Disclosure of Invention
In view of the above, the present invention provides a method for preparing a colorless transparent liquid hydrocarbon polymer. The liquid hydrocarbon polymer prepared by the preparation method has high transparency, the glue solution can still be in a colorless transparent state after aging at a certain temperature without adding an antioxidant, and the obtained liquid hydrocarbon polymer has low initiator residue and pure product.
The invention provides a preparation method of a colorless transparent liquid hydrocarbon polymer, which comprises the following steps:
a) Under the conditions of protective atmosphere and initiator existence, carrying out anionic polymerization reaction on the monomer in an organic solvent A to obtain a polymer solution;
b) Mixing the polymer solution with a terminator to terminate the reaction, then adding an organic solvent B and activated carbon, then carrying out solid-liquid separation to remove solids, and drying the obtained separation liquid to obtain a colorless transparent liquid hydrocarbon polymer;
wherein:
the initiator is an organic lithium compound;
the monomer is a conjugated diene monomer and/or an alkenyl aromatic hydrocarbon monomer;
the organic solvent A is an aprotic polar solvent or a mixed solvent of the aprotic polar solvent and an apolar solvent;
the terminator is water and/or alcohol;
the organic solvent B is a nonpolar organic solvent.
Preferably, the concentration of the initiator in the organic solvent A is 0.005-4 mol/L;
the mol ratio of the terminating agent to the initiating agent is (5.0-8.0) to 1.
Preferably, the organic solvent B is selected from one or more of cyclohexane, normal hexane, normal pentane, normal heptane, toluene, xylene and raffinate oil;
the dosage of the organic solvent B is 10-50% of the volume of the polymer solution.
Preferably, the conjugated diene monomer is butadiene and/or isoprene;
the alkenyl aromatic hydrocarbon monomer is styrene and/or alkyl-substituted styrene.
Preferably, in the organic solvent a:
the nonpolar solvent is selected from one or more of cyclohexane, n-hexane, n-pentane, n-heptane, toluene, xylene and raffinate oil;
the aprotic polar solvent is one or more selected from ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, tetrahydrofuran and N, N, N, N-tetramethyl ethylenediamine;
the mass fraction of the monomer in the organic solvent A is 8-60%.
Preferably, the temperature of the anionic polymerization reaction is-40 ℃ to 70 ℃ and the time is 2min to 5h.
Preferably, in the mixed solvent, the volume ratio of the nonpolar solvent to the aprotic polar solvent is (0.1-40) to 1;
the initiator is selected from one or more of methyllithium, n-butyllithium, sec-butyllithium, tert-butyllithium, iso-butyllithium and naphthalene lithium.
Preferably, the step b) specifically comprises:
adding a terminator into the polymer solution, stirring to terminate the reaction, then adding an organic solvent B, fully stirring, then adding activated carbon, stirring, then carrying out solid-liquid separation to remove solids, and drying the obtained separation liquid to obtain the colorless transparent liquid hydrocarbon polymer.
Preferably, the solid-liquid separation is centrifugation or filtration;
the drying is vacuum drying;
the drying temperature is 50-120 ℃ and the drying time is 1-5 h.
Preferably, the temperature for terminating the reaction is-40 ℃ to 60 ℃ and the time is 5 to 30min.
The preparation method provided by the invention is characterized in that conjugated diene and/or alkenyl arene is used as a monomer, an organic lithium compound is used as an initiator, an aprotic polar solvent is used as a solvent or a mixed solvent of the aprotic polar solvent and the nonpolar solvent is used as a solvent to carry out active polymerization, quantitative water and/or alcohol is used for stopping reaction, then an organic solvent B and active carbon are sequentially added, solid is removed by solid-liquid separation, and devolatilization and drying are carried out to obtain the liquid hydrocarbon polymer with high transparency, the glue solution is still in a colorless transparent state after aging at a certain temperature without adding antioxidants, the liquid hydrocarbon polymer shows high heat resistance and stability, and the amount of initiator residues in a tested product is 5-100 ppm and is relatively pure. And the obtained product has the number average molecular weight of 500-10000 and narrow molecular weight distribution of 1.01-1.40, and can be used in the fields of rubber processing aids, adhesives, coatings, photocuring resins, electronic communication and the like.
Detailed Description
The invention provides a preparation method of a colorless transparent liquid hydrocarbon polymer, which comprises the following steps:
a) Under the conditions of protective atmosphere and initiator existence, carrying out anionic polymerization reaction on the monomer in an organic solvent A to obtain a polymer solution;
b) Mixing the polymer solution with a terminator to terminate the reaction, then adding an organic solvent B and active carbon, performing solid-liquid separation to remove solids, and drying the obtained separation liquid to obtain a colorless transparent liquid hydrocarbon polymer;
wherein:
the initiator is an organic lithium compound;
the monomer is a conjugated diene monomer and/or an alkenyl aromatic hydrocarbon monomer;
the organic solvent A is an aprotic polar solvent or a mixed solvent of the aprotic polar solvent and the nonpolar solvent;
the terminator is water and/or alcohol;
the organic solvent B is a nonpolar organic solvent.
The preparation method provided by the invention is characterized in that conjugated diene and/or alkenyl arene is used as a monomer, an organic lithium compound is used as an initiator, an aprotic polar solvent is used as a solvent or a mixed solvent of the aprotic polar solvent and the nonpolar solvent is used as a solvent to carry out active polymerization, quantitative water and/or alcohol is used for stopping reaction, then an organic solvent B and active carbon are sequentially added, solid is removed by solid-liquid separation, and devolatilization and drying are carried out to obtain the liquid hydrocarbon polymer with high transparency, the glue solution is still in a colorless transparent state after aging at a certain temperature without adding antioxidants, the liquid hydrocarbon polymer shows high heat resistance and stability, and the amount of initiator residues in a tested product is 5-100 ppm and is relatively pure. And the obtained product has the number average molecular weight of 500-10000 and narrow molecular weight distribution of 1.01-1.40, and can be used in the fields of rubber processing aids, adhesives, coatings, photocuring resins, electronic communication and the like.
[ with respect to step a ]:
a) Under the condition of protective atmosphere and initiator, the monomer is processed with anion polymerization reaction in organic solvent A to obtain polymer solution.
In the present invention, the kind of protective gas providing the protective atmosphere is not particularly limited, and may be a conventional protective gas well known to those skilled in the art, such as nitrogen, helium, argon, or the like. The invention forms an anhydrous and anaerobic environment through protective atmosphere, so that the subsequent reaction is carried out under the anhydrous and anaerobic condition.
In the present invention, the initiator is an organolithium compound, preferably one or more of methyllithium, n-butyllithium (i.e., n-BuLi), sec-butyllithium, tert-butyllithium, iso-butyllithium, and naphthyllithium.
In the present invention, the monomer is a conjugated diene monomer and/or an alkenyl aromatic hydrocarbon monomer. Wherein the conjugated diene monomer is preferably butadiene and/or isoprene. The alkenyl aromatic hydrocarbon monomer is styrene and/or alkyl-substituted styrene.
In the invention, the organic solvent A is an aprotic polar solvent or a mixed solvent of the aprotic polar solvent and a nonpolar solvent. Wherein, the aprotic polar solvent is preferably one or more of ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, tetrahydrofuran and N, N, N, N-tetramethyl ethylenediamine; the non-polar solvent is preferably one or more of cyclohexane, n-hexane, n-pentane, n-heptane, toluene, xylene, and raffinate oil. When the organic solvent A is a mixed solvent of an aprotic polar solvent and a nonpolar solvent, the volume ratio of the nonpolar solvent to the aprotic polar solvent is preferably (0.1 to 40) to 1, and in some embodiments of the present invention is 1.5: 1, 2.25: 1, 20: 1, or 40: 1.
In the present invention, the initiator, the monomer and the organic solvent A constitute the material system of step a). The concentration of the initiator in the organic solvent A is preferably 0.005 to 4mol/L, and specifically may be 0.005mol/L, 0.10mol/L, 0.20mol/L, 0.30mol/L, 0.40mol/L, 0.50mol/L, 1mol/L, 2mol/L, 3mol/L, or 4mol/L. The mass fraction of the monomer in the organic solvent a is preferably 8% to 60%, and specifically may be 8%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%.
In the present invention, the step a) specifically includes: vacuumizing a reaction bottle, filling protective gas for gas replacement to form protective atmosphere in the reaction bottle, adding an organic solvent A and an initiator, stirring and mixing uniformly, adding a monomer, and carrying out anionic polymerization to obtain a polymer solution.
In the present invention, the temperature of the anionic polymerization reaction is preferably-40 ℃ to 70 ℃, and specifically may be-40 ℃, -30 ℃, -20 ℃, -10 ℃, 0 ℃, 10 ℃, 15 ℃, 20 ℃, 25 ℃, 30 ℃, 35 ℃, 40 ℃, 45 ℃, 50 ℃, 55 ℃, 60 ℃, 65 ℃, 70 ℃. The time of the anionic polymerization reaction is preferably 2min to 5h, and specifically may be 1h, 1.5h, 2h, 2.5h, 3h, 3.5h, 4h, 4.5h and 5h. After the above anionic polymerization reaction, a polymer solution is obtained.
[ with respect to step b ]:
b) And mixing the polymer solution with a terminator to terminate the reaction, then adding an organic solvent B and activated carbon, performing solid-liquid separation to remove solids, and drying the obtained separation liquid to obtain the colorless transparent liquid hydrocarbon polymer.
In the invention, the terminator is water and/or alcohol. Wherein the alcohol is preferably one or more of methanol, ethanol, isopropanol and n-propanol. In the present invention, the molar ratio of the terminator to the initiator is (5.0-8.0) to 1, specifically 5.0: 1, 5.2: 1, 5.5: 1, 5.8: 1, 6.0: 1, 6.2: 1, 6.5: 1, 6.8: 1, 7.0: 1, 7.2: 1, 7.5: 1, 7.8: 1, 8.0: 1, more preferably (5.5-7.5) to 1. In the present invention, it is preferable to terminate the reaction by stirring after the addition of the terminator. The temperature of the above operation (i.e., the temperature for terminating the reaction) is preferably-40 ℃ to 60 ℃, specifically-40 ℃, minus 30 ℃, minus 20 ℃, minus 10 ℃, 0 ℃, 10 ℃, 15 ℃, 20 ℃, 25 ℃, 30 ℃, 35 ℃, 40 ℃, 45 ℃, 50 ℃, 55 ℃, 60 ℃, and more preferably the same as the temperature of the anionic polymerization reaction, i.e., after the reaction of step a) is completed, the temperature is kept at the same, and the terminator is added and stirred to terminate the reaction. The stirring time is preferably 5-30 min, and specifically may be 5min, 10min, 15min, 20min, 25min, and 30min. In the present invention, the above-mentioned terminator is added in a controlled amount to terminate the anionic polymerization reaction of step a).
In the present invention, after the above treatment, the organic solvent B is added. In the invention, the organic solvent B is a non-polar organic solvent, preferably one or more of cyclohexane, n-hexane, n-pentane, n-heptane, toluene, xylene and raffinate oil. In the invention, the dosage of the organic solvent B is 10-50% of the volume of the polymer solution, namely the volume ratio of the organic solvent B to the polymer solution is (10-50) to 100, and specifically can be 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45% and 50%. In the invention, the organic solvent B is added and stirred; the stirring time is preferably 3-30 min, and specifically may be 5min, 10min, 15min, 20min, 25min, and 30min. In the invention, the letters A and B in the organic solvent A and the organic solvent B do not have special meanings, are not special limits on the types of the organic solvents, and are only used for indicating that the organic solvents are used twice in sequence and are respectively used in different steps.
In the invention, after the treatment, activated carbon is added, wherein the using amount of the activated carbon is 1-5% of the mass of the polymer solution, namely the mass ratio of the activated carbon to the polymer solution is (1-5) to 100, and specifically can be 1%, 2%, 3%, 4% and 5%. In the invention, activated carbon is added and then stirred; the stirring time is preferably 10-60 min, and specifically may be 10min, 20min, 30min, 40min, 50min, 60min.
In the present invention, after the above treatment, solid-liquid separation is performed to remove solids in the solution. The solid-liquid separation mode is not particularly limited in the invention, and the solid-liquid separation mode is a conventional solid-liquid separation mode in the field, such as centrifugal separation or filtration. Solid is removed through solid-liquid separation to obtain separated liquid.
In the present invention, the separated liquid is dried. In the present invention, the drying is preferably vacuum drying. In the present invention, the drying temperature is preferably 50 to 120 ℃, and specifically 50 ℃, 60 ℃, 70 ℃, 80 ℃, 90 ℃, 100 ℃, 110 ℃ and 120 ℃. In the present invention, the drying time is preferably 1 to 5 hours, and specifically may be 1 hour, 2 hours, 3 hours, 4 hours, or 5 hours. In the present invention, the degree of vacuum for drying is preferably-60 to-101.325 kPa. After the above treatment, a colorless transparent liquid hydrocarbon polymer is obtained.
The colorless transparent liquid hydrocarbon polymer prepared by the invention has the number average molecular weight of 500-10000 and the molecular weight distribution of 1.01-1.40.
The preparation method provided by the invention comprises the steps of taking conjugated diene and/or alkenyl aromatic hydrocarbon as monomers, taking an organic lithium compound as an initiator, taking an aprotic polar solvent or a mixture of the aprotic polar solvent and the nonpolar solvent as a solvent for active polymerization, stopping reaction by using quantitative water and/or alcohol, sequentially adding the nonpolar solvent and active carbon for stirring, separating solids, devolatilizing and drying to obtain the liquid hydrocarbon polymer with high transparency, wherein a glue solution is still in a colorless transparent state after aging at a certain temperature without adding antioxidants, the liquid hydrocarbon polymer shows high heat-resistant stability, and the amount of initiator residues in a tested product is 5-100 ppm and is relatively pure. And the obtained product has the number average molecular weight of 500-10000 and the molecular weight distribution of 1.01-1.40, and can be used in the fields of rubber processing aids, adhesives, coatings, photocuring resins, electronic communication and the like.
For a further understanding of the invention, reference will now be made to the preferred embodiments of the invention by way of example, and it is to be understood that the description is intended to further illustrate features and advantages of the invention, and not to limit the scope of the claims.
In the following examples, the starting material used was a commercially available product, and the n-butyllithium starting material itself was a liquid having a concentration of 2.5mol/L, unless otherwise specified.
Example 1
S1, vacuumizing a system, filling nitrogen for three times for replacement to remove water and oxygen, maintaining a reaction bottle in a nitrogen atmosphere, sequentially adding 160mL of dimethylbenzene and 4mL of tetrahydrofuran as an organic solvent A, adding 40mL of n-butyl lithium (the concentration in the organic solvent A is 0.5 mol/L), and fully stirring and uniformly mixing; then, 200g of butadiene monomer was added thereto, and the mixture was reacted in a cold bath at 15 ℃ for 4 hours to obtain a polymer solution.
S2, adding a certain amount of methanol into the polymer solution, wherein the molar ratio of the methanol to the n-butyllithium is about 5.5: 1, and fully stirring for 10min to obtain a water white solution; then adding 80mL of xylene (which is 19% of the volume of the polymer solution), and stirring for 5min; then, 7.4g of activated carbon (2% by mass of the polymer solution) was added and stirred for 30min; and then filtering, drying the filtrate for 1 hour at 90 ℃ and-0.1 MPa to obtain a low-molecular-weight polybutadiene glue solution which is a colorless transparent glue solution.
Comparative example 1
The procedure is as in example 1, except that the amount of methanol is increased in step S2, no xylene is added, no filtration is performed, etc. The method comprises the following specific steps:
adding a certain amount of methanol into the polymer solution, wherein the molar ratio of the methanol to the n-butyllithium is about 50: 1, fully stirring for 10min, separating out polymer glue solution, washing for 3 times, and drying for 1h at 90 ℃ and-0.1 MPa to obtain the polymer glue solution, wherein the glue solution is yellow.
Example 2
S1, vacuumizing a system, filling nitrogen for three times for replacement to remove water and oxygen, maintaining a reaction bottle in a nitrogen atmosphere, sequentially adding 80mL of n-hexane and 4mL of tetrahydrofuran as an organic solvent A, adding 20mL of n-butyllithium (the concentration in the organic solvent A is 0.3 mol/L), and fully stirring and uniformly mixing; then, 100g of butadiene monomer was added thereto, and the mixture was reacted in a cold bath at 10 ℃ for 3 hours to obtain a polymer solution.
S2, adding a certain amount of ethanol into the polymer solution, wherein the molar ratio of the ethanol to the n-butyllithium is about 6: 1, and fully stirring for 15min to obtain a water white solution; then adding 50mL of n-hexane (23% of the volume of the polymer solution), and stirring for 5min; then, 5g of activated carbon (3% by mass of the polymer solution) was added and stirred for 50min; and then filtering, and drying the filtrate for 1h at 80 ℃ and-95 KPa to obtain a low-molecular-weight polybutadiene glue solution which is a colorless transparent glue solution.
Comparative example 2
Example 2 was carried out, except that the ethanol terminator in step S2 was replaced by a solution of adipic acid in tetrahydrofuran (1.6 mol/L), in which the molar ratio of adipic acid to n-butyllithium was about 0.6: 1. The resulting polymer cement was slightly cloudy.
Example 3
S1, vacuumizing a system, filling nitrogen for three times for replacement to remove water and oxygen, maintaining a reaction bottle in a nitrogen atmosphere, adding 150mL of tetrahydrofuran serving as an organic solvent A, adding 20mL of n-butyl lithium (the concentration of the n-butyl lithium in the organic solvent A is 0.29 mol/L), and fully stirring and uniformly mixing; then, 150g of butadiene monomer was added thereto, and the mixture was reacted in a cold bath at-40 ℃ for 1.5 hours to obtain a polymer solution.
S2, adding a certain amount of water into the polymer solution, wherein the molar ratio of the water to the n-butyllithium is about 8: 1, and fully stirring for 15min to obtain a water white solution; then adding 100mL of n-heptane (30% of the volume of the polymer solution), and stirring for 10min; then, 15g of activated carbon (5% of the mass of the polymer solution) is added and stirred for 20min; then filtering, drying the filtrate for 1.5h at 90 ℃ and-0.1 MPa to obtain a low molecular weight polybutadiene glue solution which is a colorless transparent glue solution.
Comparative example 3
The method is implemented according to embodiment 3, except that step S2 is adjusted as follows:
adding a certain amount of water into the polymer solution, wherein the molar ratio of the water to the n-butyllithium is about 2.0: 1, fully stirring for 15min, introducing carbon dioxide gas (with the purity of 99 wt%) for 10min, continuously stirring for 10min, and drying at 90 ℃ and-0.1 MPa for 1.5h to obtain a polymer glue solution which is yellowish.
Example 4
S1, vacuumizing the system, filling nitrogen for three times to remove water and oxygen, maintaining a reaction bottle in a nitrogen atmosphere, sequentially adding 36mL of cyclohexane and 16mL of diethylene glycol dimethyl ether as an organic solvent A, adding 8mL of n-butyl lithium (the concentration in the organic solvent A is 0.33 mol/L), and fully stirring and uniformly mixing; then, 60g of butadiene monomer was added thereto, and the mixture was reacted in a cold bath at 10 ℃ for 1 hour to obtain a polymer solution.
S2, adding a certain amount of water into the polymer solution, wherein the molar ratio of the water to the n-butyllithium is about 7: 1, fully stirring for 10min, and then adding 0.3mL of methanol to obtain a water white solution; then adding 30mL of cyclohexane (which is 24% of the volume of the polymer solution), and stirring for 10min; then, 3.3g of activated carbon (3% of the mass of the polymer solution) is added and stirred for 20min; and then, centrifugally separating, and drying the separated solution at 95 ℃ and under the pressure of-0.1 MPa for 1 hour to obtain a low-molecular-weight polybutadiene glue solution which is a colorless transparent glue solution.
Comparative example 4
The method is implemented according to embodiment 4, except that step S2 is adjusted as follows:
the polymer solution is directly washed with 200mL of pure water for 2 times, then washed with 200mL of hydrochloric acid solution (with the concentration of 0.2%) once, then washed with 300mL of pure water for 3 times, an organic layer is separated, 10g of anhydrous magnesium sulfate is added, standing is carried out for 30min, then filtering is carried out, and the filtrate is dried for 1h at 95 ℃ and-0.1 MPa to obtain polymer glue solution which is colorless and transparent.
Example 5
S1, vacuumizing a system, filling nitrogen for three times for replacement to remove water and oxygen, maintaining a reaction bottle in a nitrogen atmosphere, sequentially adding 60mL of n-hexane and 40mL of ethylene glycol dimethyl ether as an organic solvent A, adding 5mL of n-butyllithium (the concentration in the organic solvent A is 0.12 mol/L), and fully and uniformly stirring; then, 40g of butadiene monomer and 10g of styrene monomer were added thereto, and the mixture was reacted in a cold bath at-10 ℃ for 1 hour to obtain a polymer solution.
S2, adding a certain amount of isopropanol into the polymer solution, wherein the molar ratio of the isopropanol to the n-butyl lithium is about 6: 1, and fully stirring for 10min to obtain a water white solution; then adding 30mL of n-hexane (19% of the volume of the polymer solution), and stirring for 10min; then, 5g of activated carbon (4% by mass of the polymer solution) was added and stirred for 10min; and then, centrifugally separating, and drying the separated solution for 1 hour at 95 ℃ and-0.1 MPa to obtain a low-molecular-weight polymer glue solution which is a colorless transparent glue solution.
Comparative example 5
The method is implemented according to embodiment 5, except that step S2 is adjusted as follows:
adding a certain amount of isopropanol into the polymer solution, wherein the molar ratio of the isopropanol to the n-butyllithium is about 1.5: 1, fully stirring for 10min, adding 2, 6-di-tert-butyl-p-methylphenol serving as an antioxidant (accounting for 0.1 percent of the mass of the polymer), and drying for 1h at 95 ℃ and under-0.1 MPa to obtain a polymer glue solution, wherein the glue solution is yellow.
Example 6: product testing
The content of Li contained in the polymer dope obtained after drying was measured using an ICP emission spectrometer for quantitative analysis of inorganic elements, and the analysis results are shown in table 1. Meanwhile, the product appearance statistics are in table 1. In addition, the product was tested for high temperature aging stability, specifically, the glue solution product was placed in an oven at 95 ℃ for 5 hours, after which the appearance of the glue solution was observed, and the results are shown in table 1.
Table 1: test effect of product
|
Residual amount of catalyst, ppm
|
Initial appearance
|
Appearance after high temperature aging
|
Example 1
|
93
|
Colorless and transparent
|
Colorless and transparent
|
Example 2
|
67
|
Colorless and transparent
|
Colorless and transparent
|
Example 3
|
36
|
Colorless and transparent
|
Colorless and transparent
|
Example 4
|
83
|
Colorless and transparent
|
Colorless and transparent
|
Example 5
|
25
|
Colorless and transparent
|
Colorless and transparent
|
Comparative example 1
|
387
|
Yellow colour
|
Yellow colour
|
Comparative example 2
|
860
|
Turbidity
|
Yellow turbidity
|
Comparative example 3
|
949
|
Light yellow
|
Yellow colour
|
Comparative example 4
|
173
|
Colorless and transparent
|
Light yellow
|
Comparative example 5
|
985
|
Yellow colour
|
Yellow colour |
As can be seen from the test results in Table 1, the liquid hydrocarbon polymer prepared by the invention is a colorless transparent product, the initiator residue in the product is remarkably reduced (less than 100 ppm), and the glue solution still keeps a colorless transparent state after being aged at high temperature for a certain time without adding an antioxidant, thus showing high heat-resistant stability. Compared with the effect of the comparative example 1, the invention proves that the transparency and the aging-resistant thermal stability of the polymer glue solution can be effectively improved and the impurity residue in the product can be reduced by controlling a certain amount of the terminating agent and adding the organic solvent B and the activated carbon and then separating the solid. The comparison with the effect of the comparative example 2 proves that the invention can effectively improve the transparency and the aging-resistant thermal stability of the polymer glue solution and reduce the impurity residue in the product by adopting the specific terminator. Compared with the effect of the comparative example 3, the method proves that after the reaction is terminated, the organic solvent B and the activated carbon are added, and then the solid is separated, so that the transparency and the aging-resistant thermal stability of the polymer glue solution can be effectively improved, and the impurity residue in the product is reduced. Compared with the effect of the comparative example 4, the introduction of the terminating agent, the addition of the organic solvent B and the addition of the activated carbon, and the separation of the solid can effectively improve the transparency and the aging-resistant thermal stability of the polymer glue solution and reduce the impurity residue in the product. Compared with the effect of the comparative example 5, the invention proves that after the reaction is terminated, the organic solvent B and the activated carbon are added, and then the solid is separated, so that the transparency and the aging-resistant thermal stability of the polymer glue solution can be effectively improved, the impurity residue in the product is reduced, and the aging-resistant stability can be even better improved compared with the product added with the antioxidant.
The foregoing examples are included merely to facilitate an understanding of the principles of the invention and their core concepts, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention. The scope of the invention is defined by the claims and may include other embodiments that occur to those skilled in the art. Such other embodiments are intended to be within the scope of the claims if they have structural elements that approximate the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.