Composition for high-speed production of thin-wall polyethylene drip irrigation pipe, resin and preparation method thereof

Abstract

The invention provides a composition for high-speed production of a thin-wall polyethylene drip irrigation pipe, resin and a preparation method thereof, and belongs to the technical field of polyethylene resin. The preparation method comprises the following steps: fully mixing 60-70 parts by weight of high-density polyethylene, 10-16 parts by weight of linear low-density polyethylene, 18-25 parts by weight of low-density polyethylene, 1-3 parts by weight of carbon black masterbatch and 0.1-0.2 part by weight of an anti-ultraviolet absorbent in a high-speed mixer, granulating, and drying to prepare the resin for high-speed production of the thin-wall polyethylene drip irrigation pipe. Compared with common drip irrigation pipe resin, the resin can be produced at a high speed (more than 250m / min), the longitudinal retraction rate and the hydrostatic strength meet standard requirements after the wall thickness of a pipe is reduced to 0.12 mm, the resin has excellent rigid-tough balance, the impact strength of a simply supported beam notch is more than 80kJ / m < 2 >, the bending modulus is more than 600MPa, the tensile yield stress is more than 18MPa, the tensile fracture nominal strain is more than 800%, and the tensile strength is more than 800MPa. And the oxidation induction time is longer than 18 minutes (210 DEG C).

Description

Technical Field

[0001] The invention belongs to the technical field of polyethylene resins, and in particular relates to a composition, a resin and a preparation method thereof for high-speed production of thin-wall polyethylene drip irrigation pipes. Background Art

[0002] As the contradiction between global water supply and demand becomes increasingly serious, water conservation has not only become a focus of world attention, but is also directly related to the realization of the long-term goal of sustainable development of population, resources and environment. At present, the relatively mature agricultural water-saving engineering technologies with obvious water-saving effects include: channel anti-seepage, low-pressure pipeline water delivery, plastic pipe machine well, sprinkler irrigation and micro-drip irrigation. Micro-drip irrigation pipes are divided into pipe-mounted drip irrigation pipes and inner-lined drip irrigation pipes. The drippers used are pressure compensation type and labyrinth flow channel pipe type. The main pipe and branch pipe diameters are polyethylene (PE) pipes when they are below 63mm.

[0003] Drip irrigation pipes use plastic pipes to deliver water to the roots of crops through orifices or drippers on a capillary tube with a diameter of about 10mm for local irrigation. It is through a dripper or drip irrigation pipe with a very small outflow orifice that water is dripped evenly and slowly into the soil near the roots of crops. At present, some domestic fields with low life requirements often use recycled polyethylene drip irrigation pipes for production, but cracking will occur, causing waste of water resources, and it is difficult to play the role of drip irrigation tapes. At the same time, the existing blending method or the direct use of recycled polyethylene to produce drip irrigation pipes has poor performance in the preparation of products such as environmental stress cracking resistance and flexibility, which is difficult to meet the use requirements, and the processing speed is low (usually <200m / min), which affects production efficiency. At the same time, the product thickness is >0.15mm.

[0004] At present, there are few patents and documents on the preparation method of resin for high-speed production of thin-walled polyethylene drip irrigation pipes. For example, the invention patent with publication number CN 107337836 A (application number 201710570865.5) discloses "an oxidation-resistant polyethylene drip irrigation tape and its preparation method". The patent relates to an oxidation-resistant polyethylene drip irrigation tape, including the following components: carbon black, PPA processing aid, composite antioxidant, high-density polyethylene and linear low-density polyethylene, wherein the composite antioxidant is composed of: a mixture of antioxidant B215, anti-ultraviolet absorber UV531 and low-density high-pressure polyethylene. The main body of the composite antioxidant used in the oxidation-resistant polyethylene drip irrigation tape of this invention is a polymer organic material, which not only has good oxidation resistance but also has good compatibility with polyethylene polymers, reducing structural defects in the preparation of the drip irrigation tape. Compared with ordinary drip irrigation tapes, it can provide drip irrigation tapes with higher strength oxidation resistance. It prevents the side cracking of the drip irrigation belt when it is used outdoors. Compared with ordinary polyethylene drip irrigation belt without antioxidant, it effectively enhances the oxidation resistance of the drip irrigation belt, ensures the service life of the drip irrigation belt, and reduces the possibility of damage to the drip irrigation belt during use. This patent focuses on improving the oxidation resistance of polyethylene drip irrigation pipes, and does not involve high-speed production of polyethylene drip irrigation pipes and reducing wall thickness.

[0005] The invention patent with publication number CN 106397903 A (application number 201610768093.1) discloses "a polyethylene drip irrigation tape with high tensile properties". The patent provides a polyethylene drip irrigation tape with high tensile properties, which is prepared from the following raw materials in parts by weight: 40-45 parts of high-density polyethylene; 16-18 parts of low-density polyethylene; 14-15 parts of linear low-density polyethylene; 0.75-1.5 parts of carbon black; 5-10 parts of plasticizer; 0.25-0.5 parts of PPA processing aid; 5-10 parts of glass fiber. The polyethylene drip irrigation tape with high tensile properties described in this invention has glass fiber added to the formula. Glass fiber is an inorganic non-metallic material with excellent performance, good insulation, good heat resistance, strong corrosion resistance and high mechanical strength. Compared with ordinary drip irrigation tapes, it can provide drip irrigation tapes with higher strength of pull-out resistance. However, adding glass fiber increases the cost. In addition, glass fiber and polyethylene are difficult to disperse and the process is complicated. At the same time, this patent does not involve high-speed production and wall thickness reduction of drip irrigation pipes. Summary of the invention

[0006] The purpose of the present invention is to design a composition and resin for high-speed production of thin-walled polyethylene drip irrigation pipes, in particular, by adjusting the ratio of different types of polyethylene and carbon black masterbatch and anti-ultraviolet absorber, a polyethylene drip irrigation pipe can be used for high-speed production and wall thickness reduction on the basis of ensuring the balance of rigidity and toughness of the material.

[0007] The first technical problem to be solved by the present invention is to provide a polyethylene drip irrigation pipe resin, which has excellent rigidity and toughness balance and can be produced at high speed (>250m / min). At the same time, after the pipe wall thickness is reduced to 0.12mm, the longitudinal shrinkage rate and hydrostatic strength meet the standard requirements.

[0008] The second technical problem to be solved by the present invention is to provide a method for preparing the above-mentioned polyethylene drip irrigation pipe resin, which has simple process and convenient operation.

[0009] According to one aspect of the present invention, there is provided a polyethylene composition comprising, in parts by weight:

[0010]

[0011]

[0012] Optionally, the polyethylene composition comprises, by weight:

[0013]

[0014] Optionally, the high-density polyethylene has a melt index (190°C, 5kg) of 0.5-0.7g / 10min and a density of 0.940-0.950g / cm 3 .

[0015] Optionally, the linear low-density polyethylene has a melt index (190°C, 2.16 kg) of 1.0 to 1.5 g / 10 min and a density of 0.910 to 0.915 g / cm 3 .

[0016] Optionally, the low-density polyethylene has a melt index (190°C, 2.16 kg) of 1.3-1.8 g / 10 min and a density of 0.915-0.920 g / cm 3 .

[0017] Optionally, the carbon black masterbatch is used in the present invention to achieve the purpose of anti-oxidation, and the carbon black masterbatch is composed of a linear low-density polyethylene base material and carbon black, wherein the carbon black component accounts for 40% to 60% by weight. The present invention does not specifically limit the source selection of the carbon black masterbatch.

[0018] Optionally, the anti-ultraviolet absorber includes an anti-ultraviolet absorber of model 2020 or 622 produced by BASF.

[0019] According to yet another aspect of the present invention, a polyethylene resin is provided, wherein the polyethylene resin comprises the polyethylene composition.

[0020] Optionally, the polyethylene resin has a simple supported beam notched impact strength of >80 kJ / m 2 .

[0021] Optionally, the flexural modulus of the polyethylene resin is greater than 600 MPa.

[0022] Optionally, the polyethylene resin has a tensile yield stress greater than 18 MPa.

[0023] Optionally, the polyethylene resin has a nominal tensile strain at break greater than 800%.

[0024] Optionally, the oxidation induction time of the polyethylene resin is greater than 18 min (210° C.).

[0025] According to another aspect of the present invention, there is provided a method for preparing the polyethylene resin, comprising mixing the polyethylene composition, granulating and drying.

[0026] Optionally, the mixing conditions are: first mixing at a low speed of 500 to 1000 r / min for 1 to 2 minutes, and then mixing at a high speed of 1000 to 2000 r / min for 0.5 to 1 minute.

[0027] Optionally, the granulation adopts a twin-screw extruder, and the temperature of the twin-screw extruder from feeding to the head is set to: 170℃~180℃, 180℃~190℃, 182℃~192℃, 185℃~195℃, 185℃~195℃, 180℃~190℃, 180℃~190℃, 175℃~185℃, 170℃~180℃, 170℃~180℃.

[0028] According to another aspect of the present invention, a drip irrigation pipe is provided, comprising at least one of the polyethylene composition, the polyethylene resin and the polyethylene resin prepared by the preparation method.

[0029] Optionally, the wall thickness of the drip irrigation pipe is ≥0.12 mm.

[0030] Optionally, the longitudinal retraction rate of the drip irrigation pipe is less than 8%.

[0031] And / or the hydrostatic strength of the drip irrigation pipe is greater than 20 min (0.3 MPa).

[0032] As a specific embodiment of the present invention, the specification of the drip irrigation pipe is

[0033] According to another aspect of the present invention, there is provided a method for preparing the above-mentioned drip irrigation pipe, comprising extruding resin particles by using a pipe extruder.

[0034] Optionally, the production speed of the drip irrigation pipe is greater than 250 m / min.

[0035] Optionally, the pipe extruder is a single-screw pipe extruder.

[0036] The present invention has the following beneficial effects:

[0037] The resin containing the polyethylene composition of the present invention has excellent rigidity-toughness balance performance, and the simply supported beam notched impact strength is greater than 80 kJ / m 2 , bending modulus> 600MPa, tensile yield stress> 18MPa, tensile fracture nominal strain> 800%, oxidation induction time> 18min (210°C), can be used for high-speed (> 250m / min) production of thin-walled polyethylene drip irrigation pipes, after the pipe wall thickness is reduced to 0.12mm, the longitudinal shrinkage rate and hydrostatic strength still meet the standard requirements. The preparation method of the polyethylene resin provided by the invention has simple process and convenient operation. DETAILED DESCRIPTION

[0038] The present invention will be further described below in conjunction with specific embodiments, but they do not constitute any limitation to the present invention.

[0039] In each embodiment of the present invention, the parameter conditions corresponding to the melt index of high-density polyethylene are temperature 190° C. and load 5 kg, and the parameter conditions corresponding to the melt index of linear low-density polyethylene and low-density polyethylene are temperature 190° C. and load 2.16 kg.

[0040] In each embodiment of the present invention, the high-speed mixer used is produced by Baixiong Company, model SHR-50L, and the twin-screw extruder is produced by Nanjing Ruiya Company, model TSE-35A.

[0041] In each embodiment of the present invention, GB / T 1040.2-2006, GB / T 9341-2008, GB / T1043.1-2008 and GB / T 19466.6-2009 and other national standards are respectively used to test the mechanical properties of the resin, and GB / T 6671-2001 and GB / T 6111-2003 and other national standards are respectively used to test the performance of the drip irrigation pipe.

[0042] In each embodiment of the present invention, the carbon black masterbatch used is a black masterbatch of model PE6269 produced by Cabot, and the anti-ultraviolet absorber is an anti-ultraviolet absorber of model 2020 produced by BASF.

[0043] Example 1

[0044] Expressed in parts by weight, 60 parts of a melt index of 0.5 g / 10 min and a density of 0.940 g / cm 3High-density polyethylene, 16 parts melt index 1.0g / 10min, density 0.910g / cm 3 Linear low-density polyethylene, 21 parts melt index 1.3g / 10min, density 0.915g / cm 3 Low-density polyethylene, 3 parts of carbon black masterbatch, and 0.1 parts of anti-ultraviolet absorber were added to a high-speed mixer and mixed thoroughly, mixed at 500r / min for 2 minutes and then at 1200r / min for 1 minute, and then added to a twin-screw extruder for granulation. During the granulation process, the temperatures of each section of the extruder from the feed port to the die were: 170°C, 180°C, 182°C, 185°C, 185°C, 185°C, 180°C, 180°C, 175°C, and 170°C. The mechanical properties of the resin were tested according to the national standard.

[0045] Example 2

[0046] Expressed in parts by weight, 62 parts of a melt index of 0.6 g / 10 min and a density of 0.945 g / cm 3 High-density polyethylene, 13 parts, melt index 1.2g / 10min, density 0.912g / cm 3 Linear low-density polyethylene, 23 parts melt index 1.5g / 10min, density 0.920g / cm 3 Low-density polyethylene, 2 parts of carbon black masterbatch, and 0.12 parts of anti-ultraviolet absorber were added to a high-speed mixer and mixed thoroughly, mixed at 800r / min for 1.5 minutes and then at 1500r / min for 0.5 minutes, and then added to a twin-screw extruder for granulation. The temperatures of each section of the extruder from the feed port to the die during the granulation process were: 175°C, 185°C, 188°C, 190°C, 190°C, 180°C, 185°C, 175°C, 170°C, and 175°C. The mechanical properties of the resin were tested according to the national standard.

[0047] Example 3

[0048] Expressed in parts by weight, 67 parts of a melt index of 0.55 g / 10 min and a density of 0.948 g / cm 3 High-density polyethylene, 14 parts, melt index 1.5g / 10min, density 0.915g / cm 3 Linear low-density polyethylene, 18 parts melt index 1.6g / 10min, density 0.918g / cm 3Low-density polyethylene, 1 part of carbon black masterbatch, and 0.14 parts of anti-ultraviolet absorber were added to a high-speed mixer and mixed thoroughly, mixed at 1000r / min for 1 minute and then at 1600r / min for 1 minute, and then added to a twin-screw extruder for granulation. During the granulation process, the temperatures of each section of the extruder from the feed port to the die were: 180℃, 180℃, 192℃, 195℃, 180℃, 190℃, 190℃, 185℃, 180℃, and 180℃. The mechanical properties of the resin were tested according to the national standard.

[0049] Example 4

[0050] Expressed in parts by weight, 61 parts of a melt index of 0.65 g / 10 min and a density of 0.950 g / cm 3 High-density polyethylene, 12 parts melt index is 1.2g / 10min, density is 0.912g / cm 3 Linear low-density polyethylene, 25 parts melt index 1.8g / 10min, density 0.915g / cm 3 Low-density polyethylene, 2 parts of carbon black masterbatch, and 0.16 parts of anti-ultraviolet absorber were added to a high-speed mixer and mixed thoroughly, mixed at 600r / min for 1 minute and then at 2000r / min for 0.5 minutes, and then added to a twin-screw extruder for granulation. During the granulation process, the temperatures of each section of the extruder from the feed port to the die were: 170°C, 190°C, 185°C, 185°C, 185°C, 185°C, 180°C, 180°C, 175°C, and 170°C. The mechanical properties of the resin were tested according to the national standard.

[0051] Example 5

[0052] Expressed in parts by weight, 65 parts of a melt index of 0.7 g / 10 min and a density of 0.945 g / cm 3 High-density polyethylene, 10 parts melt index is 1.4g / 10min, density is 0.910g / cm 3 Linear low-density polyethylene, 24 parts melt index 1.3g / 10min, density 0.916g / cm 3 Low-density polyethylene, 1 part of carbon black masterbatch, and 0.18 parts of anti-ultraviolet absorber were added to a high-speed mixer and mixed thoroughly, mixed at 800r / min for 2 minutes and then at 1800r / min for 1 minute, and then added to a twin-screw extruder for granulation. During the granulation process, the temperatures of each section of the extruder from the feed port to the die were: 173°C, 185°C, 185°C, 185°C, 185°C, 185°C, 180°C, 180°C, 175°C, and 175°C. The mechanical properties of the resin were tested according to the national standard.

[0053] Example 6

[0054] Expressed in parts by weight, 66 parts of a melt index of 0.55 g / 10 min and a density of 0.950 g / cm 3 High-density polyethylene, 11 parts melt index 1.0g / 10min, density 0.915g / cm 3 Linear low-density polyethylene, 20 parts melt index 1.5g / 10min, density 0.918g / cm 3 Low-density polyethylene, 3 parts of carbon black masterbatch, and 0.2 parts of anti-ultraviolet absorber were added to a high-speed mixer and mixed thoroughly, mixed at 500r / min for 2 minutes and then at 1200r / min for 1 minute, and then added to a twin-screw extruder for granulation. During the granulation process, the temperatures of each section of the extruder from the feed port to the die were: 170°C, 180°C, 185°C, 185°C, 185°C, 185°C, 180°C, 180°C, 175°C, and 170°C. The mechanical properties of the resin were tested according to the national standard.

[0055] Example 7

[0056] Expressed in parts by weight, 70 parts of a melt index of 0.65 g / 10 min and a density of 0.940 g / cm 3 High-density polyethylene, 10 parts melt index is 1.5g / 10min, density is 0.912g / cm 3 Linear low-density polyethylene, 19 parts melt index 1.8g / 10min, density 0.920g / cm 3 Low-density polyethylene, 1 part of carbon black masterbatch, and 0.15 parts of anti-ultraviolet absorber were added to a high-speed mixer and mixed thoroughly, mixed at 600r / min for 1.5 minutes and then at 1500r / min for 1 minute, and then added to a twin-screw extruder for granulation. During the granulation process, the temperatures of each section of the extruder from the feed port to the die were: 175°C, 180°C, 185°C, 185°C, 185°C, 185°C, 185°C, 180°C, 175°C, and 175°C. The mechanical properties of the resin were tested according to the national standard.

[0057] Example 8

[0058] Expressed in parts by weight, 69 parts of a melt index of 0.7 g / 10 min and a density of 0.945 g / cm 3 High-density polyethylene, 10 parts melt index is 1.3g / 10min, density is 0.910g / cm 3 Linear low-density polyethylene, 20 parts melt index is 1.3g / 10min, density is 0.916g / cm 3Low-density polyethylene, 1 part of carbon black masterbatch, and 0.15 parts of anti-ultraviolet absorber were added to a high-speed mixer and mixed thoroughly, mixed at 800r / min for 1 minute and then at 2000r / min for 0.5 minutes, and then added to a twin-screw extruder for granulation. During the granulation process, the temperatures of each section of the extruder from the feed port to the die were: 175°C, 180°C, 185°C, 190°C, 185°C, 185°C, 180°C, 180°C, 175°C, and 175°C. The mechanical properties of the resin were tested according to the national standard.

[0059] Example 9

[0060] Expressed in parts by weight, 65 parts of a melt index of 0.55 g / 10 min and a density of 0.948 g / cm 3 High-density polyethylene, 10 parts melt index is 1.5g / 10min, density is 0.915g / cm 3 Linear low-density polyethylene, 24 parts melt index 1.6g / 10min, density 0.918g / cm 3 Low-density polyethylene, 1 part of carbon black masterbatch, and 0.18 parts of anti-ultraviolet absorber were added to a high-speed mixer and mixed thoroughly, mixed at 800r / min for 1 minute and then at 2000r / min for 0.5 minutes, and then added to a twin-screw extruder for granulation. During the granulation process, the temperatures of each section of the extruder from the feed port to the die were: 175°C, 180°C, 185°C, 190°C, 185°C, 185°C, 180°C, 180°C, 175°C, and 175°C. The mechanical properties of the resin were tested according to the national standard.

[0061] Example 10

[0062] Expressed in parts by weight, 67 parts of a melt index of 0.55 g / 10 min and a density of 0.950 g / cm 3 High-density polyethylene, 14 parts, melt index 1.5g / 10min, density 0.913g / cm 3 Linear low-density polyethylene, 18 parts melt index 1.6g / 10min, density 0.916g / cm 3 Low-density polyethylene, 1 part of carbon black masterbatch, and 0.14 parts of anti-ultraviolet absorber were added to a high-speed mixer and mixed thoroughly, mixed at 800r / min for 1 minute and then at 2000r / min for 0.5 minutes, and then added to a twin-screw extruder for granulation. During the granulation process, the temperatures of each section of the extruder from the feed port to the die were: 175°C, 180°C, 185°C, 190°C, 185°C, 185°C, 180°C, 180°C, 175°C, and 175°C. The mechanical properties of the resin were tested according to the national standard.

[0063] Embodiment 11

[0064] Expressed in parts by weight, 67 parts of a melt index of 0.6 g / 10 min and a density of 0.948 g / cm 3 High-density polyethylene, 14 parts, melt index 1.2g / 10min, density 0.915g / cm 3 Linear low-density polyethylene, 18 parts, melt index 1.4g / 10min, density 0.918g / cm 3 Low-density polyethylene, 1 part of carbon black masterbatch, and 0.14 parts of anti-ultraviolet absorber were added to a high-speed mixer and mixed thoroughly, mixed at 800r / min for 1 minute and then at 2000r / min for 0.5 minutes, and then added to a twin-screw extruder for granulation. During the granulation process, the temperatures of each section of the extruder from the feed port to the die were: 175°C, 180°C, 185°C, 190°C, 185°C, 185°C, 180°C, 180°C, 175°C, and 175°C. The mechanical properties of the resin were tested according to the national standard.

[0065] Comparative Example 1

[0066] Expressed in parts by weight, 55 parts of a melt index of 0.55 g / 10 min and a density of 0.948 g / cm 3 High-density polyethylene, 18 parts, melt index 1.5g / 10min, density 0.915g / cm 3 Linear low-density polyethylene, 25 parts melt index 1.6g / 10min, density 0.918g / cm 3 Low-density polyethylene, 2 parts of carbon black masterbatch, and 0.14 parts of anti-ultraviolet absorber were added to a high-speed mixer and mixed thoroughly, mixed at 1000r / min for 1 minute and then at 1600r / min for 1 minute, and then added to a twin-screw extruder for granulation. During the granulation process, the temperatures of each section of the extruder from the feed port to the die were: 180℃, 180℃, 192℃, 195℃, 180℃, 190℃, 190℃, 185℃, 180℃, and 180℃. The mechanical properties of the resin were tested according to the national standard.

[0067] Comparative Example 2

[0068] Expressed in parts by weight, 75 parts of a melt index of 0.55 g / 10 min and a density of 0.948 g / cm 3 High-density polyethylene, 10 parts melt index is 1.5g / 10min, density is 0.915g / cm 3 Linear low-density polyethylene, 13 parts melt index 1.6g / 10min, density 0.918g / cm 3Low-density polyethylene, 2 parts of carbon black masterbatch, and 0.14 parts of anti-ultraviolet absorber were added to a high-speed mixer and mixed thoroughly, mixed at 1000r / min for 1 minute and then at 1600r / min for 1 minute, and then added to a twin-screw extruder for granulation. During the granulation process, the temperatures of each section of the extruder from the feed port to the die were: 180℃, 180℃, 192℃, 195℃, 180℃, 190℃, 190℃, 185℃, 180℃, and 180℃. The mechanical properties of the resin were tested according to the national standard.

[0069] Comparative Example 3

[0070] Expressed in parts by weight, 60 parts of a melt index of 0.55 g / 10 min and a density of 0.948 g / cm 3 High-density polyethylene, 38 parts, melt index 1.6g / 10min, density 0.918g / cm 3 Low-density polyethylene, 2 parts of carbon black masterbatch, and 0.14 parts of anti-ultraviolet absorber were added to a high-speed mixer and mixed thoroughly, mixed at 1000r / min for 1 minute and then at 1600r / min for 1 minute, and then added to a twin-screw extruder for granulation. During the granulation process, the temperatures of each section of the extruder from the feed port to the die were: 180℃, 180℃, 192℃, 195℃, 180℃, 190℃, 190℃, 185℃, 180℃, and 180℃. The mechanical properties of the resin were tested according to the national standard.

[0071] Test Example 1

[0072] Polyethylene drip irrigation pipe resin performance test results:

[0073] Table 1

[0074]

[0075] The above tests show that the test results of Examples 1 to 11 all meet the expected design (simple beam notched impact strength > 80 kJ / m 2 , flexural modulus>600MPa, tensile yield stress>18MPa, tensile nominal strain at break>800%, oxidation induction time>18min(210°C)); some performances of comparative examples 1 to 3 did not meet the design requirements.

[0076] Test Example 2

[0077] The polyethylene drip irrigation pipe resin prepared in Examples 1 to 11 and Comparative Examples 1 to 3 was used for pipe processing test. The test used a single screw pipe extruder produced by Tianjin Huaxu Shengtai Technology Co., Ltd. The screw diameter of the extruder was 60 mm, the aspect ratio was 40:1, and the specifications of the extruded pipe were The tube wall thickness is 0.12-0.15mm; the production speed is greater than 250m / min.

[0078] Polyethylene drip irrigation pipe performance test results:

[0079] Table 2

[0080]

[0081] Any numerical value mentioned in the present invention includes all values ​​that increase by one unit each time from the lowest value to the highest value if there is only an interval of two units between any minimum value and any maximum value. For example, if the amount of a component, or the value of a process variable such as temperature, pressure, time, etc. is declared to be 50-90, in this specification it means that 51-89, 52-88... and 69-71 and 70-71 are specifically listed. For non-integer values, 0.1, 0.01, 0.001 or 0.0001 can be appropriately considered as a unit. These are just some specially specified examples. In the present invention, in a similar manner, all possible combinations of numerical values ​​between the listed lowest and highest values ​​are considered to have been disclosed.

[0082] It should be noted that the embodiments described above are only used to explain the present invention and do not constitute any limitation to the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory words, rather than restrictive words. The present invention may be modified as specified within the scope of the claims of the present invention, and the present invention may be revised without departing from the scope and spirit of the present invention. Although the present invention described therein relates to specific methods, materials and embodiments, it does not mean that the present invention is limited to the specific examples disclosed therein, on the contrary, the present invention can be extended to all other methods and applications with the same functions.

Claims

1. A polyethylene composition, characterized in that Contains by weight: 60-70 parts of high-density polyethylene, 10-16 parts of linear low-density polyethylene, 18-25 parts of low-density polyethylene, 1-3 parts of carbon black masterbatch, Anti-ultraviolet absorber 0.1 to 0.2 parts.

2. The polyethylene composition according to claim 1, characterized in that Contains by weight: High-density polyethylene 65-68 parts, 12-14 parts of linear low-density polyethylene, 18-20 parts of low-density polyethylene, 1-2 parts of carbon black masterbatch, 0.12-0.16 parts of anti-ultraviolet absorber; And / or, the melt index (190°C, 5kg) of the high-density polyethylene is 0.5-0.7g / 10min, and the density is 0.940-0.950g / cm 3 ; And / or, the linear low-density polyethylene has a melt index (190°C, 2.16 kg) of 1.0 to 1.5 g / 10 min and a density of 0.910 to 0.915 g / cm 3 ; And / or, the melt index (190°C, 2.16kg) of the low-density polyethylene is 1.3-1.8g / 10min, and the density is 0.915-0.920g / cm 3 .

3. A polyethylene resin, characterized in that The polyethylene resin comprises the polyethylene composition according to claim 1 or 2.

4. The polyethylene resin according to claim 3, characterized in that The polyethylene resin has a simple supported beam notched impact strength of >80 kJ / m 2 , and / or flexural modulus>600MPa, and / or tensile yield stress>18MPa, and / or tensile break nominal strain>800%, and / or oxidation induction time>18min (210°C).

5. A method for preparing the polyethylene resin according to claim 3 or 4, characterized in that: The method comprises mixing the polyethylene composition, granulating the mixture and drying the mixture.

6. The preparation method according to claim 5, characterized in that: The mixing conditions are: first mixing at a low speed of 500 to 1000 r / min for 1 to 2 minutes, and then mixing at a high speed of 1000 to 2000 r / min for 0.5 to 1 minute.

7. The preparation method according to claim 5, characterized in that: The granulation adopts a twin-screw extruder, and the temperature of the twin-screw extruder from feeding to the head is set to: 170℃~180℃, 180℃~190℃, 182℃~192℃, 185℃~195℃, 185℃~195℃, 180℃~190℃, 180℃~190℃, 175℃~185℃, 170℃~180℃, 170℃~180℃.

8. A drip irrigation pipe, characterized in that: The drip irrigation pipe comprises at least one of the polyethylene composition according to any one of claims 1 to 2, the polyethylene resin according to any one of claims 3 to 4, and the polyethylene resin prepared by the preparation method according to any one of claims 5 to 7.

9. The drip irrigation pipe according to claim 8, characterized in that: The wall thickness of the drip irrigation pipe is ≥0.12 mm, and / or the longitudinal retraction rate of the drip irrigation pipe is <8%, and / or the hydrostatic strength of the drip irrigation pipe is >20 min (0.3 MPa).

10. A method for preparing the drip irrigation pipe according to claim 8 or 9, characterized in that: It includes extruding resin pellets using a pipe extruder; And / or, the production speed of the drip irrigation pipe is greater than 250 m / min.

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