloses a method for producing cycloolefin random copolymers, which uses a 25% sodium hydroxide alkaline solution water washing method to remove the catalyst, and uses acetone four times the mass of the polymer solution to precipitate and remove the solvent and monomer. The post-processing steps provided by the technical solution are complicated and a large amount of poor solvents are used.

[0004] The post-treatment method of cycloolefin copolymer solution polymerization provided by the prior art has complicated steps, generates a large amount of waste liquid, has high requirements for post-treatment equipment, and has low impurity removal efficiency. Therefore, how to provide a simple and convenient post-treatment method of cycloolefin copolymer solution polymerization with high impurity removal efficiency and low solvent consumption has become a technical problem that needs to be solved urgently. Summary of the invention

[0005] In view of the shortcomings of the prior art, the object of the present invention is to provide a method for post-treatment of cycloolefin copolymer solution polymerization. The present invention designs a method for post-treatment of cycloolefin copolymer obtained by solution polymerization, so that the amount of solvent used in the post-treatment process is small, and the catalyst metal impurities and volatile substances in the cycloolefin copolymer solution can be removed at the same time. The post-treatment method has simple and convenient steps, high impurity removal efficiency, and small amount of solvent.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a method for post-treatment of a cyclic olefin copolymer solution polymerization, the method comprising the following steps:

[0008] (1) adding a terminator and a poor solvent A to a cycloolefin copolymer solution after solution polymerization to perform a termination reaction to obtain a reaction solution;

[0009] (2) The reaction solution is added dropwise into the poor solvent B, stirred to precipitate, separated and dried, thereby completing the post-treatment of the cycloolefin copolymer.

[0010] The present invention designs a method for post-treating a cycloolefin copolymer obtained by solution polymerization, so that less solvent is used in the post-treating process, and catalyst metal impurities and volatile substances in the cycloolefin copolymer solution can be removed simultaneously. The post-treating method has simple and convenient steps, high impurity removal efficiency and less solvent usage.

[0011] In the present invention, a terminator and a poor solvent A are added to the cycloolefin copolymer solution after solution polymerization. The terminator terminates the reaction and forms a metal complex soluble in the poor solvent with the catalyst used in the preparation of the cycloolefin copolymer. The poor solvent B separates the cycloolefin copolymer from the cycloolefin copolymer solution and dissolves the metal complex formed by the terminator and the catalyst.

[0012] In the prior art, in order to separate the cycloolefin copolymer from the cycloolefin copolymer solution, a common treatment method is to mix the cycloolefin copolymer reaction liquid after the termination reaction with a poor solvent to precipitate the cycloolefin copolymer. The poor solvent refers to a solvent in which the solubility of the cycloolefin copolymer in the solvent is ≤0.5g. Commonly used poor solvents for cycloolefin copolymers include polar solvents such as isopropanol, n-octanol, and acetone. In the present invention, the purpose of adding the poor solvent A in advance in step (1) is to advance the mixing process of the solvent in the cycloolefin copolymer solution and the poor solvent, thereby reducing the amount of the poor solvent.

[0013] The early addition of a small amount of poor solvent A advances the mass transfer process, which is beneficial for the rapid precipitation of the polymer into powder.

[0014] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. Through the following preferred technical solutions, the objectives and beneficial effects of the present invention can be better achieved and realized.

[0015] As a preferred technical solution of the present invention, the terminator is selected from alkyl alcohols having 3-6 carbon atoms (for example, 3, 4, 5 or 6) and / or acetyl compounds having α-active hydrogen.

[0016] Preferably, the alkyl alcohol has 3 or 4 carbon atoms, and is more preferably any one of n-propanol, isopropanol or n-butanol, or a combination of at least two thereof.

[0017] Preferably, the acetyl compound having α-active hydrogen comprises acetylacetone and / or ethyl acetoacetate.

[0018] Preferably, the terminator comprises isopropanol and / or acetylacetone.

[0019] As a preferred technical solution of the present invention, the poor solvent A and the poor solvent B are independently selected from any one of n-octanol, isopropanol or acetone or a combination of at least two thereof, and isopropanol and / or acetone are further preferred.

[0020] In the present invention, isopropanol and / or acetylacetone are used as terminators, and isopropanol is used as poor solvent A and poor solvent B, so that the post-treatment effect of the cycloolefin copolymer and the impurity removal efficiency of the cycloolefin copolymer can be further improved.

[0021] As a preferred technical solution of the present invention, the cyclic olefin copolymer in the cyclic olefin copolymer solution is selected from any one of ethylene-norbornene copolymer, ethylene-tetracyclododecene copolymer or propylene-norbornene copolymer or a combination of at least two thereof.

[0022] Preferably, the concentration of the cyclic olefin copolymer in the cyclic olefin copolymer solution is 8-30wt%, for example, it can be 8wt%, 10wt%, 12wt%, 14wt%, 16wt%, 18wt%, 20wt%, 22wt%, 24wt%, 26wt%, 28wt% or 30wt%, etc.

[0023] Preferably, the solvent of the cycloolefin copolymer solution is selected from any one of toluene, xylene, n-hexane, cyclohexane or methylcyclohexane, or a combination of at least two thereof, and more preferably toluene.

[0024] Preferably, the metal element in the catalyst used to prepare the cycloolefin copolymer includes any one of Ti, Zr or Al or a combination of at least two of them.

[0025] In the present invention, there is no special restriction on the catalyst used for preparing the cycloolefin copolymer. Common Ti-based metallocene catalysts include any one or a combination of at least two of bis(cyclopentadienyl)titanium dichloride, bisindenyl titanium dichloride, ethyl-bridged bisindenyl titanium dichloride, dimethylsilyl-bridged bisindenyl titanium dichloride, bis(cyclopentadienyl)dimethyltitanium, and bisfluorenyl titanium dichloride; common Zr-based metallocene catalysts include any one or a combination of at least two of bis(cyclopentadienyl)zirconium dichloride, bismethylcyclopentadienyl dimethyl zirconium, biscyclopentadienyl dimethyl zirconium, bis(trimethylcyclopentadienyl)zirconium dichloride, bisindenyl zirconium dichloride, bisfluorenyl zirconium dichloride, ethyl-bridged bisindenyl zirconium dichloride, and dimethylsilyl-bridged bisindenyl dimethyl zirconium; common Al-containing co-catalysts include any one or a combination of at least two of methylaluminoxane, modified methylaluminoxane, trimethylaluminum, triethylaluminum, and triisobutylaluminum.

[0026] Preferably, the weight average molecular weight (Mw) of the cycloolefin copolymer is 50000-100000 g / mol, for example, 50000 g / mol, 55000 g / mol, 60000 g / mol, 65000 g / mol, 70000 g / mol, 75000 g / mol, 80000 g / mol, 85000 g / mol, 90000 g / mol, 95000 g / mol or 100000 g / mol, etc.

[0027] Preferably, the polydispersity index (PDI) of the cyclic olefin copolymer is 2-2.5, for example, 2, 2.05, 2.1, 2.15, 2.2, 2.25, 2.3, 2.35, 2.4, 2.45 or 2.5, etc.

[0028] Preferably, the glass transition temperature (Tg) of the cycloolefin copolymer is 80-160°C, for example, it may be 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C or 160°C.

[0029] In the present invention, the weight average molecular weight and PDI of the cycloolefin copolymer are tested by high temperature gel permeation chromatography (high temperature GPC), and the glass transition temperature is tested by differential scanning calorimetry (DSC).

[0030] As a preferred technical solution of the present invention, based on 100 parts by volume of the cyclic olefin copolymer solution, the volume fraction of the terminator in step (1) is 0.1-15 parts, for example, it can be 0.1 parts, 0.5 parts, 1 parts, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts or 15 parts, etc.

[0031] If the amount of terminator used is too small, the polymerization reaction of the cycloolefin copolymer cannot be completely terminated, which ultimately leads to poor post-treatment effect and incomplete removal of metal impurities; if the amount of terminator used is too large, the cycloolefin copolymer will be precipitated prematurely and the metal elements in the catalyst will be wrapped, resulting in poor post-treatment effect and low impurity removal efficiency.

[0032] As a preferred technical solution of the present invention, based on 100 parts by volume of the cycloolefin copolymer solution, the volume fraction of the poor solvent A in step (1) is 5-20 parts, for example, it can be 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, 16 parts, 17 parts, 18 parts, 19 parts or 20 parts, etc.

[0033] If the amount of the poor solvent A is too small, the cycloolefin copolymer will not form a saturated solution in the reaction solution obtained in step (1), and the cycloolefin copolymer cannot be precipitated in powder form in step (2), resulting in poor subsequent impurity removal effect. If the amount of the poor solvent A is too large, the cycloolefin copolymer will precipitate prematurely in step (1), causing the polymer to encapsulate metal impurities, resulting in poor post-treatment effect and low impurity removal efficiency.

[0034] As a preferred technical solution of the present invention, based on 100 parts by volume of the cycloolefin copolymer solution, the volume fraction of the poor solvent B in step (2) is 100-300 parts, for example, it can be 100 parts, 120 parts, 140 parts, 160 parts, 180 parts, 200 parts, 220 parts, 240 parts, 260 parts, 280 parts or 300 parts, etc.

[0035] If the amount of the poor solvent B used in step (2) is too small, the cycloolefin copolymer cannot be completely precipitated from the reaction solution of step (1); if the amount of the poor solvent B used in step (2) is too large, the poor solvent B will be wasted.

[0036] As a preferred technical solution of the present invention, the temperature of the termination reaction is 50-120°C, for example, it can be 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, 110°C or 120°C.

[0037] If the temperature of the termination reaction is too low, the fluidity of the cycloolefin copolymer solution is poor and the termination reaction speed is slow, which will lead to poor post-treatment effect, incomplete termination, and poor impurity removal effect; if the temperature of the termination reaction is too high, the solvent in the cycloolefin copolymer solution evaporates quickly, the polymer precipitates in advance and wraps the solvent and metal impurities, and the final impurity removal effect is poor.

[0038] Preferably, the termination reaction time is 10-30 min, for example, it can be 10 min, 12 min, 15 min, 18 min, 20 min, 23 min, 25 min, 27 min or 30 min.

[0039] As a preferred technical solution of the present invention, the temperature at which the reaction solution in step (2) is added dropwise to the poor solvent B is 50-120°C, for example, 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, 110°C or 120°C, etc.

[0040] Preferably, the stirring method comprises: stirring with a stirrer. The function of the stirrer in the present invention is to mix the reaction solution and the poor solvent B evenly. There is no limitation on the type of stirrer used in the present invention, as long as it can achieve the function of mixing the two solutions evenly.

[0041] Preferably, the terminal linear speed of the agitator is 4.5-8.5 m / s, for example, it can be 4.5 m / s, 5 m / s, 5.5 m / s, 6 m / s, 6.5 m / s, 7 m / s, 7.5 m / s, 8 m / s or 8.5 m / s.

[0042] If the end linear speed of the stirrer is too slow, after the reaction solution is added dropwise to the poor solvent B in step (2), the precipitated cycloolefin copolymer will be wrapped into a mass and cannot be dispersed, resulting in a poor removal effect of metal impurities; if the end linear speed of the stirrer is too fast, the stirring power is too high and the energy loss is too high.

[0043] As a preferred technical solution of the present invention, the dropping speed in step (2) is ≤3.5mL / min, for example, it can be 0.1mL / min, 0.5mL / min, 1mL / min, 1.5mL / min, 2mL / min, 2.5mL / min, 3mL / min or 3.5mL / min, etc.

[0044] If the dropping speed is too fast, after the reaction solution is added dropwise to the poor solvent B in step (2), the precipitated cycloolefin copolymer will be wrapped into a mass and cannot be dispersed, resulting in a poor removal effect of metal impurities.

[0045] As a preferred technical solution of the present invention, the separation method in step (2) includes filtering and washing.

[0046] Preferably, the washing solvent comprises anhydrous ethanol and / or poor solvent B.

[0047] Preferably, the drying method comprises vacuum drying.

[0048] Preferably, the vacuum drying temperature is 70-120°C (for example, it can be 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C or 120°C, etc.), and the pressure is 0.1-1kPa (for example, it can be 0.1kPa, 0.2kPa, 0.3kPa, 0.4kPa, 0.5kPa, 0.6kPa, 0.7kPa, 0.8kPa, 0.9kPa or 1kPa, etc.).

[0049] As a preferred technical solution of the present invention, the post-treatment method of the cycloolefin copolymer solution polymerization comprises the following steps:

[0050] (1) adding a terminator and a poor solvent A to a cyclic olefin copolymer solution after solution polymerization, and performing a termination reaction at 50-120° C. for 10-30 minutes to obtain a reaction solution;

[0051] (2) adding the reaction solution dropwise into the poor solvent B at 50-120° C. for 30-120 min, stirring with a stirrer, controlling the end linear velocity of the stirrer to 5-15 m / s, filtering, washing, and vacuum drying at a temperature of 70-120° C. and a pressure of 0.1-1 kPa to complete the post-treatment of the cycloolefin copolymer;

[0052] Based on 100 parts by weight of the cycloolefin copolymer solution, the weight of the terminator is 0.1-15 parts, the weight of the poor solvent A is 5-20 parts, and the weight of the poor solvent B is 100-300 parts.

[0053] Compared with the prior art, the present invention has the following beneficial effects:

[0054] (1) The present invention designs a method for post-treating the cycloolefin copolymer obtained by solution polymerization, so that the amount of solvent used in the post-treatment process is small, and the catalyst metal impurities and volatile substances in the cycloolefin copolymer solution can be removed simultaneously. The post-treatment method has simple and convenient steps, high impurity removal efficiency, and small amount of solvent.

[0055] (2) The present invention further improves the impurity removal efficiency of the cycloolefin copolymer by controlling the terminator, the poor solvent A, and each process condition in the post-treatment method within a specific range. The total volatile matter content in the cycloolefin copolymer is in the range of 112-353 ppm, and the total metal ion content is in the range of 0.66-18.26 ppm. DETAILED DESCRIPTION

[0056] For the convenience of understanding the present invention, the present invention lists the following embodiments. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0057] The description of the cycloolefin copolymer solution in the examples and comparative examples is shown in Table 1 below. Other reagents (such as acetylacetone, n-propanol, isopropanol, n-butanol, ethyl acetoacetate, ethanol, etc.) are all commercially available and have an analytical purity:

[0058] Table 1

[0059]

[0060]

[0061] Wherein, the preparation method of cycloolefin copolymer solution 1 (ethylene-norbornene copolymer solution) is as follows:

[0062] In a 300 mL autoclave reactor, 0.2 mol of norbornene, 100 mL of toluene and 2.4 mg of hydrogen were added in sequence, the reaction system was heated to 130° C., and under stirring at 500 rpm, 0.1 mmol of triisobutylaluminum (TIBA), 0.5 μmol of ethyl-bridged indene zirconium dichloride and 2.5 μmol of triphenylmethyltetrakis(pentafluorophenyl)borate were added in sequence, and ethylene was added by additional metering during the polymerization process to control the ethylene partial pressure to be 1.0 MPa; after the polymerization reaction was carried out for 15 min, the polymerization reaction was stopped to obtain an ethylene-norbornene copolymer solution;

[0063] Among them, the content of ethylene-norbornene copolymer in the ethylene-norbornene copolymer solution is 12wt%, Mw is 68400g / mol, and PDI is 2.24; ICP test results show that the Al content in the polymer is 205ppm, and the Zr content is 5.3ppm.

[0064] The preparation method of cycloolefin copolymer solution 2 (ethylene-tetracyclododecene copolymer solution) is as follows:

[0065] In a 300 mL autoclave reactor, 0.15 mol of tetracyclododecene, 100 mL of toluene and 2.4 mg of hydrogen were added in sequence, the reaction system was heated to 130° C., and under stirring at 500 rpm, 0.1 mmol of triisobutylaluminum (TIBA), 0.5 μmol of dimethylsilyl-bridged indene titanium dichloride and 2.5 μmol of triphenylmethyltetrakis(pentafluorophenyl)borate were added in sequence, and ethylene was added by additional metering during the polymerization process to control the ethylene partial pressure to be 1.0 MPa; after the polymerization reaction was carried out for 12 min, the polymerization reaction was stopped to obtain an ethylene-tetracyclododecene copolymer solution;

[0066] The content of ethylene-tetracyclododecene copolymer in the ethylene-tetracyclododecene copolymer solution is 10 wt%, Mw is 64600 g / mol, and PDI is 2.23. The ICP test results show that the Al content in the polymer is 245 ppm, and the Ti content is 3.2 ppm.

[0067] The preparation method of cycloolefin copolymer solution 3 (propylene-norbornene copolymer solution) is as follows:

[0068] In a 300 mL autoclave reactor, 0.4 mol of norbornene, 100 mL of toluene and 3.8 mg of hydrogen were added in sequence, the reaction system was heated to 135° C., and under stirring at 500 rpm, 0.2 mmol of triisobutylaluminum (TIBA), 1 μmol of dimethylsilyl-bridged indene titanium dichloride and 5 μmol of triphenylmethyltetrakis(pentafluorophenyl)borate were added in sequence, and propylene was added by additional metering during the polymerization process to control the propylene partial pressure to be 1.0 MPa; after the polymerization reaction was carried out for 15 min, the polymerization reaction was stopped to obtain a propylene-norbornene copolymer solution;

[0069] The content of propylene-norbornene copolymer in the propylene-norbornene copolymer solution was 27 wt%, Mw was 64600 g / mol, and PDI was 2.23. The ICP test results showed that the Al content in the polymer was 185 ppm, and the Ti content was 2.8 ppm.

[0070] Example 1-Example 20, Comparative Example 1-Comparative Example 5

[0071] Example 1 to Example 20 and Comparative Example 1 to Comparative Example 5 respectively provide a post-treatment method for a cycloolefin copolymer solution polymerization, and the post-treatment method is as follows:

[0072] (1) adding a terminator and a poor solvent A (or ethanol) to a cycloolefin copolymer solution after solution polymerization in an anhydrous and oxygen-free atmosphere to perform a termination reaction to obtain a reaction solution;

[0073] (2) adding the reaction solution dropwise into the poor solvent B (or ethanol), stirring with a stirrer, filtering, washing, and vacuum drying at a temperature of 100° C. and a pressure of 0.5 kPa for 12 h to complete the post-treatment of the cycloolefin copolymer;

[0074] Among them, the specific selection of cycloolefin copolymer solution, terminator, poor solvent A and poor solvent B in Examples 1 to 20 and Comparative Examples 1 to 5 is detailed in Tables 2 to 4 below, the temperature and time of the termination reaction in step (1), the dropping temperature and dropping speed of adding the reaction solution dropwise to the poor solvent B in step (2), and the terminal linear speed of the agitator when stirring with an agitator in step (2) are detailed in Tables 2 to 4 below.

[0075] The properties of the cycloolefin copolymers obtained by the post-treatment methods provided in the above embodiments and comparative examples were tested, and the specific testing methods are as follows:

[0076] Volatile matter content: headspace gas chromatography test, where volatile matter refers to the unreacted cycloolefin monomer in the cycloolefin copolymer solution and the solvent of the cycloolefin copolymer solution;

[0077] The headspace gas chromatograph model is Agilent 7890A, and the automatic headspace sampler model is Agilent 7697A. The specific steps are as follows: (1) Sample preparation: Take 0.5 g of solid sample and place it in a 20 mL headspace bottle. Accurately add cyclohexane on the analytical balance until the reading is 10 g, immediately press the cover to seal, put it into an ultrasonic cleaner, and ultrasonicate at 50° C. for 3 hours until the sample is completely dissolved in cyclohexane to obtain a 5 wt % sample solution for standby use; (2) Standard solution preparation: Use a micropipette to accurately measure 10 μL of toluene, 10 μL of norbornene, and 10 μL of tetracyclododecene, place them in a 10 mL volumetric flask, add cyclohexane to dilute to the scale, mix well, and obtain a mixed standard solution with a concentration of 1000 μg / mL, and dilute step by step to obtain concentrations of 50 μg / mL, 20 μg / mL, 10 μg / mL, 5 μg / mL, etc. mL, 2μg / mL, 1μg / mL, 0.5μg / mL series of mixed standard solutions (2) Establishment of standard working curve: Accurately transfer 100μL of each level of toluene, norbornene, and tetracyclododecene mixed standard solutions into 10mL headspace bottles, and immediately seal the headspace bottles with a cap; Inject and analyze in sequence from low concentration to high concentration, record the standard series target and the corresponding retention time, and draw a standard working curve with the peak area as the ordinate and the mass concentration of the target as the abscissa; (3) Sample determination: Transfer 100μL of the solution after dissolving the polymer into a 10mL headspace bottle, and immediately seal the headspace bottle with a cap. Duplicate samples should be collected for each sample; (4) Result analysis: Quantitative determination was performed using the external standard method, and the mass concentration (mg / kg) of each volatile component in the sample was calculated according to the following formula:

[0078] ω i =[(ω xi -ω0) / m1]×m2

[0079] Where:

[0080] ω i ——Mass concentration of toluene, norbornene or tetracyclododecene in the solid sample to be tested, mg / kg (mg volatile matter per kg sample);

[0081] ω xi ——Mass concentration of toluene, norbornene or tetracyclododecene obtained from the working curve, mg / kg;

[0082] ω0——the blank residual volatile matter concentration read from the working curve, mg / kg;

[0083] m1——mass of solid sample to be tested, g;

[0084] m2——mass of cyclohexane dissolved liquid sample, g.

[0085] Inductively coupled plasma spectroscopy (ICP-OES) was used to test the metal ion content (metal ions include aluminum ions, and / or zirconium ions, and / or titanium ions). The instrument model was the American Thermo Fisher ICAPPRO. The specific test steps are as follows:

[0086] (1) Preparation of standard solution and establishment of working curve: zirconium (Zr), aluminum (Al) and titanium (Ti) standard solutions (multi-element mixed standard solution for ICP analysis, purchased from the National Nonferrous Metals and Electronic Materials Analysis and Testing Center, 100.0 μg / mL) were gradually diluted with 3 wt% dilute nitric acid solution to prepare a series of standard solutions with concentrations of 0 μg / mL, 0.01 ug / mL, 0.05 μg / mL, 0.1 μg / mL, 0.2 μg / mL, and 0.5 μg / mL. The series of standard solutions with different concentrations were tested with the instrument to draw a standard curve; (2) Sample digestion pretreatment: 0.1±0.005 g (accurate to 0.001 g) of sample was weighed and the weighed mass was accurately recorded. The sample was placed in a 100 mL microwave digestion tank, 8 mL of concentrated nitric acid (mass fraction of 70 wt%) was added to the digestion tank to completely immerse the sample, and 2 mL of hydrogen peroxide was added. The digestion should be slow. Slowly drip the sample to allow it to react with concentrated nitric acid for 2 minutes, cover the digestion tank lid, place the sealed digestion tank in a microwave digestion furnace, and perform digestion according to the microwave digestion program. The microwave digestion program is: heat to 160°C for 7 minutes, heat to 200°C for another 7 minutes, and then maintain at 200°C for 40 minutes. After the digestion program is completed, wait for the temperature to cool to room temperature, take out the digestion tank as required, cool to room temperature, and obtain the digestion solution. Transfer the digestion solution to a 25mL volumetric flask, rinse the inner tank and lid with deionized water three times and transfer the rinse solution to the volumetric flask, then dilute to the scale line with distilled water, shake well, and wait for testing; (3) Sample testing: After the digestion solution is fixed to volume, use a 10mL syringe to fill the fixed volume solution, and filter it into the test tube with a 0.45μm water-based micromembrane filter, and connect the sample tube to the automatic sampler of the inductively coupled plasma atomic emission spectrometer; (4) Data processing: The content of each metal element is calculated according to the following formula:

[0087]

[0088] Where:

[0089] W——the metal element content in the sample, in milligrams per kilogram (mg / kg);

[0090] C 样 ——Concentration of digestion solution calculated from the working curve, in milligrams per liter (mg / L);

[0091] C 空白 - blank solution concentration calculated from the working curve, in milligrams per liter (mg / L);

[0092] V——digestion solution volume, in milliliters (mL);

[0093] N——digestion solution dilution multiple;

[0094] m——sample mass, in grams (g).

[0095] Refer to GB / T2410 and express it as the arithmetic mean of the test results, accurate to the last decimal place displayed on the instrument.

[0096] The above performance test results are detailed in Table 2-Table 4 below:

[0097] Table 2

[0098]

[0099]

[0100] Table 3

[0101]

[0102] Table 4

[0103]

[0104]

[0105] As can be seen from the above content, the present invention designs a method for post-treatment of the cycloolefin copolymer obtained by solution polymerization, so that the amount of solvent used in the post-treatment process is small, and the catalyst metal impurities and volatile substances in the cycloolefin copolymer solution can be removed at the same time, and the post-treatment method has simple and convenient steps, high impurity removal efficiency, and low solvent usage. The cycloolefin copolymer obtained by the post-treatment method provided by the present invention has high impurity removal efficiency, the total volatile content in the cycloolefin copolymer is in the range of 112-353ppm, and the total metal ion content is in the range of 0.66-18.26ppm.

[0106] It can be seen from the contents of Example 1 and Examples 4-9 that the present invention uses isopropanol or acetylacetone as a terminator and isopropanol or acetone as a poor solvent to improve the impurity removal efficiency of the cycloolefin copolymer.

[0107] It can be seen from the contents of Example 1, Examples 10-20 and Comparative Example 1 that the present invention further improves the impurity removal efficiency of the cycloolefin copolymer by controlling the dosage of the terminator and the poor solvent A within specific ranges, and controlling the dropping speed of step (2) within a specific range.

[0108] In Comparative Example 1, no terminator is used, and the metal impurities cannot be converted into substances soluble in poor solvents, so the impurity removal effect is poor. In Comparative Example 2, ethanol is used to replace the terminator and poor solvent A, and the acetylacetone metal compound soluble in the poor solvent cannot be formed. In addition, ethanol has a high polarity, and when it replaces the poor solvent A, part of the polymer will be precipitated in advance, wrapping the volatile matter and metal impurities, so the impurity removal effect is poor. In Comparative Example 3, ethanol is used to replace the poor solvent A, but ethanol has a high polarity, which causes part of the polymer to precipitate in advance, wrapping the volatile matter and metal impurities, so the impurity removal effect is poor. In Comparative Example 4, poor solvent A is not mixed into the polymer solution in advance, and a powdered polymer cannot be formed in step (2), and part of the impurities are wrapped, so the impurity removal effect is poor. In Comparative Example 5, ethanol is used to replace the terminator, poor solvent A, and poor solvent B. On the one hand, ethanol and the metal impurities cannot form a metal compound that is easily soluble in the poor solvent. On the other hand, ethanol has a high polarity, which easily causes the polymer to precipitate in blocks in step (2) and wrap the impurities, so the impurity removal effect is poor.

[0109] It can be seen from Comparative Example 2 that if ethanol (a good solvent for cycloolefin copolymer) is used in step (1) to replace the poor solvent A of the cycloolefin copolymer, and no terminator is used, the impurity removal efficiency of the cycloolefin copolymer will be low, the volatile matter content will be high, and the catalyst metal impurities will be high.

[0110] It can be seen from Comparative Example 3 that if ethanol (a good solvent for cycloolefin copolymer) is used in step (1) to replace the poor solvent A of cycloolefin copolymer, the impurity removal efficiency of the cycloolefin copolymer will be low, the volatile matter content will be high, and the catalyst metal impurities will be high.

[0111] It can be seen from Comparative Example 4 that if the poor solvent A for the cycloolefin copolymer is not used in step (1), but the poor solvent B for the cycloolefin copolymer is used once in step (2) to precipitate the cycloolefin copolymer, the impurity removal efficiency of the cycloolefin copolymer will be low, the volatile matter content will be high, and the catalyst metal impurities will be high.

[0112] It can be seen from Comparative Example 5 that if ethanol (a good solvent for cycloolefin copolymers) is used to replace the poor solvent A and the terminator of the cycloolefin copolymer in step (1), and ethanol (a good solvent for cycloolefin copolymers) is used to replace the poor solvent B of the cycloolefin copolymer in step (2), the impurity removal efficiency of the cycloolefin copolymer will be low, the volatile matter content will be high, and the catalyst metal impurities will be high.

[0113] It can be seen from the contents of Comparative Examples 2-5 that the present invention is designed by a method for post-treatment of cycloolefin copolymers obtained by solution polymerization, and the impurity removal efficiency of cycloolefin copolymers is improved by using terminators, poor solvents A and B and designing their addition sequence.

[0114] In summary, the present invention provides a method for post-treating a cycloolefin copolymer obtained by solution polymerization, so that the amount of solvent used in the post-treatment process is small, and the catalyst metal impurities and volatile substances in the cycloolefin copolymer solution can be removed simultaneously. The post-treatment method has simple and convenient steps, high impurity removal efficiency, and small amount of solvent used.

[0115] The applicant declares that the present invention illustrates the detailed process flow of the present invention through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned detailed process flow, that is, it does not mean that the present invention must rely on the above-mentioned detailed process flow to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of various raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for post-treatment of cycloolefin copolymer solution polymerization, characterized in that: The post-treatment method of the cycloolefin copolymer solution polymerization comprises the following steps: (1) adding a terminator and a poor solvent A to a cycloolefin copolymer solution after solution polymerization to perform a termination reaction to obtain a reaction solution; (2) The reaction solution is added dropwise into the poor solvent B, stirred to precipitate, separated and dried, thereby completing the post-treatment of the cycloolefin copolymer.

2. The post-treatment method for cycloolefin copolymer solution polymerization according to claim 1, characterized in that: The terminator is selected from an alkyl alcohol having 3 to 6 carbon atoms and / or an acetyl compound having an alpha active hydrogen; Preferably, the alkyl alcohol has 3 or 4 carbon atoms, and is more preferably any one of n-propanol, isopropanol or n-butanol, or a combination of at least two thereof; Preferably, the acetyl compound having α-active hydrogen comprises acetylacetone and / or ethyl acetoacetate; Preferably, the terminator comprises isopropanol and / or acetylacetone.

3. The post-treatment method of cycloolefin copolymer solution polymerization according to claim 1, characterized in that: The poor solvent A and the poor solvent B are each independently selected from any one of n-octanol, isopropanol or acetone, or a combination of at least two thereof, and more preferably isopropanol and / or acetone.

4. The post-treatment method of cycloolefin copolymer solution polymerization according to claim 1, characterized in that: The cyclic olefin copolymer in the cyclic olefin copolymer solution is selected from any one or a combination of at least two of ethylene-norbornene copolymer, ethylene-tetracyclododecene copolymer, propylene-norbornene copolymer or propylene-tetracyclododecene copolymer; Preferably, the concentration of the cyclic olefin copolymer in the cyclic olefin copolymer solution is 8-30wt%; Preferably, the metal element in the catalyst used to prepare the cycloolefin copolymer includes any one of Ti, Zr or Al or a combination of at least two of them.

5. The post-treatment method of cycloolefin copolymer solution polymerization according to claim 1, characterized in that: Based on 100 parts by volume of the cyclic olefin copolymer solution, the volume fraction of the terminator in step (1) is 0.1-15 parts; Preferably, based on 100 parts by volume of the cycloolefin copolymer solution, the volume fraction of the poor solvent A in step (1) is 5-20 parts.

6. The post-treatment method of cycloolefin copolymer solution polymerization according to claim 1, characterized in that: Based on 100 parts by volume of the cycloolefin copolymer solution, the volume fraction of the poor solvent B in step (2) is 100-300 parts.

7. The post-treatment method of cycloolefin copolymer solution polymerization according to claim 1, characterized in that: The temperature of the termination reaction is 50-120°C; Preferably, the termination reaction time is 10-30 min.

8. The post-treatment method of cycloolefin copolymer solution polymerization according to claim 1, characterized in that: The temperature at which the reaction solution is added dropwise to the poor solvent B in step (2) is 50-120°C.

9. The post-treatment method of cycloolefin copolymer solution polymerization according to claim 1, characterized in that: The stirring method in step (2) includes: stirring with a stirrer; Preferably, the end linear velocity of the agitator is 4.5-8.5 m / s.

10. The post-treatment method of cycloolefin copolymer solution polymerization according to claim 1, characterized in that: The dropping speed in step (2) is ≤3.5 mL / min.

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