Method for evaluating precipitation level of polyolefin composite material

Abstract

The invention discloses a polyolefin composite material precipitation level evaluation method, which comprises: mixing a polyolefin composite material and calcium carbonate, carrying out melt extrusion, collecting the precipitate accumulation amount at the extruder die head, and further evaluating the precipitation condition of the polyolefin composite material, according to the method, a detection system for simulating the thermodynamic environment of the two-way stretching process is constructed, the influence of the compatibility defect of the polyolefin composite material on the flow stability is artificially amplified, and the thermodynamic adaptability short plate of different polyolefin composite materials under dynamic shearing is quickly exposed, so that the precipitation tendency of different polyolefin composite materials is evaluated; and the polyolefin composite material with high precipitation risk is screened out in advance, so that non-planned shutdown and waste loss caused by frequent blockage of a die head by precipitates are avoided, manpower resource consumption in a production line debugging stage is reduced at the same time, and finally, double improvement of production process stability and comprehensive cost control capability is realized.

Description

Technical Field

[0001] The invention belongs to the technical field of polyolefin composite materials, and in particular relates to a method for evaluating the precipitation level of a polyolefin composite material. Background Art

[0002] Polyolefin composites are an ideal choice for biaxially oriented film production lines due to their comprehensive performance advantages. Their excellent mechanical properties provide the necessary tensile strength and toughness for the film, their outstanding chemical resistance ensures product stability in complex environments, and their excellent processing fluidity enables them to adapt to the molding requirements of high-temperature and high-speed stretching processes. This combination of functional adaptability and cost-effectiveness has earned them an irreplaceable position in film processing for fields such as packaging and electronics.

[0003] During the film preparation process of polyolefin composites through the die, melt fracture and precipitate formation occur due to the difference in internal and external flow rates. High-filler systems are more likely to exacerbate this phenomenon due to their tendency to phase separation. Existing technologies for assessing the precipitation risk of polyolefin composites rely heavily on actual production equipment test runs. After the polyolefin composites are put into the production line, the precipitation level must be reversely inferred by observing defects such as carbon deposits in the die flow channel and crystal points on the film surface. This method not only consumes a large amount of raw materials and energy, but also, due to the complex operating conditions of the production line (such as temperature gradients and irreversible shear history), it is difficult to isolate the impact of a single variable on the precipitation of polyolefin composites, resulting in low efficiency in tracing the problem. At the same time, traditional methods cannot predict precipitation tendencies during the formulation design or raw material procurement stages. They often passively adjust process parameters or replace raw materials after die blockage or product defects occur, resulting in unplanned downtime and waste losses. These technical defects of hysteresis, high cost, and low precision have made the development of evaluation methods inevitable. Summary of the Invention

[0004] In response to the above-mentioned deficiencies in the prior art, the present invention provides a method for evaluating the precipitation level of polyolefin composite materials. By constructing a detection system that simulates the thermodynamic environment of a biaxial stretching process, the impact of compatibility defects of polyolefin composite materials on flow stability is artificially amplified, and the thermodynamic adaptability shortcomings of different polyolefin composite materials under dynamic shear are quickly exposed. The precipitation tendency of different polyolefin composite materials is then evaluated, and polyolefin composite materials with high precipitation risks are screened out in advance, thereby avoiding unplanned shutdowns and waste losses caused by frequent blockage of the die head by precipitates, and reducing human resource consumption in the production line debugging stage, ultimately achieving a dual improvement in production process stability and comprehensive cost control capabilities.

[0005] The object of the present invention is to provide a method for evaluating the precipitation level of a polyolefin composite material, comprising the following steps:

[0006] The polyolefin composite material and calcium carbonate were mixed and melt-extruded, and the accumulated amount of precipitates at the extruder die was collected to evaluate the precipitation of the polyolefin composite material.

[0007] In some embodiments of the present invention, the polyolefin components in the polyolefin composite material are selected from at least two of polyethylene, polypropylene, polybutene, polypentene, polyhexene, polyoctene, poly(4-methyl-1-pentene), and polyolefin elastomer.

[0008] In some embodiments of the present invention, the mass ratio of the polyolefin composite material to calcium carbonate is 7-9:1-3.

[0009] In some embodiments of the present invention, the melt extrusion temperature is 160-230° C., and the time is ≤20 min.

[0010] In some embodiments of the present invention, the main frequency of the extruder used for the melt extrusion is 40-60 Hz, and the traction frequency is 7-11 Hz.

[0011] In some embodiments of the present invention, the filter screen used in the melt extrusion is 150-250 mesh.

[0012] Compared with the prior art, the present invention has the following beneficial effects:

[0013] (1) In the actual production process of preparing films from polyolefin composite materials, it often takes at least thirty hours. Before production, it is impossible to know whether the polyolefin composite material will precipitate, let alone the precipitation situation of the polyolefin composite material. After the polyolefin composite material is put into production to prepare films, once the polyolefin composite material precipitates, on the one hand, it will cause the die head of the extruder to be blocked, and on the other hand, it will cause the product quality to decline, thereby causing unplanned downtime (needing to clean the die head) and waste loss. The present invention adds calcium carbonate to the polyolefin composite material. The addition of calcium carbonate can accelerate the precipitation of the polyolefin composite material. Within 20 minutes, it can determine whether polyolefin composite materials with different structural characteristics will precipitate and the precipitation situation. The precipitation situation of the polyolefin composite material accelerated by adding calcium carbonate is consistent with the precipitation situation of the polyolefin composite material without adding calcium carbonate (that is, if the polyolefin composite material does not precipitate during the actual production process of preparing films, then adding calcium carbonate will not cause precipitation; if the polyolefin composite material precipitates during the actual production process of preparing films, then adding calcium carbonate will accelerate precipitation). Therefore, the method of the present invention can quickly identify the precipitation situation of the polyolefin composite material during the actual production process of preparing films or under long-term use.

[0014] (2) The present invention constructs a detection system that simulates the thermodynamic environment of the biaxial stretching process, artificially amplifies the impact of the compatibility defects of polyolefin composite materials on the flow stability, quickly exposes the thermodynamic adaptability shortcomings of different polyolefin composite materials under dynamic shear, and then evaluates the precipitation tendency of different polyolefin composite materials, screens out polyolefin composite materials with high precipitation risks in advance, avoids unplanned shutdowns and waste losses caused by frequent blockage of the die head by precipitates, and reduces human resource consumption in the production line debugging stage, ultimately achieving a dual improvement in production process stability and comprehensive cost control capabilities. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is the precipitation condition of the polyolefin composite material of Example 5. DETAILED DESCRIPTION

[0016] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0017] The polyolefin composite material PO-1 is selected from the polyolefin composite material with the brand M8009 of Lianxingxing New Material Technology (Guangzhou) Co., Ltd., and its main components are a blend of polyethylene and polypropylene;

[0018] The polyolefin composite material PO-2 is selected from the polyolefin composite material with the brand M8035 of Lianxingxing New Material Technology (Guangzhou) Co., Ltd., and its main components are a blend of polyethylene and polypropylene;

[0019] The polyolefin composite material PO-3 is a polyolefin composite material with the brand name PC684S produced by SunALLomer of Japan, and its main component is a blend of random copolymer polypropylene and block copolymer polypropylene;

[0020] The polyolefin composite material PO-4 is selected from the polyolefin composite material with the brand S0085 produced by Lianxingxing New Material Technology (Guangzhou) Co., Ltd., and its main components are a blend of polypropylene and polybutylene;

[0021] The polyolefin composite material PO-5 is selected from the polyolefin composite material with the brand M8015 of Lianxingxing New Material Technology (Guangzhou) Co., Ltd., and its main components are a blend of polypropylene, polyethylene and polyolefin plastomer;

[0022] The polyolefin composite material PO-6 is selected from the polyolefin composite material of SK Chemical of South Korea with the brand name MH502, and the main components are a blend of polyethylene and polypropylene.

[0023] Example 1

[0024] This embodiment provides a method for evaluating the precipitation level of a polyolefin composite material, comprising the following steps:

[0025] The polyolefin composite material PO-1 (70 parts by mass) and calcium carbonate (30 parts by mass) were thoroughly mixed and melt-extruded through a single-screw extruder at 160°C. The main engine frequency conversion was set to 40 Hz and the traction frequency conversion was set to 11 Hz. A 150-mesh filter was used. The processing was continued for 5 minutes, and the accumulated amount of precipitates at the extruder die head was collected to evaluate the precipitation of the polyolefin composite material.

[0026] Example 2

[0027] This embodiment provides a method for evaluating the precipitation level of a polyolefin composite material, comprising the following steps:

[0028] 80 parts by mass of the polyolefin composite material PO-1 and 20 parts by mass of calcium carbonate were thoroughly mixed and melt-extruded through a single-screw extruder at 200°C. The main frequency conversion was set to 50 Hz and the traction frequency conversion was set to 9.3 Hz. A 200-mesh filter was used. The processing was continued for 20 minutes, and the accumulated amount of precipitates at the extruder die head was collected to evaluate the precipitation of the polyolefin composite material.

[0029] Example 3

[0030] This embodiment provides a method for evaluating the precipitation level of a polyolefin composite material, comprising the following steps:

[0031] 90 parts by mass of the polyolefin composite material PO-1 and 10 parts by mass of calcium carbonate were thoroughly mixed and melt-extruded through a single-screw extruder at 300°C. The main frequency conversion was set to 60 Hz and the traction frequency conversion was set to 7 Hz. A 250-mesh filter was used. The processing was continued for 10 minutes, and the accumulated amount of precipitates at the extruder die head was collected to evaluate the precipitation of the polyolefin composite material.

[0032] Example 4

[0033] This embodiment provides a method for evaluating the precipitation level of a polyolefin composite material. The only difference from Example 1 is that "PO-1" is replaced by "PO-2". The specific steps are as follows:

[0034] The polyolefin composite material PO-2 (70 parts by mass) and calcium carbonate (30 parts by mass) were fully mixed and melt-extruded through a single-screw extruder at 160°C. The main frequency conversion was set to 40 Hz and the traction frequency conversion was set to 11 Hz. A 150-mesh filter was used. The processing was continued for 5 minutes, and the accumulated amount of precipitates at the extruder die head was collected to evaluate the precipitation of the polyolefin composite material.

[0035] Example 5

[0036] This embodiment provides a method for evaluating the precipitation level of a polyolefin composite material. The only difference from Example 2 is that "PO-1" is replaced by "PO-2". The specific steps are as follows:

[0037] 80 parts by mass of the polyolefin composite material PO-2 and 20 parts by mass of calcium carbonate were fully mixed and melt-extruded through a single-screw extruder at 200°C. The main frequency conversion was set to 50 Hz and the traction frequency conversion was set to 9.3 Hz. A 200-mesh filter was used. The processing was continued for 20 minutes, and the accumulated amount of precipitates at the extruder die head was collected to evaluate the precipitation of the polyolefin composite material.

[0038] Example 6

[0039] This embodiment provides a method for evaluating the precipitation level of a polyolefin composite material. The only difference from Example 3 is that "PO-1" is replaced by "PO-2". The specific steps are as follows:

[0040] 90 parts by mass of the polyolefin composite material PO-2 and 10 parts by mass of calcium carbonate were thoroughly mixed and melt-extruded through a single-screw extruder at 300°C. The main frequency conversion was set to 60 Hz and the traction frequency conversion was set to 7 Hz. A 250-mesh filter was used. The processing was continued for 10 minutes, and the accumulated amount of precipitates at the extruder die head was collected to evaluate the precipitation of the polyolefin composite material.

[0041] Example 7

[0042] This embodiment provides a method for evaluating the precipitation level of a polyolefin composite material. The only difference from Example 1 is that "PO-1" is replaced by "PO-3". The specific steps are as follows:

[0043] The polyolefin composite material PO-3 (70 parts by mass) and calcium carbonate (30 parts by mass) were fully mixed and melt-extruded through a single-screw extruder at 160°C. The main frequency conversion was set to 40 Hz and the traction frequency conversion was set to 11 Hz. A 150-mesh filter was used. The processing was continued for 5 minutes, and the accumulated amount of precipitates at the extruder die head was collected to evaluate the precipitation of the polyolefin composite material.

[0044] Example 8

[0045] This embodiment provides a method for evaluating the precipitation level of a polyolefin composite material. The only difference from Example 2 is that "PO-1" is replaced by "PO-3". The specific steps are as follows:

[0046] 80 parts by mass of the polyolefin composite material PO-3 and 20 parts by mass of calcium carbonate were fully mixed and melt-extruded through a single-screw extruder at 200°C. The main frequency conversion was set to 50 Hz and the traction frequency conversion was set to 9.3 Hz. A 200-mesh filter was used. The processing was continued for 20 minutes, and the accumulated amount of precipitates at the extruder die head was collected to evaluate the precipitation of the polyolefin composite material.

[0047] Example 9

[0048] This embodiment provides a method for evaluating the precipitation level of a polyolefin composite material. The only difference from Example 3 is that "PO-1" is replaced by "PO-3". The specific steps are as follows:

[0049] 90 parts by mass of the polyolefin composite material PO-3 and 10 parts by mass of calcium carbonate were fully mixed and melt-extruded through a single-screw extruder at 300°C. The main frequency conversion was set to 60 Hz and the traction frequency conversion was set to 7 Hz. A 250-mesh filter was used. The processing was continued for 10 minutes, and the accumulated amount of precipitates at the extruder die head was collected to evaluate the precipitation of the polyolefin composite material.

[0050] Example 10

[0051] This embodiment provides a method for evaluating the precipitation level of a polyolefin composite material. The only difference from Example 1 is that "PO-1" is replaced by "PO-4". The specific steps are as follows:

[0052] The polyolefin composite material PO-4 (70 parts by mass) and calcium carbonate (30 parts by mass) were fully mixed and melt-extruded through a single-screw extruder at 160°C. The main frequency conversion was set to 40 Hz and the traction frequency conversion was set to 11 Hz. A 150-mesh filter was used. The processing was continued for 5 minutes, and the accumulated amount of precipitates at the extruder die head was collected to evaluate the precipitation of the polyolefin composite material.

[0053] Example 11

[0054] This embodiment provides a method for evaluating the precipitation level of a polyolefin composite material. The only difference from Example 2 is that "PO-1" is replaced by "PO-4". The specific steps are as follows:

[0055] 80 parts by mass of the polyolefin composite material PO-4 and 20 parts by mass of calcium carbonate were fully mixed and melt-extruded through a single-screw extruder at 200°C. The main frequency conversion was set to 50 Hz and the traction frequency conversion was set to 9.3 Hz. A 200-mesh filter was used. The processing was continued for 20 minutes, and the accumulated amount of precipitates at the extruder die head was collected to evaluate the precipitation of the polyolefin composite material.

[0056] Example 12

[0057] This embodiment provides a method for evaluating the precipitation level of a polyolefin composite material. The only difference from Example 3 is that "PO-1" is replaced by "PO-4". The specific steps are as follows:

[0058] 90 parts by mass of the polyolefin composite material PO-4 and 10 parts by mass of calcium carbonate were thoroughly mixed and melt-extruded through a single-screw extruder at 300°C. The main frequency conversion was set to 60 Hz and the traction frequency conversion was set to 7 Hz. A 250-mesh filter was used. The processing was continued for 10 minutes, and the accumulated amount of precipitates at the extruder die head was collected to evaluate the precipitation of the polyolefin composite material.

[0059] Example 13

[0060] This embodiment provides a method for evaluating the precipitation level of a polyolefin composite material. The only difference from Example 1 is that "PO-1" is replaced by "PO-5". The specific steps are as follows:

[0061] The polyolefin composite material PO-5 (70 parts by mass) and calcium carbonate (30 parts by mass) were fully mixed and melt-extruded through a single-screw extruder at 160°C. The main frequency conversion was set to 40 Hz and the traction frequency conversion was set to 11 Hz. A 150-mesh filter was used. The processing was continued for 5 minutes, and the accumulated amount of precipitates at the extruder die head was collected to evaluate the precipitation of the polyolefin composite material.

[0062] Example 14

[0063] This embodiment provides a method for evaluating the precipitation level of a polyolefin composite material. The only difference from Example 2 is that "PO-1" is replaced by "PO-5". The specific steps are as follows:

[0064] 80 parts by mass of the polyolefin composite material PO-5 and 20 parts by mass of calcium carbonate were fully mixed and melt-extruded through a single-screw extruder at 200°C. The main frequency conversion was set to 50 Hz and the traction frequency conversion was set to 9.3 Hz. A 200-mesh filter was used. The processing was continued for 20 minutes, and the accumulated amount of precipitates at the extruder die head was collected to evaluate the precipitation of the polyolefin composite material.

[0065] Example 15

[0066] This embodiment provides a method for evaluating the precipitation level of a polyolefin composite material. The only difference from Example 3 is that "PO-1" is replaced by "PO-5". The specific steps are as follows:

[0067] 90 parts by mass of the polyolefin composite material PO-5 and 10 parts by mass of calcium carbonate were thoroughly mixed and melt-extruded through a single-screw extruder at 300°C. The main frequency conversion was set to 60 Hz and the traction frequency conversion was set to 7 Hz. A 250-mesh filter was used. The processing was continued for 10 minutes, and the accumulated amount of precipitates at the extruder die head was collected to evaluate the precipitation of the polyolefin composite material.

[0068] Example 16

[0069] This embodiment provides a method for evaluating the precipitation level of a polyolefin composite material. The only difference from Example 1 is that "PO-1" is replaced with "PO-6". The specific steps are as follows:

[0070] The polyolefin composite material PO-6 (70 parts by mass) and calcium carbonate (30 parts by mass) were fully mixed and melt-extruded through a single-screw extruder at 160°C. The main frequency conversion was set to 40 Hz and the traction frequency conversion was set to 11 Hz. A 150-mesh filter was used. The processing was continued for 5 minutes, and the accumulated amount of precipitates at the extruder die head was collected to evaluate the precipitation of the polyolefin composite material.

[0071] Example 17

[0072] This embodiment provides a method for evaluating the precipitation level of a polyolefin composite material. The only difference from Example 2 is that "PO-1" is replaced with "PO-6". The specific steps are as follows:

[0073] 80 parts by mass of the polyolefin composite material PO-6 and 20 parts by mass of calcium carbonate were fully mixed and melt-extruded through a single-screw extruder at 200°C. The main frequency conversion was set to 50 Hz and the traction frequency conversion was set to 9.3 Hz. A 200-mesh filter was used. The processing was continued for 20 minutes, and the accumulated amount of precipitates at the extruder die head was collected to evaluate the precipitation of the polyolefin composite material.

[0074] Example 18

[0075] This embodiment provides a method for evaluating the precipitation level of a polyolefin composite material. The only difference from Example 3 is that "PO-1" is replaced by "PO-6". The specific steps are as follows:

[0076] 90 parts by mass of the polyolefin composite material PO-6 and 10 parts by mass of calcium carbonate were fully mixed and melt-extruded through a single-screw extruder at 300°C. The main frequency conversion was set to 60 Hz and the traction frequency conversion was set to 7 Hz. A 250-mesh filter was used. The processing was continued for 10 minutes, and the accumulated amount of precipitates at the extruder die head was collected to evaluate the precipitation of the polyolefin composite material.

[0077] Example 19

[0078] Without adding calcium carbonate, the polyolefin composite material PO-1 was melt-extruded to prepare a film. The processing was continued for 36 hours, and its precipitation was observed. The specific steps are as follows:

[0079] 100 parts by weight of the polyolefin composite material PO-1 were thoroughly mixed and melt-extruded through a single-screw extruder at 200°C. The main frequency conversion was set to 50 Hz and the traction frequency conversion was set to 9.3 Hz. A 200-mesh filter was used. The processing was continued for 36 hours, and the accumulated amount of precipitates at the extruder die head was collected to evaluate the precipitation of the polyolefin composite material.

[0080] Example 20

[0081] Without adding calcium carbonate, the polyolefin composite material PO-2 was melt-extruded to prepare a film. The processing was continued for 36 hours, and its precipitation was observed. The specific steps are as follows:

[0082] 100 parts by weight of a polyolefin composite material PO-2 was thoroughly mixed and melt-extruded through a single-screw extruder at 200°C. The main frequency conversion was set to 50 Hz and the traction frequency conversion was set to 9.3 Hz. A 200-mesh filter was used. The processing was continued for 36 hours, and the accumulated amount of precipitates at the extruder die head was collected to evaluate the precipitation of the polyolefin composite material.

[0083] Example 21

[0084] Without adding calcium carbonate, the polyolefin composite material PO-3 was melt-extruded to prepare a film. The processing was continued for 36 hours, and its precipitation was observed. The specific steps are as follows:

[0085] 100 parts by mass of a polyolefin composite material PO-3 was thoroughly mixed and melt-extruded through a single-screw extruder at 200°C. The main frequency conversion was set to 50 Hz and the traction frequency conversion was set to 9.3 Hz. A 200-mesh filter was used. The processing was continued for 36 hours, and the accumulated amount of precipitates at the extruder die head was collected to evaluate the precipitation of the polyolefin composite material.

[0086] Example 22

[0087] Without adding calcium carbonate, the polyolefin composite material PO-4 was melt-extruded to prepare a film. The processing was continued for 36 hours, and its precipitation was observed. The specific steps are as follows:

[0088] 100 parts by weight of a polyolefin composite material PO-4 was thoroughly mixed and melt-extruded through a single-screw extruder at 200°C. The main frequency conversion was set to 50 Hz and the traction frequency conversion was set to 9.3 Hz. A 200-mesh filter was used. The processing was continued for 36 hours, and the accumulated amount of precipitates at the extruder die head was collected to evaluate the precipitation of the polyolefin composite material.

[0089] Example 23

[0090] Without adding calcium carbonate, the polyolefin composite material PO-5 was melt-extruded to prepare a film. The processing was continued for 36 hours, and its precipitation was observed. The specific steps are as follows:

[0091] 100 parts by weight of a polyolefin composite material PO-5 was thoroughly mixed and melt-extruded through a single-screw extruder at 200°C. The main frequency conversion was set to 50 Hz and the traction frequency conversion was set to 9.3 Hz. A 200-mesh filter was used. The processing was continued for 36 hours, and the accumulated amount of precipitates at the extruder die head was collected to evaluate the precipitation of the polyolefin composite material.

[0092] Example 24

[0093] Without adding calcium carbonate, the polyolefin composite material PO-6 was melt-extruded to prepare a film. The processing was continued for 36 hours, and its precipitation was observed. The specific steps are as follows:

[0094] 100 parts by weight of a polyolefin composite material PO-6 was thoroughly mixed and melt-extruded through a single-screw extruder at 200°C. The main frequency conversion was set to 50 Hz and the traction frequency conversion was set to 9.3 Hz. A 200-mesh filter was used. The processing was continued for 36 hours, and the accumulated amount of precipitates at the extruder die head was collected to evaluate the precipitation of the polyolefin composite material.

[0095] The precipitation conditions of the polyolefin composite materials of Examples 1 to 24 are shown in Table 1.

[0096] Table 1. Precipitation of polyolefin composite materials of Examples 1 to 24.

[0097] sample Polyolefin composite material precipitation amount (g) Example 1 No precipitation Example 2 No precipitation Example 3 No precipitation Example 4 3.08 Example 5 3.19 Example 6 3.24 Example 7 2.67 Example 8 2.72 Example 9 2.76 Example 10 0.99 Example 11 1.00 Example 12 1.05 Example 13 No precipitation Example 14 No precipitation Example 15 No precipitation Example 16 3.81 Example 17 3.89 Example 18 3.93 Example 19 No precipitation Example 20 2.96 Example 21 2.01 Example 22 0.83 Example 23 No precipitation Example 24 3.07

[0098] As shown in Table 1, by comparing Examples 1-18 with Examples 19-24, if the polyolefin composite material does not precipitate during actual film production, the addition of calcium carbonate will prevent precipitation. If the polyolefin composite material does precipitate during actual film production, the addition of calcium carbonate will accelerate precipitation. Therefore, the method of the present invention can quickly identify the precipitation behavior of a specific brand or structure of polyolefin composite material during actual film production or under long-term use, which is of great significance for the application development and research of polyolefin composite materials.

[0099] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that after reading the specification of this application, technicians can still modify or replace the specific implementation methods of the present invention with equivalents, but these modifications or changes do not depart from the scope of protection of the pending claims of the present application.

Claims

1. A method for evaluating the precipitation level of a polyolefin composite material, characterized in that: The steps include: The polyolefin composite material and calcium carbonate were mixed and melt-extruded, and the accumulated amount of precipitates at the extruder die was collected to evaluate the precipitation of the polyolefin composite material.

2. The method for evaluating the precipitation level of the polyolefin composite material according to claim 1, wherein The polyolefin components in the polyolefin composite material are selected from at least two of polyethylene, polypropylene, polybutene, polypentene, polyhexene, polyoctene, poly(4-methyl-1-pentene), and polyolefin elastomer.

3. The method for evaluating the precipitation level of the polyolefin composite material according to claim 1, wherein The mass ratio of the polyolefin composite material to calcium carbonate is 7-9:1-3.

4. The method for evaluating the precipitation level of the polyolefin composite material according to claim 1, wherein The temperature of the melt extrusion is 160-230° C., and the time is ≤20 min.

5. The method for evaluating the precipitation level of the polyolefin composite material according to claim 1, wherein: The main frequency conversion of the extruder used in the melt extrusion is 40-60 Hz, and the traction frequency conversion is 7-11 Hz.

6. The method for evaluating the precipitation level of the polyolefin composite material according to claim 1, wherein: The filter screen used in the melt extrusion is 150-250 mesh.

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