Hydrogenated styrene-butadiene block copolymer and preparation method and application thereof
Technical Field
The invention belongs to the technical field of copolymers, relates to a hydrogenated styrene-butadiene block copolymer, and particularly relates to a hydrogenated styrene-butadiene block copolymer and a preparation method and application thereof.
Background
Hydrogenated styrene-butadiene block copolymers (SEBS) are novel thermoplastic elastomers prepared by selective hydrogenation of the unsaturated double bonds in styrene-butadiene block copolymers (SBS). After hydrotreating, unsaturated double bonds on the molecular chain of the SEBS product are greatly reduced, and the performance is obviously improved compared with SBS. The SEBS has thermoplasticity of SBS and high elasticity of rubber at normal temperature, shows fluidity of resin at high temperature and can be directly processed and molded. The SEBS main chain has high saturation, so that the SEBS main chain has better stability, heat resistance, oxidation resistance, weather resistance and solvent resistance than SBS, and has wider application range.
CN 106749783a discloses a curable crosslinked liquid rubber and a preparation method thereof, wherein the preparation method comprises the following steps: adding cyclohexane and tetrahydrofuran into a high-pressure reaction kettle, stirring and heating; then adding styrene, and injecting n-butyl lithium/cyclohexane solution by using an injector; after the temperature is raised, butadiene is pressed in from a metering tank, then styrene is added from an injection, the reaction liquid is pressed into a hydrogenation kettle, hydrogen is introduced, and the reaction is stopped; after half an hour, adding methyl o-methylbenzoate and a catalyst titanocene dichloride, introducing hydrogen, controlling the pressure, and supplementing methyl o-methylbenzoate every 1 hour; and discharging after the reaction is finished, filtering, adding ethanol for washing and separating, and evaporating to remove the solvent to obtain the hydrogenated polystyrene/butadiene/styrene liquid rubber with different polystyrene chain segment ratios. However, the preparation method provided by the invention is complicated in process, and the limited-use substance methyl o-methylbenzoate is adopted, so that certain harm is caused to the environment, and the hydrogenation degree of the product needs to be further improved.
Therefore, how to provide a preparation method of the hydrogenated styrene-butadiene block copolymer avoids using limited substances, further improves the hydrogenation degree of the product and simplifies the preparation process, and becomes a problem which needs to be solved by technical personnel in the field at present.
Disclosure of Invention
Aiming at the defects in the prior art, the invention aims to provide a hydrogenated styrene-butadiene block copolymer, a preparation method and application thereof.
In order to achieve the purpose, the invention adopts the following technical scheme:
in a first aspect, the present invention provides a method for preparing a hydrogenated styrene-butadiene block copolymer, the method comprising the steps of:
(1) preparing a base adhesive by utilizing a three-stage polymerization reaction, and then introducing hydrogen to terminate the polymerization reaction;
(2) mixing titanocene dichloride and n-butyllithium, and carrying out an aging reaction to obtain a hydrogenation catalyst;
(3) and (3) mixing the basic adhesive obtained in the step (1) and the hydrogenation catalyst obtained in the step (2), and introducing hydrogen to carry out hydrogenation reaction to prepare the hydrogenated styrene-butadiene block copolymer with the hydrogenation degree of more than or equal to 98%.
Wherein, the step (1) and the step (2) are not in sequence; and (4) adopting recycle hydrogen at the later stage of the hydrogenation reaction in the step (3).
According to the preparation method provided by the invention, before hydrogenation reaction, titanocene dichloride and n-butyl lithium are mixed for aging reaction, then the obtained hydrogenation catalyst is mixed with a basic glue phase for subsequent hydrogenation reaction, compared with the conventional method that n-butyl lithium is added firstly and then hydrogen is terminated, titanocene dichloride and phthalate substances are added for hydrogenation reaction, the stability of the hydrogenation catalyst is improved, and the use of co-catalyst phthalate in the hydrogenation process is avoided; in addition, the invention adopts the circulating hydrogen in the later stage of the hydrogenation reaction, increases the contact area of the hydrogenation catalyst and the hydrogen, improves the hydrogenation degree of the obtained product and simplifies the preparation process.
Preferably, the three-stage polymerization reaction in step (1) is specifically: adding styrene and an initiator into a system of a nonpolar hydrocarbon solvent to carry out a first-stage polymerization reaction; after the first-stage polymerization reaction is finished, adding butadiene into the system to perform a second-stage polymerization reaction; and after the second-stage polymerization reaction is finished, adding styrene into the system to perform a third-stage polymerization reaction.
Preferably, the initiator comprises n-butyllithium and/or sec-butyllithium.
Preferably, the non-polar hydrocarbon solvent comprises cyclohexane and/or n-hexane.
Preferably, the initiation temperature of the three-stage polymerization reaction in step (1) is 55-65 ℃, for example 55 ℃, 56 ℃, 57 ℃, 58 ℃, 59 ℃, 60 ℃, 61 ℃, 62 ℃, 63 ℃, 64 ℃ or 65 ℃, but is not limited to the recited values, and other values not recited in the range of the values are also applicable.
Preferably, the glue solution content of the base glue in step (1) is 8-15wt%, for example 8 wt%, 9 wt%, 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt% or 15wt%, but not limited to the recited values, and other values not recited in the range of the recited values are also applicable.
Preferably, the molecular weight of the base gum in step (1) is 30000-200000, such as 30000, 40000, 60000, 80000, 100000, 120000, 140000, 160000, 180000 or 200000, but not limited to the recited values, and other non-recited values within the range of values are equally applicable.
In the present invention, the base rubber obtained in step (1) is not particularly limited as long as it can satisfy the requirement that the solid content of the rubber solution is 8-15wt% and the molecular weight is 30000-200000.
Preferably, the three-stage polymerization reaction in the step (1) is performed in a polymerization kettle, and hydrogen is introduced to terminate the polymerization reaction after the obtained base rubber is transferred into a hydrogenation kettle.
Preferably, the aging reaction in step (2) is carried out in an aging kettle.
Preferably, the titanocene dichloride of step (2) is used in an amount of 0.2-0.3mmol per 100g of base gum, which may be, for example, 0.2mmol per 100g of base gum, 0.22mmol per 100g of base gum, 0.24mmol per 100g of base gum, 0.26mmol per 100g of base gum, 0.28mmol per 100g of base gum or 0.3mmol per 100g of base gum, but is not limited to the values listed, and other values not listed in this range of values are equally applicable.
Preferably, the molar ratio Li/Ti of titanocene dichloride and n-butyllithium in step (2) is 10 to 15, and may be, for example, 10, 10.5, 11, 11.5, 12, 12.5, 13, 13.5, 14, 14.5 or 15, but is not limited to the recited values, and other values not recited in this range are also applicable.
Preferably, the temperature of the aging reaction in step (2) is 25 to 75 ℃, for example 25 ℃, 30 ℃, 35 ℃, 40 ℃, 45 ℃, 50 ℃, 55 ℃, 60 ℃, 65 ℃, 70 ℃ or 75 ℃, but is not limited to the recited values, and other unrecited values within the range of the recited values are equally applicable.
Preferably, the hydrogenation reaction in step (3) is carried out in a hydrogenation kettle.
Preferably, the hydrogenation in step (3) is carried out at a hydrogenation temperature of 70-80 deg.C, such as 70 deg.C, 71 deg.C, 72 deg.C, 73 deg.C, 74 deg.C, 75 deg.C, 76 deg.C, 77 deg.C, 78 deg.C, 79 deg.C or 80 deg.C, but not limited to the recited values, and other values not recited in the recited values are also applicable.
Preferably, the hydrogenation pressure in the hydrogenation reaction in step (3) is 1 to 2.5MPa, and may be, for example, 1MPa, 1.1MPa, 1.3MPa, 1.5MPa, 1.7MPa, 1.9MPa, 2MPa, 2.1MPa, 2.3MPa or 2.5MPa, but is not limited to the values listed, and other values not listed in the range of the values are also applicable.
Preferably, the hydrogenation time of the hydrogenation reaction in step (3) is 90-180min, such as 90min, 100min, 110min, 120min, 130min, 140min, 150min, 160min, 170min or 180min, but is not limited to the recited values, and other values not recited in the range of the values are also applicable.
Preferably, the latter stage of the hydrogenation reaction in the step (3) specifically refers to the reaction stage after the hydrogenation temperature reaches a peak value.
As a preferred technical solution of the first aspect of the present invention, the preparation method comprises the steps of:
(1) preparing a base adhesive with 8-15wt% of solid glue solution and molecular weight of 30000-200000 in a polymerization kettle by utilizing three-stage polymerization with initiation temperature of 55-65 ℃, transferring the obtained base adhesive into a hydrogenation kettle, and introducing hydrogen to terminate the polymerization reaction; the three-stage polymerization reaction specifically comprises the following steps: adding styrene and an initiator into a system of a nonpolar hydrocarbon solvent to carry out a first-stage polymerization reaction; after the first-stage polymerization reaction is finished, adding butadiene into the system to perform a second-stage polymerization reaction; after the second-stage polymerization reaction is finished, adding styrene into the system to carry out a third-stage polymerization reaction; the initiator comprises n-butyllithium and/or sec-butyllithium, and the non-polar hydrocarbon solvent comprises cyclohexane and/or n-hexane;
(2) mixing titanocene dichloride and n-butyllithium in an aging kettle according to the Li/Ti molar ratio of 10-15, and carrying out an aging reaction at the temperature of 25-75 ℃ to obtain a hydrogenation catalyst; the dosage of the titanocene dichloride is 0.2-0.3mmol/100g of base glue;
(3) and (3) mixing the basic adhesive obtained in the step (1) and the hydrogenation catalyst obtained in the step (2) in a hydrogenation kettle, and introducing hydrogen to carry out hydrogenation reaction at the hydrogenation temperature of 70-80 ℃, the hydrogenation pressure of 1-2.5MPa and the hydrogenation time of 90-180min to obtain the hydrogenated styrene-butadiene block copolymer with the hydrogenation degree of more than or equal to 98%.
Wherein, the step (1) and the step (2) are not in sequence; and (4) adopting recycle hydrogen after the hydrogenation temperature reaches a peak value in the hydrogenation reaction in the step (3).
In a second aspect, the present invention provides a hydrogenated styrene-butadiene block copolymer prepared by the preparation method according to the first aspect.
In a third aspect, the present invention provides a use of the hydrogenated styrene-butadiene block copolymer according to the first aspect for a polymeric film, a toy or a medical article.
Compared with the prior art, the invention has the beneficial effects that:
(1) before the hydrogenation reaction, the preparation method provided by the invention firstly mixes the cyclopentadienyl titanium dichloride and the n-butyl lithium to carry out an aging reaction, then mixes the obtained hydrogenation catalyst with the basic glue phase to carry out a subsequent hydrogenation reaction, compared with the conventional method that the n-butyl lithium is firstly added and then the hydrogen is terminated, and then the cyclopentadienyl titanium dichloride and the phthalate are added to carry out the hydrogenation reaction, the stability of the hydrogenation catalyst is improved, and the use of a cocatalyst of phthalate in the hydrogenation process is avoided;
(2) the invention adopts the circulating hydrogen in the later stage of the hydrogenation reaction, increases the contact area of the hydrogenation catalyst and the hydrogen, improves the hydrogenation degree of the obtained product and simplifies the preparation process.
Detailed Description
The technical solution of the present invention is further explained by the following embodiments.
Example 1
This example provides a method of preparing a hydrogenated styrene-butadiene block copolymer, the method comprising the steps of:
(1) preparing a base adhesive with 12 wt% of solid glue solution and 120000 molecular weight by utilizing three-stage polymerization reaction at the initiation temperature of 60 ℃ in a polymerization kettle, transferring the obtained base adhesive into a hydrogenation kettle, and introducing hydrogen to terminate the polymerization reaction; the three-stage polymerization reaction specifically comprises the following steps: adding styrene and n-butyllithium into a cyclohexane system, and carrying out a first-stage polymerization reaction; after the first-stage polymerization reaction is finished, adding butadiene into the system to perform a second-stage polymerization reaction; after the second-stage polymerization reaction is finished, adding styrene into the system to carry out a third-stage polymerization reaction;
(2) mixing titanocene dichloride and n-butyllithium in an aging kettle according to the Li/Ti molar ratio of 12, and performing an aging reaction at the temperature of 50 ℃ to obtain a hydrogenation catalyst; the dosage of the titanocene dichloride is 0.25mmol/100g of base adhesive;
(3) and (3) mixing the basic adhesive obtained in the step (1) and the hydrogenation catalyst obtained in the step (2) in a hydrogenation kettle, and introducing hydrogen to carry out hydrogenation reaction at the hydrogenation temperature of 75 ℃, the hydrogenation pressure of 2MPa and the hydrogenation time of 140min to prepare the hydrogenated styrene-butadiene block copolymer with the hydrogenation degree of 99%.
Wherein, the hydrogenation reaction in the step (3) adopts recycle hydrogen after the hydrogenation temperature reaches a peak value.
Example 2
This example provides a method of preparing a hydrogenated styrene-butadiene block copolymer, comprising the steps of:
(1) preparing a base adhesive with 10 wt% of solid glue solution and 100000 molecular weight by utilizing three-stage polymerization reaction at the initiation temperature of 58 ℃ in a polymerization kettle, transferring the obtained base adhesive into a hydrogenation kettle, and introducing hydrogen to terminate the polymerization reaction; the three-stage polymerization reaction specifically comprises the following steps: adding styrene and sec-butyl lithium into a normal hexane system to carry out a first-stage polymerization reaction; after the first-stage polymerization reaction is finished, adding butadiene into the system to perform a second-stage polymerization reaction; after the second-stage polymerization reaction is finished, adding styrene into the system to carry out a third-stage polymerization reaction;
(2) mixing titanocene dichloride and n-butyllithium in an aging kettle according to the Li/Ti molar ratio of 11, and carrying out an aging reaction at the temperature of 40 ℃ to obtain a hydrogenation catalyst; the dosage of the titanocene dichloride is 0.25mmol/100g of base rubber;
(3) and (3) mixing the basic adhesive obtained in the step (1) and the hydrogenation catalyst obtained in the step (2) in a hydrogenation kettle, and introducing hydrogen to carry out hydrogenation reaction at a hydrogenation temperature of 72 ℃, a hydrogenation pressure of 1.8MPa and a hydrogenation time of 120min to obtain the hydrogenated styrene-butadiene block copolymer with a hydrogenation degree of 98%.
Wherein, the hydrogenation reaction in the step (3) adopts recycle hydrogen after the hydrogenation temperature reaches a peak value.
Example 3
This example provides a method of preparing a hydrogenated styrene-butadiene block copolymer, the method comprising the steps of:
(1) preparing a base adhesive with 14 wt% of solid glue solution and 180000 molecular weight by utilizing three-stage polymerization reaction at the initiation temperature of 62 ℃ in a polymerization kettle, transferring the obtained base adhesive into a hydrogenation kettle, and introducing hydrogen to terminate the polymerization reaction; the three-stage polymerization reaction specifically comprises the following steps: adding styrene and n-butyllithium into a system of n-hexane for carrying out a first-stage polymerization reaction; after the first-stage polymerization reaction is finished, adding butadiene into the system to perform a second-stage polymerization reaction; after the second-stage polymerization reaction is finished, adding styrene into the system to carry out a third-stage polymerization reaction;
(2) mixing titanocene dichloride and n-butyllithium in an aging kettle according to the Li/Ti molar ratio of 14, and carrying out an aging reaction at the temperature of 60 ℃ to obtain a hydrogenation catalyst; the dosage of the titanocene dichloride is 0.25mmol/100g of base adhesive;
(3) and (3) mixing the basic adhesive obtained in the step (1) and the hydrogenation catalyst obtained in the step (2) in a hydrogenation kettle, and introducing hydrogen to carry out hydrogenation reaction at a hydrogenation temperature of 78 ℃, a hydrogenation pressure of 2.2MPa and a hydrogenation time of 160min to obtain the hydrogenated styrene-butadiene block copolymer with the hydrogenation degree of 98%.
Wherein, the hydrogenation reaction in the step (3) adopts recycle hydrogen after the hydrogenation temperature reaches a peak value.
Example 4
This example provides a method of preparing a hydrogenated styrene-butadiene block copolymer, comprising the steps of:
(1) preparing a base adhesive with 8 wt% of solid glue solution and 30000 molecular weight in a polymerization kettle by utilizing three-stage polymerization reaction with the initiation temperature of 55 ℃, transferring the obtained base adhesive into a hydrogenation kettle, and introducing hydrogen to terminate the polymerization reaction; the three-stage polymerization reaction specifically comprises the following steps: adding styrene and sec-butyl lithium into a cyclohexane system to carry out a first-stage polymerization reaction; after the first-stage polymerization reaction is finished, adding butadiene into the system to perform a second-stage polymerization reaction; after the second-stage polymerization reaction is finished, adding styrene into the system to carry out a third-stage polymerization reaction;
(2) mixing titanocene dichloride and n-butyl lithium in an aging kettle according to the Li/Ti molar ratio of 10, and performing an aging reaction at the temperature of 25 ℃ to obtain a hydrogenation catalyst; the dosage of the titanocene dichloride is 0.2mmol/100g of base adhesive;
(3) and (3) mixing the basic adhesive obtained in the step (1) and the hydrogenation catalyst obtained in the step (2) in a hydrogenation kettle, and introducing hydrogen to carry out hydrogenation reaction at the hydrogenation temperature of 70 ℃, the hydrogenation pressure of 1MPa and the hydrogenation time of 180min to prepare the hydrogenated styrene-butadiene block copolymer with the hydrogenation degree of 98%.
Wherein, the hydrogenation reaction in the step (3) adopts recycle hydrogen after the hydrogenation temperature reaches a peak value.
Example 5
This example provides a method of preparing a hydrogenated styrene-butadiene block copolymer, the method comprising the steps of:
(1) preparing a base adhesive with 15wt% of solid content of adhesive liquid and 200000 molecular weight by using a three-stage polymerization reaction at the initiation temperature of 65 ℃ in a polymerization kettle, transferring the obtained base adhesive into a hydrogenation kettle, and introducing hydrogen to terminate the polymerization reaction; the three-stage polymerization reaction specifically comprises the following steps: adding styrene and n-butyllithium into a system of n-hexane for carrying out a first-stage polymerization reaction; after the first-stage polymerization reaction is finished, adding butadiene into the system to perform a second-stage polymerization reaction; after the second-stage polymerization reaction is finished, adding styrene into the system to carry out a third-stage polymerization reaction;
(2) mixing titanocene dichloride and n-butyllithium in an aging kettle according to the Li/Ti molar ratio of 15, and carrying out an aging reaction at the temperature of 75 ℃ to obtain a hydrogenation catalyst; the dosage of the titanocene dichloride is 0.3mmol/100g of base adhesive;
(3) and (3) mixing the basic adhesive obtained in the step (1) and the hydrogenation catalyst obtained in the step (2) in a hydrogenation kettle, and introducing hydrogen to carry out hydrogenation reaction at a hydrogenation temperature of 80 ℃, a hydrogenation pressure of 2.5MPa and a hydrogenation time of 90min to prepare the hydrogenated styrene-butadiene block copolymer with a hydrogenation degree of 98%.
Wherein, the hydrogenation reaction in the step (3) adopts recycle hydrogen after the hydrogenation temperature reaches a peak value.
Comparative example 1
This comparative example provides a method of preparing a hydrogenated styrene-butadiene block copolymer, the method comprising the steps of:
(1) preparing a base adhesive with 12 wt% of solid glue solution and 120000 molecular weight by utilizing three-stage polymerization reaction at the initiation temperature of 60 ℃ in a polymerization kettle, transferring the obtained base adhesive into a hydrogenation kettle, and introducing hydrogen to terminate the polymerization reaction; the three-stage polymerization reaction specifically comprises the following steps: adding styrene and n-butyllithium into a cyclohexane system, and carrying out a first-stage polymerization reaction; after the first-stage polymerization reaction is finished, adding butadiene into the system to perform a second-stage polymerization reaction; after the second-stage polymerization reaction is finished, adding styrene into the system to carry out a third-stage polymerization reaction;
(2) mixing the base glue obtained in the step (1) and n-butyllithium in a hydrogenation kettle, and stopping introducing hydrogen; then adding titanocene dichloride and methyl o-methylbenzoate, and introducing hydrogen to carry out hydrogenation reaction at the hydrogenation temperature of 75 ℃, the hydrogenation pressure of 2MPa and the hydrogenation time of 140min to prepare a hydrogenated styrene-butadiene block copolymer with the hydrogenation degree of 98%; the mol ratio of the n-butyllithium to the titanocene dichloride is 12 according to Li/Ti, and the using amount of the titanocene dichloride is 0.25mmol/100g of base rubber.
Wherein, the hydrogenation reaction in the step (2) adopts recycle hydrogen after the hydrogenation temperature reaches a peak value.
Compared with example 1, the comparative example adopts the substance of o-methyl benzoate with limited use, and although hydrogenated styrene-butadiene block copolymer with the hydrogenation degree of more than or equal to 98 percent can be prepared, the comparative example does not meet the requirement of environmental protection.
Comparative example 2
The present comparative example provides a method for preparing a hydrogenated styrene-butadiene block copolymer, comprising the steps of:
(1) preparing a base adhesive with 12 wt% of solid content of adhesive liquid and 120000 molecular weight by utilizing three-stage polymerization reaction at the initiation temperature of 60 ℃ in a polymerization kettle, transferring the obtained base adhesive into a hydrogenation kettle, and introducing hydrogen to terminate the polymerization reaction; the three-stage polymerization reaction specifically comprises the following steps: adding styrene and n-butyllithium into a cyclohexane system, and carrying out a first-stage polymerization reaction; after the first-stage polymerization reaction is finished, adding butadiene into the system to perform a second-stage polymerization reaction; after the second-stage polymerization reaction is finished, adding styrene into the system to carry out a third-stage polymerization reaction;
(2) mixing titanocene dichloride and n-butyllithium in an aging kettle according to the Li/Ti molar ratio of 12, and performing an aging reaction at the temperature of 50 ℃ to obtain a hydrogenation catalyst; the dosage of the titanocene dichloride is 0.25mmol/100g of base rubber;
(3) and (3) mixing the basic adhesive obtained in the step (1) and the hydrogenation catalyst obtained in the step (2) in a hydrogenation kettle, and introducing hydrogen to carry out hydrogenation reaction at the hydrogenation temperature of 75 ℃, the hydrogenation pressure of 2MPa and the hydrogenation time of 140min to prepare the hydrogenated styrene-butadiene block copolymer with the hydrogenation degree of 97%.
Compared with the example 1, the comparative example does not adopt recycle hydrogen in the later stage of the hydrogenation reaction, and the contact area of the hydrogenation catalyst and hydrogen is reduced, so that the hydrogenation degree of the obtained product is reduced to a certain extent.
Therefore, according to the preparation method provided by the invention, before the hydrogenation reaction is carried out, titanocene dichloride and n-butyl lithium are mixed for an aging reaction, then the obtained hydrogenation catalyst is mixed with the basic glue for a subsequent hydrogenation reaction, compared with the conventional method that n-butyl lithium is added firstly and then hydrogen is terminated, titanocene dichloride and phthalate substances are added for the hydrogenation reaction, the stability of the hydrogenation catalyst is improved, and the use of co-catalyst phthalate in the hydrogenation process is avoided; in addition, the invention adopts the circulating hydrogen in the later stage of the hydrogenation reaction, increases the contact area of the hydrogenation catalyst and the hydrogen, improves the hydrogenation degree of the obtained product and simplifies the preparation process.
The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are only exemplary embodiments of the present invention, and are not intended to limit the present invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the protection scope of the present invention.