SEBS hydrogenation degree prediction and precision control method

Abstract

This invention relates to the field of SEBS preparation, specifically to a method for predicting the degree of hydrogenation of SEBS. The method utilizes the designed values ​​of the amount m of the main catalyst, the lithium / main catalyst molar ratio n, and the co-catalyst / main catalyst molar ratio X in the selective hydrogenation process of SBS gel polymerized by active lithium anion polymerization and the main catalyst and co-catalyst. Formulas 1 to 9 are then used to calculate and predict the degree of hydrogenation Y of the prepared SEBS. Formula 1: Y = 0.12 + 0.88 * X, Formula 2: Y = 0.19 + 0.81 * X, Formula 3: Y = 0.25 + 0.75 * X, Formula 4: Y = 0.17 + 0.83 * X, Formula 5: Y = 0.25 + 0.75 * X, Formula 6: Y = 0.31 + 0.69 * X, Formula 7: Y = 0.2 + 0.8 * X, Formula 8: Y = 0.32 + 0.68 * X, Formula 9: Y = 0.4 + 0.6 * X. This invention also includes a synthesis method for precisely controlling the degree of hydrogenation of SEBS using the aforementioned prediction method. The process described in this invention can predict the degree of hydrogenation of SEBS with high accuracy.

Description

Technical Field

[0001] This invention belongs to the field of styrene-based thermoplastic elastomer synthesis technology, specifically relating to a method for predicting and controlling the degree of hydrogenation in the selective hydrogenation of SEBS. Background Technology

[0002] SEBS is a linear triblock copolymer with polystyrene as the terminal block and hydrogenated polybutadiene as the intermediate elastic block. Because it does not contain unsaturated double bonds, this type of polymer has good light aging resistance and stability. It can be blended with filler oils, polypropylene, additives and inorganic fillers and is widely used for tool handle coating, shoe materials, headphone wires, wires and cables, medical infusion equipment, etc.

[0003] SEBS typically has a hydrogenation degree of ≥97%. These products exhibit good aging resistance, but due to their low double bond content and insufficient polarity, they do not adhere well to polar materials. When used to coat materials like nylon and epoxy resin, increasing the number of double bonds can improve adhesion through chemical bonding. Furthermore, SEBS containing a certain amount of double bonds is used in foaming applications, producing products with high resilience, fast vulcanization speed, and long half-life. For example, Asahi Kasei P1083, Zhongli 5583, and 5083, widely used in foamed midsoles of athletic shoes, all have a hydrogenation degree of around 80%. Partial double bond vulcanization crosslinking can also improve tear strength. For instance, patent CN101668805A uses a vinyl aromatic-conjugated diene copolymer with a hydrogenation degree of 30%-80% as a key component in tire formulations to achieve optimal balance between rolling resistance and wet grip. Patent CN103848948A... This invention discloses partially hydrogenated terpolymers, their preparation methods, and applications. In these terpolymers, the hydrogenation degree of the butadiene-derived structural units is 5-90%, specifically 60-95% for butadiene-formed units via 1,2 polymerization and 2-20% for butadiene-formed units via 1,4 polymerization. The hydrogenation degree of the isoprene-derived structural units is 5-90%, 10-40% for isoprene-formed units via 3,4 polymerization, and 2-30% for isoprene-formed units via 1,4 polymerization. This invention achieves a good balance between high anti-slip properties, low rolling resistance, and high wear resistance. Therefore, partially hydrogenated grades should have broad application scenarios. However, neither of the aforementioned patents mentions a precise method for controlling the partial hydrogenation of the butadiene segments. CN106317350B discloses a method for preparing partially hydrogenated polystyrene-b-random copolymer conjugated diene / styrene copolymer and its application in asphalt modification. The preparation method involves first homopolymerizing styrene monomer, then randomly copolymerizing it with a mixture of styrene, conjugated diene, and divinylbenzene monomers. The copolymer product is then hydrogenated to obtain the final product. The partially hydrogenated polystyrene-b-random copolymer conjugated diene / styrene copolymer prepared by this method exhibits high strength, good heat resistance, and good processability. When used to modify asphalt, it can produce modified asphalt with excellent cold resistance, heat resistance, weather resistance, ozone resistance, and UV resistance, as well as high elasticity and strength, thus improving the adhesion and bonding strength between asphalt and concrete pavement. The partial hydrogenation method in this patent utilizes the principle that titanium stannosa catalysts can hydrogenate polybutadiene segments but not polyisoprene segments. The degree of hydrogenation is accurately controlled by adjusting the amounts of styrene, butadiene, and isoprene added. Because isoprene is added to the soft segments, the influence of the polymerization competition rate between butadiene and isoprene must be considered during the polymerization process. This results in high control requirements, difficult operation, and difficulty in stabilizing product quality and performance.

[0004] Although some selective hydrogenation methods have been reported in the existing technology, there is still a lack of accurate prediction methods for the degree of hydrogenation of SEBS, and it is difficult to obtain SEBS that meets the design requirements in a simple and accurate manner. Summary of the Invention

[0005] To address the lack of SEBS prediction in existing technologies, the primary objective of this invention is to provide a method for predicting the degree of selective hydrogenation (SEBS), aiming to offer a method that can accurately calculate and predict the degree of hydrogenation in selective hydrogenation.

[0006] The second objective of this invention is to provide a method for precisely controlling the degree of hydrogenation of SEBS, which aims to facilitate the calculation of key parameter values ​​by the aforementioned prediction method, thereby obtaining SEBS that meets the design requirements for the degree of hydrogenation with high purpose and high precision.

[0007] A method for predicting the degree of hydrogenation of SEBS is proposed. The method utilizes the designed values ​​of the amount of main catalyst m, the lithium / main catalyst molar ratio n, and the co-catalyst / main catalyst molar ratio X in the selective hydrogenation process of SBS gel polymerized by active lithium anion polymerization and main catalyst and co-catalyst to calculate the degree of hydrogenation Y of the prepared SEBS using formulas 1 to 9.

[0008] Formula 1: Y=0.12+0.88*X

[0009] Formula 2: Y=0.19+0.81*X

[0010] Formula 3: Y=0.25+0.75*X

[0011] Formula 4: Y=0.17+0.83*X

[0012] Formula 5: Y=0.25+0.75*X

[0013] Formula 6: Y=0.31+0.69*X

[0014] Formula 7: Y=0.2+0.8*X

[0015] Formula 8: Y=0.32+0.68*X

[0016] Formula 9: Y=0.4+0.6*X

[0017] The term m refers to the ratio of the molar amount of the main catalyst to the weight of butadiene forming the SBS solution (in mmol / 100g); the term n refers to the molar ratio of lithium ions to the main catalyst in the selective hydrogenation starting system.

[0018] When the design range of m is 0.14 - 0.16 mmol / 100g and the design range of 7 ≤ n ≤ 9, substitute X into Formula 1 to calculate the hydrogenation degree Y; when 9 < n ≤ 11, substitute X into Formula 2 to calculate the hydrogenation degree Y; when 11 < n ≤ 13, substitute X into Formula 3 to calculate the hydrogenation degree Y.

[0019] When the design range of m is 0.17 - 0.19 mmol / 100g and the design range of 7 ≤ n ≤ 9, substitute X into Formula 4 to calculate the hydrogenation degree Y; when 9 < n ≤ 11, substitute X into Formula 5 to calculate the hydrogenation degree Y; when 11 < n ≤ 13, substitute X into Formula 6 to calculate the hydrogenation degree Y.

[0020] When the design range of m is 0.19 - 0.21 mmol / 100g and the design range of 7 ≤ n ≤ 9, substitute X into Formula 7 to calculate the hydrogenation degree Y; when 9 < n ≤ 11, substitute X into Formula 8 to calculate the hydrogenation degree Y; when 11 < n ≤ 13, substitute X into Formula 9 to calculate the hydrogenation degree Y.

[0021] The present invention innovatively uses m, n, and X as key factors and innovatively uses the above-mentioned Formulas 1 - 9 for calculation, so that the hydrogenation degree can be predicted with high precision. It is found that through the prediction calculation method of the present invention, the error between the predicted value and the actually verified hydrogenation degree can be controlled within 1%, showing excellent prediction accuracy.

[0022] In the present invention, the Formulas 1 - 9 can be located and selected through the two parameters m and n, and then X is calculated based on the selected formula, thus unexpectedly improving the accuracy of hydrogenation degree calculation.

[0023] In the present invention, n is the molar ratio of lithium ions to the main catalyst in the starting system for selective hydrogenation; the lithium ions can be completely introduced by an active lithium initiator or can be artificially regulated.

[0024] A typical embodiment (Embodiment A) of the present invention: when the design range of m is 0.145 - 0.155 mmol / 100g, preferably 0.15 mmol / 100g, and the design range of n is 7.5 - 8.5, preferably 7.9 - 8.1, and more preferably 8, Formula 1 is used for calculation;

[0025] Preferably, when the design range of m is 0.145 - 0.155 mmol / 100g, preferably 0.15 mmol / 100g, and the design range of n is 9.5 - 10.5, preferably 9.9 - 10.1, and more preferably 10, Formula 2 is used for calculation;

[0026] Preferably, the design range of m is 0.145 to 0.155 mmol / 100g, more preferably 0.15 mmol / 100g, and the design range of n is 11.5 to 12.5, more preferably 11.9 to 12.1, and even more preferably 12, and the calculation is performed using Formula 3.

[0027] Another typical embodiment of the present invention (method B): when the design range of m is 0.175 to 0.185 mmol / 100g, preferably 0.18 mmol / 100g, and the design range of n is 7.5 to 8.5, preferably 7.9 to 8.1, and more preferably 8, the calculation is performed using formula 4;

[0028] Preferably, when the design range of m is 0.175 to 0.185 mmol / 100g, and more preferably 0.18 mmol / 100g, the design range of n is 9.5 to 10.5, more preferably 9.9 to 10.1, and even more preferably 10, and the calculation is performed using Formula 5.

[0029] Preferably, when the design range of m is 0.175 to 0.185 mmol / 100g, and more preferably 0.18 mmol / 100g, the design range of n is 11.5 to 12.5, more preferably 11.9 to 12.1, and even more preferably 12, and the calculation is performed using Formula 6.

[0030] Another typical embodiment of the present invention (method C): when the design range of m is 0.195 to 0.205 mmol / 100g, preferably 0.2 mmol / 100g, and the design range of n is 7.5 to 8.5, preferably 7.9 to 8.1, and more preferably 8, the calculation is performed using formula 7;

[0031] Preferably, when the design range of m is 0.195 to 0.205 mmol / 100g, and more preferably 0.2 mmol / 100g, the design range of n is 9.5 to 10.5, more preferably 9.9 to 10.1, and even more preferably 10, and the calculation is performed using formula 8.

[0032] Preferably, the design range of m is 0.195 to 0.205 mmol / 100g, more preferably 0.2 mmol / 100g, and the design range of n is 11.5 to 12.5, more preferably 11.9 to 12.1, and even more preferably 12, calculated using formula 9.

[0033] In this invention, there are no special requirements for the operation period of X. Considering the reaction conditions in the field of selective hydrogenation, it can usually be 0.05 to 1.

[0034] In this invention, the prediction method is applicable to any SBS adhesive obtained by conventional active lithium anion polymerization.

[0035] For example, the steps to obtain SBS adhesive are as follows: In an anionic polymerization solution system, a solvent, styrene monomer, active lithium activator and initiator are added to initiate and carry out a first-stage polymerization reaction; after the first-stage polymerization is completed, a structure regulator is added, and butadiene monomer is continuously and uniformly added to carry out a second-stage polymerization reaction; after the second-stage polymerization reaction is completed, styrene monomer is added to carry out a third-stage polymerization reaction; after the third-stage polymerization reaction is completed, SBS adhesive is obtained.

[0036] The concentration of the monomer is 10-15%.

[0037] The solvent is one of cyclohexane, n-hexane, or cyclopentane.

[0038] The structure modifier includes at least one of ethylene glycol dimethyl ether, bis(tetrahydrofurfuryl)propane, ethylene glycol diethyl ether, tetrahydrofurfuryl ethyl ether, tetramethylethylenediamine, and hexamethylphosphoric triamine.

[0039] The total time for the continuous and uniform addition of the butadiene monomer is 40 to 60 minutes.

[0040] The initial temperature of the two-stage polymerization reaction is controlled at 62-65℃, the maximum temperature is 70-85℃, and the total reaction time is in the range of 30-80 minutes.

[0041] The activator includes tetrahydrofuran.

[0042] The active lithium initiator includes at least one of n-butyllithium, sec-butyllithium, and isobutyllithium.

[0043] The temperature for the first and third stage polymerization reactions is 50℃~70℃, and the time is 20~50min.

[0044] In this invention, the prediction method is applicable to any selective hydrogenation conditions known in the industry.

[0045] In this invention, the main catalyst is a titanium cyclopentadienyl catalyst, which includes at least one of bis(cyclopentadienyl)titanium dichloride, bis(cyclopentadienyl)titanium dibromide, bis(cyclopentadienyl)titanium diiodide, bis(cyclopentadienyl)titanium difluoride, bis(cyclopentadienyl)dicarbonyltitanium, bis(cyclopentadienyl)dimethyltitanium, bis(cyclopentadienyl)diethyltitanium, and bis(cyclopentadienyl)dibutyltitanium.

[0046] Preferably, the co-catalyst is a carboxylic acid ester containing a benzene ring, and more preferably at least one of benzoic acid C1-C5 alkyl ester and phthalic acid C1-C5 alkyl ester;

[0047] Further optimization is achieved by setting the molar ratio of the main catalyst to the co-catalyst to be 1–20:1.

[0048] In this invention, during the selective hydrogenation process, the initial temperature is 72-80℃ and the hydrogen pressure is 1.2-1.4MPa. After the reaction reaches the highest temperature (80-130℃), the hydrogen valve is closed and the pressure inside the reactor is released to 0.05MPa to discharge the hydrogen.

[0049] This invention also provides a method for precisely controlling the degree of hydrogenation of SEBS. Based on the SEBS hydrogenation degree prediction method of this invention, m, n, and X of the selective hydrogenation stage are calculated, and the calculated m, n, and X are used as conditions to carry out the selective hydrogenation reaction, so as to accurately obtain SEBS with the hydrogenation degree that meets the design requirements.

[0050] Beneficial effects

[0051] This invention innovatively uses m, n, and X as key factors and innovatively utilizes formulas 1 to 9 for calculation, thus enabling high-precision prediction of the degree of hydrogenation. Research has found that the error between the prediction calculation using this method and the actually verified degree of hydrogenation can be controlled within 1%, demonstrating excellent prediction accuracy. Attached Figure Description

[0052] Figure 1 The image shows the 1H NMR spectrum of the SBS base adhesive prepared in Example 1.

[0053] Figure 2 The image shows the 1H NMR spectrum of the partially hydrogenated SEBS prepared in Example 1. Detailed Implementation

[0054] The following embodiments are intended to further illustrate the content of the present invention and do not constitute a limitation on the scope of protection of the claims or the implementation methods of the present invention.

[0055] This invention provides a calculation formula for selecting the appropriate X based on two factors: the amount of main catalyst (m) and the Li / main catalyst ratio (n) in the selective hydrogenation stage. This formula is further combined with the control of formulas 1 to 9, which can unexpectedly predict the degree of hydrogenation of SEBS selective hydrogenation with high accuracy.

[0056] The prediction method described in this invention is applicable to predicting the degree of hydrogenation of SBS solutions formed by arbitrary selective hydrogenation methods using any active lithium anion polymerization. The lithium ions in the SBS solution can be introduced by an active lithium initiator or artificially controlled.

[0057] As a typical example, the preparation method of the SBS adhesive is as follows:

[0058] In this invention, a solvent, styrene monomer, activator, and initiator are added to an anionic polymerization solution system to initiate a first-stage polymerization reaction. After the first-stage polymerization is completed, a structure modifier is added, and butadiene monomer is continuously and uniformly added simultaneously to initiate a second-stage polymerization reaction. After the second-stage polymerization is completed, styrene monomer is added to initiate a third-stage polymerization reaction. After the third-stage polymerization is completed, an SBS adhesive is obtained. The concentration of the monomer is 10-15%. The solvent is one of cyclohexane, n-hexane, and cyclopentane. The structure modifier includes at least one of ethylene glycol dimethyl ether, bis(tetrahydrofurfuryl)propane, ethylene glycol diethyl ether, tetrahydrofurfuryl ethyl ether, tetramethylethylenediamine, and hexamethylphosphoric triamine. The total time for the continuous and uniform addition of the butadiene monomer is 40-60 minutes. The initial temperature of the second-stage polymerization reaction is controlled at 62-65°C, the maximum temperature is 70-85°C, and the total reaction time is within the range of 30-80 minutes. The activator includes tetrahydrofuran. The active lithium initiator includes at least one of n-butyllithium, sec-butyllithium, and isobutyllithium. The temperature of the one-stage and three-stage polymerization reactions is 50℃~70℃, and the time is 20~50min.

[0059] The prediction method described in this invention is applicable to any selective hydrogenation process. For example, as a typical example, the selective catalyst can be a titanium catalyst. The addition of a titanium catalyst to the SBS solution is controlled, and hydrogenation is performed using hydrogen gas. The degree of hydrogenation is calculated based on the ratio of lithium ions to the titanium catalyst and the amount of catalyst used. The hydrogenation catalyst is a catalyst for selectively hydrogenating olefin double bonds, wherein the main catalyst can be a titanium catalyst, or more specifically, a titanium-benzoate composite catalytic system, including at least one of bis(cyclopentadienyl)titanium chloride, bis(cyclopentadienyl)titanium dibromide, bis(cyclopentadienyl)titanium diiodide, bis(cyclopentadienyl)titanium difluoride, bis(cyclopentadienyl)dicarbonyl titanium, bis(cyclopentadienyl)dimethyl titanium, bis(cyclopentadienyl)diethyl titanium, and bis(cyclopentadienyl)dibutyl titanium. The co-catalyst can be at least one of C1-C5 alkyl benzoate and C1-C5 alkyl phthalate; more preferably, the molar ratio of the main catalyst to the co-catalyst is 1-20:1. m is the ratio of the molar amount of the main catalyst to the weight of SBS butadiene formed. The conditions for the selective hydrogenation reaction are: using a titanoceramsite-benzoate composite catalytic system, an initial temperature of 72-80℃, a hydrogen pressure of 1.2-1.4 MPa, and after reaching the highest temperature, closing the hydrogen valve and depressurizing the reactor to 0.05 MPa to discharge hydrogen.

[0060] In this invention, typical prediction calculation methods are shown in Table 1:

[0061] As shown in Table 1:

[0062]

[0063]

[0064] In the formula described in this invention, * refers to the multiplication sign.

[0065] The present invention is particularly suitable for a solution concentration of 10-15% and a number-average molecular weight (Mn) of SEBS controlled between 100,000 and 300,000.

[0066] In this invention, linear plotting can be performed based on the prediction formula, and a suitable formula can be adapted according to the subsequent hydrogenation degree design requirements to obtain more suitable m / n and X preparation parameters. Based on the back-predicted preparation parameters, SEBS with the hydrogenation degree required by the design can be prepared more accurately and efficiently.

[0067] It should be noted that: in the following examples, gel permeation chromatography (mobile phase: tetrahydrofuran) was used to test the number-average molecular weight (Mn) of the gel solution; and ¹H-NMR nuclear magnetic resonance spectroscopy was used to analyze the degree of hydrogenation of the partially hydrogenated SEBS. (Appendix) Figure 1 This is a typical 1H NMR spectrum of SBS polymerized basic gel. The peaks shifted between 5.3 and 5.6 ppm represent hydrogen atoms on the 1,4 double bonds of polybutadiene and single hydrogen atoms on the 1,2 side chain double bonds, with an area of ​​A. The peaks shifted around 4.96 ppm represent two hydrogen atoms on the 1,2 side chain double bonds of polybutadiene, with an area of ​​B. The molar amount of butadiene is (2A+B) / 4. After partial hydrogenation, the remaining peaks are... Figure 2 The peaks with shifts of 5.3-5.6 ppm represent hydrogen atoms on the 1,4-structure double bonds and single hydrogen atoms on the 1,2-structure side chain double bonds of polybutadiene, with a peak area of ​​C. The peaks with shifts around 4.96 ppm represent two hydrogen atoms on the 1,2-structure side chain double bonds of polybutadiene, with a peak area of ​​D. The molar amount of butadiene is (2C+D) / 4; the degree of hydrogenation = {1-(2C+D) /

[0068] (2A+B)}*100%.

[0069] Example 1

[0070] The designed m is 0.15 mmol / 100g butadiene, n is 8, and X = 0.1 is substituted into Formula 1 in Table 1 for calculation. The calculated degree of hydrogenation Y under this condition is 20.8%.

[0071] Experimental verification of the prediction results:

[0072] SEBS with a number-average molecular weight (Mn) of 6 ± 10,000 was produced using an anionic polymerization method known in the industry. The amount of tantalum catalyst per 100g butadiene was 0.15 mmol, the molar ratio of lithium ions to tantalum catalyst was 8, and the molar ratio of co-catalyst to tantalum catalyst (i.e., main catalyst) was 0.1.

[0073] In a polymerization reactor purged with a dry protective gas (e.g., nitrogen), 40 kg of cyclohexane, 12 g of tetrahydrofuran, 3.74 g of tetramethylethylenediamine, and 66 mmol of butyllithium were added. The polymerization reactor temperature was maintained at 65 °C and the pressure at 0.3 MPa. First, 600 g of styrene monomer was added to initiate a first-stage reaction for 30 min. After the reaction was completed, the polymerization temperature was lowered to 63 °C. Then, 2800 g of butadiene monomer was continuously added over 40 min. After reaching the high temperature, the reaction was carried out for 10 min. For the third-stage reaction, 600 g of styrene monomer was added, and the reaction was carried out for 30 min. Finally, 32.4 mmol of methanol was added to terminate the partial butyllithium reaction. The prepared polymer solution was poured into a hydrogenation reactor, and 4.2 mmol of dicyclopentadiene titanium dichloride and 0.42 mmol of methyl benzoate were added. The initial reaction temperature was controlled at 75°C, and hydrogen gas was introduced to make the pressure inside the reactor 1.2 MPa. When the reaction reached 82°C, the hydrogen gas supply was immediately stopped, and the pressure inside the reactor was released to 0.05 MPa. The polymer solution was dried and the degree of hydrogenation was tested. It was 20.5%, which is close to the result of 20.8% obtained by applying formula ① in Table 1.

[0074] Example 2

[0075] The design value of m is 0.15 mmol / 100g butadiene, and n is 10. Substituting X = 0.3 into Formula 2 in Table 1, the calculated degree of hydrogenation Y under this condition is 43.3%.

[0076] Experimental verification of the prediction results:

[0077] SEBS with a number-average molecular weight (Mn) of 10 ± 10,000 was produced using an anionic polymerization method known in the industry. The amount of tantalum catalyst per 100g butadiene was 0.15 mmol, the molar ratio of lithium ions to tantalum catalyst was 10, and the molar ratio of co-catalyst to tantalum catalyst was 0.3.

[0078] In a polymerization reactor purged with a dry protective gas (e.g., nitrogen), add 40 kg of cyclohexane, 12 g of tetrahydrofuran, 2.8 g of ethylene glycol dimethyl ether, and 40 mmol of sec-butyllithium. Maintain the polymerization reactor temperature at 64 °C and the pressure at 0.3 MPa. First, add 400 g of styrene monomer and carry out a first-stage reaction for 30 min. After the reaction is completed, lower the polymerization temperature to 63 °C. Then, continuously add 3200 g of butadiene monomer over 40 min. After reaching the high temperature, react for 10 min. For the third-stage reaction, add 400 g of styrene monomer and react for 30 min. Finally, add 8 mmol of sec-butyllithium. The prepared polymer solution was poured into a hydrogenation reactor, and 4.8 mmol of dicyclopentadiene titanium dichloride and 1.44 mmol of ethyl benzoate were added. The initial reaction temperature was controlled at 74°C, and hydrogen gas was introduced to make the pressure inside the reactor 1.3 MPa. The reaction was carried out to a high temperature of 91°C, and the hydrogen gas supply was immediately stopped. The pressure inside the reactor was then released to 0.05 MPa. The polymer solution was dried and tested, and the degree of hydrogenation was 43.9%, which is close to the result of 43.3% obtained by applying formula ② in Table 1.

[0079] Example 3

[0080] The designed m is 0.15 mmol / 100g butadiene, and n is 12. Substituting X = 0.7 into Formula 3 in Table 1, the calculated degree of hydrogenation Y under this condition is 77.5%.

[0081] Experimental verification of the prediction results:

[0082] SEBS with a number-average molecular weight (Mn) of 20 ± 10,000 was produced using an anionic polymerization method known in the industry. The amount of tantalum catalyst per 100g butadiene was 0.15 mmol, the molar ratio of lithium ions to tantalum catalyst was 12, and the molar ratio of co-catalyst to tantalum catalyst was 0.7.

[0083] In a polymerization reactor purged with a dry protective gas (e.g., nitrogen), add 40 kg of cyclohexane, 12 g of tetrahydrofuran, 4 g of tetrahydrofurfuryl ethyl ether, and 40 mmol of isobutyllithium. Maintain the polymerization reactor temperature at 64 °C and the pressure at 0.3 MPa. First, add 200 g of styrene monomer and carry out a first-stage reaction for 30 min. After the reaction is completed, lower the polymerization temperature to 63 °C. Then, continuously add 3600 g of butadiene monomer over 40 min. After reaching the high temperature, react for 10 min. For the third-stage reaction, add 200 g of styrene monomer and react for 30 min. Finally, add 37.6 mmol of sec-butyllithium. The prepared polymer solution was poured into a hydrogenation reactor, and 4.8 mmol of dicyclopentadiene titanium dichloride and 3.36 mmol of ethyl benzoate were added. The initial reaction temperature was controlled at 74°C. Hydrogen gas was introduced to make the pressure inside the reactor 1.4 MPa. The reaction was carried out until the temperature reached 103°C. The hydrogen gas supply was immediately stopped, and the pressure inside the reactor was released to 0.05 MPa. The polymer solution was dried and tested. The degree of hydrogenation was 77.8%, which is close to the result of 77.5% obtained by applying formula ③ in Table 1.

[0084] Example 4

[0085] The designed m is 0.18 mmol / 100g butadiene, n is 8, and X = 0.2 is substituted into Formula 4 in Table 1 for calculation. The calculated degree of hydrogenation Y under this condition is 33.6%.

[0086] Experimental verification of the prediction results:

[0087] SEBS with a number-average molecular weight (Mn) of 6 ± 10,000 was produced using an anionic polymerization method known in the industry. The amount of tantalum catalyst per 100g butadiene was 0.18 mmol, the molar ratio of lithium ions to tantalum catalyst was 8, and the molar ratio of co-catalyst to tantalum catalyst was 0.2.

[0088] In a polymerization reactor purged with a dry protective gas (e.g., nitrogen), 40 kg of cyclohexane, 12 g of tetrahydrofuran, 3.6 g of tetrahydrofurfuryl ethyl ether, and 66.7 mmol of butyllithium were added. The polymerization reactor temperature was maintained at 64 °C and the pressure at 0.3 MPa. First, 600 g of styrene monomer was added to initiate a first-stage reaction for 30 min. After the reaction was completed, the polymerization temperature was lowered to 63 °C. Then, 2800 g of butadiene monomer was continuously added over 40 min. After reaching the high temperature, the reaction was carried out for 10 min. For the third-stage reaction, 600 g of styrene monomer was added, and the reaction was carried out for 30 min. Finally, 26.3 mmol of methanol was added to terminate the partial butyllithium reaction. The prepared polymer solution was poured into a hydrogenation reactor, and 5.04 mmol of dicyclopentadiene titanium dichloride and 1.08 mmol of methyl benzoate were added. The initial reaction temperature was controlled at 75°C, and hydrogen gas was introduced to make the pressure inside the reactor 1.2 MPa. The reaction was carried out to a high temperature of 87°C, and the hydrogen gas supply was immediately stopped. The pressure inside the reactor was then released to 0.05 MPa. The polymer solution was dried and tested, and the degree of hydrogenation was 34.4%, which is close to the result of 33.6% obtained by applying formula ④ in Table 1.

[0089] Example 5

[0090] The designed m is 0.18 mmol / 100g butadiene, n is 10, and X = 0.5 is substituted into Formula 5 in Table 1 for calculation. The calculated degree of hydrogenation Y under this condition is 62.5%.

[0091] Experimental verification of the prediction results:

[0092] SEBS with a number-average molecular weight (Mn) of 10 ± 10,000 was produced using an anionic polymerization method known in the industry. The amount of tantalum catalyst per 100g butadiene was 0.18 mmol, the molar ratio of lithium ions to tantalum catalyst was 10, and the molar ratio of co-catalyst to tantalum catalyst was 0.5. In a polymerization reactor purged with a dry protective gas (e.g., nitrogen), 40 kg of cyclohexane, 12 g of tetrahydrofuran, 2.8 g of hexamethylphosphoric triamine, and 48 mmol of butyllithium were added. The reactor temperature was maintained at 66°C and the pressure at 0.3 MPa. First, 800 g of styrene monomer was added for a first-stage reaction, which lasted 30 min. After the reaction, the polymerization temperature was lowered to 63°C, and then 3200 g of butadiene monomer was continuously added over 40 min. After reaching the high temperature, the reaction was continued for 10 min. For the third-stage reaction, 800 g of styrene monomer was added, and the reaction was continued for 30 min. Finally, 9.6 mmol of butyllithium was added. The prepared polymer solution was poured into a hydrogenation reactor, and 5.76 mmol of dicyclopentadiene titanium dichloride and 2.88 mmol of ethyl benzoate were added. The initial reaction temperature was controlled at 75°C, and hydrogen gas was introduced to make the pressure inside the reactor 1.3 MPa. The reaction was carried out to a high temperature of 97°C, and the hydrogen gas supply was immediately stopped. The pressure inside the reactor was then released to 0.05 MPa. The polymer solution was dried and tested, and the degree of hydrogenation was 63.1%, which is close to the result of 62.5% obtained by applying formula ⑤ in Table 1.

[0093] Example 6

[0094] The designed m is 0.18 mmol / 100g butadiene, n is 12, and X = 0.9 is substituted into Formula 6 in Table 1 for calculation. The calculated degree of hydrogenation Y under this condition is 93.1%.

[0095] Experimental verification of the prediction results:

[0096] SEBS with a number-average molecular weight (Mn) of 20 ± 10,000 was produced using an anionic polymerization method known in the industry. The amount of tektene catalyst per 100g butadiene was 0.18 mmol, the molar ratio of lithium ions to tektene catalyst was 12, and the molar ratio of co-catalyst to tektene catalyst was 0.9. In a polymerization reactor purged with a dry protective gas (e.g., nitrogen), 40 kg of cyclohexane, 12 g of tetrahydrofuran, 2.4 g of tetrahydrofurfuryl ethyl ether, and 28 mmol of isobutyllithium were added. The reactor temperature was maintained at 64°C and the pressure at 0.3 MPa. First, 1000 g of styrene monomer was added for a first-stage reaction, which lasted 30 min. After the reaction, the polymerization temperature was lowered to 63°C, and then 3600 g of butadiene monomer was continuously added over 40 min. After reaching the high temperature, the reaction was continued for 10 min. For the third-stage reaction, 1000 g of styrene monomer was added, and the reaction was continued for 30 min. Finally, 49.76 mmol of isobutyllithium was added. The prepared polymer solution was poured into a hydrogenation reactor, and 6.48 mmol of dicyclopentadiene titanium dichloride and 5.83 mmol of ethyl benzoate were added. The initial reaction temperature was controlled at 74°C, and hydrogen gas was introduced to make the pressure inside the reactor 1.4 MPa. The reaction was carried out until the high temperature of 122°C. The hydrogen gas supply was immediately stopped, and the pressure inside the reactor was released to 0.05 MPa. The polymer solution was dried and tested. The degree of hydrogenation was 93.8%, which is close to the result of 93.1% obtained by applying formula ⑥ in Table 1.

[0097] Example 7

[0098] The design m is 0.2 mmol / 100g butadiene, and n is 8. Substituting X = 0.2 into Formula 7 in Table 1, the calculated degree of hydrogenation Y under this condition is 36%.

[0099] Experimental verification of the prediction results:

[0100] SEBS with a number-average molecular weight (Mn) of 6 ± 10,000 was produced using an anionic polymerization method known in the industry. The amount of tektene catalyst per 100g butadiene was 0.2 mmol, the molar ratio of lithium ions to tektene catalyst was 8, and the molar ratio of co-catalyst to tektene catalyst was 0.2. In a polymerization reactor purged with a dry protective gas (e.g., nitrogen), 40 kg of cyclohexane, 12 g of tetrahydrofuran, 3.6 g of tetrahydrofurfuryl ethyl ether, and 66.7 mmol of butyllithium were added. The reactor temperature was maintained at 64°C and the pressure at 0.3 MPa. First, 600 g of styrene monomer was added for a first-stage reaction, which lasted 30 min. After the reaction, the polymerization temperature was lowered to 63°C. Then, 2800 g of butadiene monomer was continuously added over 40 min, and the reaction was continued at the high temperature for 10 min. For the third-stage reaction, 600 g of styrene monomer was added, and the reaction was continued for 30 min. Finally, 21.9 mmol of methanol was added to terminate the partial butyllithium polymerization. The prepared polymer solution was poured into a hydrogenation reactor, and 5.6 mmol of dicyclopentadiene titanium dichloride and 1.12 mmol of methyl benzoate were added. The initial reaction temperature was controlled at 75°C, and hydrogen gas was introduced to make the pressure inside the reactor 1.2 MPa. The reaction was carried out to a high temperature of 89°C, and the hydrogen gas supply was immediately stopped. The pressure inside the reactor was then released to 0.05 MPa. The polymer solution was dried and tested, and the degree of hydrogenation was 35.4%, which is close to the result of 36% obtained by applying formula ⑦ in Table 1.

[0101] Example 8

[0102] The designed m is 0.2 mmol / 100g butadiene, n is 10, and X = 0.6 is substituted into Formula 8 in Table 1 for calculation. The calculated degree of hydrogenation Y under this condition is 72.8%.

[0103] Experimental verification of the prediction results:

[0104] SEBS with a number-average molecular weight (Mn) of 10 ± 10,000 was produced using an anionic polymerization method known in the industry. The amount of tektene catalyst per 100g butadiene was 0.18 mmol, the molar ratio of lithium ions to tektene catalyst was 10, and the molar ratio of co-catalyst to tektene catalyst was 0.6. In a polymerization reactor purged with a dry protective gas (e.g., nitrogen), 40 kg of cyclohexane, 12 g of tetrahydrofuran, 3 g of hexamethylphosphoric triamine, and 48 mmol of butyllithium were added. The reactor temperature was maintained at 66°C and the pressure at 0.3 MPa. First, 800 g of styrene monomer was added for a first-stage reaction, which lasted 30 min. After the reaction, the polymerization temperature was lowered to 63°C, and then 3200 g of butadiene monomer was continuously added over 40 min. After reaching the high temperature, the reaction was continued for 10 min. For the third-stage reaction, 800 g of styrene monomer was added, and the reaction was continued for 30 min. Finally, 9.6 mmol of butyllithium was added. The prepared polymer solution was poured into a hydrogenation reactor, and 6.4 mmol of dicyclopentadiene titanium dichloride and 3.84 mmol of ethyl benzoate were added. The initial reaction temperature was controlled at 75°C, and hydrogen gas was introduced to make the pressure inside the reactor 1.4 MPa. The reaction was carried out until the temperature reached 106°C. The hydrogen gas supply was immediately stopped, and the pressure inside the reactor was released to 0.05 MPa. The polymer solution was dried and tested, and the degree of hydrogenation was 73.1%, which is close to the result of 72.8% obtained by applying formula ⑧ in Table 1.

[0105] Example 9

[0106] The design m is 0.2 mmol / 100g butadiene, n is 12, and X = 0.8 is substituted into Formula 9 in Table 1 for calculation. The calculated degree of hydrogenation Y under this condition is 88%.

[0107] Experimental verification of the prediction results:

[0108] SEBS with a number-average molecular weight (Mn) of 20 ± 10,000 was produced using an anionic polymerization method known in the industry. The amount of tektene catalyst per 100g butadiene was 0.2 mmol, the molar ratio of lithium ions to tektene catalyst was 12, and the molar ratio of co-catalyst to tektene catalyst was 0.8. In a polymerization reactor purged with a dry protective gas (e.g., nitrogen), 40 kg of cyclohexane, 12 g of tetrahydrofuran, 2.8 g of tetrahydrofurfuryl ethyl ether, and 28 mmol of isobutyllithium were added. The reactor temperature was maintained at 64°C and the pressure at 0.3 MPa. First, 1000 g of styrene monomer was added for a first-stage reaction, which lasted 30 min. After the reaction, the polymerization temperature was lowered to 63°C, and then 3600 g of butadiene monomer was continuously added over 40 min. After reaching the high temperature, the reaction was continued for 10 min. For the third-stage reaction, 1000 g of styrene monomer was added, and the reaction was continued for 30 min. Finally, 49.76 mmol of isobutyllithium was added. The prepared polymer solution was poured into a hydrogenation reactor, and 7.2 mmol of dicyclopentadiene titanium dichloride and 5.76 mmol of ethyl benzoate were added. The initial reaction temperature was controlled at 74°C, and hydrogen gas was introduced to make the pressure inside the reactor 1.3 MPa. The reaction was carried out until the high temperature of 124°C. The hydrogen gas supply was immediately stopped, and the pressure inside the reactor was released to 0.05 MPa. The polymer solution was dried and tested. The degree of hydrogenation was 87.6%, which is close to the result of 88% obtained by applying formula ⑨ in Table 1.

[0109] As can be seen from Examples 1-9, the prediction method described in this invention can accurately predict the hydrogenation result, and based on the prediction result, a more accurate hydrogenation method can be developed.

Claims

1. A method for predicting the degree of hydrogenation of SEBS, characterized in that, The amounts m of the main catalyst, the molar ratio n of lithium to the main catalyst, and the molar ratio X of the cocatalyst to the main catalyst in the selective hydrogenation process of the SBS solution prepared by living lithium anionic polymerization are designed and used to calculate Formulas 1 to 9 to predict the hydrogenation degree Y of the prepared SEBS; Formula 1: Y = 0.12 + 0.88×X Formula 2: Y = 0.19 + 0.81×X Formula 3: Y = 0.25 + 0.75×X Formula 4: Y = 0.17 + 0.83×X Formula 5: Y = 0.25 + 0.75×X Formula 6: Y = 0.31 + 0.69×X Formula 7: Y = 0.2 + 0.8×X Formula 8: Y = 0.32 + 0.68×X Formula 9: Y = 0.4 + 0.6×X The m described is the proportion of the molar amount of the main catalyst relative to the weight of butadiene forming the SBS solution, with the unit of mmol / 100g; the n described is the molar ratio of lithium ions to the main catalyst in the initial system of selective hydrogenation; When the design range of m is 0.14 - 0.16 mmol / 100g and 7 ≤ the design range of n ≤ 9, substitute X into Formula 1 to calculate the hydrogenation degree Y; when 9 < n ≤ 11, substitute X into Formula 2 to calculate the hydrogenation degree Y; when 11 < n ≤ 13, substitute X into Formula 3 to calculate the hydrogenation degree Y; When the design range of m is 0.17 - 0.19 mmol / 100g and 7 ≤ the design range of n ≤ 9, substitute X into Formula 4 to calculate the hydrogenation degree Y; when 9 < n ≤ 11, substitute X into Formula 5 to calculate the hydrogenation degree Y; when 11 < n ≤ 13, substitute X into Formula 6 to calculate the hydrogenation degree Y; When the design range of m is 0.19 - 0.21 mmol / 100g and 7 ≤ the design range of n ≤ 9, substitute X into Formula 7 to calculate the hydrogenation degree Y; when 9 < n ≤ 11, substitute X into Formula 8 to calculate the hydrogenation degree Y; when 11 < n ≤ 13, substitute X into Formula 9 to calculate the hydrogenation degree Y; The selection range of X is 0.05 - 1; The main catalyst is a metallocene titanium catalyst; The cocatalyst is a carboxylic acid ester containing a benzene ring; The molar ratio of the main catalyst to the cocatalyst is 1 - 20:

1.

2. The SEBS hydrogenation degree prediction method as described in claim 1, characterized in that, When the design range of the described m is 0.145 - 0.155 mmol / 100g and the design range of n is 7.5 - 8.5, use Formula 1 for calculation.

3. The SEBS hydrogenation degree prediction method as described in claim 1, characterized in that, When the design range of the described m is 0.145 - 0.155 mmol / 100g and the design range of n is 9.9 - 10.1, use Formula 2 for calculation.

4. The SEBS hydrogenation degree prediction method as described in claim 1, characterized in that, When the design range of the described m is 0.145 - 0.155 mmol / 100g and the design range of n is 11.5 - 12.5, use Formula 3 for calculation.

5. The SEBS hydrogenation degree prediction method as described in claim 1, characterized in that, When the design range of the described m is 0.175 - 0.185 mmol / 100g and the design range of n is 7.5 - 8.5, use Formula 4 for calculation.

6. The SEBS hydrogenation degree prediction method as described in claim 1, characterized in that, When the design range of the described m is 0.175 - 0.185 mmol / 100g and the design range of n is 9.5 - 10.5, use Formula 5 for calculation.

7. The SEBS hydrogenation degree prediction method as described in claim 1, characterized in that, When the design range of m is 0.175~0.185mmol / 100g and the design range of n is 11.5~12.5, the calculation is performed using Formula 6.

8. The SEBS hydrogenation degree prediction method as described in claim 1, characterized in that, When the design range of m is 0.195~0.205mmol / 100g and the design range of n is 7.5~8.5, the calculation is performed using Formula 7.

9. The SEBS hydrogenation degree prediction method as described in claim 1, characterized in that, When the design range of m is 0.195~0.205mmol / 100g and the design range of n is 9.5~10.5, the calculation is performed using Formula 8.

10. The SEBS hydrogenation degree prediction method as described in claim 1, characterized in that, When the design range of m is 0.195~0.205mmol / 100g and the design range of n is 11.5~12.5, the calculation is performed using Formula 9.

11. The SEBS hydrogenation degree prediction method according to any one of claims 1 to 10, characterized in that, SBS adhesive is a block polymer adhesive formed by active lithium anion polymerization.

12. The SEBS hydrogenation degree prediction method as described in claim 11, characterized in that, The steps to obtain SBS adhesive are as follows: In an anionic polymerization solution system, solvent, styrene monomer, active lithium activator and initiator are added to initiate and carry out a first-stage polymerization reaction; after the first-stage polymerization is completed, a structure regulator is added, and butadiene monomer is continuously and uniformly added to carry out a second-stage polymerization reaction; after the second-stage polymerization reaction is completed, styrene monomer is added to carry out a third-stage polymerization reaction; after the third-stage polymerization reaction is completed, SBS adhesive is obtained.

13. The SEBS hydrogenation degree prediction method as described in claim 12, characterized in that, The concentration of the monomer is 10-15%; The solvent is one of cyclohexane, n-hexane, and cyclopentane; The structure modifier is at least one of ethylene glycol dimethyl ether, bis(tetrahydrofurfuryl)propane, ethylene glycol diethyl ether, tetrahydrofurfuryl ethyl ether, tetramethylethylenediamine, and hexamethylphosphoric triamine. The total time for the butadiene monomer to be added continuously and uniformly is 40-60 minutes. The initial temperature of the two-stage polymerization reaction is controlled at 62~65℃, the maximum temperature is 70~85℃, and the total reaction time is in the range of 30~80 min. The activator is tetrahydrofuran; The active lithium initiator is at least one of n-butyllithium, sec-butyllithium, and isobutyllithium; The temperature for the first and third stage polymerization reactions is 50℃~70℃, and the time is 20~50min.

14. The SEBS hydrogenation degree prediction method as described in claim 1, characterized in that, The main catalyst is at least one of bis(cyclopentadienyl)titanium dichloride, bis(cyclopentadienyl)titanium dibromide, bis(cyclopentadienyl)titanium diiodide, bis(cyclopentadienyl)titanium difluoride, bis(cyclopentadienyl)dicarbonyltitanium, bis(cyclopentadienyl)dimethyltitanium, bis(cyclopentadienyl)diethyltitanium, and bis(cyclopentadienyl)dibutyltitanium; The co-catalyst is at least one of C1-C5 alkyl benzoate and C1-C5 alkyl phthalate.

15. The SEBS hydrogenation degree prediction method as described in claim 14, characterized in that, In the selective hydrogenation process, the initial temperature is 72~80℃ and the hydrogen pressure is 1.2~1.4MPa. After the reaction reaches a high temperature of 80-130℃, the hydrogen valve is closed and the pressure in the reactor is released to 0.05MPa to discharge the hydrogen.

16. A method for precisely controlling the degree of hydrogenation of SEBS, characterized in that, Based on the required degree of hydrogenation, m, n, and X of the selective hydrogenation stage are calculated using the SEBS hydrogenation degree prediction method according to any one of claims 1 to 15, and the calculated m, n, and X are used as conditions to carry out the selective hydrogenation reaction, so as to accurately obtain SEBS with a hydrogenation degree that meets the design requirements.

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