Radiation-sterilizable polyethylene non-woven material and preparation method thereof

Abstract

The invention provides a radiation-sterilizable polyethylene non-woven material and a preparation method thereof, the radiation-sterilizable polyethylene non-woven material is formed by melt-blowing spinning of high melt index polyethylene and polybutadiene epoxide, and the melt index of the high melt index polyethylene is greater than or equal to 200g / 10min. The polybutadiene epoxide is used as a plasticizer, so that on one hand, the flowability of a high-melt-index polyethylene melt is improved, and melt-blowing processing of polyethylene is facilitated; on the other hand, microchemical cross-linking reaction is promoted in the heat treatment and radiation sterilization process of the microfibers, and the structural stability of the microfibers is improved.

Description

Technical Field

[0001] The invention relates to the field of nonwoven materials, and in particular to a radiation sterilizable polyethylene nonwoven material and a preparation method thereof. Background Art

[0002] At present, medical protective materials, such as masks and protective clothing, mostly use meltblown polypropylene nonwoven materials. Whether it is polypropylene prepared by metallocene or high melt index polypropylene prepared by degradation method, the meltblown nonwoven materials prepared by them need ethylene oxide sterilization, so it takes 7-14 days of decomposition time after sterilization to remove residual ethylene oxide. Therefore, it is of great significance to explore and establish a preparation method for medical protective materials that can be quickly sterilized.

[0003] High-density polyethylene non-woven fabrics have good radiation resistance and high long-term storage stability after radiation sterilization. DuPont of the United States selected it as the polymer matrix material for the preparation of limited-time high-end protective clothing. However, polyethylene has a low melt index, high melt viscosity, and is not easily soluble in solvents at room temperature and pressure. Therefore, conventional spinning methods cannot process it into microfiber non-woven materials. Compared with traditional non-woven fabric technology, the flash evaporation polyethylene non-woven fabric technology was invented by DuPont of the United States and has been used for the industrial development of high-density polyethylene non-woven fabrics. Its product "Tyvek" is used in advanced medical protection products and other fields, and has been selected as a special protective textile for Ebola virus protection in Africa. The flash evaporation technology sprays a saturated solution of high-density polyethylene under high temperature and pressure into the atmospheric environment to obtain a non-woven fabric. However, the flash evaporation method has environmental pollution problems, which is not conducive to industrial application. Summary of the invention

[0004] The main purpose of the present invention is to provide a radiation sterilizable polyethylene nonwoven material and a preparation method thereof, so as to overcome the problems in the prior art that meltblown polypropylene fibers are not resistant to rapid radiation sterilization and the mechanical strength of meltblown polyethylene microfibers is insufficient.

[0005] In order to achieve the above object, the present invention provides a radiation sterilizable polyethylene nonwoven material, which is formed by melt-blowing high melt index polyethylene and polybutadiene epoxide, wherein the melt index of the high melt index polyethylene is greater than or equal to 200g / 10min.

[0006] The radiation sterilizable polyethylene nonwoven material of the present invention comprises: a melt index of the high melt index polyethylene of 200-1500 g / 10 min; and an epoxy molar content of the polybutadiene epoxide of 5%-8%.

[0007] The radiation sterilizable polyethylene nonwoven material of the present invention comprises the following: the mass ratio of the high melt index polyethylene to the polybutadiene epoxide is 90-99:10-1; the number average molecular weight of the polybutadiene epoxide is 4000-5000, and the viscosity is 2500-3000.

[0008] The radiation sterilizable polyethylene nonwoven material of the present invention further comprises an antioxidant, wherein the antioxidant is 4,4'-thiobis(6-tert-butyl-3-methylphenol), and the amount of the antioxidant added is 0.1 to 0.3% of the sum of the mass of the high melt index polyethylene and the polybutadiene epoxide.

[0009] In order to achieve the above object, the present invention also provides a method for preparing a radiation sterilizable polyethylene nonwoven material, comprising the following steps:

[0010] Step 1, mixing and granulating high melt index polyethylene and polybutadiene epoxide;

[0011] Step 2, melt-blowing the resin obtained in step 1 to form an initial polyethylene nonwoven material;

[0012] Step 3, heat-treating the initial polyethylene nonwoven material to obtain a radiation sterilizable polyethylene nonwoven material;

[0013] Wherein, the melt index of the high melt index polyethylene is greater than or equal to 200 g / 10 min.

[0014] The method for preparing the radiation sterilizable polyethylene nonwoven material of the present invention comprises the following steps: the melt index of the high melt index polyethylene is 200-1500 g / 10 min; and the epoxy content of the polybutadiene epoxide is 5%-8%.

[0015] The method for preparing the radiation sterilizable polyethylene nonwoven material of the present invention comprises the following steps: the mass ratio of the high melt index polyethylene to the polybutadiene epoxide is 90-99:10-1.

[0016] The method for preparing the radiation sterilizable polyethylene nonwoven material of the present invention comprises the following steps: step 2 is carried out in a melt-blown spinning machine, the screw temperature is 200-240° C., the hot air temperature is 230-260° C., the hot air frequency is 40-50 Hz, and the receiving distance is 20-35 cm.

[0017] The method for preparing the radiation sterilizable polyethylene nonwoven material of the present invention comprises the following steps: in step 1, an antioxidant is added during the mixing and granulation of the high melt index polyethylene and the polybutadiene epoxide, wherein the antioxidant is 4,4'-thiobis(6-tert-butyl-3-methylphenol), and the amount of the antioxidant added is 0.1 to 0.3% of the sum of the mass of the high melt index polyethylene and the polybutadiene epoxide.

[0018] In the method for preparing the radiation sterilizable polyethylene nonwoven material of the present invention, the heat treatment temperature is 90-110°C.

[0019] Beneficial effects of the present invention:

[0020] The present invention utilizes polybutadiene epoxide as a plasticizer, which, on the one hand, improves the fluidity of high melt index polyethylene melt, which is beneficial to polyethylene melt-blowing processing; on the other hand, promotes the occurrence of trace chemical cross-linking reactions during microfiber heat treatment and radiation sterilization, thereby improving the structural stability of the microfiber. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Schematic diagram of the processing of polyethylene nonwoven material in one embodiment of the present invention;

[0022] Figure 2 This is a SEM picture of the polyethylene nonwoven material of Example 1 of the present invention;

[0023] Figure 3 This is a statistical table of SEM diameters of the polyethylene nonwoven material of Example 1 of the present invention.

[0024] Wherein, the reference numerals are:

[0025] 1 Feeding device

[0026] 2 Screw Extruder

[0027] 3 Metering pump

[0028] 4. Web forming device

[0029] 5. Meltblown die head

[0030] 6 Heat treatment device

[0031] 7. Winding device DETAILED DESCRIPTION

[0032] The technical scheme of the present invention is described in detail below. The following implementation modes are implemented on the premise of the technical scheme of the present invention, and a detailed implementation process is given. However, the protection scope of the present invention is not limited to the following implementation modes. The structures or experimental methods of specific conditions are not specified in the following implementation modes, and generally conventional conditions are followed.

[0033] The invention provides a radiation sterilizable polyethylene nonwoven material, which is formed by melt-blowing high melt index polyethylene and polybutadiene epoxide, wherein the melt index of the high melt index polyethylene is greater than or equal to 200 g / 10 min (wherein the melt index refers to the melt index tested under a load of 2.16 kg and a temperature of 190° C.).

[0034] The present invention utilizes polybutadiene epoxide as a plasticizer, which, on the one hand, improves the fluidity of high melt index polyethylene melt, which is beneficial to polyethylene melt-blowing processing; on the other hand, promotes the occurrence of trace chemical cross-linking reactions during microfiber heat treatment and radiation sterilization, thereby improving the structural stability of the microfiber.

[0035] In one embodiment, the melt index of the high melt index polyethylene is 200-1500 g / 10 min; the epoxy content of the polybutadiene epoxide is 5%-8%. In another embodiment, the molecular weight of the polybutadiene epoxide is about 4000-5000, and the viscosity is 2500-3000. In another embodiment, the mass ratio of the high melt index polyethylene to the polybutadiene epoxide is 90-99:10-1.

[0036] In one embodiment, an antioxidant is further added to the radiation sterilizable polyethylene nonwoven material. The antioxidant is, for example, 4,4'-thiobis(6-tert-butyl-3-methylphenol). The amount of the antioxidant added is 0.1-0.3% of the sum of the mass of the high melt index polyethylene and the polybutadiene epoxide.

[0037] In one embodiment, the ratio of each substance in the radiation sterilizable polyethylene nonwoven material of the present invention is: 90 kg of high melt index polyethylene, 0.91-10 kg of polybutadiene epoxide, and 0.09-0.3 kg of antioxidant.

[0038] The present invention also provides a method for preparing a radiation sterilizable polyethylene nonwoven material, comprising the following steps:

[0039] Step 1, mixing and granulating high melt index polyethylene and polybutadiene epoxide;

[0040] Step 2, melt-blowing the resin obtained in step 1 to form an initial polyethylene nonwoven material;

[0041] Step 3, heat-treating the initial polyethylene nonwoven material to obtain a radiation sterilizable polyethylene nonwoven material;

[0042] Wherein, the melt index of the high melt index polyethylene is greater than or equal to 200 g / 10 min.

[0043] In one embodiment, the melt index of the high melt index polyethylene is 200-1500 g / 10 min (2.16 kg, 190° C.); the epoxy molar content of the polybutadiene epoxide is 5%-8%. In another embodiment, the mass ratio of the high melt index polyethylene to the polybutadiene epoxide is 90-99:10-1.

[0044] The present invention does not particularly limit the specific method of mixing and granulating the high melt index polyethylene and polybutadiene epoxide, for example, granulation is performed in a screw extruder, and kneading and granulation is performed in a kneader, the kneading and granulation temperature is, for example, 100-120° C., and the kneading and granulation time is, for example, 10-30 minutes.

[0045] In one embodiment, an antioxidant is added during the mixing and granulation of the high melt index polyethylene and polybutadiene epoxide. The antioxidant is 4,4'-thiobis(6-tert-butyl-3-methylphenol). The amount of the antioxidant added is 0.1 to 0.3% of the sum of the mass of the high melt index polyethylene and the polybutadiene epoxide.

[0046] Then, the kneaded and granulated resin is melt-blown spun, and the melt-blown spinning is carried out, for example, by a melt-blown spinning machine, with a screw temperature of 200-240° C., a hot air temperature of 230-260° C., a hot air frequency of 40-50 Hz, and a receiving distance of 20-35 cm. The melt-blown fibers are deposited on a web-forming device to form an initial polyethylene nonwoven material.

[0047] Finally, the initial polyethylene nonwoven material is heat treated to obtain a radiation sterilizable polyethylene nonwoven material. In one embodiment, the heat treatment temperature is 90 to 110° C.; in another embodiment, the initial polyethylene nonwoven material is heat treated during the conveying process after melt-blown spinning, and the conveying speed is 50 to 110 m / min.

[0048] In one embodiment, the polyethylene nonwoven material processing of the present invention is as follows Figure 1 As shown, but the present invention is not limited thereto. The high melt index polyethylene and polybutadiene epoxide enter the screw extruder 2 through the feeding device 1, and the composite resin is extruded and granulated, and then passes through the metering pump 3 and the melt-blowing die head 5, and settles on the web forming device 4 to obtain an initial polyethylene nonwoven material, and then the initial polyethylene nonwoven material is heat-treated by the heat treatment device 6 to obtain a polyethylene nonwoven material, and the polyethylene nonwoven material is wound up by the winding device 7.

[0049] The radiation sterilization method of the radiation sterilizable polyethylene nonwoven material of the present invention can be selected from electron beam radiation sterilization or X-ray sterilization, and the metering control is 16-27 kGy.

[0050] The present invention adopts high melt index polyethylene as the polymer matrix. The polyethylene material is more flexible than polypropylene, which greatly improves the drape / softness of the material, and the non-woven fabric made has better comfort; the thermal conductivity of polyethylene fiber is much greater than that of polypropylene, which is beneficial to the heat dissipation of the non-woven fabric.

[0051] The polyethylene nonwoven material obtained by the method of the invention has transverse and longitudinal breaking strengths greater than 3N, a filtration efficiency of ≥95%, and a resistance of <200Pa.

[0052] The technical solution of the present invention will be further described in detail below through specific embodiments.

[0053] Source of raw materials or equipment:

[0054] (1) Raw materials:

[0055] High melt index polyethylene, provided by Daqing Chemical Research Center of PetroChina Co., Ltd.;

[0056] Polybutadiene epoxide, 62000 epoxy resin, produced by Guangzhou Kafen Biotechnology Co., Ltd.;

[0057] The antioxidant 4,4'-thiobis(6-tert-butyl-3-methylphenol) was produced by Wuhan Smack Biotechnology Co., Ltd.

[0058] (2) Equipment:

[0059] Kneading and mixing equipment, designed and manufactured by Donghua University;

[0060] Meltblown spinning machine, produced by Tuoren Group;

[0061] X-ray irradiation equipment, produced by Bruker GmbH of Germany.

[0062] Example 1

[0063] 1) Preparation of high melt index polyethylene, polybutadiene epoxide, antioxidant 4,4'-thiobis(6-tert-butyl-3-methylphenol) composite resin:

[0064] Using a kneading and mixing device, 90 kg of polyethylene powder with a melt index of 300, 1 kg of polybutadiene epoxide (epoxide molar content 5%) and 0.095 kg of 4,4'-thiobis(6-tert-butyl-3-methylphenol) were stirred and added into a kneader at a temperature of 110°C. The mixture was rapidly stirred and kneaded for 15 minutes. It was observed that the powder had no agglomeration phenomenon. The powder was kneaded into a granular resin state through an injection molding component.

[0065] 2) Meltblown microfiber nonwoven materials:

[0066] The above resin was melt-blown by Tuoren Group melt-blown spinning machine to prepare polyethylene microfibers. During the preparation process, the temperature of the screw compression section and the homogenization section was set at 120-240°C, the temperature of the melt-blown component was 240°C, the hot air temperature was set at 260°C, the hot air frequency was set at 45Hz, and the receiving distance was 35cm to obtain a melt-blown polyethylene microfiber nonwoven material.

[0067] Figure 2 This is the SEM picture of the polyethylene nonwoven material of Example 1 of the present invention, obtained by dimensional measurement Figure 3 Statistical table of SEM diameters of polyethylene nonwoven materials in Example 1 of the present invention. Figure 2 and Figure 3 As shown, the diameter of polyethylene microfibers is mainly 2-5 μm, and a small amount is 6-8 μm. This fiber diameter distribution helps to form a spatial structure that is beneficial to mechanical enhancement.

[0068] The transverse and longitudinal breaking strengths of the microfiber nonwoven material reach 4±0.23N and 3.5±0.14N. The mask filter material prepared by using the microfiber nonwoven material through disposable mask equipment has a filtration efficiency of ≥95% and a resistance of ﹤200Pa.

[0069] 3) Post-processing and sterilization of nonwoven materials:

[0070] The nonwoven material obtained by meltblowing is transported to a heat treatment device via a 50 m / min conveyor belt, and the temperature is set at 100°C to obtain a finalized meltblown nonwoven material. After irradiation with 27 kGy X-rays, the nonwoven material is tested to have no E. coli colonies, bacterial colonies, fungal colonies, etc.

[0071] Example 2

[0072] 1) Preparation of high melt index polyethylene, polybutadiene epoxide, antioxidant 4,4'-thiobis(6-tert-butyl-3-methylphenol) composite resin:

[0073] Using a kneading and mixing device, 90 kg of high melt index polyethylene (700 g / 10 min) powder, 10 kg of polybutadiene epoxide (epoxide molar content 8%) and 0.2 kg of 4,4'-thiobis(6-tert-butyl-3-methylphenol) were stirred and added into a kneader at a temperature of 110°C. The mixture was rapidly stirred and kneaded for 15 minutes. No agglomeration of the powder was observed. The powder was kneaded into a granular resin through an injection molding assembly.

[0074] 2) Meltblown microfiber nonwoven materials:

[0075] The above resin was melt-blown by Tuoren Group melt-blown spinning machine to prepare polyethylene microfibers. The temperature of the screw compression section and the homogenization section was set at 120-240°C, the temperature of the melt-blown assembly was 220°C, the hot air temperature was set at 250°C, the hot air frequency was set at 50Hz, and the receiving distance was 20cm to obtain a melt-blown polyethylene microfiber nonwoven material. The transverse and longitudinal breaking strengths of the microfiber nonwoven material reached 3.5±0.21N and 3.2±0.22N, and the filter material prepared therefrom had a filtration efficiency of ≥95% and a resistance of ﹤200Pa.

[0076] 3) Post-processing and sterilization of nonwoven materials:

[0077] The nonwoven material obtained by meltblowing is transported to a heat treatment device via a 110 m / min conveyor belt, and the temperature is set at 90°C to obtain a shaped meltblown nonwoven material. After the nonwoven material is irradiated with 16 kGy electron beam radiation, it is tested that there is no E. coli colony, bacterial colony, fungal colony, etc.

[0078] Example 3

[0079] 1) Preparation of high melt index polyethylene, polybutadiene epoxide, antioxidant 4,4'-thiobis(6-tert-butyl-3-methylphenol) composite resin:

[0080] Using a kneading and mixing device, 95 kg of high melt index polyethylene (200 g / 10 min) powder, 5 kg of polybutadiene epoxide (epoxy value 6%) and 0.3 kg of 4,4'-thiobis(6-tert-butyl-3-methylphenol) were stirred and added into a kneader at a temperature of 110°C. The mixture was rapidly stirred and kneaded for 15 minutes. No agglomeration of the powder was observed. The powder was kneaded into a granular resin through an injection molding assembly.

[0081] 2) Meltblown microfiber nonwoven materials:

[0082] The above resin was melt-blown by Tuoren Group melt-blown spinning machine to prepare polyethylene microfibers. The temperature of the screw compression section and the homogenization section was set to 120-240°C, the temperature of the melt-blown assembly was 240°C, the hot air temperature was set to 260°C, the hot air frequency was set to 45Hz, and the receiving distance was 25cm to obtain a melt-blown polyethylene microfiber nonwoven material. The transverse and longitudinal breaking strengths of the microfiber nonwoven material reached 5.3±0.27N and 4.5±0.24N, and the filter material prepared therefrom had a filtration efficiency of ≥95% and a resistance of ﹤200Pa.

[0083] 3) Post-processing and sterilization of nonwoven materials:

[0084] The nonwoven material obtained by meltblowing is transported to a heat treatment device via a 75m / min conveyor belt, and the temperature is set at 100°C to obtain a finalized meltblown nonwoven material. After 25kGy X-ray irradiation, the nonwoven material is tested to have no E. coli colonies, bacterial colonies, fungal colonies, etc.

[0085] Example 4

[0086] 1) Preparation of high melt index polyethylene, polybutadiene epoxide, antioxidant 4,4'-thiobis(6-tert-butyl-3-methylphenol) composite resin:

[0087] Using a kneading and mixing device, 95 kg of high melt index (1500 g / 10 min) polyethylene powder, 5 kg of polybutadiene epoxide (epoxy value 6%) and 0.1 kg of 4,4'-thiobis(6-tert-butyl-3-methylphenol) were stirred and added into a kneader at a temperature of 110°C. The mixture was rapidly stirred and kneaded for 15 minutes. No agglomeration of the powder was observed. The powder was kneaded into a granular resin through an injection molding assembly.

[0088] 2) Meltblown microfiber nonwoven materials:

[0089] The above resin was melt-blown by Tuoren Group melt-blown spinning machine to prepare polyethylene microfibers. The temperature of the screw compression section and the homogenization section was set at 120-240°C, the temperature of the melt-blown assembly was 200°C, the hot air temperature was set at 230°C, the hot air frequency was set at 40Hz, and the receiving distance was 20cm to obtain a melt-blown polyethylene microfiber nonwoven material. The transverse and longitudinal breaking strengths of the microfiber nonwoven material reached 5.3±0.15N and 4.5±0.21N, and the filter material prepared therefrom had a filtration efficiency of ≥95% and a resistance of ﹤200Pa.

[0090] 3) Post-processing and sterilization of nonwoven materials:

[0091] The nonwoven material obtained by meltblowing is transported to a heat treatment device via a 60m / min conveyor belt, and the temperature is set at 110°C to obtain a finalized meltblown nonwoven material. After 25kGy X-ray irradiation, the nonwoven material is tested to have no E. coli colonies, bacterial colonies, fungal colonies, etc.

[0092] Of course, the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, technicians familiar with the field may make various corresponding changes and deformations based on the present invention, but these corresponding changes and deformations should all fall within the scope of protection of the claims of the present invention.

Claims

1. A radiation sterilizable polyethylene nonwoven material, characterized in that: The high melt index polyethylene and polybutadiene epoxide are melt-blown and spun, wherein the melt index of the high melt index polyethylene is greater than or equal to 200 g / 10 min.

2. The radiation sterilizable polyethylene nonwoven material according to claim 1, characterized in that The melting index of the high melting index polyethylene is 200-1500 g / 10 min; the epoxy molar content of the polybutadiene epoxide is 5%-8%.

3. The radiation sterilizable polyethylene nonwoven material according to claim 1, characterized in that The mass ratio of the high melt index polyethylene to the polybutadiene epoxide is 90-99:10-1; the number average molecular weight of the polybutadiene epoxide is 4000-5000, and the viscosity is 2500-3000.

4. The radiation sterilizable polyethylene nonwoven material according to claim 1, characterized in that The radiation sterilizable polyethylene nonwoven material also contains an antioxidant, which is 4,4'-thiobis(6-tert-butyl-3-methylphenol), and the amount of the antioxidant added is 0.1-0.3% of the total mass of the high melt index polyethylene and the polybutadiene epoxide.

5. A method for preparing a radiation sterilizable polyethylene nonwoven material, characterized in that: The steps include: Step 1, mixing and granulating high melt index polyethylene and polybutadiene epoxide; Step 2, melt-blowing the resin obtained in step 1 to form an initial polyethylene nonwoven material; Step 3, heat-treating the initial polyethylene nonwoven material to obtain a radiation sterilizable polyethylene nonwoven material; Wherein, the melt index of the high melt index polyethylene is greater than or equal to 200 g / 10 min.

6. The method for preparing the radiation sterilizable polyethylene nonwoven material according to claim 5, characterized in that: The melting index of the high melting index polyethylene is 200-1500 g / 10 min; the epoxy content of the polybutadiene epoxide is 5%-8%.

7. The method for preparing the radiation sterilizable polyethylene nonwoven material according to claim 5, characterized in that: The mass ratio of the high melt index polyethylene to the polybutadiene epoxide is 90-99:10-1.

8. The method for preparing the radiation sterilizable polyethylene nonwoven material according to claim 5, characterized in that: Step 2 is carried out in a melt-blown spinning machine, with a screw temperature of 200-240°C, a hot air temperature of 230-260°C, a hot air frequency of 40-50Hz, and a receiving distance of 20-35cm.

9. The method for preparing the radiation sterilizable polyethylene nonwoven material according to claim 5, characterized in that: In step 1, an antioxidant is added during the mixing and granulation of high melt index polyethylene and polybutadiene epoxide. The antioxidant is 4,4'-thiobis(6-tert-butyl-3-methylphenol). The amount of the antioxidant added is 0.1-0.3% of the sum of the mass of the high melt index polyethylene and the polybutadiene epoxide.

10. The method for preparing the radiation sterilizable polyethylene nonwoven material according to claim 5, characterized in that: The heat treatment temperature is 90-110°C.

Images