Polyisobutylene copolymer and its application

Abstract

The present invention belongs to the field of polymer compounds and their preparation, specifically to a polyisomonoolefin copolymer and its applications. The copolymer is prepared by copolymerizing a first monomer and a second monomer in the presence of an initiator system, wherein the first monomer is selected from an isomonoolefin and the second monomer comprises an unsubstituted or substituted vinyl aromatic hydrocarbon. The copolymer is useful as an asphalt modifier, medical material, 5G optical fiber protective layer, or elastomer in hot melt adhesives.

Description

Technical Field

[0001] The present invention belongs to the field of polymer compounds and their preparation, and in particular relates to a polyisobutylene copolymer and its application. Background Art

[0002] Polystyrene-isobutylene-styrene (SIBS) is a triblock copolymer prepared through living carbocationic polymerization of isobutylene as the primary monomer and styrene as the secondary monomer. Polystyrene, as the hard segment, and polyisobutylene, as the soft segment, undergo covalent bonding and microphase separation. The polystyrene phase is physically crosslinked within the polyisobutylene phase to form a thermoplastic elastomer. During the polymerization process, SIBS can achieve varying mechanical properties by varying the styrene / isobutylene ratio and molecular weight. SIBS with a lower styrene ratio has mechanical properties similar to rubber, while SIBS with a higher ratio behaves like toughened plastic.

[0003] Patent document CN1982350A reports that cationic polymerization is carried out using water as an initiator and a Lewis acid as a co-initiator, and then a second monomer containing an additive, such as an isoolefin or styrene, is added to obtain a diblock copolymer. A first monomer containing an additive is then added and a third stage of polymerization is performed to obtain a triblock copolymer. However, the SIBS polymer prepared by this method has a low molecular weight, an unstable active center, and is easily transferred, resulting in side reactions that are difficult to control. In addition, the processes reported in other documents also have many problems, such as a wide molecular weight distribution of the obtained product and a molecular weight that is too high to be processed. For example, patent document CN1283681C reports a method for preparing an isobutylene block copolymer by sequential initiation, but this preparation method requires the addition of a new Lewis acid during the copolymerization of the second stage monomers, making the synthesis process cumbersome. Summary of the Invention

[0004] To improve the above problems, the present invention provides a copolymer prepared by copolymerizing a first monomer and a second monomer in an initiator system, wherein the first monomer is selected from isomonoolefins, and the second monomer comprises unsubstituted or substituted vinyl aromatic hydrocarbons.

[0005] According to an embodiment of the present invention, the copolymer is a thermoplastic copolymer (thermoplastic elastomer) or a thermosetting copolymer (thermosetting elastomer).

[0006] According to an embodiment of the present invention, the copolymer has polyisomonoolefin as the soft segment.

[0007] According to an embodiment of the present invention, the first monomer is selected from isobutylene.

[0008] According to an embodiment of the present invention, in the second monomer, the substituent of the substituted vinyl aromatic hydrocarbon is located on the aromatic hydrocarbon ring and can be selected from one or more of the following groups: halogen, unsubstituted or halogenated C1-10 alkyl.

[0009] According to an embodiment of the present invention, the aromatic hydrocarbon is selected from C 6-20 Aromatic hydrocarbon, preferably benzene.

[0010] According to an embodiment of the present invention, the second monomer may include styrene or a styrene derivative. Preferably, the styrene derivative is selected from substituted styrenes. The substituent of styrene is substituted on the phenyl group or the vinyl group, and the substituent is selected from one or more of the following groups: halogen, C 1-10 Alkyl or halogenated C 1-10 alkyl.

[0011] Preferably, the second monomer is selected from one, two or more of the following compounds: styrene; 1-10 Styrenes substituted with alkyl groups, such as α-methylstyrene, p-methylstyrene, m-methylstyrene, p-ethylstyrene, and p-tert-butylstyrene; Styrenes substituted with one or more halogens, such as p-chlorostyrene and p-bromostyrene; Styrenes substituted with one or more monohalogenated alkyls or polyhalogenated C 1-10 Alkyl-substituted styrenes, such as p-chloromethylstyrene, p-bromomethylstyrene; phenyl and C 4-8 Cycloalkenyl-fused styrenes, such as 4-vinylbenzocyclobutene (4-VBCB).

[0012] According to a preferred embodiment of the present invention, the second monomer comprises monomer A, which is selected from one, two or more of the following compounds: styrene; 1-10 Styrenes substituted with alkyl groups, such as α-methylstyrene, p-methylstyrene, m-methylstyrene, p-ethylstyrene, and p-tert-butylstyrene; Styrenes substituted with one or more halogens, such as p-chlorostyrene and p-bromostyrene; Styrenes substituted with one or more monohalogenated alkyls or polyhalogenated C 1-10 Alkyl-substituted styrenes, such as p-chloromethylstyrene and p-bromomethylstyrene;

[0013] as well as,

[0014] The optional presence or absence of monomer B is selected from one, two or more of the following compounds: phenyl and C 4-8 Cycloalkenyl-fused styrenes, such as 4-vinylbenzocyclobutene.

[0015] According to an embodiment of the present invention, the copolymer may be a thermoplastic elastomer.

[0016] According to an exemplary embodiment of the present invention, the second monomer of the thermoplastic elastomer is selected from monomer A, which is selected from one, two or more of the following compounds: styrene;1-10 Alkyl-substituted styrenes, such as α-methylstyrene, p-methylstyrene, m-methylstyrene, p-ethylstyrene, p-tert-butylstyrene; styrenes substituted with one or more halogens, such as p-chlorostyrene, p-bromosty ... 1-10 Styrene substituted with an alkyl substituent, such as p-chloromethylstyrene and p-bromomethylstyrene. Preferably, the monomer A is selected from styrene.

[0017] According to an embodiment of the present invention, the thermoplastic elastomer copolymer includes a linear polystyrene-isobutylene-styrene (SIBS) triblock copolymer, a three-arm star polystyrene-isobutylene-styrene (SIBS) triblock copolymer;

[0018] Preferably, the linear polystyrene-isobutylene-styrene (SIBS) triblock copolymer has a structure as shown in formula (i), and the three-arm star polystyrene-isobutylene-styrene (SIBS) triblock copolymer has a structure as shown in formula (ii).

[0019]

[0020] wherein each x is the same or different and is independently selected from a number of 40-7000, preferably a number of 80-5000, for example, 80, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 2000, 3000, 4000 or 5000;

[0021] Each y is the same or different and is independently selected from a number in the range of 20-3000, preferably 50-2000, for example 50, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000 or 2000.

[0022] According to an embodiment of the present invention, the copolymer may be a thermosetting elastomer.

[0023] According to a preferred embodiment of the present invention, the second monomer of the thermosetting elastomer comprises a monomer A, which is selected from one, two or more of the following compounds: styrene; 1-10 Styrenes substituted with alkyl groups, such as α-methylstyrene, p-methylstyrene, m-methylstyrene, p-ethylstyrene, and p-tert-butylstyrene; Styrenes substituted with one or more halogens, such as p-chlorostyrene and p-bromostyrene; Styrenes substituted with one or more monohalogenated alkyls or polyhalogenated C 1-10 Alkyl-substituted styrenes, such as p-chloromethylstyrene and p-bromomethylstyrene;

[0024] as well as,

[0025] Monomer B is selected from one, two or more of the following compounds: phenyl and C 4-8 Cycloalkenyl-fused styrenes, such as 4-vinylbenzocyclobutene.

[0026] According to an exemplary embodiment of the present invention, the second monomer of the thermosetting elastomer includes styrene and 4-vinylbenzocyclobutene.

[0027] According to an embodiment of the present invention, in the second monomer, the molar ratio of monomer A to monomer B is (80-100):(0-20), preferably (90-100):(0-10), and preferably, the content of monomer B is not 0. For example, the molar ratio of monomer A to monomer B is 95:5.

[0028] According to an embodiment of the present invention, the thermosetting elastomer copolymer includes a linear poly(styrene-coblock-4-vinylbenzocyclobutene)-polyisobutylene-poly(styrene-coblock-4-vinylbenzocyclobutene) triblock copolymer (xSIBS), a three-arm star poly(styrene-coblock-4-vinylbenzocyclobutene)-polyisobutylene-poly(styrene-coblock-4-vinylbenzocyclobutene) triblock copolymer (xSIBS).

[0029] Preferably, the linear poly(styrene-coblock-4-vinylbenzocyclobutene)-polyisobutylene-poly(styrene-coblock-4-vinylbenzocyclobutene) triblock copolymer (xSIBS) has a structure as shown in formula (iii), and the three-arm star poly(styrene-coblock-4-vinylbenzocyclobutene)-polyisobutylene-poly(styrene-coblock-4-vinylbenzocyclobutene) triblock copolymer (xSIBS) has a structure as shown in formula (iv):

[0030]

[0031]

[0032] wherein each x is the same or different and is independently selected from a number of 40-7000, preferably 80-5000, for example 80, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 2000, 3000, 4000 or 5000;

[0033] Each y is the same or different and is independently selected from a number in the range of 20-3000, preferably 50-2000, for example 50, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000 or 2000.

[0034] Each m is the same or different and is independently selected from a number of 0-10, preferably 0-1, for example 0.01, 0.02, 0.03, 0.04, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 or 1.

[0035] According to an embodiment of the present invention, the Mn of the copolymer may be 4.0×10 3 to 5.0×10 5 , for example 2.0×10 4 to 2.0×10 5 .

[0036] According to an embodiment of the present invention, the molecular weight distribution coefficient Mw / Mn of the copolymer may be 1.10 to 2.50, such as 1.10 to 2.00, for example 1.15 to 1.40, preferably 1.17 to 1.36.

[0037] According to an embodiment of the present invention, in the copolymer, the content of the second monomer is selected from 5wt% to 50wt%, for example, its content can be selected from 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt%, 11wt%, 12wt%, 13wt%, 14wt%, 15wt%, 16wt%, 17wt%, 18wt%, 19wt%, 20wt%, 21wt%, 22wt%, 23wt%, 24wt% t%, 25wt%, 26wt%, 27wt%, 28wt%, 29wt%, 30wt%, 31wt%, 32wt%, 33wt%, 34wt%, 35wt%, 36wt%, 37wt %, 38wt%, 39wt%, 40wt%, 41wt%, 42wt%, 43wt%, 44wt%, 45wt%, 46wt%, 47wt%, 48wt%, 49wt% or 50wt%.

[0038] According to an embodiment of the present invention, in the copolymer, when monomer A is present and monomer B is absent, the total content of the second monomer is 20 wt % to 50 wt %.

[0039] According to an embodiment of the present invention, in the copolymer, when monomers A and B are present at the same time, the content of the second monomer is 5 wt % to 50 wt %.

[0040] According to an embodiment of the present invention, in the copolymer, the molecular weight of the first monomer segment can be 2,000 to 400,000, for example, 2,000, 5,000, 10,000, 50,000, 100,000, 150,000, 200,000, 250,000, 300,000, 350,000 or 400,000; the molecular weight of the second monomer segment can be in the range of 2,000 to 300,000, for example, 2,000, 5,000, 10,000, 50,000, 100,000, 150,000, 200,000, 250,000 or 300,000.

[0041] According to a preferred embodiment of the present invention, the mass percentage of gel in the copolymer is below 5 wt%, preferably below 5 wt%, for example, below 3 wt%, below 2 wt%, below 1 wt%, below 0.5 wt%, below 0.4 wt%, below 0.3 wt%.

[0042] % or less, 0.2 wt% or less, or 0.1 wt% or less.

[0043] According to an embodiment of the present invention, the elongation at break of the thermoplastic elastomer copolymer is 200% to 1100%, and the ultimate tensile strength is 4 MPa to 30 MPa.

[0044] According to an embodiment of the present invention, the elongation at break of the thermosetting elastomer copolymer is 200% to 1100%, and the ultimate tensile strength is 4.5 MPa to 50 MPa.

[0045] The present invention also provides a method for preparing a copolymer, preferably a method for preparing the copolymer as described above, such as a method for preparing the thermoplastic elastomer or the thermosetting elastomer, the preparation method comprising copolymerizing a first monomer and a second monomer in an initiator system to obtain the copolymer, such as the thermoplastic elastomer or the thermosetting elastomer, wherein the first monomer and the second monomer have the definitions described above.

[0046] Preferably, the first monomer is added to the initiator system in batches.

[0047] According to an embodiment of the present invention, the initiator system comprises at least one initiator, for example selected from a main initiator or a combination of a main initiator and a co-initiator.

[0048] According to an embodiment of the present invention, the primary initiator is selected from at least one of a bifunctional initiator and a multifunctional initiator. Exemplarily, the bifunctional initiator is used to prepare a linear polymer. Exemplarily, the multifunctional initiator is used to prepare a three-arm star polymer.

[0049] According to an embodiment of the present invention, the bifunctional initiator has two functional groups which are the same as or different from each other.

[0050] Preferably, the bifunctional initiator includes but is not limited to at least one selected from the following: p-cumyl alcohol, p-cumyl chloride, 1,3-bis(2-chloroisopropyl)benzene, 5-tert-butyl-1,3-bis(2-chloroisopropyl)benzene, 1,3-bis(2-methoxyisopropyl)benzene or 5-tert-butyl-1,3-bis(2-methoxyisopropyl)benzene.

[0051] According to an embodiment of the present invention, the multifunctional initiator has three or more functional groups that are identical to each other, or has three or more functional groups, at least one of which is different from the other functional groups.

[0052] Preferably, the multifunctional initiator includes but is not limited to at least one selected from the following: 1,3,5-tricumyl alcohol, 1,3,5-tris(2-chloroisopropyl)benzene or 1,3,5-tris(2-methoxyisopropyl)benzene.

[0053] According to an embodiment of the present invention, the main initiator is selected from at least one of the compounds represented by the following formula (A):

[0054]

[0055] wherein X is selected from tBu (tert-butyl), iPr (isopropyl), OMe (methoxy), 2-methoxyisopropyl, 2-chloroisopropyl, NO2, Cl, Br, I or H;

[0056] Each Y is the same or different and is independently selected from H, NO2, isopropyl or tert-butyl;

[0057] Z is selected from H, NO2 or tert-butyl;

[0058] R is selected from Cl, methyl (—Me) or methoxy (—OMe).

[0059] According to an embodiment of the present invention, the compound represented by formula (A) can be selected from compounds 1-22 having the following groups X, Y, Z and R:

[0060]

[0061] According to an embodiment of the present invention, when X is tBu, Y is H, Z is H, and R is Me, the compound represented by formula (A) is compound 1, i.e. 5-tert-butyl-1,3-di(2-chloroisopropyl)benzene.

[0062] According to an embodiment of the present invention, when X is ClC(CH3)2-, Y is H, Z is H, and R is Cl, the compound represented by formula (A) is compound 21, namely 1,3,5-tris(2-chloroisopropyl)benzene.

[0063] According to an embodiment of the present invention, when X is CH3OC(CH3)2-, Y is H, Z is H, and R is OMe, the compound represented by formula (A) is compound 22, namely 1,3,5-tris(2-methoxyisopropyl)benzene.

[0064] According to an embodiment of the present invention, the method for preparing the copolymer includes a cationic polymerization reaction. For example, a first monomer is added to the initiator system in batches to initiate polymerization, and then a second monomer is added for copolymerization to prepare the copolymer.

[0065] According to an embodiment of the present invention, the copolymer is prepared by first adding a first portion of the first monomer to the initiator system, then adding a second portion of the first monomer, and then adding the second monomer.

[0066] According to an embodiment of the present invention, an exemplary method for adding the first monomer in batches may include: first, adding a first portion of the first monomer to the initiator system to initiate polymerization to form stable primary active centers; then, adding a second portion of the first monomer to produce a polyisomonoolefin containing multiple active chain ends. The inventors have discovered that this method of adding the first monomer in batches effectively avoids severe chain transfer and chain termination reactions caused by excessive exothermic concentration.

[0067] Preferably, the amount of the first monomer added in the first portion is less than the amount of the first monomer added in the second portion. Further preferably, the first monomer in the first portion accounts for less than 40 wt% of the total mass of the first monomer, for example, 3 wt% to 40 wt%, preferably 10 wt% to 30 wt%; and the second portion of the first monomer is the remainder of the first monomer excluding the first monomer in the first portion.

[0068] According to an embodiment of the present invention, the conversion rate of the second monomer reaches 50 wt % to 100 wt %.

[0069] According to an embodiment of the present invention, the preparation method is carried out in the presence of a solvent. The solvent is selected from at least one of chloroalkane, methylcyclohexane or cyclohexane.

[0070] Preferably, the chlorinated alkanes are selected from mono- or poly-chlorinated methanes.

[0071] Furthermore, the chloromethane is selected from at least one of monochloromethane, dichloromethane or chloroform.

[0072] Further preferably, the solvent system is selected from a mixed solvent. Exemplarily, the mixed solvent is selected from cyclohexane and methyl chloride, or hexane and methyl chloride.

[0073] According to an embodiment of the present invention, preferably, in order to increase the participation of the second monomer styrene and its derivatives in block polymerization, the second monomer is provided in the form of a second monomer solution.

[0074] Preferably, the second monomer solution is added at a flow rate of 0.1 to 10 mL / s, for example, by controlling the flow rate through a metering pump or a separatory funnel, thereby reducing heat release per unit time, ensuring uniform heat release during the reaction, and avoiding side reactions.

[0075] According to an embodiment of the present invention, the initiator system further comprises a third component.

[0076] According to a preferred embodiment of the present invention, the initiator system further comprises a proton scavenger.

[0077] Preferably, the third component is selected from aromatic compounds having P-π conjugation.

[0078] Preferably, the aromatic compound is selected from at least one of aromatic esters, aromatic ethers or aromatic ketones.

[0079] More preferably, the aromatic ketone is selected from at least one of benzophenone, acetophenone, 2,4-dimethylacetophenone, and phenylacetone.

[0080] More preferably, the aromatic ether is at least one selected from anisole, phenethyl ether, diphenyl ether, p-ethyl phenethyl ether, n-butyl phenethyl ether, p-tert-butyl phenethyl ether, and the like.

[0081] Further preferably, the aromatic ester is selected from at least one of methyl benzoate, ethyl benzoate, ethyl phenylacetate, dimethyl terephthalate, diethyl terephthalate, diethyl terephthalate, diethyl isophthalate, diethyl phthalate, dibutyl terephthalate, 2,6-dimethyl diethyl terephthalate, dimethyl phthalate, diethyl phthalate, and diisooctyl phthalate.

[0082] Preferably, the proton scavenger is selected from tertiary amine compounds, such as substituted or unsubstituted aromatic tertiary amine compounds, examples of which can be selected from at least one of 2,6-di-tert-butylpyridine, 2,6-di-tert-butyl-4-methylpyridine or 2,4,6-tri-tert-butylpyridine.

[0083] According to an embodiment of the present invention, the initiator system further comprises a coinitiator.

[0084] Preferably, the co-initiator is selected from at least one of titanium tetrachloride, ferric chloride, boron trifluoride, boron trichloride, gallium trichloride, aluminum chloride, and alkylaluminum chloride (such as monoethylaluminum dichloride or triethylaluminum trichloride).

[0085] According to an embodiment of the present invention, the co-initiator can be added to the initiator system after the first part of the first monomer is added to initiate the polymerization reaction of the first part of isobutylene.

[0086] Furthermore, the mass fraction of the total of the first monomer and the second monomer raw materials in the total reaction system is 5wt% to 45wt%.

[0087] Furthermore, when preparing a thermosetting elastomer, the molar ratio of monomer A (such as styrene) to monomer B (such as 4-vinylbenzocyclobutene) in the second monomer is (80-100):(0-20), preferably (90-100):(0-10), for example (90-100):(1-10); wherein, in the molar ratio of monomer A to monomer B, when the ratio value of monomer A is 90-100, it can be selected from 90, 91, 92, 93, 94, 96, 97, 98, 99, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, 300, 310, 320, 330, 340, 350, 360, 370, 380, 390, 400, 410, 420, 430, 440, 450, 460, 470, 480, 490, 500, 510, 520, 530, 540, 550, 560, 570, 580, 590, 610, 620, 630, 640, 650, 660, 670, 680, 690, 710, 720, 730, 740, 750, 760, 770, 780, 790, 80 When the ratio of monomer A to monomer B is 0 to 10, it can be selected from 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5 or 10.0. As an example, the molar ratio of monomer A to monomer B can be 95:5.

[0088] According to an embodiment of the present invention, in the initiator system, when the third component is present, the molar ratio of the third component to the main initiator is (0-10):1, for example, 0:1, 0.1:1, 0.2:1, 0.3:1, 0.4:1, 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1.0:1, 1.5:1, 2.0:1, 2.5:1, 3.0:1, 3.5:1, 4.0:1, 4.5:1, 5.0:1, 5.5:1, 6.0:1, 6.5:1, 7.0:1, 7.5:1, 8.0:1, 8.5:1, 9.0:1, 9.5:1 or 10.0:1.

[0089] According to an embodiment of the present invention, in the initiator system, when a co-initiator is present, the molar ratio of the main initiator to the co-initiator is 1:(2-50), for example, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:15, 1:20, 1:25, 1:30, 1:35, 1:40, 1:45, and 1:50.

[0090] According to an embodiment of the present invention, the molar ratio of the main initiator to the first monomer is 1:(40-7000), for example 1:50, 1:100, 1:200, 1:500, 1:1000, 1:1500, 1:2000, 1:2500, 1:3000, 1:3500, 1:4000, 1:4500, 1:5000, 1:5500, 1:6000, 1:6500 or 1:7000.

[0091] According to an exemplary embodiment of the present invention, when a proton scavenger is present, the molar ratio of the proton scavenger to the main initiator in the initiator system is (0-5):1, for example, 0.1:1, 0.2:1, 0.3:1, 0.4:1, 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1.0:1, 1.5:1, 2.0:1, 2.5:1, 3.0:1, 3.5:1, 4.0:1, 4.5:1 or 5.0:1.

[0092] According to an embodiment of the present invention, in the preparation method, the temperature range of the copolymerization reaction is -100°C to -50°C, preferably -90°C to -50°C, for example -90°C, -80°C, -70°C, -60°C or -50°C.

[0093] According to an embodiment of the present invention, the mass percentage of gel in the copolymer obtained by the preparation method is less than 5wt%, preferably less than 5wt%, for example, less than 3wt%, less than 2wt%, less than 1wt%, less than 0.5wt%, less than 0.4wt%, less than 0.3wt%, less than 0.2wt% or less than 0.1wt%.

[0094] According to an embodiment of the present invention, the preparation method forms a stable linear and / or star-shaped polymer structure.

[0095] The inventors unexpectedly discovered that styrene and its derivatives, due to their electron-rich structure, are susceptible to nucleophilic attack by carbocations, resulting in alkylation reactions (as shown in the reaction process of Reaction Equation V below). This results in severe crosslinking between macromolecular chains, thereby forming an insoluble gel in the system. For example, the styrene content in the block copolymer disclosed in CN201710177847.0 does not exceed 20wt%. This is because in the process of this document, if the styrene content in the block copolymer is further increased, intermolecular crosslinking is likely to occur in the later stages of polymerization, forming a high-content gel. The reaction mechanism is shown in Reaction Equation V below.

[0096]

[0097] The present invention has found that using at least one selected from aromatic esters, aromatic ethers or aromatic ketones as the third component, or combining the third component with a proton scavenger, can effectively reduce the gel content generated during copolymerization, thereby effectively improving the conversion rate of the second monomer styrene and its derivatives participating in the reaction, and can also reduce the charge of the active center of the carbocation and stabilize the active center of the carbocation.

[0098] According to an embodiment of the present invention, 4-vinylbenzocyclobutene is mixed with styrene as a second monomer, thereby copolymerizing 4-vinylbenzocyclobutene units into the polystyrene-based hard segment of SIBS to produce a thermosetting elastomer. The addition of at least one of aromatic esters, aromatic ethers, or aromatic ketones as a third component, or the combination with a proton scavenger, effectively addresses the difficulty of 4-VBCB in copolymerization and its resistance to copolymerization with the first monomer during block polymerization. Subsequent thermal crosslinking (as shown in the reaction process shown in Reaction Scheme VI below) significantly enhances the material's mechanical properties.

[0099]

[0100] The present invention also provides an initiator having a structure represented by formula (A) as described above, such as compound 1-22 described above.

[0101] The present invention also provides a method for preparing an initiator, which specifically comprises the following steps:

[0102] (1) Compound B is subjected to an esterification reaction with methanol in concentrated sulfuric acid to produce an intermediate product B-1;

[0103] (2) reacting the intermediate product B-1 with a Grignard reagent in an organic solvent to produce the intermediate product B-2;

[0104] (3) acidifying the intermediate product B-2 with methanol to obtain compound A, or

[0105] (4) Dry hydrogen chloride gas is introduced into a solution of intermediate product B-2 in dichloromethane to obtain compound A.

[0106]

[0107] Wherein, in compound B, X' is selected from tBu, iPr, OMe, -COOH, NO2, Cl, Br, I or H;

[0108] In intermediate B-1, X" is selected from tBu, iPr, OMe, -COOMe, NO2, Cl, Br, I or H;

[0109] In intermediate B-2, X'' is selected from tBu, iPr, OMe, -C(CH3)2OH, NO2, Cl, Br, I or H;

[0110] X, Y, Z, and R have the meanings as described above.

[0111] According to an embodiment of the present invention, the preparation method is preferably carried out under an atmosphere inert to the reaction, such as a nitrogen atmosphere.

[0112] According to an embodiment of the present invention, in step (2), the Grignard reagent is selected from CH3MgBr and / or CH3MgI.

[0113] According to an embodiment of the present invention, in step (2), the organic solvent comprises at least one selected from tetrahydrofuran, 2-methyltetrahydrofuran, and cyclopentyl methyl ether.

[0114] Preferably, the organic solvent further comprises an optional aromatic hydrocarbon solvent, such as benzene or toluene. For example, the aromatic hydrocarbon solvent accounts for 0% to 50% by volume of the organic solvent. When present, the aromatic hydrocarbon solvent accounts for 1% to 50% by volume of the organic solvent, such as 1%, 2%, 3%, 4%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45% or 50%.

[0115] According to an embodiment of the present invention, in step (2), the reaction temperature is 0°C to 40°C.

[0116] According to an embodiment of the present invention, in step (3), the acidification reaction is carried out in the presence of an acidification catalyst. Preferably, the acidification catalyst is selected from sulfuric acid.

[0117] According to an embodiment of the present invention, in the preparation method, the intermediate products B-1 and B-2 of the reaction process are subjected to extraction, washing, recrystallization and drying processes, which improves the difficult problems of the preparation and post-processing process, and the product purity is at least 95%.

[0118] According to an embodiment of the present invention, in the preparation method, steps (2) and (3) preferably include a quenching step. The quenching step can be carried out by slowly adding the terminator dropwise first and then pouring the terminator to avoid a violent exothermic reaction that affects the quality of the product. Preferably, the terminator is selected from an aqueous sodium sulfite solution and / or an ammonium chloride solution, preferably a saturated sodium sulfite solution and / or a saturated ammonium chloride solution.

[0119] According to an embodiment of the present invention, in the preparation method, in step (4), the dry hydrogen chloride gas is continuously introduced for 12 to 48 hours. Preferably, in step (4), the tail gas is slowly absorbed with an alkaline aqueous solution to prevent environmental pollution, such as an aqueous sodium hydroxide solution.

[0120] According to an embodiment of the present invention, in the preparation method, when X' in B is selected from tBu, iPr, OMe, NO2, Cl, Br, I or H, B can be obtained by oxidizing B' with potassium permanganate.

[0121]

[0122] According to an exemplary embodiment of the present invention, the preparation method of compound 1-20 specifically comprises the following steps:

[0123] (1) SM-0 is oxidized by adding acidic potassium permanganate to generate product SM-01;

[0124] (2) SM-01 reacts with methanol in concentrated sulfuric acid to form product SM-02;

[0125] (3) SM-02 reacts with Grignard reagent to produce product SM-03;

[0126] (4) Dry hydrogen chloride gas is introduced into a dichloromethane solution of SM-03 to obtain product SM-04; wherein SM-04 is selected from any one of compounds 1-20;

[0127]

[0128] Wherein, X, Y, and Z have the meanings as described above;

[0129] IPA stands for isopropyl alcohol, THF stands for tetrahydrofuran, and DCM stands for dichloromethane.

[0130] According to an exemplary embodiment of the present invention, the preparation method of compound 21-22 may include the following steps:

[0131] (1) Ⅰ reacts with methanol in concentrated sulfuric acid to produce product Ⅱ;

[0132] (2) Ⅱ undergoes Grignard reaction with Grignard reagent in a solvent to generate product Ⅲ;

[0133] (3) III is reacted with concentrated sulfuric acid in methanol to produce product IV, i.e., compound 22; or dry hydrogen chloride gas is introduced into a dichloromethane solution of III to obtain product V, i.e., compound 21;

[0134]

[0135] The present invention also provides a method for preparing the above-mentioned compound B-2, comprising subjecting compound B-1 to a Grignard reaction with a Grignard reagent in an organic solvent to prepare compound B-2, wherein the organic solvent and the Grignard reagent have the meanings as described above.

[0136] The present invention also provides use of an organic solvent comprising at least one selected from tetrahydrofuran, 2-methyltetrahydrofuran, and cyclopentyl methyl ether in the preparation of compound B2.

[0137] Preferably, the organic solvent further comprises an aromatic hydrocarbon solvent, such as benzene or toluene. For example, the toluene accounts for 0% to 50% of the volume of the organic solvent.

[0138] The present invention also provides the use of the copolymer (such as a thermoplastic elastomer or a thermosetting elastomer). For example, the copolymer can be used in asphalt modifiers, medical fields such as medical materials, 5G optical fiber protective layers or hot melt adhesives, for example, as an elastomer in asphalt modifiers, medical materials, 5G optical fiber protective layers or hot melt adhesives.

[0139] The medical material can be selected from materials such as glaucoma catheters (drainage tubes), intracorneal contact lenses, intraocular lenses, drug release carriers, artificial blood vessels, and tissue fillers.

[0140] Definitions and Explanations of Terms

[0141] Unless otherwise indicated, the definitions of groups and terms in this specification and claims, including definitions used as examples, exemplary definitions, preferred definitions, definitions in tables, and definitions of specific compounds in the Examples, may be arbitrarily combined and coupled with one another. The resulting group definitions and compound structures shall fall within the scope of the description of this specification.

[0142] Unless otherwise indicated, the numerical ranges described in this specification and claims are equivalent to describing at least each specific integer value therein. For example, the numerical range "1-10" is equivalent to describing each integer value in the numerical range "1-10", namely 1, 2, 3, 4, 5, 6, 7, 8, 9, 10. In addition, when certain numerical ranges are defined as "numbers", it should be understood that the two endpoints of the range, each integer in the range, and each decimal in the range are described. For example, "a number from 1 to 10" should be understood as describing not only each integer of 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10, but also at least the sum of each integer therein and 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, respectively.

[0143] It should be understood that when describing one or more, "plurality" should refer to more than two, for example, an integer greater than or equal to 2, such as 3, 4, 5, 6, 7, 8, 9 or 10.

[0144] The term "halogen" denotes fluorine, chlorine, bromine and iodine, preferably chlorine or bromine.

[0145] The term "C 1-10 "Alkyl" is understood to mean a straight-chain or branched saturated monovalent hydrocarbon group having 1 to 10 carbon atoms. For example, "C 1-6The term "alkyl" refers to straight-chain and branched alkyl groups having 1, 2, 3, 4, 5 or 6 carbon atoms. The alkyl group is, for example, methyl, ethyl, propyl, butyl, pentyl, hexyl, isopropyl, isobutyl, sec-butyl, tert-butyl, isopentyl, 2-methylbutyl, 1-methylbutyl, 1-ethylpropyl, 1,2-dimethylpropyl, neopentyl, 1,1-dimethylpropyl, 4-methylpentyl, 3-methylpentyl, 2-methylpentyl, 1-methylpentyl, 2-ethylbutyl, 1-ethylbutyl, 3,3-dimethylbutyl, 2,2-dimethylbutyl, 1,1-dimethylbutyl, 2,3-dimethylbutyl, 1,3-dimethylbutyl or 1,2-dimethylbutyl, or the like or isomers thereof.

[0146] The term "halogenated C 1-10 "Alkyl" means a C 1-10 Unless otherwise indicated, C 1-10 Alkyl has the meaning given above.

[0147] The term "vinyl arene" means an aromatic hydrocarbon substituted with a vinyl group.

[0148] The term "aromatic hydrocarbon" is understood to mean a monocyclic, bicyclic (such as fused, bridged, spiro) or tricyclic hydrocarbon ring having aromaticity, which may be a single aromatic ring or multiple aromatic rings fused together, preferably "C 6-20 Aromatics" or "C 6-14 Aromatic hydrocarbons". For example, "C 6-14 "Aromatic hydrocarbon" is understood to mean preferably a monovalent aromatic or partially aromatic monocyclic, bicyclic or tricyclic hydrocarbon ring ("C 6-14 Arenes"), particularly those having a ring of 6 carbon atoms ("C6 arenes"), such as benzene. When the C 6-20 When the aromatic hydrocarbon is substituted, it may be monosubstituted or polysubstituted. Furthermore, there is no limitation on the substitution site, and for example, substitution may be at the ortho, para, or meta position.

[0149] Beneficial effects

[0150] 1. The inventors unexpectedly discovered that the present invention significantly reduces the gel content of polyisocyanate copolymers (such as thermoplastic / thermosetting elastomers). The prepared copolymers have controllable structure, molecular weight, and comonomer ratio, excellent mechanical properties, a narrow molecular weight distribution, and excellent biocompatibility. They have broad application prospects. For example, they can be used as raw materials for the preparation of controlled drug release, extracorporeal catheters, implantable stents, etc., such as ophthalmic implant materials, vascular stent coatings, glaucoma catheters, and heart valves.

[0151] 2. The present invention adds a third component to the initiator system of the polyisomonoolefin copolymer to form stable primary active centers. Furthermore, by controlling the feed rate of the second monomer, gelation during block polymerization is effectively suppressed, the conversion rate of styrene and its derivatives in the reaction is increased, and stable linear and star-shaped structures are formed.

[0152] 3. The present invention copolymerizes 4-vinylbenzocyclobutene (4-VBCB) units into the polystyrene-based hard segment of SIBS to produce a poly(styrene-coblock-4-vinylbenzocyclobutene)-polyisobutylene-poly(styrene-coblock-4-vinylbenzocyclobutene) triblock thermosetting elastomeric copolymer. This overcomes the difficulty of 4-VBCB in copolymerization due to its low activity. Subsequent thermal crosslinking significantly improves the ultimate tensile strength of the material. Furthermore, the hardness of the material and its strength after thermal crosslinking can be controlled by adjusting the amount of 4-VBCB used.

[0153] 4. The present invention uses a living / controllable cationic polymerization system, in an initiator system, to prepare a copolymer elastomer with polyisobutylene as a soft segment by batch addition. In the preparation method of the present invention, a first portion of low-concentration isobutylene is first initiated for polymerization to form a stable primary active center; a second portion of isobutylene monomer is then added to prepare a polyisobutylene containing multiple active chain ends, and then a second monomer, styrene and its derivatives are added to prepare a linear or three-arm star-shaped polystyrene-isobutylene-styrene triblock copolymer (SIBS), a linear or three-arm star-shaped poly(styrene-coblock-4-vinylbenzocyclobutene)-polyisobutylene-poly(styrene-coblock-4-vinylbenzocyclobutene) triblock copolymer (xSIBS). The present invention effectively avoids severe chain transfer and chain termination reactions caused by excessive exothermic concentration by adding isobutylene in batches, and the polymer molecular weight distribution is narrow, thereby obtaining a linear or three-arm star-shaped polymer with a controllable molecular structure.

[0154] 5. The present invention also provides a new method for preparing bifunctional and multifunctional main initiators by improving process conditions, which solves the potential danger of explosion when the solvent comes into contact with air in traditional format reactions and promotes the complete conversion of the product. In the preparation method of the main initiator, the present invention improves the difficult problems of the preparation and post-processing process, greatly improves production efficiency, and successfully scales up the main initiator preparation process to a scale that meets industrial production levels. By developing a series of new initiator derivatives, initiators for cationic polymerization with higher initiation efficiency and high purity have been prepared. The initiators of the present invention can be used to synthesize linear or three-arm star polymers with controllable molecular structures. BRIEF DESCRIPTION OF THE DRAWINGS

[0155] Figure 1This is the NMR image of the bifunctional initiator (Compound 1) of Preparation Example 1. DETAILED DESCRIPTION

[0156] The technical solutions of the present invention will be described in further detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanations of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are encompassed within the scope of protection that the present invention is intended to protect.

[0157] Unless otherwise specified, the raw materials and reagents used in the following examples are commercially available or can be prepared by known methods.

[0158] I. Preparation Example

[0159] Preparation Example 1 Preparation of bifunctional initiator (Compound 1)

[0160] SM-0, SM-1, SM-2, and SM-3 in this example below have the chemical structures described above, wherein when present, X is tBu, Y is H, Z is H, and R is Cl.

[0161] (1) IPA (isopropyl alcohol), water, and SM-0 were first added to a reactor in sequence; the temperature was then raised, and 3.0 kg of KMnO4 was added in batches, followed by reaction under reflux and stirring. After the reaction system cooled to room temperature, saturated sodium sulfite was added dropwise to terminate the reaction. The centrifuged liquid was collected, the solid was collected and air-dried, and then oven-dried to obtain the product SM-01.

[0162] (2) Methanol and SM-01 were added sequentially to a reaction vessel, heated to reflux, and concentrated sulfuric acid was then added dropwise. The reaction was allowed to proceed after the addition was complete. The system was then cooled to room temperature and centrifuged to obtain a white solid, which was then dried to obtain the white solid product SM-02.

[0163] (3) SM-02, 2-methyltetrahydrofuran, and toluene solvent (v:v = 60:40) were added sequentially to a reaction kettle. CH3MgBr was slowly added dropwise under nitrogen protection throughout the reaction. The reaction was stirred at room temperature. After the raw material conversion was complete, saturated ammonium chloride was added dropwise to quench the reaction. The aqueous phase was extracted once with ethyl acetate, and the organic phases were combined, washed, dried, and concentrated to obtain a crude white solid. The white solid was recrystallized to obtain SM-03 in a yield of 95%.

[0164] (4) SM-03 and dichloromethane were added to the reactor in sequence. Dry hydrogen chloride gas was continuously introduced into the reaction system, and the tail gas was slowly absorbed with a sodium hydroxide aqueous solution. The solid in the reaction system was filtered out, then washed with dichloromethane, and recrystallized to obtain a white solid final product SM-04. The initiator was obtained as compound 1, i.e., 5-tert-butyl-1,3-di(2-chloroisopropyl)benzene, with a yield of 92%.

[0165] Preparation Example 2 Preparation of trifunctional initiators (compounds 21, 22)

[0166] (1) In a 1000 mL single-necked flask, add 18 g (0.086 mol) of reactant I, 500 mL of anhydrous methanol, and 20 mL of concentrated sulfuric acid. In I, X is ClC(CH3)2-, Y is H, and Z is H. Turn on stirring and circulating cooling water, and react at room temperature. After the reaction is completed, seal the container and allow it to stand at low temperature. The product is filtered with a funnel to obtain a white solid, which is then fully dried to obtain product II with a yield of 90%.

[0167] (2) Grignard reaction: In a 1000 mL three-necked flask, add 16 g (0.063 mol) of II and 280 mL of THF. Stirring and circulating cooling water are started, and the reaction environment is maintained under a nitrogen atmosphere. 150 mL of methylmagnesium bromide is slowly added dropwise to the reaction system using a syringe to react. The product is then poured into a mixture of 280 g of crushed ice and 18 g of ammonium chloride for extraction and drying. Finally, recrystallization is performed to obtain product III with a yield of 93%.

[0168] (3) In a 250 mL single-necked flask, 14 g of III, 72.5 mL of methanol, and 0.0084 mL of concentrated sulfuric acid were added for reaction. After cooling, 100 mL of n-hexane was added. The supernatant was washed to neutrality and dried. Finally, product IV was recrystallized several times to obtain the compound 21, 5-tert-butyl-1,3-tris(2-chloroisopropyl)benzene, with a yield of 95%.

[0169] (4) Add III and dichloromethane to the flask in sequence, continue to pass dry hydrogen chloride gas into the reaction system, and slowly absorb the tail gas with aqueous sodium hydroxide solution. Filter the solid from the reaction system, wash the solid with dichloromethane, concentrate to obtain a solid, and recrystallize to obtain the white solid final product V, i.e., the compound 22, which is 1,3,5-tris(2-methoxyisopropyl)benzene, with a yield of 96%.

[0170] II. Examples

[0171] Example 1

[0172] A 4-liter low-temperature polymerization kettle was baked, evacuated, and filled with nitrogen, then cooled to -70°C. 40 ml of dichloromethane, 60 ml of hexane, 8 ml of isobutylene (1.25 M), 5 ml of 5-tert-butyl-1,3-bis(1-methoxy-1-methylethyl)benzene (0.1 M), and 0.1 M of ethyl benzoate were added to the reactor. 5 ml of titanium tetrachloride (0.4 M) was then added to initiate a small amount of isobutylene prepolymerization. Subsequently, a 1.57 ml (3 M) solution of the hard segment monomer styrene was added to the polymerization system at a controlled flow rate (0.1 mL / s) using a metering pump to initiate the second block polymerization. Finally, a small amount of methanol was added to terminate the reaction. The product was then freed of solvent and vacuum dried at 45°C to a constant weight, yielding thermoplastic elastomer 1.

[0173] Example 2

[0174] A 4-liter low-temperature polymerization kettle was baked, evacuated, and filled with nitrogen, then cooled to -80°C. Then, 40 ml of dichloromethane, 60 ml of methylcyclohexane, 25 ml of isobutylene (1.25 M), 5 ml of 5-tert-butyl-1,3-bis(1-methoxy-1-methylethyl)benzene (0.1 M), 0.1 M of acetophenone, and 0.1 M of anisole were added to the reactor. 5 ml of titanium tetrachloride (0.4 M) was then added to initiate isobutylene prepolymerization. Subsequently, 2.2 ml of 3 M styrene solution was added to the polymerization system at a controlled flow rate (0.1 mL / s) using a metering pump to initiate the second block polymerization. Finally, a small amount of methanol was added to terminate the reaction. The product was then freed of solvent and vacuum dried at 45°C to constant weight, yielding thermoplastic elastomer 2.

[0175] Example 3

[0176] A 4-liter low-temperature polymerization kettle was baked, evacuated, and filled with nitrogen, then cooled to -60°C. Then, 40 ml of dichloromethane, 60 ml of cyclohexane, 8 ml of isobutylene (1.25 M), 5 ml of 5-tert-butyl-1,3-bis(1-methoxy-1-methylethyl)benzene (0.1 M), 5 ml of 2,6-di-tert-butylpyridine (0.2 M), and 5 ml of ethyl benzoate (0.2 M) were added to the reactor. Then, 5 ml of titanium tetrachloride (0.4 M) was added to initiate isobutylene polymerization. Subsequently, 1.57 ml of a 3 M styrene solution was added to the polymerization system at a controlled flow rate (0.2 mL / s) using a metering pump to initiate the second block polymerization. Finally, a small amount of methanol was added to terminate the reaction. The product was then freed of solvent and vacuum dried at 45°C to constant weight, yielding thermoplastic elastomer 3.

[0177] Example 4

[0178] A 4-liter low-temperature polymerization kettle was baked, evacuated, and filled with nitrogen, then cooled to -80°C. 300 g of methyl chloride, 450 g of methylcyclohexane, 20 g of isobutylene, 0.0034 mol of 5-tert-butyl-1,3-bis(1-methoxy-1-methylethyl)benzene, 0.0034 mol of ethyl benzoate, and 2,4-dimethylacetophenone were added to the reactor. A small amount of isobutylene prepolymerization was initiated by the addition of 0.11 mol of boron trifluoride in etherate. A second portion of 120 g of isobutylene was then added in batches to continue the reaction. Subsequently, 120 g of p-tert-butylstyrene solution was added to the polymerization system using a metering pump at a controlled flow rate of 2 mL / s to initiate the second block polymerization. Finally, a small amount of methanol was added to terminate the reaction. The product was then freed of solvent and vacuum-dried at 45°C to constant weight, yielding thermoplastic elastomer 4.

[0179] Example 5

[0180] A 4-liter low-temperature polymerization kettle was baked, evacuated, and filled with nitrogen, then cooled to -70°C. 500 g of dichloromethane, 750 g of cyclohexane, 50 g of isobutylene, 0.0062 mol of 5-tert-butyl-1,3-bis(1-methoxy-1-methylethyl)benzene, 0.0032 mol of dimethyl terephthalate, and 0.012 mol of 2,6-di-tert-butylpyridine were added to the reactor. A small amount of isobutylene prepolymerization was initiated by the addition of 0.14 mol of boron trichloride in ether. A second portion of 170 g of isobutylene was then added in batches to continue the reaction. Subsequently, 200 g of styrene solution was added to the polymerization system at a controlled flow rate of 4 mL / s using a metering pump to initiate the second block polymerization. Finally, a small amount of methanol containing aqueous ammonia was added to terminate the reaction. The product was then desolventized and vacuum-dried at 45°C to constant weight, yielding thermoplastic elastomer 5.

[0181] Example 6

[0182] A 4-liter low-temperature polymerization kettle was baked, evacuated, and filled with nitrogen, then cooled to -50°C. 115 g of methyl chloride, 175 g of methylcyclohexane, 20 g of isobutylene, 0.0062 mol of 5-tert-butyl-1,3-bis(1-methoxy-1-methylethyl)benzene, 0.0032 mol of diethyl phthalate, and 0.0032 mol of p-tert-butylphenyl ethyl ether were added to the reactor. A small amount of isobutylene prepolymerization was initiated with 0.14 mol of titanium tetrachloride. A second portion of 100 g of isobutylene was then added in batches to continue the reaction. Subsequently, 94 g of styrene solution was added to the polymerization system at a controlled flow rate of 5 mL / s using a metering pump to initiate the second block polymerization. Finally, a small amount of methanol containing aqueous ammonia was added to terminate the reaction. The product was then desolventized and vacuum-dried at 45°C to constant weight, yielding thermoplastic elastomer 6.

[0183] Example 7

[0184] A 4-liter low-temperature polymerization kettle was baked, evacuated, and filled with nitrogen, then cooled to -90°C. 500 g of methyl chloride, 750 g of cyclohexane, 50 g of isobutylene, 0.0072 mol of 1,3,5-triisopropylchlorobenzene, 0.012 mol of acetophenone, and 0.0062 mol of 2,6-di-tert-butyl-4-methylpyridine were added to the reactor. A small amount of isobutylene prepolymerization was initiated by the addition of 0.186 mol of titanium tetrachloride. A second portion of 170 g of isobutylene was then added in batches and the reaction continued for 70 minutes. Subsequently, 270 g of p-methylstyrene solution was added to the polymerization system using a metering pump at a controlled flow rate of 2 mL / s to initiate the second block polymerization. Finally, a small amount of methanol was added to terminate the reaction. The product was then freed of solvent and vacuum-dried at 45°C to constant weight, yielding thermoplastic elastomer 7.

[0185] Example 8

[0186] A 4-liter low-temperature polymerization kettle was baked, evacuated, and filled with nitrogen, then cooled to -80°C. 130 g of dichloromethane, 300 g of methylcyclohexane, 20 g of isobutylene, 0.0034 mol of 1,3,5-tris(1-methoxy-1-methylethyl)benzene (i.e., Compound 22 in Preparation Example 2), and 0.0012 mol of phenethyl ether were added to the polymerization kettle. 0.136 mol of ferric chloride was then added to initiate a small amount of isobutylene prepolymerization. A second portion of 90 g of isobutylene was then added in batches to continue the reaction. Subsequently, 185 g of p-ethylstyrene solution was added to the polymerization system using a metering pump at a controlled flow rate (2 mL / s) to initiate the second block polymerization. Finally, a small amount of methanol was added to terminate the reaction. The product was then freed of solvent and vacuum dried at 45°C to constant weight to obtain thermoplastic elastomer 8.

[0187] Example 9

[0188] A 4-liter low-temperature polymerization kettle was baked, evacuated, and filled with nitrogen, then cooled to -50°C. 160 g of dichloromethane, 240 g of cyclohexane, 30 g of isobutylene, 0.003 mol of 5-tert-butyl-1,3-di(2-chloroisopropyl)benzene (i.e., Compound 1 from Preparation Example 1), 0.0017 mol of 2,6-di-tert-butylpyridine, and 0.0017 mol of phenethyl ether were added to the polymerization kettle. A small amount of isobutylene prepolymerization was initiated, and a second portion of 70 g of isobutylene was added in batches to continue the reaction. Subsequently, 130 g of styrene solution was added to the polymerization system using a metering pump at a controlled flow rate (2 mL / s) to initiate the second block polymerization. Finally, a small amount of methanol was added to terminate the reaction. The product was then freed of solvent and vacuum dried at 45°C to constant weight to obtain thermoplastic elastomer 9.

[0189] Example 10

[0190] A 4-liter low-temperature polymerization kettle was baked, evacuated, and filled with nitrogen, then cooled to -60°C. 240 g of methyl chloride, 240 g of methylcyclohexane, 25 g of isobutylene, 0.0025 mol of the trifunctional initiator 1,3,5-tris(2-chloroisopropyl)benzene (i.e., Compound 21 in Preparation Example 2), 0.0012 mol of anisole, 0.0012 mol of benzophenone, and 0.002 mol of 2,4,6-tri-tert-butylpyridine were added to the polymerization kettle. A small amount of isobutylene prepolymerization was initiated by adding 0.096 mol of boron trifluoride in ethereal solution. A second portion of 80 g of isobutylene was then added to continue the reaction. Subsequently, 160 g of p-tert-butylstyrene solution was added to the polymerization system at a controlled flow rate (2 mL / s) using a metering pump to initiate the second block polymerization. Finally, a small amount of methanol was added to terminate the reaction. The product was then freed of solvent and vacuum dried at 45°C to constant weight, yielding thermoplastic elastomer 10.

[0191] Example 11

[0192] A 4-liter low-temperature polymerization kettle was baked, evacuated, and filled with nitrogen, then cooled to -80°C. 400 g of dichloromethane, 930 g of methylcyclohexane, 50 g of isobutylene, 0.0062 mol of 5-tert-butyl-1,3-bis(1-methoxy-1-methylethyl)benzene, and 0.0032 mol of methyl benzoate were added to the reactor. A small amount of isobutylene prepolymerization was initiated by adding 0.14 mol of boron trichloride in ether. A second portion of 170 g of isobutylene was then added in batches to continue the reaction. Subsequently, 200 g of α-methylstyrene solution was added to the polymerization system at a controlled flow rate (4 mL / s) using a metering pump to initiate the second block polymerization. Finally, a small amount of methanol containing aqueous ammonia was added to terminate the reaction. The product was then desolventized and vacuum-dried at 45°C to constant weight, yielding thermoplastic elastomer 11.

[0193] Example 12

[0194] A 4-liter low-temperature polymerization kettle was baked, evacuated, and filled with nitrogen, then cooled to -70°C. 400 g of dichloromethane, 930 g of methylcyclohexane, 60 g of isobutylene, 0.0062 mol of 5-tert-butyl-1,3-bis(1-methoxy-1-methylethyl)benzene, 0.005 mol of phenylethyl ether, and 0.005 mol of ethyl phenylacetate were added to the reactor. A small amount of isobutylene prepolymerization was initiated by the addition of 0.14 mol of boron trifluoride in etherate. A second portion of 170 g of isobutylene was then added in batches to continue the reaction. Subsequently, 200 g of styrene solution was added to the polymerization system at a controlled flow rate (2 mL / s) using a metering pump to initiate the second block polymerization. Finally, a small amount of methanol containing aqueous ammonia was added to terminate the reaction. The product was then desolventized and vacuum-dried at 45°C to constant weight, yielding thermoplastic elastomer 12.

[0195] Example 13

[0196] A 4-liter low-temperature polymerization kettle was used, which was baked, vacuumed, and filled with nitrogen and then refrigerated to -70°C. 100 ml of n-hexane / dichloromethane with a volume ratio of 60 / 40 was added as a solvent and mixed evenly. 2 ml of isobutylene, 5 ml (0.1 M) of 5-tert-butyl-1,3-di(2-chloroisopropyl)benzene (i.e., compound 1 of Preparation Example 1), and 5 ml of diisooctyl phthalate were added to the polymerization kettle. 5 ml (0.4 M) of boron trichloride ether solution was then added to initiate isobutylene prepolymerization. Then, a second portion of 6 ml of isobutylene was added in batches to continue the reaction. Subsequently, 1.57 ml (3 M) of hard segment monomer styrene and 0.16 ml (0.3 M) of 4-vinylbenzocyclobutene were added to the polymerization system using a metering pump to control the flow rate (0.1 mL / s) to initiate the second block polymerization. Finally, pre-cooled methanol containing a small amount of ammonia solution was added to terminate the polymerization. The product was then freed from the solvent and vacuum dried at 45°C to constant weight to obtain thermosetting elastomer 13.

[0197] Example 14

[0198] A 4-liter low-temperature polymerization kettle was baked, evacuated, and filled with nitrogen, then cooled to -80°C. 200 g of dichloromethane, 300 g of methylcyclohexane, 25 g of isobutylene, 0.003 mol of the trifunctional initiator 1,3,5-tris(2-chloroisopropyl)benzene, 0.0015 mol of diisooctyl phthalate, and 0.0015 mol of acetophenone were added to the reactor. A small amount of isobutylene prepolymerization was initiated by adding 0.14 mol of boron trifluoride in ethereal solution. A second portion of 160 g of isobutylene was then added in batches to continue the reaction. Subsequently, 170 g of styrene and 50 g of 4-vinylbenzocyclobutene solution were added to the polymerization system at a controlled flow rate of 1.5 mL / s using a metering pump to initiate the second block polymerization. Finally, precooled methanol containing a small amount of ammonia solution was added to terminate the polymerization. The product was then desolventized and vacuum-dried at 45°C to constant weight, yielding thermoset elastomer 14.

[0199] Example 15

[0200] A 4-liter low-temperature polymerization kettle was baked, evacuated, and filled with nitrogen, then cooled to -80°C. 300g of methyl chloride, 300g of methylcyclohexane, 25g of isobutylene, 0.003mol of the trifunctional initiator 1,3,5-tris(2-chloroisopropyl)benzene, 0.0015mol of anisole, and 0.0015mol of acetophenone were added to the reactor. A small amount of isobutylene prepolymerization was initiated by the addition of 0.14mol of titanium tetrachloride. A second portion of 160g of isobutylene was then added in batches to continue the reaction. Subsequently, 40g of styrene and 14g of a 4-vinylbenzocyclobutene solution were added to the polymerization system at a controlled flow rate of 1.5mL / s using a metering pump to initiate the second block polymerization. Finally, precooled methanol containing a small amount of ammonia solution was added to terminate the polymerization. The product was then desolventized and vacuum-dried at 45°C to constant weight, yielding thermoset elastomer 15.

[0201] Example 16

[0202] A 4-liter low-temperature polymerization kettle was baked, evacuated, and filled with nitrogen, then cooled to -80°C. 300 g of dichloromethane, 300 g of cyclohexane, 30 g of isobutylene, 0.003 mol of 5-tert-butyl-1,3-di(2-chloroisopropyl)benzene, 0.002 mol of anisole, and 0.002 mol of dibutyl terephthalate were added to the reactor. A small amount of isobutylene prepolymerization was initiated with 0.14 mol of ferric chloride. A second portion of 160 g of isobutylene was then added in batches to continue the reaction. Subsequently, 45 g of styrene and 20 g of a 4-vinylbenzocyclobutene solution were added to the polymerization system at a controlled flow rate of 1.5 mL / s using a metering pump to initiate the second block polymerization. Finally, precooled methanol containing a small amount of ammonia solution was added to terminate the polymerization. The product was then desolventized and vacuum-dried at 45°C to constant weight, yielding thermosetting elastomer 16.

[0203] III. Comparative Examples

[0204] Comparative Example 1a

[0205] Pour cold liquid into the vacuum glove box and cool to the polymerization temperature of -70°C. Add 100 ml of n-hexane / dichloromethane with a volume ratio of 60 / 40 as a solvent to the treated polymerization bottle and mix evenly. Then, add 5 ml (0.1 M) of the main initiator 5-tert-butyl-1,3-bis(1-methoxy-1-methylethyl)benzene, 5 ml (0.4 M) of the co-initiator titanium tetrachloride, and 5 ml (0.2 M) of the third component EtOAc to form an initiator system. After aging for 5 minutes, add 8 ml (1.25 M) of the intermediate monomer isobutylene. After reacting for 45 to 60 minutes, add 1.57 ml (3 M) of the hard segment monomer styrene and continue to react for 90 minutes. Finally, add methanol (CH3OH) based on the termination of the reaction. After terminating the reaction, remove the solvent from the product and vacuum dry it at 45°C to constant weight.

[0206] Comparative Example 2b

[0207] Pour cold liquid into the vacuum glove box and cool to the polymerization temperature of -80°C. Add 100 ml of n-hexane / dichloromethane with a volume ratio of 40 / 60 as a solvent to the treated polymerization bottle and mix evenly. Then, add 5 ml (0.1 M) of the main initiator 5-tert-butyl-1,3-bis(1-methoxy-1-methylethyl)benzene, 5 ml (0.4 M) of the co-initiator titanium tetrachloride, and 5 ml (0.2 M) of the proton scavenger DTBP (2,6-di-tert-butylpyridine) to form an initiator system for aging. After aging for 15 minutes, add 25 ml (1.25 M) of the intermediate monomer isobutylene. After reacting for 45 to 60 minutes, add 2.2 ml (3 M) of the hard segment monomer styrene and continue the reaction for 90 minutes. Finally, add methanol (CH3OH) until the reaction is terminated. After terminating the reaction, remove the solvent from the product and vacuum dry it at 45°C to constant weight.

[0208] Comparative Example 3c

[0209] Pour cold liquid into the vacuum glove box and cool to the polymerization temperature of -80°C. Add 100 ml of n-hexane / dichloromethane with a volume ratio of 60 / 40 as a solvent to the treated polymerization bottle and mix evenly. Then, add 5 ml (0.1 M) of the main initiator 5-tert-butyl-1,3-bis(2-methoxy-1-methylethyl)benzene, 5 ml (0.4 M) of the co-initiator titanium tetrachloride, and 5 ml (0.2 M) of the proton scavenger DTBP to form an initiator system for aging. After aging for 5 minutes, add 8 ml (1.25 M) of the intermediate monomer isobutylene. After reacting for 45 to 60 minutes, add 1.57 ml (3 M) of the hard segment monomer styrene and continue the reaction for 90 minutes. Finally, add methanol (CH3OH) until the reaction is terminated. After terminating the reaction, remove the solvent from the product and vacuum dry it at 45°C to constant weight.

[0210] Comparative Example 13d

[0211] A cold liquid was injected into the vacuum glove box and cooled to the polymerization temperature of -70°C. 100 ml of a solvent consisting of n-hexane / dichloromethane with a volume ratio of 60 / 40 was added to the treated polymerization bottle and mixed evenly. Then, an initiator system consisting of 5 ml (0.1 M) of the main initiator 5-tert-butyl-1,3-bis(2-methoxy-1-methylethyl)benzene, 5 ml (0.4 M) of the co-initiator boron trifluoride ether solution, and 5 ml (0.2 M) of the proton scavenger DTBP was added and aged. After aging for 5 minutes, 8 ml (1.25 M) of the intermediate monomer isobutylene was added. After reacting for 45 to 60 minutes, 1.57 ml (3 M) of the hard segment monomer styrene and 0.16 ml (0.3 M) of 4-vinylbenzocyclobutene were added and the reaction was continued for 90 minutes. Finally, methanol (CH3OH) was added until the reaction was terminated. After terminating the reaction, the product was freed from the solvent and dried in vacuo at 45°C to constant weight.

[0212] The test conditions and results of the above examples and comparative examples are summarized in Table 1, Table 2 and Table 3 below:

[0213] Table 1

[0214]

[0215] Table 2

[0216]

[0217] Table 3

[0218] Examples / Comparative Examples Elongation at break % Ultimate tensile strength MPa Example 1 793 20.1 Comparative Example 1a 602 15.5 Example 2 589 19.6 Comparative Example 2b 550 16.1 Example 3 700 18.2 Comparative Example 3c 603 17.8 Example 4 724 18.8 Example 5 662 16.3 Example 6 761 19.6 Example 7 635 15.6 Example 8 540 14.5 Example 9 610 14.8 Example 10 520 14.2 Example 11 630 19.2 Example 12 665 20.9 Example 13 698 21.2 Comparative Example 13d 563 17.6 Example 14 682 21.8 Example 15 320 9.6 Example 16 342 10.5

[0219] The above experimental data demonstrates that the present invention provides a method for preparing a copolymer having polyisobutylene as a soft segment, namely a thermoplastic / thermosetting elastomer, by batch addition using a living / controlled cationic polymerization system in the presence of an initiator system. In this method, a first portion of low-concentration isobutylene is first initiated for polymerization to form a stable primary active center; a second portion of isobutylene monomer is then added to prepare a polyisobutylene containing multiple active chain ends; styrene and its derivatives are then added to prepare a linear or three-arm star-shaped polystyrene-isobutylene-styrene triblock copolymer (SIBS) or a linear or three-arm star-shaped poly(styrene-coblock-4-vinylbenzocyclobutene)-polyisobutylene-poly(styrene-coblock-4-vinylbenzocyclobutene) triblock copolymer (xSIBS).

[0220] Furthermore, the polymers were tested according to the Petrochemical Industry Standard of the People's Republic of China SH / T 1050-2014 for determination of gel content of synthetic raw rubber. The mass percentage of gel in the copolymers prepared in the embodiments of the present invention was less than 5%.

[0221] The above embodiment effectively avoids serious chain transfer and chain termination reactions caused by excessive heat concentration by adding isobutylene in batches, thereby obtaining a linear or three-arm star polymer with controllable molecular structure.

[0222] The embodiment of the present invention adopts an initiator system to synthesize thermoplastic / thermosetting elastomers, which can form stable primary active centers. The initiator system includes a main initiator, a co-initiator, a third component and a proton scavenger, wherein the main initiator includes a bifunctional group or a multifunctional group. The above embodiment stabilizes the active center by adding a third component to the initiator system, effectively reduces the gel content in the copolymer, and increases the conversion rate of styrene and its derivatives participating in the reaction (the conversion rate of the second monomer reaches 50wt% to 100wt%), forming stable linear and star-shaped polymer structures. In the polymerization preparation process of the present invention, different mechanical properties can also be obtained by changing the first monomer / second monomer feed ratio and relative molecular weight, and the molecular weight distribution of the obtained product is narrow.

[0223] The present invention also provides a new method for preparing a primary initiator by improving process conditions, thereby resolving the potential danger of explosion of the solvent in traditional Format reactions upon contact with air and promoting the complete conversion of the product. In the method for preparing the primary initiator, the present invention further improves the purification process of the intermediate product in each process, further improving the difficulties in the preparation and post-processing process, greatly improving production efficiency, and successfully scaling up the primary initiator preparation process to a scale that meets industrial production levels. By developing a series of new initiator derivatives, initiators for cationic polymerization with higher initiation efficiency and higher purity have been prepared. The initiators of the present invention can be used to synthesize linear or three-arm star polymers with controllable molecular structures.

[0224] The copolymer can be used as raw material for the preparation of drug controlled release, extracorporeal catheters, implant stents, etc., for example, it can be used for ophthalmic implant materials, vascular stent coatings, glaucoma catheters, artificial blood vessels and heart valves.

[0225] The above describes exemplary embodiments of the present invention. However, the scope of protection of this application is not limited to the above embodiments. Any modifications, equivalent substitutions, improvements, etc. made by those skilled in the art within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A copolymer, characterized in that The preparation method of the copolymer comprises: adding a first monomer to the initiator system in batches to initiate polymerization, and then adding a second monomer for copolymerization to prepare the copolymer; Wherein, the temperature of the copolymerization reaction is -100°C to -50°C; In the preparation method, the first portion of the first monomer is first added to the initiator system, the second portion of the first monomer is then added, and then the second monomer is added to prepare the copolymer; the first portion of the first monomer accounts for less than 40 wt% of the total mass of the first monomer; the second monomer is provided by a second monomer solution, and the addition flow rate of the second monomer solution is 0.1 to 10 mL / s; The first monomer is selected from isobutylene, and the second monomer comprises monomer A and optionally monomer B; The monomer A is selected from one, two or more of the following compounds: styrene; 1-6 Alkyl-substituted styrenes; The monomer B is selected from phenyl and C 4-6 Cycloalkenyl-fused styrenes; The molar ratio of monomer A to monomer B is 80-100: 0-20; The initiator system comprises a third component, a main initiator, a co-initiator and a proton scavenger; The third component is selected from at least one of aromatic esters, aromatic ethers or aromatic ketones; The main initiator has a structure shown in the following formula (A): （A） wherein X is selected from tert-butyl, isopropyl, methoxy, 2-methoxyisopropyl, 2-chloroisopropyl, NO2, Cl, Br, I or H; each Y is the same or different and is independently selected from H, NO2, isopropyl or tert-butyl; Z is selected from H, NO2 or tert-butyl; R is selected from Cl, methyl or methoxy; The co-initiator is at least one selected from titanium tetrachloride, ferric chloride, boron trifluoride, boron trichloride, gallium trichloride, aluminum chloride, and alkyl aluminum chloride; The proton scavenger is selected from tertiary amine compounds.

2. The copolymer according to claim 1, wherein The first portion of the first monomer accounts for 3 wt % to 40 wt % of the total mass of the first monomer; The monomer A is selected from styrene, α-methylstyrene, p-methylstyrene, m-methylstyrene, p-ethylstyrene, and p-tert-butylstyrene; The monomer B is selected from 4-vinylbenzocyclobutene; The molar ratio of monomer A to monomer B is 90-100:0-10.

3. The copolymer according to claim 1, wherein The first portion of the first monomer accounts for 10 wt % to 30 wt % of the total mass of the first monomer.

4. The copolymer according to claim 1, wherein In the copolymer, the total content of the second monomer is 5 wt% to 50 wt%, wherein: When monomer A is present and monomer B is absent, the total content of the second monomer is 20 wt % to 50 wt %; When monomers A and B are present at the same time, the content of the second monomer is 5 wt % to 50 wt %.

5. The copolymer according to claim 1, wherein The aromatic ester is selected from at least one of methyl benzoate, ethyl benzoate, ethyl phenylacetate, dimethyl terephthalate, diethyl terephthalate, diethyl terephthalate, diethyl isophthalate, diethyl phthalate, dibutyl terephthalate, 2,6-dimethyl diethyl terephthalate, dimethyl phthalate, and diisooctyl phthalate; The aromatic ether is selected from at least one of anisole, phenethyl ether, diphenyl ether, p-ethyl phenethyl ether, n-butyl phenethyl ether, and p-tert-butyl phenethyl ether; The aromatic ketone is selected from at least one of benzophenone, acetophenone, 2,4-dimethylacetophenone and phenylacetone.

6. The copolymer according to claim 1, wherein The compound represented by formula (A) is selected from compounds 1-22 having the following groups X, Y, Z and R.

7. The copolymer according to claim 1, wherein The proton scavenger is selected from at least one of 2,6-di-tert-butylpyridine, 2,6-di-tert-butyl-4-methylpyridine, and 2,4,6-tri-tert-butylpyridine.

8. The copolymer according to claim 1, wherein In the preparation method, the mass fraction of the total of the first monomer and the second monomer raw materials in the total reaction system is 5wt% to 45wt%; The conversion rate of the second monomer reaches 50wt% to 100wt%; The molar ratio of the main initiator to the first monomer is 1:40~7000; The molar ratio of the third component to the main initiator is 0.1 to 10:1; When a co-initiator is present, the molar ratio of the main initiator to the co-initiator is 1:2 to 50; When a proton scavenger is present, the molar ratio of the proton scavenger to the primary initiator is 0 to 5:1; The preparation method is carried out in the presence of a solvent, and the solvent is selected from at least one of chloroalkane, methylcyclohexane or cyclohexane; The chlorinated alkane is selected from at least one of monochloromethane, dichloromethane or chloroform.

9. The copolymer according to claim 1, wherein The mass percentage of gel in the copolymer is less than 5wt%; The Mn of the copolymer is 4.0×10 3 to 5.0×10 5 , wherein the molecular weight of the first monomer segment is 2,000 to 400,000, and the molecular weight of the second monomer segment is 2,000 to 300,000; The molecular weight distribution coefficient Mw / Mn of the copolymer is 1.10 to 2.50; The copolymer is selected from the structure shown in formula (i), (ii), (iii) or (iv): (i) (ii) (iii) （ⅳ） wherein each x is the same or different and is independently selected from a number between 40 and 7000; Each y is the same or different and is independently selected from a number between 20 and 3000; Each m is the same or different and is independently selected from a number of 0-10.

10. Use of the copolymer according to any one of claims 1 to 9, characterized in that The copolymer is used as an asphalt modifier, a medical material, a 5G optical fiber protective layer, or an elastomer in a hot melt adhesive.

11. The use according to claim 10, characterized in that The medical material is selected from the group consisting of glaucoma catheters, intracorneal contact lenses, intraocular lenses, drug release carriers, artificial blood vessels, and tissue fillers.

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