Polypropylene composite material and gamma ray irradiation resistant non-woven fabric

Abstract

The invention discloses a polypropylene composite material and gamma ray irradiation resistant non-woven fabric. The polypropylene composite material is prepared from the following raw materials in parts by mass: 100 parts of polypropylene, 5 to 15 parts of irradiation resistant master batch, 5 to 20 parts of thermoplastic elastomer and 0.05 to 1 part of antioxidant, the irradiation-resistant master batch is obtained by mixing and granulating polypropylene, a hindered amine light stabilizer and an initiator according to the mass ratio of 100: (2-6): (0.1-1.2). The polypropylene composite material provided by the invention has good irradiation resistance, and still keeps good mechanical properties and yellowing resistance after irradiation, and when the polypropylene composite material is used in the non-woven fabric, the obtained non-woven fabric also has good irradiation resistance, for example, the non-woven fabric is not easy to yellow after irradiation, and the mechanical properties are good.

Description

Technical Field

[0001] The invention belongs to the technical field of polypropylene materials, and in particular relates to a polypropylene composite material and a gamma ray irradiation-resistant non-woven fabric. Background Art

[0002] Polypropylene is one of the most widely used polymer materials both domestically and internationally. Its advantages include high quality, low price, odorlessness, non-toxicity, widespread availability, excellent mechanical strength, and good chemical stability. It is widely used in many fields, such as the medical field. Non-woven fabrics made from polypropylene can be further manufactured into products such as drapes, surgical packs, surgical gowns, and sterilization wraps. These medical supplies require disinfection and sterilization before use.

[0003] Traditional sterilization methods include high-temperature and high-pressure steam, ethylene oxide fumigation, and irradiation sterilization. Since the high-temperature and high-pressure method has incomplete sterilization and is not suitable for heat-sensitive polymer materials, and the ethylene oxide sterilization method requires a long time to decompose and may have chemical residues, these two sterilization methods have major disadvantages. Currently, the sterilization method of medical materials is increasingly tending to use irradiation technology for sterilization. Irradiation sterilization is to directly irradiate medical products with high-energy rays (such as gamma rays) to eliminate microorganisms. It has many advantages, such as energy saving, thorough sterilization, no pollution, fast sterilization speed, and continuous operation. In addition, irradiation sterilization is a "cold disinfection" method that can be sterilized at room temperature and is particularly suitable for some heat-sensitive materials.

[0004] However, conventional medical polypropylene nonwovens have poor radiation stability. After irradiation, the product's mechanical properties deteriorate and it easily yellows, leading to a loss of performance. This is primarily due to the highly reactive hydrogen atoms on the tertiary carbon atoms in the polypropylene molecular chain. Irradiation easily generates free radicals, which lead to chain scission reactions, causing yellowing and fading on the surface, degradation, and reduced performance. Degradation is further severe after storage for a period of time after irradiation. Therefore, polypropylene for irradiation sterilization requires a special formulation to produce medical products that can withstand the high-energy radiation used during sterilization.

[0005] Patent CN111393745A discloses the use of acetonethiosemicarbazone to eliminate free radicals generated after polypropylene irradiation. A combination of phenolic, thioester, and phosphite antioxidants is used to prevent or slow the generation of free radicals during oxidative aging. The resulting polypropylene resin composition exhibits excellent radiation resistance and meets the requirements for electron beam sterilization of medical nonwovens. However, phenolic antioxidants are easily oxidized by free radicals generated during irradiation to form quinone and methylquinone colorants, exacerbating discoloration of the material. Summary of the Invention

[0006] Based on the above technical problems, the application provides a polypropylene composite material and a gamma ray irradiation resistant non-woven fabric, the polypropylene composite material has good irradiation resistance, and still has good mechanical properties and yellowing resistance after irradiation, and when used in the non-woven fabric, the obtained non-woven fabric also has good irradiation resistance, for example, the non-woven fabric is not prone to yellowing after irradiation, and has good mechanical properties.

[0007] The polypropylene composite material provided by the application comprises, by mass fraction, 100 parts of polypropylene, 5-15 parts of irradiation resistant master batch, 5-20 parts of thermoplastic elastomer and 0.05-1 part of antioxidant.

[0008] The irradiation resistant master batch is obtained by mixing polypropylene, hindered amine light stabilizer and initiator according to a mass ratio of 100:2-6:0.1-1.2 and granulating, and the structure formula of the hindered amine light stabilizer is as follows:

[0009]

[0010] n is an integer of 1-5.

[0011] In the application, the hindered amine light stabilizer is blended with polypropylene and then modified by heat crosslinking of the initiator, the hindered amine light stabilizer contains an end alkenyl group with an unsaturated bond, the hindered amine group can be grafted onto the polypropylene molecular chain by heat initiation technology, on the one hand, the light stabilizer is not prone to migration to the material surface and dissolution and precipitation, the light stability of the obtained polypropylene composite material is obviously enhanced, and the polypropylene composite material plays a role in shielding and absorbing gamma rays (i.e. γ rays); on the other hand, the heat crosslinking modification also makes the polypropylene crosslink to form a three-dimensional space grid structure, stabilizes the molecular chain, and the generated crosslinking branch chain can also absorb and convert radiation energy, further improving the irradiation resistance of the material.

[0012] Preferably, the polypropylene is homopolymer polypropylene or copolymer polypropylene, and preferably has a melt index of 1-100 g / 10 min under the condition of 230 DEG C and 2.16 kg.

[0013] Preferably, the hindered amine light stabilizer is prepared by the following method: first, nucleophilic substitution reaction is carried out on cyanuric chloride and N-n-butyl-2,2,6,6-tetramethyl-4-piperidinamine, then, nucleophilic substitution reaction is continuously carried out on the reaction product and dipropylene triamine, and then, electrophilic substitution reaction is carried out on the reaction product and an end alkenyl halogenated hydrocarbon, thereby obtaining the hindered amine light stabilizer.

[0014] Preferably, the end alkenyl halogenated hydrocarbon has the following structure formula:

[0015]

[0016] X is Br or Cl, and n is an integer of 1-5.

[0017] Preferably, the terminal alkenyl halogenated hydrocarbon is at least one of 3-bromo-1-propene, 3-chloro-1-propene, 4-bromo-1-butene, 4-chloro-1-butene, 5-bromo-1-pentene, 5-chloro-1-pentene, 6-bromo-1-hexene or 6-chloro-1-hexene.

[0018] Preferably, the initiator is at least one of dicumyl peroxide, di-tert-butyl peroxide, dibenzoyl peroxide or 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane.

[0019] Preferably, the radiation-resistant master batch is obtained by adding polypropylene, hindered amine light stabilizer and initiator into a high-speed mixer for mixing, and then adding into a twin-screw extruder for melt extrusion and granulation;

[0020] Preferably, the high-speed mixer has a rotation speed of 800-1000 r / min and a mixing time of 5-10 min; the twin-screw extruder has a screw rotation speed of 100-200 r / min, a feeding section temperature of 100-120℃, a melting section temperature of 150-170℃ and a conveying section temperature of 170-190℃.

[0021] Preferably, the thermoplastic elastomer is at least one of hydrogenated polystyrene-butadiene-styrene triblock copolymer, hydrogenated polyethylene-polyisoprene-poly-styrene triblock copolymer, ethylene-octene copolymer or ethylene-propylene copolymer.

[0022] Preferably, the antioxidant is a phosphite antioxidant, preferably at least one of antioxidant 168, antioxidant 626 or antioxidant 627.

[0023] Preferably, the polypropylene composite raw material further comprises 0.1-1 parts by mass of a lubricant and 0.05-0.5 parts by mass of an acid absorbent.

[0024] Preferably, the lubricant is at least one of ethylene bis-stearamide, polyethylene wax, oleic acid amide or erucic acid amide, and the acid absorbent is at least one of calcium stearate or magnesium aluminum hydrotalcite.

[0025] Preferably, the preparation method of the polypropylene composite comprises: adding polypropylene, radiation-resistant master batch, thermoplastic elastomer and antioxidant into a high-speed mixer for mixing, and then adding into a twin-screw extruder for melt extrusion and granulation, and drying to obtain the polypropylene composite;

[0026] Preferably, the high mixer speed is 1000-1200 r / min, and the mixing time is 5-10 min; the screw speed of the twin-screw extruder is 100-200 r / min, the feeding section temperature is 120-140°C, the melting section temperature is 150-170°C, and the conveying section temperature is 180-200°C; the drying temperature is 80-100°C, and the drying time is 4-6 hours.

[0027] The present invention also provides a gamma ray irradiation-resistant non-woven fabric, which is made of the polypropylene composite material.

[0028] Compared with the prior art, the present invention has the following technical effects:

[0029] (1) The polypropylene composite material of the present invention comprises polypropylene, a radiation-resistant masterbatch, a thermoplastic elastomer and an antioxidant. Since the radiation-resistant masterbatch is obtained by blending and modifying polypropylene and a hindered amine light stabilizer in the presence of an initiator, and the thermoplastic elastomer and polypropylene are combined with the antioxidant for synergistic effect, the polypropylene composite material has good radiation resistance and still maintains good mechanical properties and yellowing resistance after irradiation.

[0030] (2) After irradiation with a gamma ray dose of 50 KGy, the tensile yield strength (MPa) of the polypropylene composite material of the present invention decreases by no more than 2%, the flexural modulus (MPa) increases by no more than 2%, and the yellowness index increases by no more than 20%.

[0031] (3) When the polypropylene composite material of the present invention is applied to non-woven fabrics, the non-woven fabrics have good radiation resistance. For example, after irradiation, the non-woven fabrics are not easy to turn yellow and have good mechanical properties, which is conducive to the use of non-woven fabrics in the medical field. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 The synthetic route of the hindered amine light stabilizer described in the embodiments of the present invention is shown in FIG. DETAILED DESCRIPTION

[0033] Hereinafter, the present invention will describe the technical solution in detail through specific embodiments. However, it should be clearly stated that these embodiments are provided for illustration only and are not to be construed as limiting the scope of the present invention.

[0034] In the embodiment, the hindered amine light stabilizer is prepared by the following method:

[0035] Reference Figure 1The synthetic route comprises dissolving cyanuric chloride (18.44 g, 100 mmol) in toluene (200 mL), slowly adding N-n-butyl-2,2,6,6-tetramethyl-4-piperidinamine (42.46 g, 200 mmol) in an ice-water bath, stirring and reacting for 2 h, then dropwise adding an aqueous solution (20 mL) of sodium hydroxide (8.00 g, 200 mmol), heating to 70° C. and stirring and reacting for 12 h. After cooling to room temperature, the mixture is extracted three times with water and ethyl acetate, the organic phases are combined, dried, and the solvent is removed by rotary evaporation to obtain compound A.

[0036] Compound A was dissolved in toluene (200 mL), and an aqueous solution (1500 mL) containing sodium hydroxide (400.0 g, 10 mol) was added, followed by dipropylene triamine (6.56 g, 50 mmol). The mixture was heated to 110°C under nitrogen and stirred for 16 h. After cooling to room temperature, the mixture was separated, the solvent was removed by rotary evaporation, and the mixture was washed with water and dried to obtain compound B.

[0037] Compound B was dissolved in dichloromethane (150 mL), and 3-bromo-1-propene (6.05 g, 50 mmol) and triethylamine (7.59 g, 75 mmol) were added. The mixture was heated to 45° C. and stirred for 2 h. After cooling to room temperature, water was added, the mixture was separated, the solvent was removed by rotary evaporation, and the mixture was washed with water, dried, and purified by n-hexane / ethyl acetate column chromatography to obtain compound TM, which is the hindered amine light stabilizer.

[0038] The HNMR spectrum of the above hindered amine light stabilizer is: 1 H NMR(400MHz, CDCl3)δ5.87(s,1H),5.17(m,2H),5.05-5.01(m,4H),4.09-4.03(m,2H),3.37-3.32 (m,8H),3.06(m,12H),2.30(m,10H),1.66-1.59(m,24H),1.29-1.12(m,52H),0.95-0.90(m,12H).

[0039] Example 1

[0040] This embodiment provides a polypropylene composite material, the raw materials of which include, by mass, 100 parts of polypropylene (LG R6400), 10 parts of radiation-resistant masterbatch, and ethylene-octene copolymer (Dow ENGAGE TM 7447) 10 parts and antioxidant 1680.1 parts;

[0041] The radiation-resistant masterbatch is prepared by adding polypropylene (LG R6400), a hindered amine light stabilizer, and dicumyl peroxide in a mass ratio of 100:4:0.5 into a high-speed mixer and mixing them uniformly. The high-speed mixer rotates at 900 r / min and the mixing time is 8 minutes. The masterbatch is then added into a twin-screw extruder for melt extrusion and granulation. The screw speed of the twin-screw extruder is 150 r / min, the feeding section temperature is 110° C., the melting section temperature is 160° C., and the conveying section temperature is 180° C.

[0042] The preparation method of the polypropylene composite material comprises: mixing 100 parts of polypropylene (LG R6400), 10 parts of radiation-resistant masterbatch, and ethylene-octene copolymer (Dow ENGAGE TM 7447) 10 parts and antioxidant 1680.1 parts are added into a high mixer and mixed evenly, the high mixer speed is 1100r / min, the mixing time is 8min, and then added into a twin-screw extruder for melt extrusion and granulation, the twin-screw extruder screw speed is 150r / min, the feeding section temperature is 130℃, the melting section temperature is 160℃, the conveying section temperature is 190℃, and after drying at 90℃ for 5h, the polypropylene composite material is obtained.

[0043] Example 2

[0044] This embodiment provides a polypropylene composite material, the raw materials of which include, by mass, 100 parts of polypropylene (LG R6400), 5 parts of radiation-resistant masterbatch, 20 parts of hydrogenated polystyrene-butadiene-styrene triblock copolymer (Kraton G1652), and 6261 parts of antioxidant;

[0045] The radiation-resistant masterbatch is prepared by adding polypropylene (LG R6400), a hindered amine light stabilizer, and dicumyl peroxide in a mass ratio of 100:6:1.2 into a high-speed mixer and mixing them uniformly. The high-speed mixer rotates at 800 r / min and the mixing time is 10 minutes. The masterbatch is then added into a twin-screw extruder for melt extrusion and granulation. The screw speed of the twin-screw extruder is 100 r / min, the feeding section temperature is 120° C., the melting section temperature is 150° C., and the conveying section temperature is 190° C.

[0046] The preparation method of the polypropylene composite material comprises: adding 100 parts of polypropylene (LG R6400), 5 parts of radiation-resistant masterbatch, 20 parts of hydrogenated polystyrene-butadiene-styrene triblock copolymer (Kraton G1652) and 6261 parts of antioxidant into a high-speed mixer and mixing them uniformly, wherein the high-speed mixer rotates at 1000 r / min and the mixing time is 10 minutes; then adding the mixture into a twin-screw extruder for melt extrusion and granulation, wherein the screw speed of the twin-screw extruder is 200 r / min, the temperature of the feed section is 120°C, the temperature of the melting section is 170°C, the temperature of the conveying section is 200°C, and the polypropylene composite material is obtained after drying at 80°C for 6 hours.

[0047] Example 3

[0048] This embodiment provides a polypropylene composite material, the raw materials of which include, by mass, 100 parts of polypropylene (LG R6400), 15 parts of radiation-resistant masterbatch, 5 parts of ethylene-octene copolymer (Dow ENGAGE™ 7447), 0.05 parts of antioxidant 627, 0.5 parts of oleamide, and 0.1 parts of calcium stearate;

[0049] The radiation-resistant masterbatch is prepared by adding polypropylene (LG R6400), a hindered amine light stabilizer, and dicumyl peroxide in a mass ratio of 100:2:0.1 into a high-speed mixer and mixing them uniformly. The high-speed mixer rotates at 1000 r / min and the mixing time is 5 minutes. The masterbatch is then added into a twin-screw extruder for melt extrusion and granulation. The screw speed of the twin-screw extruder is 200 r / min, the feeding section temperature is 100° C., the melting section temperature is 170° C., and the conveying section temperature is 190° C.

[0050] The preparation method of the polypropylene composite material comprises: adding 100 parts of polypropylene (LG R6400), 15 parts of radiation-resistant masterbatch, 5 parts of ethylene-octene copolymer (Dow ENGAGE™ 7447), 0.05 parts of antioxidant 627, 0.5 parts of oleamide and 0.1 parts of calcium stearate into a high-speed mixer and mixing them uniformly, wherein the high-speed mixer rotates at 1200 r / min and the mixing time is 5 minutes; then adding the mixture into a twin-screw extruder for melt extrusion and granulation, wherein the screw speed of the twin-screw extruder is 200 r / min, the temperature of the feeding section is 140° C., the temperature of the melting section is 150° C., and the temperature of the conveying section is 180° C.; and drying at 100° C. for 4 hours to obtain the polypropylene composite material.

[0051] Comparative Example 1

[0052] This comparative example proposes a polypropylene composite material, the raw materials of which include, by mass, 100 parts of polypropylene (LG R6400), 9440.4 parts of light stabilizer, ethylene-octene copolymer (Dow ENGAGE TM 7447) 10 parts and antioxidant 1680.1 parts.

[0053] The preparation method of the polypropylene composite material comprises: mixing 100 parts of polypropylene (LG R6400), 9440.4 parts of light stabilizer, ethylene-octene copolymer (Dow ENGAGE TM7447) 10 parts and antioxidant 1680.1 parts are added into a high mixer and mixed evenly, the high mixer speed is 1100r / min, the mixing time is 8min, and then added into a twin-screw extruder for melt extrusion and granulation, the twin-screw extruder screw speed is 150r / min, the feeding section temperature is 130℃, the melting section temperature is 160℃, the conveying section temperature is 190℃, and after drying at 90℃ for 5h, the polypropylene composite material is obtained.

[0054] Comparative Example 2

[0055] This comparative example proposes a polypropylene composite material, the raw materials of which include, by mass, 100 parts of polypropylene (LG R6400), 10 parts of radiation-resistant masterbatch, and ethylene-octene copolymer (Dow ENGAGE TM 7447) 10 parts and antioxidant 1680.1 parts;

[0056] The radiation-resistant masterbatch is prepared by adding polypropylene (LG R6400), light stabilizer 119, and dicumyl peroxide in a mass ratio of 100:4:0.5 into a high-speed mixer and mixing them uniformly. The high-speed mixer speed is 900 r / min and the mixing time is 8 minutes. The masterbatch is then added into a twin-screw extruder for melt extrusion and granulation. The screw speed of the twin-screw extruder is 150 r / min, the feeding section temperature is 110° C., the melting section temperature is 160° C., and the conveying section temperature is 180° C.

[0057] The preparation method of the polypropylene composite material comprises: mixing 100 parts of polypropylene (LG R6400), 10 parts of radiation-resistant masterbatch, and ethylene-octene copolymer (Dow ENGAGE TM 7447) 10 parts and antioxidant 1680.1 parts are added into a high mixer and mixed evenly, the high mixer speed is 1100r / min, the mixing time is 8min, and then added into a twin-screw extruder for melt extrusion and granulation, the twin-screw extruder screw speed is 150r / min, the feeding section temperature is 130℃, the melting section temperature is 160℃, the conveying section temperature is 190℃, and after drying at 90℃ for 5h, the polypropylene composite material is obtained.

[0058] Comparative Example 3

[0059] This comparative example proposes a polypropylene composite material, the raw materials of which include, by mass, 100 parts of polypropylene (LG R6400), 10 parts of radiation-resistant masterbatch, and ethylene-octene copolymer (Dow ENGAGE TM 7447) 10 parts and antioxidant 1680.1 parts;

[0060] The radiation-resistant masterbatch is prepared by adding polypropylene (LG R6400), compound B, and dicumyl peroxide in a mass ratio of 100:4:0.5 into a high-speed mixer, mixing the mixture at a speed of 900 r / min and a mixing time of 8 min, and then adding the mixture into a twin-screw extruder for melt extrusion and granulation. The twin-screw extruder has a screw speed of 150 r / min, a feed section temperature of 110° C., a melting section temperature of 160° C., and a conveying section temperature of 180° C.

[0061] The preparation method of the polypropylene composite material comprises: mixing 100 parts of polypropylene (LG R6400), 10 parts of radiation-resistant masterbatch, and ethylene-octene copolymer (Dow ENGAGE TM 7447) 10 parts and antioxidant 1680.1 parts are added into a high mixer and mixed evenly, the high mixer speed is 1100r / min, the mixing time is 8min, and then added into a twin-screw extruder for melt extrusion and granulation, the twin-screw extruder screw speed is 150r / min, the feeding section temperature is 130℃, the melting section temperature is 160℃, the conveying section temperature is 190℃, and after drying at 90℃ for 5h, the polypropylene composite material is obtained.

[0062] The polypropylene composite materials prepared in Examples 1-3 and Comparative Examples 1-3 were injection molded at high speed using an injection molding machine (standard plates with a thickness of 1 mm and mechanical splines with standard dimensions). The properties of the composite materials were tested before and after irradiation in a cobalt source (absorbed dose of 30 kGy, dose rate of 0.114 kGy / min). The results are shown in Table 1 below:

[0063] Table 1 Radiation resistance of the polypropylene composite materials described in Examples and Comparative Examples

[0064]

[0065]

[0066] In Table 1 above, the tensile yield strength is measured using the ISO 527-1 standard; the flexural modulus is measured using the ISO-178 standard; the Izod impact strength is measured using the GB / T 1843-2008 standard; the yellowness index is measured with reference to the GB / T 2409-1998 standard; and the haze is measured with reference to the GB / T 2410-2008 standard.

[0067] It can be seen from the above test data that the polypropylene composite material of the present invention still has excellent mechanical properties and yellowing resistance after being irradiated with a large dose of gamma rays due to the optimized formulation.

[0068] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A polypropylene composite material, characterized in that The raw materials include, by mass: 100 parts of polypropylene, 5-15 parts of radiation-resistant masterbatch, 5-20 parts of thermoplastic elastomer and 0.05-1 part of antioxidant; The radiation-resistant masterbatch is obtained by mixing and granulating polypropylene, a hindered amine light stabilizer, and an initiator in a mass ratio of 100:2-6:0.1-1.

2. The structural formula of the hindered amine light stabilizer is as follows: n is an integer from 1 to 5.

2. The polypropylene composite material according to claim 1, characterized in that The polypropylene is homopolymer polypropylene or copolymer polypropylene, and preferably has a melt index of 1-100 g / 10 min at 230° C. and 2.16 kg.

3. The polypropylene composite material according to claim 1 or 2, characterized in that: The hindered amine light stabilizer is prepared by the following method: firstly subjecting cyanuric chloride to a nucleophilic substitution reaction with N-n-butyl-2,2,6,6-tetramethyl-4-piperidinamine, then subjecting the cyanuric chloride to a nucleophilic substitution reaction with dipropylenetriamine, and then subjecting the cyanuric chloride to an electrophilic substitution reaction with a terminal alkenyl halide, thereby obtaining the hindered amine light stabilizer; Preferably, the structural formula of the terminal alkenyl halide is as follows: X is Br or Cl, and n is an integer from 1 to 5; Preferably, the terminal alkenyl halohydrocarbon is at least one of 3-bromo-1-propene, 3-chloro-1-propene, 4-bromo-1-butene, 4-chloro-1-butene, 5-bromo-1-pentene, 5-chloro-1-pentene, 6-bromo-1-hexene or 6-chloro-1-hexene.

4. The polypropylene composite material according to any one of claims 1 to 3, characterized in that: The initiator is at least one of dicumyl peroxide, di-tert-butyl peroxide, dibenzoyl peroxide or 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane.

5. The polypropylene composite material according to any one of claims 1 to 4, characterized in that: The radiation-resistant masterbatch is prepared by adding polypropylene, hindered amine light stabilizer and initiator into a high-speed mixer and mixing them evenly, and then adding them into a twin-screw extruder for melt extrusion and granulation. Preferably, the high speed mixer speed is 800-1000r / min, and the mixing time is 5-10min; the screw speed of the twin-screw extruder is 100-200r / min, the feeding section temperature is 100-120°C, the melting section temperature is 150-170°C, and the conveying section temperature is 170-190°C.

6. The polypropylene composite material according to any one of claims 1 to 5, characterized in that: The thermoplastic elastomer is at least one of hydrogenated polystyrene-butadiene-styrene triblock copolymer, hydrogenated polyethylene-polyisoprene-polystyrene triblock copolymer, ethylene-octene copolymer or ethylene-propylene copolymer.

7. The polypropylene composite material according to any one of claims 1 to 6, characterized in that: The antioxidant is a phosphite antioxidant, preferably at least one of antioxidant 168, antioxidant 626 or antioxidant 627.

8. The polypropylene composite material according to any one of claims 1 to 7, characterized in that: The raw materials thereof further include, by weight: 0.1-1 parts of lubricant and 0.05-0.5 parts of acid absorbent; Preferably, the lubricant is at least one of ethylene bisstearamide, polyethylene wax, oleamide or erucamide, and the acid scavenger is at least one of calcium stearate or magnesium aluminum hydrotalcite.

9. The polypropylene composite material according to any one of claims 1 to 8, characterized in that: The preparation method of the polypropylene composite material comprises: adding polypropylene, radiation-resistant masterbatch, thermoplastic elastomer and antioxidant into a high-speed mixer and mixing them uniformly; then adding them into a twin-screw extruder for melt extrusion and granulation; and drying to obtain the polypropylene composite material; Preferably, the high mixer speed is 1000-1200 r / min, and the mixing time is 5-10 min; the screw speed of the twin-screw extruder is 100-200 r / min, the feeding section temperature is 120-140°C, the melting section temperature is 150-170°C, and the conveying section temperature is 180-200°C; the drying temperature is 80-100°C, and the drying time is 4-6 hours.

10. A gamma ray resistant nonwoven fabric, characterized in that: The polypropylene composite material is made of the polypropylene composite material according to any one of claims 1 to 9.

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