High-weather-resistance medical elastomer and preparation method thereof

Abstract

The invention relates to the field of medical elastomers, and discloses a high-weather-resistance medical elastomer and a preparation method thereof.The medical elastomer is prepared from, by weight, 65-75 parts of polypropylene, 8-12 parts of SEBS, 18-22 parts of nitrile rubber, 1-3 parts of lubricant, 0.5-1.5 parts of antioxidant and 5-15 parts of organic silicon microspheres; the preparation method of the organic silicon microspheres comprises the following steps: in inert gas, carrying out polymerization reaction on 15-25 parts by weight of organic silicon monomer, 5-15 parts by weight of styrene and 0.3-0.5 part by weight of double-end vinyl polydimethylsiloxane under the action of 0.007-0.013 part by weight of initiator for 3-4 hours, then adding 0.4-0.6 part by weight of cross-linking agent, continuously stirring and reacting to obtain a mixed solution, filtering, cleaning and drying the precipitate, thereby obtaining the organic silicon microspheres. The organic silicon microspheres are obtained; the method has the advantage of improving the low-temperature resistance of the medical polypropylene elastomer.

Description

Technical Field

[0001] The present application relates to the technical field of medical elastomers, and in particular to a highly weather-resistant medical elastomer and a preparation method thereof. Background Art

[0002] There are many types of medical elastomers, including polypropylene elastomers, polyethylene elastomers and polyurethane elastomers. Among them, polyurethane elastomers, as polymers made by dehydration polycondensation, are easily degraded by absorbing water, thus affecting their service life. Polypropylene elastomers are polypropylene materials with polyethylene or rubber components added. Although polypropylene elastomers and polypropylene elastomers are widely available, simple to process, and have excellent environmental performance, they have poor low-temperature resistance. Their products are easily affected by low-temperature environments, resulting in cracks in their products, etc., causing the contained drugs to leak. Summary of the invention

[0003] In order to improve the low temperature resistance of medical polypropylene elastomer, the present application provides a high weather resistance medical elastomer and a preparation method thereof.

[0004] In the first aspect, the present application provides a highly weather-resistant medical elastomer, which adopts the following technical solution: A highly weather-resistant medical elastomer comprises the following raw materials in parts by weight: 65-75 parts of polypropylene, 8-12 parts of SEBS, 18-22 parts of nitrile rubber, 1-3 parts of lubricant, 0.5-1.5 parts of antioxidant and 5-15 parts of organosilicon microspheres; the preparation method of the organosilicon microspheres is as follows: S1. Under an inert gas atmosphere, using DMF as a solvent, 15-25 parts by weight of an organosilicon monomer, 5-15 parts by weight of styrene and 0.3-0.5 parts by weight of a double-terminated vinyl polydimethylsiloxane are polymerized with 0.007-0.013 parts by weight of an initiator for 3-4 hours, and then 0.4-0.6 parts by weight of a cross-linking agent is added, and the reaction is continued with stirring to obtain a mixed solution; S2. Filter the mixed solution obtained in S1, wash and dry the obtained precipitate to obtain organosilicon microspheres.

[0005] By adopting the above technical solution, SEBS, which is a styrene-ethylene-butylene-styrene block copolymer, can greatly improve the low-temperature resistance of medical elasticity through the selection and proportion of various raw materials in the system and the addition of silicone microspheres. On the one hand, as an organosilicon polymer, the organosilicon microspheres can exert their own excellent properties such as non-toxicity, low temperature resistance, high temperature resistance, low viscosity, and oxidation resistance. After being added, the low temperature resistance of the polypropylene and nitrile rubber composite medical elastomer can be greatly improved. The high silicon content can also greatly reduce the interfacial tension between the organosilicon microspheres and the system, making it excellent in compatibility and making it fully exert its low temperature resistance. On the other hand, during the preparation of the organosilicon microspheres prepared in the present application, a large amount of cross-linking agent is added after a certain period of reaction, so that the prepared organosilicon microspheres have a low internal cross-linking degree and a large external cross-linking degree in terms of physical structure, so that they have macroscopic elasticity, and the organosilicon microspheres have a higher melting point, so that they do not melt when the medical elastomer is melted and mixed, and still exist in the original form during the mixing process. Therefore, after the preparation of the medical elastomer, it can still maintain its structure and have its own elasticity. It is evenly distributed inside the medical elastomer, so that the medical elastomer can be buffered when subjected to external force, greatly improving the impact strength of the medical elastomer; under the action of both aspects, the low temperature resistance of the medical elastomer is greatly improved.

[0006] Preferably, the added amount of the organosilicon microspheres is 10 parts by weight.

[0007] By adopting the above technical scheme, when other raw materials in the system remain unchanged, as the amount of added silicone microspheres increases, the low-temperature resistance of the medical elastomer gradually increases. When the added amount increases to 10kg, the increase in its low-temperature resistance gradually decreases. Therefore, considering the two factors of production cost and the overall performance of the medical elastomer, the addition amount is the best when it is in parts by weight.

[0008] Preferably, in S1, the amount of the organic silicon monomer added is 20 parts by weight, and the amount of the styrene added is 10 parts by weight.

[0009] By adopting the above technical scheme, when preparing silicone microspheres, when the proportion of vinyl triethoxysilane added is too large, the rigidity of the silicone polymer is relatively large, which reduces the elasticity of the silicone microspheres and its buffering effect is relatively low, resulting in a decrease in the impact resistance of the medical elastomer; when vinyl triethoxysilane is not added, the performance of the silicone polymer cannot be exerted, and it is not enough to improve the low-temperature resistance of the medical elastomer; at this ratio, the obtained silicone microspheres can optimize the low-temperature resistance of the medical elastomer.

[0010] Preferably, the organic silicon monomer is one or more of vinyl triethoxysilane, methyl vinyl chlorosilane and vinyl trimethoxysilane.

[0011] By adopting the above technical solution, the organic silicon monomer can be selected within this range. Although not listed one by one in the embodiments of the present application specification, the expected technical effects can be obtained in theory.

[0012] Preferably, the initiator is azobisisobutyronitrile or azobisisoheptanenitrile.

[0013] By adopting the above technical scheme, the silicone microspheres of the present application are obtained by free radical polymerization reaction, the initiator is azobisisobutyronitrile or azobisisoheptanenitrile, the reaction can be obtained under controllable conditions, and the particle size range of the obtained silicone microspheres is small. After adding medical elastomer, its low temperature resistance can be improved.

[0014] Preferably, the crosslinking agent is one or both of divinylbenzene and N,N-methylenebisacrylamide.

[0015] By adopting the above technical solution, the crosslinking agent can be any one of the two or a mixture of the two; they are not listed one by one in the embodiments of the present application specification, but in principle they are all possible.

[0016] Preferably, the precipitate obtained in S2 is first washed with DMF, then washed with ethanol, and then dried.

[0017] By adopting the above technical scheme, unreacted monomers, cross-linking agents, initiators, etc. can be removed by DMF washing first, and then DMF is replaced by ethanol. Since the boiling point of DMF is higher and the boiling point of ethanol is lower, the solvent can be removed at a lower temperature and in a shorter time. This setting can reduce the energy consumption required for drying.

[0018] In a second aspect, the present application provides a method for preparing a highly weather-resistant medical elastomer, using the following technical solution: A method for preparing a highly weather-resistant medical elastomer comprises the following steps: The polypropylene, SEBS and nitrile rubber are washed with water and dried, and then added into a screw extruder together with silicone microspheres, melt-blended at 165-185° C., and then extruded and granulated to obtain a highly weather-resistant medical elastomer.

[0019] By adopting the above technical scheme, the preparation method of the present application has simple steps and has no special requirements for equipment and production process. It only needs to pay attention to controlling the temperature. The qualified rate of the produced products is high and it is suitable for large-scale production in factories.

[0020] In summary, the present application includes at least one of the following beneficial technical effects: 1. Adding silicone microspheres can greatly improve the low-temperature resistance of medical elastics. On the one hand, as silicone polymers, silicone microspheres can exert their own excellent properties such as non-toxicity, low-temperature resistance, high-temperature resistance, low viscosity, and oxidation resistance. After being added, they can greatly improve the low-temperature resistance of polypropylene and nitrile rubber composite medical elastomers. Its high silicon content can also greatly reduce the interfacial tension between the silicone microspheres and the system, making it highly compatible and giving full play to its low-temperature resistance. On the other hand, during the preparation of the silicone microspheres prepared in this application, a large amount of cross-linking agent is added after a certain period of reaction, so that the prepared silicone microspheres have a low internal cross-linking degree and a large external cross-linking degree in terms of physical structure, thereby having a macroscopic appearance. The elasticity of the silicone microspheres is high, and the silicone microspheres have a higher melting point, so that they do not melt when the medical elastomer is melted and mixed, and they still exist in the original form during the mixing process. Therefore, after the preparation of the medical elastomer, it can still maintain its structure and have its own elasticity. The silicone microspheres are evenly distributed inside the medical elastomer, so that the medical elastomer can be buffered when subjected to external forces, greatly improving the impact strength of the medical elastomer. Under the action of these two aspects, the low-temperature resistance of the medical elastomer is greatly improved; the polypropylene medical elastomer can maintain excellent impact strength when used at low temperatures, and is not prone to cracks and drug leakage.

[0021] 2. When preparing silicone microspheres, if the proportion of vinyl triethoxysilane added is too large, the rigidity of the silicone polymer is relatively large, which reduces the elasticity of the silicone microspheres and reduces their buffering effect, resulting in a decrease in the impact resistance of the medical elastomer. When vinyl triethoxysilane is not added, the performance of the silicone polymer cannot be exerted, which is not enough to improve the low-temperature resistance of the medical elastomer. At this ratio, the silicone microspheres obtained can optimize the low-temperature resistance of the medical elastomer.

[0022] 3. The present application can significantly improve the impact strength and low-temperature impact strength of the medical elastomer by adding silicone microspheres and adjusting the styrene and vinyl triethoxysilane added during the preparation of the silicone microspheres, and its brittle temperature is also reduced, thereby greatly improving the application potential of polypropylene and nitrile rubber composite medical elastomers; wherein, its impact strength is 41-50 kJ / m2, and its low-temperature impact strength is 11-22 kJ / m2, while the brittle temperature can be as low as -61°C. DETAILED DESCRIPTION

[0023] The present application is further described in detail below in conjunction with the specific contents.

[0024] raw material The raw materials used in the examples of the present application are all commercially available, among which the model of double-terminated vinyl polydimethylsiloxane is QL-2311VDV, with a specification of 30 viscosity; the processing grade of SEBS is injection molding grade, with the item number 7551; the processing grade of polypropylene is injection molding grade; the model of nitrile rubber is MY60M; the grade of silicone masterbatch is premium grade, with the model kJSI660; the model of hindered phenolic oxidant is antioxidant 1010, with a product grade of premium grade; the remaining raw materials are all common commercially available products with an analytical purity.

[0025] Preparation Example Preparation Example 1 A kind of organosilicon microsphere, the preparation method of which is as follows: S1. In a nitrogen atmosphere, add 20 g of vinyl triethoxysilane, 10 g of styrene, 0.4 g of double-terminal vinyl polydimethylsiloxane to 50 g of DMF, then add 0.01 g of azobisisobutyronitrile, heat to 67 ° C, stir and react for 3.5 hours, then add 0.5 g of a cross-linking agent, the cross-linking agent is divinylbenzene, continue stirring and reacting for 20 hours to obtain an emulsion mixture; S2. Filter the emulsion mixture obtained in S1, wash the obtained precipitate with DMF, then with ethanol, and dry at 70° C. to obtain organosilicon microspheres with a particle size range of 2-15 μm.

[0026] Preparation Example 2 A kind of organosilicon microspheres, which is different from Preparation Example 1 in that the added amount of vinyltriethoxysilane is 15g, the added amount of styrene is 15g, and the remaining steps are the same as Preparation Example 1.

[0027] Preparation Example 3 A kind of organosilicon microspheres, which is different from Preparation Example 1 in that the added amount of vinyltriethoxysilane is 25g, the added amount of styrene is 5g, and the remaining steps are the same as Preparation Example 1. Example

[0028] Example 1 A highly weather-resistant medical elastomer, the raw materials and the amounts of the raw materials are shown in Table 1, and the preparation method is as follows: The polypropylene, SEBS and nitrile rubber are washed and dried, and then added into a screw extruder together with silicone microspheres, melt-blended at 170°C, and then extruded and granulated to obtain a highly weather-resistant medical elastomer; The organosilicon microspheres are from Preparation Example 1; the lubricant is silicone masterbatch; and the antioxidant is a hindered phenolic oxidant, model number of which is antioxidant 1010.

[0029] Table 1 Raw materials and amounts of raw materials in Example 1 (kg) Polypropylene 70 SEBS 10 Nitrile rubber 20 Silicone microspheres 10 Lubricants 2 Antioxidants 0.5 Example 2 A highly weather-resistant medical elastomer is different from Example 1 in that the silicone microspheres are from Preparation Example 2, and the remaining steps are the same as those of Example 1.

[0030] Example 3 A highly weather-resistant medical elastomer is different from Example 1 in that the silicone microspheres are from Preparation Example 3, and the remaining steps are the same as those of Example 1.

[0031] Example 4 A highly weather-resistant medical elastomer is different from Example 1 in that the amount of silicone microspheres added is 5 kg, and the remaining steps are the same as those of Example 1.

[0032] Example 5 A highly weather-resistant medical elastomer is different from Example 1 in that the amount of silicone microspheres added is 15 kg, and the remaining steps are the same as those of Example 1.

[0033] Comparative Example Comparative Example 1 A highly weather-resistant medical elastomer is different from Example 1 in that the silicone microspheres added in the raw materials are replaced by an equal amount of polypropylene, and the remaining steps are the same as Example 1.

[0034] Comparative Example 2 A highly weather-resistant medical elastomer is different from Example 1 in that, during the preparation of its silicone microspheres, styrene is replaced by an equimolar amount of vinyltriethoxysilane, and the remaining steps are the same as those of Example 1.

[0035] Comparative Example 3 A highly weather-resistant medical elastomer is different from Example 1 in that, during the preparation of its silicone microspheres, vinyltriethoxysilane is replaced with an equal molar amount of styrene, and the remaining steps are the same as those of Example 1.

[0036] Performance testing Detection method / test method Highly weather-resistant medical elastomers were prepared by the preparation methods of Examples 1-5 and Comparative Examples 1-3, respectively, and then tested according to the following preparation methods. The test results are shown in Table 2.

[0037] Impact strength: The medical elastic system is made into a strip sample of 80mm×10mm×4mm, and the sample is tested at 23℃. According to the method in GB / T12670-2008, the simply supported beam notch impact strength of the long specimen is tested; Low-temperature impact strength: The medical elastic system is made into a long strip sample of 80mm×10mm×4mm, and the long strip sample is placed in an environment of -40℃ for 24h. The long strip sample is taken out and the simply supported beam notch impact strength of the long strip sample is tested at 23℃ using the method in GB / T12670-2008; Brittle temperature: Test according to the test method in GB / T5470-2008.

[0038] Table 2 Test results of Examples 1-5 and Comparative Examples 1-3 It can be seen from Examples 1-5 and Comparative Examples 1-3, as well as the test data in Table 2, that the present application can significantly improve the impact strength and low-temperature impact strength of the medical elastomer by adding silicone microspheres and adjusting the styrene and vinyl triethoxysilane added during the preparation of the silicone microspheres, and its brittle temperature is also reduced, greatly improving the application potential of the polypropylene and nitrile rubber composite medical elastomer; wherein, its impact strength is 41-50 kJ / m 2 , low temperature impact strength is 11-22kJ / m 2 , and the lowest brittle temperature can reach -61°C.

[0039] It can be seen from the test data of Example 1 and Comparative Example 1 that the low temperature resistance of medical elasticity can be greatly improved by adding organosilicon microspheres. This is because the organosilicon microspheres prepared in this application, as organosilicon polymers, can exert their own excellent properties such as non-toxicity, low temperature resistance, high temperature resistance, low viscosity, and oxidation resistance. After being added, the low temperature resistance of polypropylene and nitrile rubber composite medical elastomers can be greatly improved. Its silicon content is relatively high, and it can also greatly reduce the interfacial tension between the organosilicon microspheres and the system, so that it has excellent compatibility and can give full play to its low temperature resistance. On the other hand, the organosilicon microspheres prepared in this application have a low internal crosslinking degree and a large outer crosslinking degree, which makes them elastic, and the organosilicon microspheres have a higher melting temperature, so that they do not melt when the medical elastomer is melted and mixed, and still exist in the original form during the mixing process. Therefore, after the preparation of the medical elastomer, it can still have elasticity, so that the medical elastomer can be buffered when subjected to external force, and its impact strength is improved; under the action of both aspects, the low temperature resistance of the medical elastomer is greatly improved.

[0040] In combination with Example 2-3 and Comparative Example 2-3, when preparing silicone microspheres, when the proportion of vinyl triethoxysilane added is too large, the rigidity of the silicone polymer is relatively large, which reduces the elasticity of the silicone microspheres and its buffering effect is relatively low, resulting in a decrease in the impact resistance of the medical elastomer; when vinyl triethoxysilane is not added, the performance of the silicone polymer cannot be exerted, which is not enough to improve the low temperature resistance of the medical elastomer.

[0041] It can be seen from the test data of Example 1 and Examples 4-5 that, when other raw materials in the system remain unchanged, with the increase in the amount of added silicone microspheres, the low-temperature resistance of the medical elastomer gradually increases, and when the addition amount increases to 10 kg, the increase in its low-temperature resistance gradually decreases; therefore, considering all factors, the addition amount of 10 kg is the optimal addition amount.

[0042] This specific embodiment is merely an explanation of the present invention and is not a limitation of the present invention. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed. However, as long as they are within the scope of the claims of the present invention, they are protected by the patent law.

Claims

1. A highly weather-resistant medical elastomer, Features: The invention comprises the following raw materials in parts by weight: 65-75 parts of polypropylene, 8-12 parts of SEBS, 18-22 parts of nitrile rubber, 1-3 parts of lubricant, 0.5-1.5 parts of antioxidant and 5-15 parts of organosilicon microspheres; the preparation method of the organosilicon microspheres is as follows: S1. Under an inert gas atmosphere, using DMF as a solvent, 15-25 parts by weight of an organosilicon monomer, 5-15 parts by weight of styrene and 0.3-0.5 parts by weight of a double-terminated vinyl polydimethylsiloxane are polymerized with 0.007-0.013 parts by weight of an initiator for 3-4 hours, and then 0.4-0.6 parts by weight of a cross-linking agent is added, and the reaction is continued with stirring to obtain a mixed solution; S2. Filter the mixed solution obtained in S1, wash and dry the obtained precipitate to obtain organosilicon microspheres.

2. A highly weather-resistant medical elastomer according to claim 1, Features: The added amount of the organosilicon microspheres is 10 parts by weight.

3. The highly weather-resistant medical elastomer according to claim 1, Features: In the S1, the added amount of the silicone monomer is 20 parts by weight, and the added amount of the styrene is 10 parts by weight.

4. The highly weather-resistant medical elastomer according to claim 1, Features: The organic silicon monomer is one or more of vinyl triethoxysilane, methyl vinyl chlorosilane and vinyl trimethoxysilane.

5. The highly weather-resistant medical elastomer according to claim 1, Features: The initiator is azobisisobutyronitrile or azobisisoheptanenitrile.

6. The highly weather-resistant medical elastomer according to claim 1, Features: The cross-linking agent is one or both of divinylbenzene and N,N-methylenebisacrylamide.

7. The highly weather-resistant medical elastomer according to claim 1, Features: The precipitate obtained in S2 is first washed with DMF, then washed with ethanol, and then dried.

8. A method for preparing the highly weather-resistant medical elastomer according to any one of claims 1 to 7, Features: It includes the following steps: The polypropylene, SEBS and nitrile rubber are washed with water and dried, and then added into a screw extruder together with silicone microspheres, melt-blended at 165-185° C., and then extruded and granulated to obtain a highly weather-resistant medical elastomer.

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