A cyclic block copolymer, and a method for preparing and using the same

Abstract

The application discloses a kind of cyclic block copolymer and its preparation method and application.Cyclic block copolymer has the following expression: CBC;Wherein, C block is obtained by hydrogenation of polyaryl ethylene block, and the hydrogenation degree of aryl in polyaryl ethylene block is ≥95%;B block is obtained by hydrogenation of poly conjugated diene block, and the hydrogenation degree of alkenyl in poly conjugated diene block is ≥95%.The polymer has good processing performance, mechanical properties, high temperature resistance, and radiation resistance, ultra-clean and high transparency, which can greatly reduce the use of auxiliary agent when used for radiation-resistant medical materials, and can solve the technical problems such as small molecule precipitation, color yellowing, transparency reduction and physical property reduction during radiation sterilization process.

Description

Technical Field

[0001] This invention relates to a polymer material, specifically a cyclic block copolymer, and also to its preparation method and its application as a radiation-resistant medical material, belonging to the field of cyclic block copolymer preparation technology. Background Technology

[0002] Common sterilization methods for pharmaceutical packaging materials or rubber and plastic parts for medical devices include high-temperature steam sterilization, ethylene oxide steam sterilization, and irradiation sterilization. Each method has its advantages and disadvantages. High-temperature steam sterilization often fails to meet sterilization efficiency standards. While ethylene oxide can kill various microorganisms and has strong penetrability and minimal damage to materials, it also presents problems such as toxicity, flammability, explosiveness, long sterilization cycles, and potential residue buildup. Irradiation sterilization offers advantages such as high sterilization capacity, rapid speed, and immediate usability after irradiation. The shortcomings of ethylene oxide sterilization became even more apparent after the COVID-19 pandemic. For example, nebulizers, humidification bottles, nasal oxygen cannulas, and humidification bottles used in respiratory wards and general wards contain liquids that are unsuitable for ethylene oxide sterilization, leading to shortages of epidemic prevention materials due to the inability to sterilize them quickly and promptly. Given these circumstances, ethylene oxide sterilization has significant limitations. Irradiation sterilization is one possible solution.

[0003] Irradiation sterilization is an effective method that uses electromagnetic waves generated by ionizing radiation to kill most microorganisms on materials. Gamma-ray irradiation sterilization using Co-60 is becoming increasingly popular and is currently a widely adopted method. This sterilization method has many advantages, such as simple process, easy control, no environmental pollution, no chemical residues, no introduction of impurities during processing, and the ability to process materials in their packaging. Styrene-based polymers such as polystyrene (PS), methyl methacrylate-acrylonitrile-butadiene-styrene copolymer (MABS), and styrene-butadiene transparent impact-resistant resin (SBC) have advantages such as high transparency, low cost, non-toxicity, and odorless properties, and are widely used in transparent medical devices such as catheters, nebulizers, breathing filters, and infusion tubing. However, when irradiated, styrene-based polymers are prone to problems such as small molecule precipitation, yellowing, decreased transparency, and deterioration of physical properties.

[0004] Generally, improving the radiation resistance of polymer materials is related to the material's molecular structure, the properties of additives, and its physical properties. Existing patents related to radiation-resistant materials involve a wide range of material formulations. For example, Chinese patent (publication number CN 110776699 B) discloses a radiation-resistant thermoplastic elastomer for pharmaceutical use, and Chinese patent (CN107674277B) discloses a radiation-resistant antibacterial plastic. However, the materials in these patented products contain a variety of small-molecule auxiliaries and additives, which greatly increases the risk of small molecule migration, yellowing, decreased transparency, and deterioration of physical properties during radiation sterilization. Summary of the Invention

[0005] In view of the deficiencies in the prior art, the first objective of this invention is to provide a polymer with a fully saturated molecular chain containing cyclic block structures. This polymer has good processing performance, mechanical properties, high temperature resistance, radiation resistance, ultra-cleanliness, and high transparency, thus meeting the requirements of the field of medical materials technology.

[0006] The second objective of this invention is to provide a method for preparing cyclic block copolymers, which is simple in process, low in raw material cost, and conducive to large-scale production.

[0007] The third objective of this invention is to provide an application of a cyclic block copolymer, which itself has good processing performance, mechanical properties, high temperature resistance, and characteristics such as radiation resistance, ultra-cleanliness, and high transparency. Using it in radiation-resistant medical materials can greatly reduce the use of additives.

[0008] To achieve the above-mentioned technical objectives, the present invention provides a cyclic block copolymer having the following expression: CBC; wherein, the C block is obtained by hydrogenation of a polyarylene block, and the degree of hydrogenation of the aryl group in the polyarylene block is ≥95%; the B block is obtained by hydrogenation of a polyconjugated diene block, and the degree of hydrogenation of the alkenyl group in the polyconjugated diene block is ≥95%. The cyclic block copolymer of the present invention has a triblock structure. Compared with the CB or BC diblock structure, the cyclic block copolymer with the CBC triblock structure has good processability and injection molding performance.

[0009] As a preferred embodiment, the number-average molecular weight of the C-block is between 6,300 and 135,000.

[0010] As a preferred embodiment, the number-average molecular weight of the B-block is between 3,500 and 123,000. The molecular weight of the B-block and C-block directly affects the processing and molding properties of the cyclic block copolymer. If the molecular weight is too high, the flowability will decrease, while if the molecular weight is too low, it will be difficult to mold.

[0011] As a preferred embodiment, the polyarylene block is obtained by homopolymerization or copolymerization of at least one of styrene, α-methylstyrene, methylstyrene (including ortho, meta, and para isomers), ethylstyrene (including ortho, meta, and para isomers), propylstyrene (including ortho, meta, and para isomers), p-tert-butylstyrene, butylstyrene (including ortho, meta, and para isomers), and 4-phenylstyrene. As a further preferred embodiment, the polyarylene block is obtained by homopolymerization or copolymerization of at least one of styrene, methylstyrene (p-methylstyrene, or ortho-methylstyrene), and p-tert-butylstyrene. When a single arylene monomer is selected, it is homopolymerized to obtain the polyarylene block; when two or more arylene monomers are selected, they are randomly copolymerized to obtain the polyarylene block.

[0012] As a preferred embodiment, the polyconjugated diene block is obtained by homopolymerization or copolymerization of at least one selected from 1,3-butadiene, 2-methyl-1,3-butadiene, 2-ethyl-1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, and 3-butyl-1,3-octadiene. As a further preferred embodiment, the polyconjugated diene block is obtained by homopolymerization or copolymerization of butadiene and / or isoprene. When a single conjugated diene monomer is selected, it is homopolymerized to obtain the polyconjugated diene block; when two or more conjugated diene monomers are selected, they are randomly copolymerized to obtain the polyconjugated diene block.

[0013] As a preferred embodiment, the weight ratio of C-block to B-block is 18:82 to 90:10; more preferably 20:80 to 75:25; and even more preferably 20:80 to 70:30. Maintaining a suitable block ratio of C-block to B-block imparts better processing and mechanical properties to the cyclic block copolymer. If the C-block content is too low, the copolymer strength is low; if the C-block content is too high, the copolymer toughness is low.

[0014] As a preferred embodiment, the degree of hydrogenation of the aryl groups in the polyarylene ethylene block is ≥98%; more preferably ≥99%. The higher the degree of hydrogenation, the higher the content of saturated bonds, the better the aging performance, and the stronger the radiation resistance.

[0015] As a preferred embodiment, the degree of hydrogenation of the alkenyl group in the polyconjugated diene block is ≥98%, more preferably ≥99%.

[0016] As a preferred embodiment, the cyclic block copolymer comprises a number-average molecular weight of 35,000 to 150,000 g / mol, more preferably 45,000 to 100,000 g / mol; and more preferably 60,000 to 90,000 g / mol.

[0017] The following are examples of several typical cyclic block copolymers, but the cyclic block copolymers of the present invention include, but are not limited to, the following structural formulas:

[0018]

[0019]

[0020] Where n is an integer between 60 and 1300; m x It is an integer from 64 to 2300; R is a hydrogenated polyconjugated diene block; the molecular weight distribution index is ≤1.5.

[0021] The present invention also provides a method for preparing a cyclic block copolymer, which involves first adding an arylethylene monomer and an initiator to an anionic polymerization system for a single-stage polymerization; then adding a conjugated diene monomer for a two-stage polymerization; then adding an arylethylene monomer for a three-stage polymerization to obtain a triblock copolymer; and finally subjecting the triblock copolymer to a hydrogenation reaction to obtain the final product.

[0022] As a preferred embodiment, the hydrogenation reaction employs a silicon salt-supported Ni and Co complex catalyst, with a reaction temperature of 70–240°C and a hydrogen pressure ≥0.2 MPa. Typical hydrogenation temperatures are ≥70°C, preferably ≥110°C, more preferably ≥150°C, and ≤240°C, preferably ≤210°C, more preferably ≤200°C, and most preferably ≤190°C. Higher hydrogen pressure is more beneficial to the hydrogenation rate; the preferred hydrogen pressure is 0.7–10.3 MPa, more preferably 1.0–8.0 MPa.

[0023] As a preferred option, the hydrogenation reaction can be carried out in the absence of a solvent, but it is preferable to carry it out in a solvent that has good solubility in the polymer and does not hinder the hydrogenation reaction.

[0024] As a preferred embodiment, the anionic polymerization system contains a nonpolar hydrocarbon solvent and may also contain a polar structure modifier. As a more preferred embodiment, the nonpolar hydrocarbon solvent includes at least one selected from cyclohexane, n-hexane, benzene, toluene, and solvent oil; cyclohexane is more preferably used. The polar structure modifier is commonly used in the industry, such as tetrahydrofuran.

[0025] The present invention also provides an application of a cyclic block copolymer as a radiation-resistant medical material.

[0026] As a preferred option, the cyclic block copolymer is used in combination with antioxidants and lubricants.

[0027] As a preferred embodiment, the mass ratio of the cyclic block polymer to the antioxidant and lubricant is 100:0.1-30:0.1-20.

[0028] As a preferred embodiment, the antioxidant is at least one of 1010, 1076, 168, 1330, 626, 264, 164, and 245.

[0029] As a preferred embodiment, the lubricant is at least one selected from white oil, erucamide, oleamide, ethylene bis-stearamide, polyethylene wax, and silicone oil.

[0030] Compared with the prior art, the technical solution of this invention application brings the following beneficial technical effects:

[0031] The cyclic block polymer of the present invention has highly saturated polymer chains and a special molecular chain structure, which endows the cyclic block polymer with excellent physicochemical properties, mainly manifested in good processing performance, mechanical properties, high temperature resistance, and ultra-cleanliness and high transparency.

[0032] The method for preparing the cyclic block polymer of the present invention has low raw material costs, requires no special equipment, and has simple production process steps, which is conducive to large-scale production.

[0033] The cyclic block polymer of the present invention can be used in radiation-resistant medical materials, which can greatly reduce the use of additives, meet the requirements of safety and effectiveness in the medical field, and avoid problems such as small molecule precipitation, yellowing, decreased transparency and decreased physical properties that easily occur during radiation sterilization. Attached Figure Description

[0034] 【 Figure 1 [Image caption: Typical 1H NMR spectrum of the cyclic block polymer precursor prepared in Example 1 of this invention.]

[0035] 【 Figure 2 [Image caption: Typical 1H NMR spectrum of the cyclic block polymer prepared in Example 1 of this invention.] Detailed Implementation

[0036] The present invention will be further described below with reference to specific embodiments. It should be understood that the following embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. Those skilled in the art can make some non-essential improvements and adjustments based on the content of the above invention.

[0037] Example 1

[0038] Add 2.5 liters of a mixture of cyclohexane and raffinate oil (water value <20 ppm) to a 5-liter polymerization reactor purified with nitrogen. Heat the mixture to 50°C. First, add 24 mL of styrene and the initiator n-butyllithium (or sec-butyllithium), and start stirring. React for 40 minutes. Then, add 169 mL of butadiene in the second stage, and finally, add 24 mL of styrene in the third stage, stirring for another 40 minutes. Control the maximum temperature not to exceed 65°C. After polymerization, transfer the solution to a 5-liter hydrogenation reactor, add a hydrogenation catalyst, and hydrogenate at a pressure of 5.0 MPa. Stir and hydrogenate for 200 minutes. After hydrogenation, the solution coagulates to obtain a white polymer, which is then dried to obtain the final product. The obtained cyclic block polymer had a vinyl aromatic hydrogenation degree of 99% and a conjugated diene hydrogenation degree of 100%, with a molecular weight of approximately 80,000. Further addition of 0.45% antioxidant 1010, 0.45% antioxidant 168, and 0.15% erucamide resulted in a medical-grade radiation-resistant cyclic block polymer. Its physical properties were measured after irradiation with different doses of gamma rays, and the results are shown in Table 1 below.

[0039] Table 1 Physical properties of cyclic block polymers after irradiation with different doses of gamma rays

[0040]

[0041] The chemical properties of the aqueous solution were measured after irradiation with different doses of gamma rays. The measurement results are shown in Table 2 below.

[0042] Table 2 Chemical properties of cyclic block polymers in aqueous solution after irradiation with different doses of gamma rays.

[0043]

[0044] The test results of the above examples show that after irradiation with gamma rays at energy levels of 0 kJ, 20 kJ, 30 kJ, and 40 kJ, respectively, the properties of the cyclic block polymers remained largely unchanged, and their chemical properties still met the requirements for medical consumables, all within the specified range. The cyclic block polymers prepared in this invention exhibit excellent radiation sterilization resistance.

[0045] Examples 2-6

[0046] Following the method of Example 1, but changing the amount of materials added in the first, second, and third stages and other additives, cyclic block polymers numbered 2, 3, 4, 5, and 6 in Table 3 were prepared.

[0047] Table 3 Examples 2-6

[0048]

[0049] The obtained cyclic block polymer had a vinyl aromatic hydrogenation degree of 99% and a conjugated diene hydrogenation degree of 100%, with a synthetic molecular weight of approximately 80,000. After adding 0.45% antioxidant, 0.15% antioxidant, and 0.15% lubricant, a medical-grade radiation-resistant cyclic block polymer was obtained. Its physical properties were measured after irradiation with different doses of gamma rays, and the results are shown in Tables 4–15.

[0050] Table 4 Physical properties of cyclic block polymers after irradiation with different doses of gamma rays in Example 2

[0051]

[0052]

[0053] Table 5 Chemical properties of aqueous solutions of the cyclic block polymers in Example 2 after irradiation with different doses of gamma rays

[0054]

[0055] Table 6 Physical properties of cyclic block polymers after irradiation with different doses of gamma rays in Example 3

[0056]

[0057] Table 7 Chemical properties of aqueous solutions of the cyclic block polymers in Example 3 after irradiation with different doses of gamma rays

[0058]

[0059] Table 8 Physical properties of the cyclic block polymer in Example 4 after irradiation with different doses of gamma rays

[0060]

[0061] Table 9 Chemical properties of aqueous solutions of the cyclic block polymers in Example 3 after irradiation with different doses of gamma rays

[0062]

[0063]

[0064] Table 10 Physical properties of cyclic block polymers in Example 4 after irradiation with different doses of gamma rays

[0065]

[0066] Table 11 Chemical properties of aqueous solutions of the cyclic block polymer in Example 4 after irradiation with different doses of gamma rays.

[0067]

[0068] Table 12 Physical properties of the cyclic block polymer in Example 5 after irradiation with different doses of gamma rays.

[0069]

[0070]

[0071] Table 13 Chemical properties of aqueous solutions of the cyclic block polymer in Example 5 after irradiation with different doses of gamma rays

[0072]

[0073] Table 14 Physical properties of the cyclic block polymer in Example 6 after irradiation with different doses of gamma rays.

[0074]

[0075] Table 15 Chemical properties of aqueous solutions of the cyclic block polymer in Example 6 after irradiation with different doses of gamma rays

[0076]

[0077]

Claims

1. An application of a cyclic block copolymer, characterized in that: A cyclic block copolymer is mixed with an antioxidant and a lubricant for use as a radiation-resistant medical material, wherein the mass ratio of the cyclic block copolymer to the antioxidant and lubricant is 100:0.1~30:0.1~20; the cyclic block copolymer is characterized by having the following expression: CBC; wherein the C block is obtained by hydrogenation of a polyarylene ethylene block, and the degree of hydrogenation of the aryl group in the polyarylene ethylene block is ≥95%; the B block is obtained by hydrogenation of a polyconjugated diene block, and the degree of hydrogenation of the alkenyl group in the polyconjugated diene block is ≥95%.

2. The application of the cyclic block copolymer according to claim 1, characterized in that: The antioxidant is at least one of 1010, 1076, 168, 1330, 626, 264, and 164; The lubricant is at least one of white oil, erucamide, oleamide, ethylene bis-stearamide, polyethylene wax, and silicone oil.

3. The application of the cyclic block copolymer according to claim 1, characterized in that: The number-average molecular weight of the C-block is 6,300 to 135,000; the number-average molecular weight of the B-block is 3,500 to 123,000.

4. The application of the cyclic block copolymer according to claim 1, characterized in that: The polyarylene ethylene block is obtained by homopolymerization or copolymerization of at least one of styrene, α-methylstyrene, methylstyrene, ethylstyrene, propylstyrene, p-tert-butylstyrene, butylstyrene, and 4-phenylstyrene. The polyconjugated diene block is obtained by homopolymerization or copolymerization of at least one of 1,3-butadiene, 2-methyl-1,3-butadiene, 2-ethyl-1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, and 3-butyl-1,3-octadiene.

5. The application of the cyclic block copolymer according to claim 4, characterized in that: The polyconjugated diene block is obtained by homopolymerization or copolymerization of butadiene and / or isoprene; The polyarylene ethylene block is obtained by homopolymerization or copolymerization of at least one of styrene, methylstyrene, and p-tert-butylstyrene.

6. The application of the cyclic block copolymer according to claim 1, characterized in that: The weight ratio of C-blocks to B-blocks is 18:82 to 90:

10.

7. The application of the cyclic block copolymer according to claim 6, characterized in that: The weight ratio of C-blocks to B-blocks is 20:80 to 75:

25.

8. The application of the cyclic block copolymer according to claim 1, characterized in that: The degree of hydrogenation of the aryl groups in the polyarylethylene block is ≥98%; The degree of hydrogenation of the alkenyl group in the polyconjugated diene block is ≥98%.

9. The application of the cyclic block copolymer according to claim 1, characterized in that: The number-average molecular weight of the cyclic block copolymers is 35,000 to 150,000 g / mol.

10. The application of a cyclic block copolymer according to claim 1 or 9, characterized in that: The number average molecular weight of the cyclic block copolymers is 60,000 to 90,000 g / mol.

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