A process for the production of polypropylene, polypropylene and low odor polypropylene resin and process for the production thereof

Abstract

This invention discloses a method for preparing polypropylene, polypropylene and low-odor polypropylene resin, and the method for preparing the same, belonging to the field of polypropylene resin technology. The method for preparing polypropylene includes the following steps: (1) mixing propylene, alkyl aluminum, silane compounds, a highly active catalyst, and a polymeric nucleating agent to perform propylene prepolymerization to obtain a propylene prepolymer; (2) mixing the propylene prepolymer with hydrogen and an olefin, and performing propylene polymerization under heating and pressure to obtain polypropylene; the olefin is selected from one or more of propylene, ethylene, and α-olefins, and contains at least propylene; the method adds a highly active catalyst and a polymeric nucleating agent during the polypropylene synthesis process, resulting in a polypropylene resin prepared from the polypropylene having low odor and excellent rigidity and toughness.

Description

Technical Field

[0001] This invention relates to the technical field of polypropylene resins, and more particularly to a method for preparing polypropylene, polypropylene and low-odor polypropylene resins, and the method for preparing the same. Background Technology

[0002] Polypropylene (PP) possesses excellent comprehensive mechanical properties, heat resistance, and ease of processing and molding, leading to its wide range of applications, including automotive interiors, home appliances, packaging materials, pipes, medical supplies, transparent containers, and daily necessities. With rising living standards and increasing environmental awareness, people are placing increasingly stringent safety requirements on polypropylene products used in their daily lives, such as car seats and armrests; casings and components of home appliances like electric kettles, rice cookers, coffee makers, microwave ovens, fans, washing machines, and refrigerators; shock-absorbing packaging for food bags, bottle caps, precision instruments, and electronic products; water pipes and underfloor heating pipes; medical syringes and infusion tubing; food containers, microwave-safe tableware, and beverage bottles; condiment containers, snack boxes, bathtubs, and buckets. Specifically, there is a demand for polypropylene materials to have the lowest possible volatile organic compound (VOC) content during processing and use to ensure the release of harmful substances or irritating odors, providing consumers with a more comfortable user experience.

[0003] The odor of polypropylene resin mainly comes from the following aspects: the catalytic system used in polymerization contains irritating ester compounds or peroxides; during processing, a large number of additives, such as small molecule nucleating agents, antioxidants, and halogen absorbers, also have a certain irritating odor when subjected to high temperatures by the screw; moreover, during granulation, polypropylene resin melts at high temperatures and is subjected to shearing to produce thermally decomposed small molecule compounds, such as ketones and aldehydes, all of which have odors; in addition, plastic products may also be affected by environmental factors such as temperature, humidity, and light during transportation, storage, and use, leading to the generation of odors.

[0004] To reduce the odor of polypropylene materials, existing methods typically involve adding odor adsorbents during the granulation process. The adsorbents physically adsorb small volatile molecules through their porous structure, and then filter out the adsorbents during vacuum degassing. Commonly used and effective odor adsorbents are microporous crystals, primarily including aluminosilicates, diatomaceous earth, and magnesium silicate types.

[0005] However, the above methods are costly, complex to process, and have poor deodorization effects, which seriously affect product performance. Therefore, it is of great significance to research and develop a new type of low-odor polypropylene resin to solve the above technical problems. Summary of the Invention

[0006] In view of this, the technical problem to be solved by the present invention is to provide a method for preparing polypropylene, polypropylene and low-odor polypropylene resin, and the method for preparing the same. The polypropylene used to prepare polypropylene resin yields a polypropylene resin with low odor and excellent mechanical properties.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] This invention provides a method for preparing polypropylene, comprising the following steps:

[0009] (1) Propylene, alkylaluminum, silane compounds, highly active catalysts and polymer nucleating agents are mixed and propylene is prepolymerized to obtain propylene prepolymer;

[0010] (2) The propylene prepolymer is mixed with hydrogen and olefins, and propylene is polymerized under heating and pressure to obtain polypropylene;

[0011] The olefin is selected from one or more of propylene, ethylene, and α-olefins, and contains at least propylene;

[0012] The highly active catalyst is selected from one or more of HR, SP-4, CS-2, and BCZ-208;

[0013] The polymer nucleating agent is selected from one or more of polyvinylcyclopentane, polyvinylcyclohexane, polyvinyl-2-methylcyclohexane, poly-3-methyl-1-butene, poly-3-ethyl-1-hexene, poly-3-methyl-1-pentene, and polystyrene.

[0014] Preferably, in step (1), the prepolymerization temperature is -10℃ to 20℃;

[0015] Preferably, the heating temperature in step (2) is 50℃-100℃;

[0016] Preferably, the pressure applied in step (2) is 1-5 MPa.

[0017] Preferably, the α-olefin is selected from one or more of 1-butene, 1-pentene, 1-hexene, 1-heptene, and 1-octene.

[0018] Preferably, the alkylaluminum is selected from one or more of triethylaluminum, triisobutylaluminum, trihexylaluminum, trioctylaluminum, diethylaluminum chloride, diisobutylaluminum chloride, dihexylaluminum chloride, and dioctylaluminum chloride; more preferably, it is triethylaluminum, triisobutylaluminum, or trihexylaluminum.

[0019] Preferably, the silane compound in this invention is selected from vinyltriethoxysilane, vinyltrimethoxysilane, methyltriethoxysilane, dimethyldimethoxysilane, diethyldimethoxysilane, dipropyldimethoxysilane, diisopropyldimethoxysilane, dibutyldimethoxysilane, diisobutyldimethoxysilane, di-tert-butyldimethoxysilane, di-tert-hexyldimethoxysilane, diphenyldimethoxysilane, dicyclohexyldimethoxysilane, dicyclopentyldimethoxysilane, dimethyldiethoxysilane, diethyldiethoxysilane, dipropyldiethoxysilane, and diisopropyldiethoxysilane. One or more of the following: dibutyldiethoxysilane, diisobutyldiethoxysilane, di-tert-butyldiethoxysilane, di-tert-hexyldiethoxysilane, diphenyldiethoxysilane, dicyclohexyldiethoxysilane, dicyclopentyldiethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, cyclopentylmethyldiethoxysilane, cyclopentyltrimethoxysilane, cyclohexylmethyldiethoxysilane, cyclohexyltrimethoxysilane, tert-hexyltrimethoxysilane, and tert-hexyltrimethoxysilane; more preferably, cyclohexylmethyldiethoxysilane or cyclohexyltrimethoxysilane.

[0020] The present invention also provides a polypropylene prepared by the above-described preparation method.

[0021] Preferably, the polypropylene has a melt index of 5-80 g / 10 min at 230°C and a load of 2.16 kg;

[0022] Preferably, the polypropylene contains a highly active catalyst at a concentration of 10-20 ppm; more preferably, it contains 10-15 ppm.

[0023] Preferably, the polypropylene contains a polymeric nucleating agent at a concentration of 30-100 ppm.

[0024] The present invention also provides a low-odor polypropylene resin, which, by weight, comprises the following components:

[0025] The aforementioned polypropylene: 95-100 parts by weight;

[0026] Polyethylene or polyalphaolefin: 0 to 5 parts by weight;

[0027] Antioxidant: 0.1–0.3 parts by weight;

[0028] Halogen absorber: 0.01 to 0.1 parts by weight;

[0029] Other additives: 0-0.3 parts by weight;

[0030] Among them, the monomer α-olefin in polyα-olefin is selected from one or more of 1-butene, 1-pentene, 1-hexene, 1-heptene, and 1-octene;

[0031] The antioxidant is composed of a primary antioxidant and a co-antioxidant in a mass ratio of 1:(1-4); more preferably, it is 1:(2-3).

[0032] The primary antioxidant is selected from one or more of antioxidant 2246, antioxidant 1010, antioxidant 1076, and antioxidant 1330; more preferably, it is antioxidant 1010 or antioxidant 2246.

[0033] The antioxidant is selected from one or more of antioxidant 168, antioxidant 626, and antioxidant 9228; more preferably, antioxidant 168.

[0034] In a further preferred embodiment of the present invention, the antioxidant is 0.15 parts by weight.

[0035] More preferably, the antioxidant is selected from antioxidant 1010 and antioxidant 168.

[0036] More preferably, the mass ratio of antioxidant 1010 to antioxidant 168 is 1:2. Preferably, the halogen absorber is selected from one or more of sodium stearate, calcium stearate, and zinc stearate; more preferably, it is calcium stearate.

[0037] Preferably, the low-odor polypropylene resin of the present invention has a melt index of 5-80 g / 10 min at 230°C and a load of 2.16 kg;

[0038] Preferably, the low-odor polypropylene resin of the present invention has an odor rating of 3.5 or lower and a volatile organic compound test value of ≤50μg / g.

[0039] The present invention also provides a method for preparing the above-mentioned low-odor polypropylene resin, comprising the following steps:

[0040] Antioxidant, halogen absorber, other additives and the above-mentioned polypropylene are mixed, extruded by twin-screw extruder, pelletized and dried to obtain the low-odor polypropylene resin.

[0041] The screw temperature in each zone of the twin-screw extruder is controlled between 170℃ and 235℃ during extrusion, and the highest temperature in each zone during extrusion must be greater than 230℃.

[0042] Compared with the prior art, the polypropylene preparation method provided by the present invention includes the following steps: (1) mixing propylene, alkyl aluminum, silane compound, highly active catalyst and polymer nucleating agent to perform propylene prepolymerization to obtain propylene prepolymer; (2) mixing the propylene prepolymer with hydrogen and olefin, and performing propylene polymerization under heating and pressure to obtain polypropylene; wherein the olefin is selected from one or more of propylene, ethylene, and α-olefin and contains at least propylene; the highly active catalyst is selected from one or more of HR, SP-4, CS-2, and BCZ-208; and the polymer nucleating agent is selected from one or more of polyvinylcyclopentane, polyvinylcyclohexane, polyvinyl-2-methylcyclohexane, poly-3-methyl-1-butene, poly-3-ethyl-1-hexene, poly-3-methyl-1-pentene and polystyrene. The method adds a highly active catalyst and a polymer nucleating agent during the polypropylene synthesis process, so that the polypropylene resin prepared by the polypropylene has low odor and excellent rigidity and toughness. Detailed Implementation

[0043] To further illustrate the present invention, the following detailed description of the preparation method of polypropylene, polypropylene and low-odor polypropylene resin and their preparation methods provided by the present invention is given in conjunction with embodiments.

[0044] The unit ppm below is expressed as 10 to the power of negative six, representing a mass percentage, specifically the percentage of a certain substance in the mass of homopolymer or copolymer polypropylene. For example, in Example 1 of Table 1 below, HR / ppm is 0.028 / 2000 = 0.000014 = 14ppm, and so on for others.

[0045] Example 1

[0046] Preparation of polypropylene:

[0047] (1) 1 kg propylene, 3 mL triethylaluminum (1M), 0.06 mL cyclohexylmethyldimethoxysilane, 0.028 g highly active catalyst HR and 0.06 g polyvinylcyclohexane (PVCH) were added to a 3 L prepolymerization reactor at 10 °C and propylene was prepolymerized for 15 min to obtain propylene prepolymer.

[0048] (2) The propylene prepolymer was transferred from the prepolymerization kettle to a 10L polymerization kettle, 18L of hydrogen and 2kg of propylene were added, the temperature was raised, and propylene polymerization was carried out at 70℃ and a certain pressure for 1.5h to obtain 2000g of homopolymer polypropylene.

[0049] Processing and granulation:

[0050] Weigh the materials according to the components and formulations provided in Table 1 (all ppm are mass percentages, and the same applies to the following examples and comparative examples), mix them evenly, and then extrude and granulate them in a twin-screw extruder with an aspect ratio of 60:1 and a diameter of 35mm to obtain a low-odor polypropylene special material; wherein, the temperatures of each zone of the extruder are: zone 1 180℃, zone 2 200℃, zone 3 230℃, zone 4 235℃, zone 5 210℃, and die head 190℃.

[0051] The performance test results are shown in Table 3.

[0052] Example 2

[0053] The only difference from Example 1 is that the amount of PVCH used in the polypropylene preparation stage is 0.1g, and 1900g of homopolymer polypropylene is obtained.

[0054] Example 3

[0055] The only difference from Example 1 is that the amount of PVCH used in the polypropylene preparation stage is 0.18g, and 1800g of homopolymer polypropylene is obtained.

[0056] Example 4

[0057] The only difference from Example 2 is that 0.024g of highly active catalyst SP-4 was used instead of highly active catalyst HR in the polypropylene preparation stage, resulting in 1900g of homopolymer polypropylene.

[0058] Example 5

[0059] Preparation of polypropylene:

[0060] (1) 1 kg propylene, 3 mL triethylaluminum (1M), 0.06 mL cyclohexylmethyldimethoxysilane, 0.028 g highly active catalyst HR and 0.11 g polyvinylcyclohexane were added to a 3 L prepolymerization reactor at 10 °C and propylene was prepolymerized for 15 min to obtain propylene prepolymer.

[0061] (2) The propylene prepolymer was transferred from the prepolymerization reactor to a 10L polymerization reactor, 17L of hydrogen and 2kg of propylene were added, and 140g of ethylene was slowly and continuously added. The temperature was raised, and propylene polymerization was carried out at 70℃ and under certain pressure for 1.5h to obtain 2200g of copolymer polypropylene.

[0062] Processing and granulation:

[0063] Weigh the materials according to the components and formula provided in Table 1, mix them evenly, and then extrude and granulate them in a twin-screw extruder with a length-to-diameter ratio of 60:1 and a diameter of 35mm to obtain a low-odor polypropylene special material. The temperatures of each zone of the extruder are as follows: Zone 1 180℃, Zone 2 200℃, Zone 3 230℃, Zone 4 235℃, Zone 5 210℃, and the die head 190℃.

[0064] Table 1. Components of the low-odor polypropylene resins prepared in Examples 1-5

[0065]

[0066] The number of polyethylene parts in Example 5 in Table 1 above was obtained by infrared detection of the low-odor polypropylene resin. The number of polypropylene parts was 100 minus the number of polyethylene parts. The amounts of HR, SP-4 and PVCH in the table were calculated (i.e., initial addition amount / production yield of polypropylene).

[0067] Comparative Example 1

[0068] Preparation of polypropylene:

[0069] (1) 1 kg of propylene, 3 mL of triethylaluminum (1M), 0.06 mL of cyclohexylmethyldimethoxysilane and 0.028 g of highly active catalyst HR were added sequentially to a 3 L prepolymerization reactor at 10 °C to carry out propylene prepolymerization for 15 min to obtain propylene prepolymer;

[0070] (2) The propylene prepolymer was transferred from the prepolymerization kettle to a 10L polymerization kettle, 18L of hydrogen and 2kg of propylene were added, the temperature was raised, and propylene polymerization was carried out at 70℃ and a certain pressure for 1.5h to obtain 2010g of homopolymer polypropylene.

[0071] Processing and granulation:

[0072] Weigh the materials according to the components and formulation provided in Table 2 (compared with Example 1, with the addition of 1g of small molecule nucleating agent NA-21), mix them evenly, and then extrude and granulate them in a twin-screw extruder with a length-to-diameter ratio of 60:1 and a diameter of 35mm to obtain polypropylene special material (polypropylene material); wherein, the temperature of each zone of the extruder is: zone 1 180℃, zone 2 200℃, zone 3 230℃, zone 4 235℃, zone 5 210℃, and die head 190℃.

[0073] The performance test results are shown in Table 4.

[0074] Comparative Example 2

[0075] The only difference from Comparative Example 1 is that 0.2g of high molecular weight nucleating agent PVCH was used instead of low molecular weight nucleating agent NA-21 in the processing and granulation stage.

[0076] Comparative Example 3

[0077] The only difference from Example 3 is that 0.04g of catalyst SP-2 was used instead of the highly active catalyst HR in the polypropylene preparation stage, and 0.2g of PVCH was added to obtain 2000g of homopolymer polypropylene. (Note: Catalyst SP-2 has lower activity than catalysts SP-4 and HR.)

[0078] Comparative Example 4

[0079] The difference from Comparative Example 1 is that 0.04g of catalyst SP-2 was used instead of the highly active catalyst HR in the polypropylene preparation stage to obtain 2100g of homopolymer polypropylene; and 1.05g of small molecule nucleating agent NA-21 was added in the processing and granulation stage.

[0080] Comparative Example 5

[0081] The steps (1) for preparing polypropylene are the same as in Comparative Example 4, and the steps (2) for preparing polypropylene are the same as in Example 5.

[0082] Processing and granulation were performed in the same manner as in comparative example 4.

[0083] Comparative Example 6

[0084] The only difference from Example 1 is that the temperatures of each zone of the extruder during the granulation stage are: Zone 1 170°C, Zone 2 190°C, Zone 3 200°C, Zone 4 210°C, Zone 5 200°C, and the die head 180°C.

[0085] Comparative Example 7 (Existing technology for preparing low-odor polypropylene)

[0086] The only difference from Comparative Example 4 was the addition of 2g of odor adsorbent nano-silica in the granulation stage, resulting in 2100g of homopolymer polypropylene.

[0087] Table 2. Composition of polypropylene resin materials prepared in Comparative Examples 1-7

[0088]

[0089] The number of polyethylene parts in Comparative Example 5 in Table 2 above was obtained by infrared detection of the polypropylene resin material. The number of polypropylene parts was 100 minus the number of polyethylene parts. The amounts of HR, SP-2 and PVCH in the table were calculated (i.e., initial addition amount / production yield of polypropylene).

[0090] Table 3. Properties of the low-odor polypropylene resin materials prepared in Examples 1-5

[0091]

[0092]

[0093] Table 4. Properties of the polypropylene resin materials prepared in Comparative Examples 1-7

[0094]

[0095] The odor rating test in the table above is as follows: Weigh (20±2)g of sample (the amount of sample should just cover the bottom of the odor bottle) and place it into the odor bottle; next, place the odor bottle containing the sample into an oven and store it at (80±2)℃ for 2h±10min; then, remove the odor bottle from the oven and cool it to 60±5℃ (approximately 5min); finally, evaluate the odor of the cooled sample (specifically, 5 people simultaneously evaluate the sample, and the average value is taken), and the evaluation criteria are as follows:

[0096] Odor rating Scent description 1 Odorless 2 It has an odor, but no interfering or irritating odor. 3 It has a distinct odor, but no interfering or irritating odor. 4 It has a disturbing and irritating odor. 5 It has a strong, irritating odor. 6 It has an unbearable odor.

[0097] Volatile organic compound (VOC) testing: Gas chromatography-mass spectrometry (GC-MS) was used to test the samples using a thermal desorption-gas chromatography-mass spectrometry (TCMS) system. The data in Table 3 show that the odor level of the low-odor polypropylene resins in Examples 1-5 was no higher than 3.0 (note: required to be no higher than 3.5), and the VOC value was less than 50 μg / g. Both the homopolymer (Examples 1-4) and copolymer (Example 5) polypropylene resins had low odor levels and low VOC values. Simultaneously, the homopolymer flexural modulus was ≥1890 MPa, and the impact strength was ≥3.0 KJ / m². 2 This indicates that the low-odor homopolymer polypropylene resin of the present invention not only has low odor, but also excellent rigidity and toughness.

[0098] The comparison between Comparative Example 1 and Examples 1-4 shows that when 500 ppm of small molecule nucleating agent is added during the granulation stage, the resulting polypropylene has a higher odor level and VOC value than that of Examples 1-4, and does not meet the requirements for low-odor polypropylene.

[0099] The comparison between Comparative Example 2 and Example 3 shows that although the odor level and VOC value meet the requirements when the polymer nucleating agent is added to polypropylene during the granulation stage, the product has a lower flexural modulus and impact strength, resulting in poor product performance.

[0100] The comparison between Comparative Example 3 and Example 3 shows that when a low-activity catalyst is used instead of a high-activity catalyst, the odor level and VOC value are slightly higher than the requirements for low-odor polypropylene.

[0101] The comparison between Comparative Examples 4, 7 and Examples 1-4 shows that the existing technology cannot simultaneously meet the requirements of product physical and mechanical properties, product odor level and VOC value. Comparative Example 4 is an existing polypropylene preparation technology, which meets the requirements for physical and mechanical properties, but does not meet the odor requirements; Comparative Example 7 is an existing low-odor polypropylene preparation technology, which meets the requirements for odor, but the physical and mechanical properties deteriorate.

[0102] The comparison between Comparative Example 5 and Example 5 shows that the low-odor polypropylene preparation technology is also applicable to copolymer products. Comparative Example 5 added a low-activity catalyst and a small molecule nucleating agent, and the amount added was relatively large. Therefore, Comparative Example 5 has a higher odor level and VOC value than Example 5.

[0103] The comparison between Comparative Example 6 and Examples 1-4 shows that the granulation temperature of low-odor polypropylene needs to be higher than 230°C, otherwise the product performance will be affected.

[0104] In summary, the low-odor polypropylene resin provided by this invention has low odor and excellent physical properties. The essential technical features of the preparation method of the low-odor polypropylene resin are: (1) a highly active catalyst; (2) a polymer nucleating agent; (3) the polymer nucleating agent is added during the polymerization stage; and (4) the granulation temperature exceeds 230°C.

[0105] The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A method for preparing polypropylene, characterized in that, Includes the following steps: (1) Propylene, alkylaluminum, silane compound, highly active catalyst and polymer nucleating agent are mixed and propylene is prepolymerized to obtain propylene prepolymer; (2) The propylene prepolymer is mixed with hydrogen and olefins, and propylene is polymerized under heating and pressure to obtain polypropylene; The olefin is selected from one or more of propylene, ethylene, and α-olefins, and contains at least propylene; The highly active catalyst is selected from HR or SP-4; The polymer nucleating agent is selected from one or more of polyvinylcyclopentane, polyvinylcyclohexane, polyvinyl-2-methylcyclohexane, poly-3-methyl-1-butene, poly-3-ethyl-1-hexene, poly-3-methyl-1-pentene, and polystyrene.

2. The preparation method according to claim 1, characterized in that, The prepolymerization temperature in step (1) is -10℃ to 20℃; The heating temperature in step (2) is 50℃-100℃; The pressure applied in step (2) is 1-5 MPa.

3. The preparation method according to claim 1, characterized in that, The α-olefin is selected from one or more of 1-butene, 1-pentene, 1-hexene, 1-heptene, and 1-octene.

4. The preparation method according to claim 1, characterized in that, The alkylaluminum is selected from one or more of triethylaluminum, triisobutylaluminum, trihexylaluminum, trioctylaluminum, diethylaluminum chloride, diisobutylaluminum chloride, dihexylaluminum chloride, and dioctylaluminum chloride; The silane compound is selected from vinyltriethoxysilane, vinyltrimethoxysilane, methyltriethoxysilane, dimethyldimethoxysilane, diethyldimethoxysilane, dipropyldimethoxysilane, diisopropyldimethoxysilane, dibutyldimethoxysilane, diisobutyldimethoxysilane, di-tert-butyldimethoxysilane, di-tert-hexyldimethoxysilane, diphenyldimethoxysilane, dicyclohexyldimethoxysilane, dicyclopentyldimethoxysilane, dimethyldiethoxysilane, diethyldiethoxysilane, dipropyldiethoxysilane, diethyl ... One or more of the following: oxysilane, diisopropyldiethoxysilane, dibutyldiethoxysilane, diisobutyldiethoxysilane, di-tert-butyldiethoxysilane, di-tert-hexyldiethoxysilane, diphenyldiethoxysilane, dicyclohexyldiethoxysilane, dicyclopentyldiethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, cyclopentylmethyldimethoxysilane, cyclopentyltrimethoxysilane, cyclohexylmethyldimethoxysilane, cyclohexyltrimethoxysilane, tert-butyltrimethoxysilane, and tert-hexyltrimethoxysilane.

5. A polypropylene, characterized in that, It is prepared by the preparation method according to any one of claims 1-4.

6. The polypropylene according to claim 5, characterized in that, The polypropylene has a melt index of 5-80 g / 10min at 230℃ and a load of 2.16 kg. The polypropylene contains a highly active catalyst at a concentration of 10-20 ppm; The polypropylene contains a high molecular weight nucleating agent at a concentration of 30-100 ppm.

7. A low-odor polypropylene resin, characterized in that, By weight, Includes the following ingredients: The polypropylene according to claim 5 or 6: 95-100 parts by weight; Polyethylene or polyalphaolefin: 0~5 parts by weight; Antioxidant: 0.1~0.3 parts by weight; Halogen absorber: 0.01~0.1 parts by weight; Other additives: 0-0.3 parts by weight; Among them, the monomer α-olefin in polyα-olefin is selected from one or more of 1-butene, 1-pentene, 1-hexene, 1-heptene, and 1-octene; The antioxidant consists of a primary antioxidant and a co-antioxidant in a mass ratio of 1:(1-4); The primary antioxidant is selected from one or more of antioxidant 2246, antioxidant 1010, antioxidant 1076, and antioxidant 1330; The antioxidant is selected from one or more of antioxidant 168, antioxidant 626, and antioxidant 9228.

8. The low-odor polypropylene resin according to claim 7, characterized in that, The halogen absorber is selected from one or more of sodium stearate, calcium stearate, and zinc stearate.

9. The low-odor polypropylene resin according to claim 7 or 8, characterized in that, The low-odor polypropylene resin has a melt index of 5-80 g / 10min at 230℃ and a load of 2.16 kg. The low-odor polypropylene resin has an odor rating of 3.5 or lower and a volatile organic compound (VOC) test value of ≤50 μg / g.

10. A method for preparing the low-odor polypropylene resin according to any one of claims 7-9, characterized in that, Includes the following steps: Antioxidant, halogen absorber, other additives and polypropylene as described in claim 5 or 6 are mixed, extruded by twin-screw extruder, pelletized and dried to obtain the low-odor polypropylene resin. The screw temperature in each zone of the twin-screw extruder is controlled between 170℃ and 235℃ during extrusion, and the highest temperature in each zone during extrusion must be greater than 230℃.

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