A transparent perhydropolystyrene-piperylene resin and a method for producing the same

Abstract

This invention discloses a transparent, fully hydrogenated polystyrene-isoprene resin and its preparation method, which is obtained by the complete hydrogenation of the following block copolymer: wherein S1 and S2 are styrene homopolymer blocks, and SP is a styrene and isoprene alternating copolymer block, and the hydrogenation rate of both the benzene ring unit and the isoprene unit in the block copolymer is greater than 99%. This resin exhibits good chemical stability, UV resistance, heat resistance, weather resistance, ozone resistance, as well as high toughness and high strength, making it particularly suitable for the preparation of optical, electronic, transportation, remote sensing scientific and technological equipment, packaging materials, and instrument panels.

Description

Technical Field

[0001] This invention relates to a resin, particularly to a transparent, fully hydrogenated polystyrene-isoprene resin, and also to its preparation method, belonging to the field of resin material technology. Background Technology

[0002] Common unsaturated polymer materials often have poor heat resistance, UV resistance, and yellowing resistance due to the presence of unsaturated double bonds (such as benzene ring double bonds, diene double bonds, etc.). Hydrogenation modification of unsaturated polymers is an effective way to improve their performance.

[0003] Hydrogenation of the benzene ring double bonds in polystyrene (PS) yields fully saturated polycyclohexylethylene (PVCH), which has a glass transition temperature of 147℃, significantly improving the heat resistance and UV resistance of PS. It possesses advantages such as high light transmittance, light weight, high glass transition temperature, low water absorption, good optical properties, high strength, and ease of molding. It can be used in optical materials, electronics, transportation, remote sensing science and technology, and other fields. However, hydrogenation of the benzene ring double bonds in polystyrene is more difficult than hydrogenation of the carbon-carbon double bonds in olefins, typically requiring high temperature and high pressure conditions. Traditional homogeneous catalysts are difficult to use for hydrogenation, and currently, heterogeneous hydrogenation is mainly employed for PS.

[0004] Chinese patent (CN104140480A) discloses a method for hydrogenating polystyrene by loading the active component Pd (or Pt, Rh) onto a silica hollow microsphere carrier with macropores (pore size 250-650 nm). The catalyst addition amount is 10-50% of the polystyrene. Under the conditions of temperature 100-170℃, hydrogen pressure 5-15 MPa, and hydrogenation time of 5-15 h, the degree of hydrogenation of polystyrene benzene rings reaches more than 91.3%. However, the use of precious metal catalysts results in large catalyst addition amounts, high cost, long hydrogenation time, molecular chain degradation, and a benzene ring hydrogenation rate of less than 98%. Chinese patent (CN115364876A) discloses a method for hydrogenating polystyrene by loading active component Pt, additives, and modifiers onto a support. The catalyst addition amount is 2-10% of the polystyrene. The hydrogenation time is 1-3 hours at a temperature of 120-180℃ and a hydrogen pressure of 1-5 MPa. The degree of hydrogenation of the benzene ring in polystyrene reaches more than 96%. However, the use of a precious metal hydrogenation catalyst results in high cost.

[0005] Meanwhile, due to the influence of the cyclohexyl group on the PVCH molecular chain, the product has high rigidity and is brittle, affecting its application. To improve its brittleness, dienes can be copolymerized with styrene to increase its toughness and thus reduce its brittleness. Chinese patent (CN105175659A) discloses a transparent hydrogenated polystyrene-b-random copolymer diene / styrene resin and its preparation method. This resin is composed of styrene blocks and styrene and conjugated diene random copolymer blocks. The C=C hydrogenation rate in the conjugated diene unit of the block copolymer reaches over 98%. The preparation method involves first homopolymerizing styrene monomers under alkyllithium initiation, and then randomly copolymerizing a mixture of styrene, conjugated diene, and divinylbenzene monomers. The copolymer product is then hydrogenated using a dichlorodicyclopentadiene system. Random copolymerization of styrene, conjugated diene, and divinylbenzene monomers is complex to control. Using a dichlorodicyclopentadiene system for hydrogenation only hydrogenates the diene C=C, resulting in a hydrogenation rate of less than 3% for the benzene ring. US Patent (US2018258276) discloses a fully hydrogenated polystyrene-conjugated diene multiblock copolymer with a benzene ring hydrogenation rate of more than 99%. However, it uses precious metals and catalysts, and the hydrogenation pressure is high, making production difficult to control and resulting in high production costs. Summary of the Invention

[0006] To address the problems existing in the prior art, the first objective of this invention is to provide a transparent, fully hydrogenated polystyrene-isoprene resin. This resin has the characteristics of good chemical stability, UV resistance, heat resistance, weather resistance, ozone resistance, as well as high toughness and high strength. It is particularly suitable for the preparation of optical, electronic, transportation, remote sensing scientific and technological equipment, packaging materials, and instrument panels.

[0007] The second objective of this invention is to provide a simple and low-cost method for preparing the transparent fully hydrogenated polystyrene-isoprene resin.

[0008] To achieve the above-mentioned technical objectives, the present invention provides a transparent fully hydrogenated polystyrene-isoprene resin, which is obtained by fully hydrogenating the following block copolymer: S1-SP-S2.

[0009]

[0010] S1 and S2 are styrene homopolymer blocks; SP is a styrene and isoprene alternating copolymer block; the hydrogenation rate of both benzene ring units and isoprene units in the block copolymer is greater than 99%.

[0011] The fully hydrogenated polystyrene-isoprene resin of the present invention has a special triblock structure. Its hydrogenated styrene blocks can provide mechanical strength through physical crosslinking, while the special alternating sequence of hydrogenated styrene and isoprene alternating copolymer blocks provides high toughness and transparency. Moreover, the uniformly dispersed isoprene and styrene units are fully saturated, which is beneficial to improving its chemical stability, increasing its glass transition temperature, and making it resistant to ultraviolet light and ozone. It also has good stability during high-temperature processing and can be directly injection molded.

[0012] As a preferred embodiment, the mass percentage composition of styrene units to isoprene units in the block copolymer is 70-90%:30-10%. If the proportion of isoprene units is too low, the volume of the intermediate block phase will be too small, resulting in a significant reduction in toughness. If the proportion of isoprene is too high, the proportion of polystyrene segments at both ends will be too low, directly reducing the mechanical strength of the material.

[0013] As a preferred option, the number-average molecular weights of S1 and S2 are 30,000 to 60,000; the number-average molecular weight of SP is 60,000 to 100,000. The molecular weights of the S1 and S2 blocks at both ends have a significant impact on the overall polymer properties. Compared to SBS, the difference in solubility parameters between the alternating SP sequence blocks and the polystyrene blocks in the middle is smaller, resulting in a lower degree of phase separation. Therefore, the molecular weights of the S1 and S2 blocks must be relatively large, while the molecular weight of the middle SP segment needs to be controlled within an appropriate range to ensure the toughness of the entire polymer material.

[0014] This invention provides a method for preparing a transparent, fully hydrogenated polystyrene-isoprene resin. The method involves first adding styrene monomer and an initiator to an anionic polymerization solution system for homopolymerization I, then adding a mixture of styrene and isoprene monomers for alternating copolymerization, followed by adding styrene monomer for homopolymerization II or adding a coupling agent for coupling, to obtain an S1-SP-S2 block copolymer. The S1-SP-S2 block copolymer is then subjected to catalytic hydrogenation using a supported nickel catalyst.

[0015] As a preferred embodiment, the anionic polymerization solution system uses at least one of cyclopentane, cyclohexane, benzene, and toluene as a solvent. The preferred solvents are cyclopentane and / or cyclohexane. The amount of solvent used is sufficient to ensure that the mass percentage concentration of the monomer in the solvent is approximately 15%.

[0016] As a preferred embodiment, the initiator is an organolithium compound, preferably n-butyllithium. The amount of initiator used is determined based on the molecular weight of the polymer being designed, which is a well-known technique in the industry.

[0017] As a preferred embodiment, the temperature of homopolymerization I is 25–80°C, and the time is 20–30 min. The temperature of homopolymerization I is further preferably 50–70°C.

[0018] As a preferred embodiment, the alternating copolymerization temperature is 35–85°C, and the time is 40–60 min. The alternating copolymerization temperature is further preferably 50–70°C. This invention selects a mixture of styrene and isoprene monomers for copolymerization. Based on the electronic and steric effects of styrene and isoprene, under the preferred temperature conditions, the copolymerization process tends towards alternating copolymerization, with an alternating copolymerization rate exceeding 90%, and isoprene primarily tends towards 1,4 polymerization.

[0019] As a preferred embodiment, the homopolymer II is produced at a temperature of 50–70°C for 20–40 minutes.

[0020] As a preferred embodiment, the coupling temperature is 50–70°C, and the time is 20–40 min. The coupling agent used is preferably silicon dichloride, silicon tetrachloride, etc., and the amount of coupling agent added is 1 / 3 to 1 / 4 of the molar amount of butyllithium.

[0021] As a preferred embodiment, the catalytic hydrogenation reaction is carried out at a temperature of 160–260°C, a hydrogenation pressure of 5–9 MPa, and a time of 0.5–4 h. More preferably, the temperature is 200–240°C, the hydrogenation pressure is 6–8 MPa, and the time is 0.5–4 h. Under these preferred hydrogenation reaction conditions, the degree of hydrogenation in both the styrene and pentadiene units of the S1-SP-S2 block copolymer is greater than 99%.

[0022] As a preferred embodiment, the amount of the supported nickel hydrogenation catalyst used in the catalytic hydrogenation reaction is 3-20% of the mass of the S1-SP-S2 block copolymer. The nickel loading in the supported nickel hydrogenation catalyst is 50-65%, and the support is silica or alumina. More preferably, the amount of the supported nickel hydrogenation catalyst is 8-15% of the mass of the S1-SP-S2 block copolymer.

[0023] The preparation method of transparent fully hydrogenated polystyrene-isoprene resin provided by this invention is as follows: A hydrocarbon solvent and styrene monomer are added to a polymerization reactor, followed by the addition of an organolithium initiator for a first-stage polymerization at a temperature of 50–70°C for 20–30 min. A second-stage polymerization is then carried out with a mixture of styrene and isoprene monomers, controlled at a temperature of 50–70°C for 40–60 min. After the second-stage polymerization is completed, styrene is added again for a third-stage polymerization, or a coupling agent is added for a coupling reaction, with a reaction time of 20–40 min.

[0024] The polymer was then fed into a hydrogenation reactor, and a supported nickel catalyst was added. Hydrogenation was carried out at a temperature of 200–240 °C and a pressure of 6–8 MPa for 1–3 hours. After hydrogenation, the reactor was cooled until it reached room temperature. The hydrogen gas inside the reactor was then released, and the solution was centrifuged to separate the catalyst. Ethanol was added to the resulting clear liquid and stirred, causing a white product to precipitate. Finally, the product was dried in a 60 °C oven to obtain the hydrogenated product.

[0025] Compared with the prior art, the beneficial effects of the technical solution of the present invention are as follows:

[0026] 1) The fully hydrogenated styrene-isoprene triblock copolymer provided by the present invention has a special molecular structure. Its two ends are hydrogenated products of homopolymer styrene blocks, and the middle part is a hydrogenated product of alternating copolymer blocks of styrene and isoprene. Its special molecular structure endows it with good heat resistance, anti-aging properties, weather resistance, ozone resistance, and high toughness, transparency, good processability and film-forming properties. It is particularly suitable for preparing optical, electronic, transportation, remote sensing scientific and technological equipment, packaging materials and instrument panels, etc.

[0027] 2) In the preparation process of the fully hydrogenated styrene-isoprene triblock copolymer of the present invention, a small amount of isoprene is introduced into alternating copolymerization with styrene, which effectively solves the problem of brittleness of homopolymer styrene. At the same time, its special molecular structure reduces the difficulty of hydrogenation, solves the problems of difficult hydrogenation of polystyrene, long hydrogenation time, and easy degradation of molecular chains. The hydrogenation rate of benzene ring in the fully hydrogenated polystyrene-isoprene resin is greater than 99%, and the hydrogenation rate of C=C in isoprene unit is greater than 99%.

[0028] 3) The preparation process of the fully hydrogenated styrene-isoprene triblock copolymer of the present invention uses a highly active supported nickel hydrogenation catalyst, which has low production cost, high hydrogenation efficiency, and is easy to industrialize. Attached Figure Description

[0029] Figure 1 The image shows a comparison of the HNMR spectra of the polystyrene-isoprene resin prepared in Example 1 before and after hydrogenation.

[0030] Figure 2 The HNMR spectra of the hydrogenated polystyrene-isoprene resins prepared in Examples 2, 3 and 4 are shown.

[0031] Figure 3 The HNMR spectra of the hydrogenated polystyrene-isoprene resins prepared in Comparative Example 1 and Comparative Example 2 are shown. Detailed Implementation

[0032] The following detailed description of the invention is provided with reference to specific embodiments, but the scope of protection of the claims of the invention is not limited thereto.

[0033] The resin samples were analyzed and characterized using nuclear magnetic resonance spectroscopy (NMR 1H-1N), and the degree of hydrogenation was quantitatively calculated. The molecular weight (Mn) and molecular weight distribution (MWD) of the samples were analyzed and characterized using gel permeation chromatography (GPC). The physical properties of the samples were determined using an INSTRON-5565 electronic tensile testing machine, and the transmittance of the samples was determined using a DRTG-81 visible light transmittance meter.

[0034] Example 1

[0035] 3500 mL of a cyclohexane solution containing 10% n-hexane was added to a 5 L polymerization reactor. After the reactor was heated to 50 °C, 120 mL of styrene was added, and stirring was started. Then, 6.5 mL of 0.5 mol / L n-butyllithium was added to carry out a first-stage polymerization for 30 min. Next, 140 mL of styrene and 123 mL of a mixture of isoprene monomers were added to carry out a second-stage copolymerization, maintaining the temperature for 60 min. After the second-stage copolymerization was completed, 120 mL of styrene was added again, and a third-stage polymerization was carried out at 60 °C for 25 min. A small amount of methanol was added to terminate the polymerization. The polymer had a Mn of 156000 and a MWD of 1.03.

[0036] Then, the polymer was pressed into a hydrogenation reactor, and 40g of powdered supported nickel catalyst (Shanghai Xunkai New Material Technology Co., Ltd. SNCAT-6210P) was added. The hydrogen pressure was controlled at 7.0MPa, and the reaction was stirred at 220℃ for 2h. After hydrogenation was completed, the temperature was lowered. After the temperature of the high-pressure reactor dropped to room temperature, the hydrogen in the reactor was discharged and the solution was released. The solution was centrifuged, and ethanol was added to the resulting clear liquid and stirred. A white product precipitated out. Finally, it was placed in a 60℃ oven to dry and obtain the hydrogenated product.

[0037] The hydrogenation rate of the benzene ring in the hydrogenated polystyrene-isoprene resin was measured to be 100%, and the C=C hydrogenation rate in the diene unit was also 100%. The resin was injection molded at 260℃, and its physical properties were measured: tensile strength 52.7 MPa, notched impact strength 16.3 kJ / m². 2 Light transmittance is 92.8%.

[0038] Example 2

[0039] 3500 mL of a cyclohexane solution containing 10% n-hexane was added to a 5 L polymerization reactor. After heating the reactor to 60 °C, 185 mL of styrene was added, and stirring was started. Then, 8.3 mL of 0.5 mol / L n-butyllithium was added for a first-stage polymerization, which lasted for 25 min. Next, 70 mL of a styrene-62 mL mixture of isoprene monomers was added for a second-stage copolymerization, which was maintained at the temperature for 40 min. After the second-stage copolymerization was completed, 164 mL of styrene was added, and a third-stage polymerization was carried out at 70 °C for 30 min. A small amount of methanol was added to terminate the polymerization. The polymer Mn was 124300, and the MWD was 1.03.

[0040] Then, the polymer was pressed into a hydrogenation reactor, and 60g of powdered supported nickel catalyst (Shanghai Xunkai New Material Technology Co., Ltd. SNCAT-6210P) was added. The hydrogen pressure was controlled at 6.0MPa, and the reaction was stirred at 210℃ for 1 hour. After hydrogenation, the temperature was lowered until the autoclave temperature dropped to room temperature. The hydrogen gas in the autoclave was then released, and the solution was centrifuged. Ethanol was added to the resulting clear liquid and stirred, resulting in the precipitation of a white product. Finally, the product was dried in a 60℃ oven to obtain the hydrogenated product. The hydrogenation rate of the benzene ring in the hydrogenated polystyrene-isoprene resin was measured to be 100%, and the C=C hydrogenation rate in the diene unit was also measured to be 100%. The resin was injection molded, and its physical properties were measured: tensile strength 58.3MPa, notched impact strength 11.2kJ / m. 2 Light transmittance is 92.6%.

[0041] Example 3

[0042] 3500 mL of a cyclohexane solution containing 10% n-hexane was added to a 5 L polymerization reactor. After the reactor was heated to 65 °C, 120 mL of styrene was added, and stirring was started. Then, 7.5 mL of 0.5 mol / L n-butyllithium was added for a first-stage polymerization, which lasted for 25 min. Next, 140 mL of a styrene and 123 mL of a m-pentadiene monomer mixture were added for a second-stage copolymerization, which was maintained at the temperature for 40 min. After the second-stage copolymerization, a calculated amount of silicon tetrachloride was added for coupling, with a [SiCl4] / [BuLi] molar ratio of 0.38. The coupling was maintained at the temperature for 30 min to obtain the polymer solution. The polymer Mn was 272000, and the MWD was 1.13.

[0043] Then, the polymer was pressed into a hydrogenation reactor, and 40g of powdered supported nickel catalyst (Shanghai Xunkai New Material Technology Co., Ltd. SNCAT-6210P) was added. The hydrogen pressure was controlled at 8.0MPa, and the reaction was stirred at 230-240℃ for 2 hours. After hydrogenation, the temperature was lowered until the autoclave temperature dropped to room temperature. The hydrogen gas in the autoclave was then released, and the solution was centrifuged. Ethanol was added to the resulting clear liquid and stirred, resulting in the precipitation of a white product. Finally, the product was dried in a 60℃ oven to obtain the hydrogenated product. The hydrogenation rate of the benzene ring in the hydrogenated polystyrene-isoprene resin was measured to be 100%, and the C=C hydrogenation rate in the diene unit was also 100%. The resin was injection molded, and its physical properties were measured: tensile strength 53.8MPa, notched impact strength 14.7kJ / m. 2 Light transmittance is 92.3%.

[0044] Example 4

[0045] 3500 mL of cyclopentane solution was added to a 5 L polymerization reactor. After the reactor temperature was raised to 55 °C, 60 mL of styrene was added, and stirring was started. Then, 6.5 mL of 0.5 mol / L n-butyllithium was added to carry out a first-stage polymerization for 20 min. Next, 210 mL of styrene and 185 mL of a mixture of isopentadiene monomers were added to carry out a second-stage polymerization, maintaining the temperature for 60 min. After the second-stage polymerization was completed, 60 mL of styrene was added again, and a third-stage polymerization was carried out at 65 °C for 25 min. A small amount of methanol was added to terminate the polymerization. The polymer Mn was 149000, and the MWD was 1.03.

[0046] Then, the polymer was pressed into a hydrogenation reactor, and 34g of powdered supported nickel catalyst (Shanghai Xunkai New Material Technology Co., Ltd. SNCAT-6210P) was added. The hydrogen pressure was controlled at 7.5MPa, and the reaction was stirred at 220℃ for 3 hours. After hydrogenation, the temperature was lowered until the autoclave temperature dropped to room temperature. The hydrogen gas in the autoclave was then released, and the solution was centrifuged. Ethanol was added to the resulting clear liquid, and the mixture was stirred. A white product precipitated out. Finally, it was dried in a 60℃ oven to obtain the hydrogenated product. The hydrogenation rate of the benzene ring in the hydrogenated polystyrene-isoprene resin was measured to be 99.7%, and the C=C hydrogenation rate in the diene unit was 100%. The resin was injection molded, and its physical properties were measured: tensile strength 48.6MPa, notched impact strength 18.5kJ / m. 2 Light transmittance is 91.8%.

[0047] Comparative Example 1

[0048] 3500 mL of cyclopentane solution was added to a 5 L polymerization reactor. After the reactor was heated to 50 °C, 120 mL of styrene was added, and stirring was started. Then, 3.0 mL of 1.0 mol / L structure modifier bis(tetrahydrofuran)propane and 6.5 mL of 0.5 mol / L n-butyllithium were added for a first-stage polymerization for 20 min. Next, 140 mL of styrene and 125 mL of isoprene mixed monomers were added for a second-stage polymerization. The second-stage monomer mixture was fed in five separate 53 mL increments, with each increment 10 min apart, and the temperature was maintained for a polymerization time of 40 min. After the second-stage polymerization was completed, 120 mL of styrene was added for a third-stage polymerization for 25 min, and a small amount of methanol was added to terminate the polymerization. The polymer Mn was 165000, and the MWD was 1.04.

[0049] Then, the polymer was pressed into a hydrogenation reactor, and 40g of powdered supported nickel catalyst (SNCAT-6210P from Shanghai Xunkai New Material Technology Co., Ltd.) was added. The hydrogen pressure was controlled at 8MPa, and the reaction was stirred at 210-230℃ for 6 hours. After hydrogenation, the temperature was lowered until the autoclave temperature dropped to room temperature. The hydrogen gas in the autoclave was then released, and the solution was centrifuged. Ethanol was added to the resulting clear liquid and stirred, resulting in the precipitation of a white product. Finally, the product was dried in a 60℃ oven to obtain the hydrogenated product. The hydrogenation rate of the benzene ring in the hydrogenated resin was measured to be 99.5%, and the C=C hydrogenation rate in the isoprene unit was 100%. The resin was injection molded, and its physical properties were measured: tensile strength 32.6MPa, notched impact strength 2.5kJ / m. 2 Light transmittance is 85.8%.

[0050] Comparative Example 2

[0051] 3500 mL of cyclopentane solution was added to a 5 L polymerization reactor. After the reactor was heated to 50 °C, 120 mL of styrene was added, and stirring was started. Then, 3.0 mL of 1.0 mol / L structure modifier bis(tetrahydrofuran)propane and 6.5 mL of 0.5 mol / L n-butyllithium were added for a first-stage polymerization for 20 min. Next, 140 mL of a styrene and 110 mL of a butadiene mixed monomer mixture were added for a second-stage polymerization. The mixed monomer mixture was fed in five 50 mL increments, with each increment 10 min apart, and the temperature was maintained for a polymerization time of 60 min. After the second-stage polymerization was completed, 120 mL of styrene was added again, and a third-stage polymerization was carried out at 60 °C for 25 min. A small amount of methanol was added to terminate the polymerization. The polymer Mn was 167000, and the MWD was 1.04.

[0052] Then, the polymer was pressed into a hydrogenation reactor, and 40g of powdered supported nickel catalyst (Shanghai Xunkai New Material Technology Co., Ltd. SNCAT-6210P) was added. The hydrogen pressure was controlled at 8MPa, and the reaction was stirred at 220℃ for 7h. After hydrogenation, the temperature was lowered until the autoclave temperature dropped to room temperature. The hydrogen gas in the autoclave was then released, and the solution was centrifuged. Ethanol was added to the resulting clear liquid and stirred, resulting in the precipitation of a white product. Finally, it was dried in a 60℃ oven to obtain the hydrogenated product. The hydrogenation rate of the benzene ring in the hydrogenated resin was measured to be 99.2%, and the C=C hydrogenation rate in the butadiene unit was 100%. The resin was injection molded, and its physical properties were measured: tensile strength 42.1MPa, notched impact strength 4.6kJ / m. 2 Light transmittance is 87.8%.

Claims

1. A transparent, fully hydrogenated polystyrene-isoprene resin, characterized in that: It is obtained by complete hydrogenation of the following block copolymer: S1-SP-S2; in, S1 and S2 are styrene homopolymer blocks; SP is a styrene and isoprene alternating copolymer block; The hydrogenation rates of both the benzene ring units and the isoprene units in the block copolymer are greater than 99%. The block copolymer has a styrene unit to isoprene unit mass percentage composition of 70-90%:30-10%; The number-average molecular weights of S1 and S2 are 30,000 to 60,000; The number-average molecular weight of SP is between 60,000 and 100,000.

2. The method for preparing a transparent, fully hydrogenated polystyrene-isoprene resin according to claim 1, characterized in that: In an anionic polymerization solution system, styrene monomer and initiator are first added for homopolymerization I, then styrene-isoprene mixed monomers are added for alternating copolymerization, and then styrene monomer is added for homopolymerization II or coupling agent is added for coupling to obtain S1-SP-S2 block copolymer; the S1-SP-S2 block copolymer is obtained by catalytic hydrogenation reaction using a supported nickel catalyst.

3. The method for preparing a transparent fully hydrogenated polystyrene-isoprene resin according to claim 2, characterized in that: The anionic polymerization solution system uses at least one of cyclopentane, cyclohexane, benzene, and toluene as a solvent.

4. The method for preparing a transparent fully hydrogenated polystyrene-isoprene resin according to claim 2, characterized in that: The initiator is an organolithium compound.

5. A method for preparing a transparent, fully hydrogenated polystyrene-isoprene resin according to claim 2, 3, or 4, characterized in that: The homopolymer I was produced at a temperature of 25–80°C for 20–30 minutes.

6. A method for preparing a transparent, fully hydrogenated polystyrene-isoprene resin according to claim 2, 3, or 4, characterized in that: The alternating copolymerization temperature is 35–85°C, and the time is 40–60 min.

7. A method for preparing a transparent, fully hydrogenated polystyrene-isoprene resin according to claim 2, 3, or 4, characterized in that: The homopolymer II is produced at a temperature of 50–70°C for 20–40 minutes.

8. A method for preparing a transparent, fully hydrogenated polystyrene-isoprene resin according to claim 2, 3, or 4, characterized in that: The coupling temperature is 50–70°C, and the time is 20–40 min.

9. A method for preparing a transparent, fully hydrogenated polystyrene-isoprene resin according to claim 2, 3, or 4, characterized in that: The catalytic hydrogenation reaction is carried out at a temperature of 160–260°C, a hydrogenation pressure of 5–9 MPa, and a time of 0.5–4 h.

10. The method for preparing a transparent fully hydrogenated polystyrene-isoprene resin according to claim 9, characterized in that: The amount of the supported nickel hydrogenation catalyst used in the catalytic hydrogenation reaction is 3 to 20% of the mass of the S1-SP-S2 block copolymer.

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