Metallocene polyethylene material, composite mulching film and preparation method thereof

Abstract

The invention discloses a metallocene polyethylene material, a composite mulching film and a preparation method thereof, and the metallocene polyethylene material comprises the following raw materials by mass: 75-85 parts of metallocene polyethylene resin, 15-25 parts of high density polyethylene, 0.05-0.2 part of a main antioxidant, 0.1-0.25 part of an auxiliary antioxidant, 1-2 parts of silane coupling agent modified nano zinc oxide, and 1-2 parts of silane coupling agent modified mica powder. And 0.05 to 0.2 part of a slipping agent. The prepared metallocene polyethylene composition has the advantages of excellent processability, tensile strength, mechanical strength, aging resistance and the like.

Description

Technical Field

[0001] The present invention belongs to the field of metallocene polyethylene films, and particularly relates to a metallocene polyethylene material, a composite plastic film and a preparation method thereof. Background Art

[0002] The statements herein only provide background art related to the present invention and do not necessarily constitute prior art.

[0003] Metallocene polyethylene is a product produced by polymerizing ethylene and α-olefin under the action of a metallocene catalyst, and is widely used due to its excellent properties. Metallocene polyethylene films have the advantages of high transparency, high tensile strength, puncture resistance, etc., and are widely used in the fields of packaging films, agricultural films and heat shrinkable films. At present, the production processes of metallocene polyethylene in China mainly include two polymerization processes: gas phase method and slurry method. However, metallocene polyethylene is prone to sharkskin phenomenon and crystal points during extrusion, which affects the performance of film products.

[0004] In addition, the catalyst technology and reaction process of high-density polyethylene are relatively mature. The production processes of high-density polyethylene mainly include gas phase method, solution method and slurry method. The resins produced by the above processes usually have the advantages of good impact resistance, excellent low temperature resistance, good chemical stability, etc., but the environmental stress cracking resistance and tensile strength are usually poor. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a metallocene polyethylene material, a composite plastic film and a preparation method thereof. The prepared metallocene polyethylene composition has the advantages of excellent processing performance, tensile strength, mechanical strength and excellent aging resistance.

[0006] In order to achieve the above purpose, the present invention is realized through the following technical solutions:

[0007] In the first aspect, the present invention provides a metallocene polyethylene material, which is composed of the following raw materials in parts by mass: 75-85 parts of metallocene polyethylene resin, 15-25 parts of high-density polyethylene, 0.05-0.2 part of a main antioxidant, 0.1-0.25 part of an auxiliary antioxidant, 1-2 parts of silane coupling agent modified nano-zinc oxide, 1-2 parts of silane coupling agent modified mica powder, and 0.05-0.2 part of a slip agent.

[0008] In some embodiments, the primary antioxidant is at least one of pentaerythritol tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (antioxidant 1010), octadecyl 3,5-di-tert-butyl-4-hydroxyhydrocinnamate (antioxidant 1076), tris(3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate (antioxidant 3114), 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene (antioxidant 1330), tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanuric acid (antioxidant 1790), N,N'-bis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanoyl)hexanediamine (antioxidant 1098), octadecyl 3,5-di-tert-butyl-4-hydroxyhydrocinnamate (antioxidant 1076), bis(3,5-di-tert-butyl-4-hydroxybenzoyl) hydrazine (antioxidant 1024).

[0009] In some embodiments, the secondary antioxidant is at least one of tris(2,4-di-tert-butylphenyl) phosphite (antioxidant 168), 3,9-bis(octadecyloxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane (antioxidant 618) or bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite (antioxidant 626).

[0010] In some embodiments, the slip agent is oleic acid amide or erucic acid amide.

[0011] In some embodiments, the silane-coupled nano zinc oxide is vinyltriethoxysilane-modified nano zinc oxide.

[0012] Preferably, the preparation method of the vinyltriethoxysilane-modified nano zinc oxide is as follows: spraying a vinyltriethoxysilane solution on the nano zinc oxide filler, stirring and mixing evenly, and then drying to obtain the product.

[0013] Preferably, the mass ratio of nano zinc oxide to vinyltriethoxysilane is 1-3:0.01-0.05.

[0014] Preferably, the stirring time is 10-30 min and the stirring speed is 600-1000 r / min.

[0015] Preferably, the drying temperature is 100-120 °C and the drying time is 1-2 h.

[0016] In some embodiments, the comonomer of the high-density polyethylene is 1-butene, and the density is 0.944-0.959 g / cm 3 ; the melt flow rate is 0.24-0.45 g / 10 min, at 190 °C / 5 kg.

[0017] The high-density polyethylene is a multi-peak high-density polyethylene produced by a Ziegler-Natta catalyst slurry process.

[0018] In some embodiments, the comonomer of the metallocene polyethylene resin is 1-hexene, and the density is 0.916 - 0.92 g / cm 3 , and the melt flow rate is 3.3 - 3.7 g / 10 min, at 190 °C / 2.16 kg.

[0019] The metallocene polyethylene resin is a metallocene polyethylene resin produced by a Basell slurry process.

[0020] In some embodiments, the silane coupling agent-modified mica powder is vinyltriethoxysilane-modified mica powder.

[0021] By pretreating the surface of mica powder with the coupling agent vinyltriethoxysilane, the compatibility between mica powder and polyethylene resin can be increased, thus fully ensuring the reinforcing effect of mica powder on the polyethylene composite resin and improving the rigidity of the polyethylene resin.

[0022] Preferably, the preparation method of the vinyltriethoxysilane-modified mica powder is: spraying a vinyltriethoxysilane solution on the mica powder and stirring and mixing to obtain it.

[0023] More preferably, the temperature of stirring and mixing is 20 - 30 °C, and the time of stirring and mixing is 10 - 20 min.

[0024] More preferably, the mass ratio of mica powder to vinyltriethoxysilane is 1 - 3:0.01 - 0.05.

[0025] In a second aspect, the present invention provides a preparation method of the metallocene polyethylene material, including the following steps:

[0026] Mixing a primary antioxidant, a secondary antioxidant, a metallocene polyethylene resin, and high-density polyethylene in proportion and stirring for 1 - 3 min;

[0027] Then adding a slip agent, a silane coupling agent-modified nano-zinc oxide, and a silane coupling agent-modified mica powder in proportion and performing secondary blending to obtain a mixed material;

[0028] Performing melt mixing on the obtained mixed material and then extruding and pelletizing to obtain it.

[0029] In some embodiments, the temperature of the melt mixing is 180 - 200 °C.

[0030] Preferably, during melt mixing, the screw speed of the extruder is 100 - 300 r / min, the feeding speed is 5 - 10 r / min, and the vacuum negative pressure is above -0.09.

[0031] In a third aspect, the present invention provides a metallocene polyethylene composite ground film, which is prepared from the metallocene polyethylene material.

[0032] In some embodiments, the preparation method of the metallocene polyethylene composite ground film is: extruding and blowing the metallocene polyethylene material to obtain it.

[0033] The beneficial effects obtained by one or more of the above embodiments of the present invention are as follows:

[0034] The modified nano-zinc oxide filler. Nano-zinc oxide has extremely strong ultraviolet and infrared reflection characteristics. When added to the coating, it can form a shielding effect to achieve the purpose of anti-ultraviolet aging and thermal aging, and at the same time increase the heat insulation of the coating. In addition, nano-zinc oxide as an agricultural seed treatment agent can improve crop yield and increase biocompatibility.

[0035] The modified nano-mica powder filler can reduce the shrinkage rate, warpage degree and bending degree of the product, improve the mechanical properties, heat resistance, insulation and chemical stability of the product, increase the surface gloss of the product, prevent plastic aging. In addition, the active flaky mica improves the mechanical properties of polyethylene and has a reinforcing effect.

[0036] Different types of polyethylene resins provide complementary mechanical strengths. Among them, metallocene polyethylene has good flexibility and light transmittance, while high-density polyethylene provides higher mechanical reinforcement.

[0037] The metallocene polyethylene material prepared by the present invention has the advantages of excellent processing performance, tensile strength, mechanical strength and excellent aging resistance. Detailed implementation manners

[0038] It should be noted that the following detailed description is illustrative and is intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0039] In order to further elaborate the technical solution of the present invention, the present invention will be described in detail below in combination with some embodiments. However, it should be understood that the specific embodiments described here are only for explaining the present invention and not for limiting its content.

[0040] The silane coupling agent in the following examples and comparative examples is vinyltriethoxysilane.

[0041] Example 1

[0042] Preparation of polyethylene composite ground film:

[0043] S1: Weigh 75 parts of metallocene polyethylene (MFR is 3.5 g / 10 min, density 0.9560 g / cm 3 ), 25 parts of high-density polyethylene (MFR is 0.25 g / 10 min, density 0.9549 g / cm 3 ), 0.05 part of primary antioxidant 1098, and 0.1 part of auxiliary antioxidant 168, and premix them in a high-speed mixer to obtain a premix, with a rotation speed of 2000 r / min.

[0044] S2: According to the proportion, add 1 part of silane-coupled nano-zinc oxide, 1 part of silane-coupled mica powder, and 0.05 part of oleic acid amide to the premix and mix them thoroughly, with a rotation speed of 2000 r / min.

[0045] S3: Feed the thoroughly mixed mixture into a twin-screw extruder. The working temperature of the twin-screw extruder is 220 °C and the rotation speed is 25 r / min. Extrusion blow molding is carried out to obtain the ground film of Example 1.

[0046] Example 2

[0047] Preparation of polyethylene composite ground film

[0048] S1: Weigh 78 parts of metallocene polyethylene (MFR is 3.4 g / 10 min, density 0.9560 g / cm 3 ), 22 parts of high-density polyethylene (MFR is 0.32 g / 10 min, density 0.9549 g / cm 3 ), 0.1 part of primary antioxidant 1790, and 0.15 part of auxiliary antioxidant 626, and premix them in a high-speed mixer to obtain a premix, with a rotation speed of 1500 r / min.

[0049] S2: According to the proportion, add 1.3 parts of silane-coupled nano-zinc oxide, 1.3 parts of silane-coupled mica powder, and 0.1 part of erucic acid amide to the premix and mix them thoroughly, with a rotation speed of 1500 r / min.

[0050] According to the steps of S3 in Example 1, the polyethylene ground film of Example 2 is prepared.

[0051] Example 3

[0052] S1: First, weigh 82 parts of metallocene polyethylene (MFR is 3.4 g / 10 min, density 0.9561 g / cm 3 ), 18 parts of high-density polyethylene (MFR is 0.36 g / 10 min, density 0.9472 g / cm 3) 0.15 parts of primary antioxidant 1024 and 0.2 parts of secondary antioxidant 168 were premixed in a high-speed mixer to obtain a premix at a rotation speed of 2000 r / min.

[0053] S2: Weigh 1.6 parts of silane coupling agent-modified nano zinc oxide, 1.6 parts of silane coupling agent-modified mica powder, and 0.2 parts of erucamide according to the ratio, and add them to the premix for thorough blending at a rotation speed of 2000 r / min.

[0054] According to the steps of S3 in Example 1, the polyethylene mulch film of Example 3 was prepared.

[0055] Example 4

[0056] S1: Weigh 85 parts of metallocene polyethylene (MFR is 3.5 g / 10 min, density 0.9558 g / cm 3 ), 15 parts of high-density polyethylene (MFR is 0.24 g / 10 min, density 0.9503 g / cm 3 ), 0.2 parts of primary antioxidant 1098, and 0.25 parts of secondary antioxidant 626, and premix them in a high-speed mixer to obtain a premix at a rotation speed of 2000 r / min.

[0057] S2: Weigh 2 parts of silane coupling agent-modified nano zinc oxide, 2 parts of silane coupling agent-modified mica powder, and 0.2 parts of erucamide according to the ratio, and add them to the premix for thorough blending. Preferably, the rotation speed is 2000 r / min.

[0058] According to the steps of S3 in Example 1, the polyethylene mulch film of Example 4 was prepared.

[0059] Comparative Example 1

[0060] S1: Weigh 82 parts of metallocene polyethylene (MFR is 3.5 g / 10 min, density 0.9560 g / cm 3 ), 18 parts of high-density polyethylene (MFR is 0.25 g / 10 min, density 0.9549 g / cm 3 ), 0.1 part of primary antioxidant 1024, and 0.2 part of secondary antioxidant 626, and premix them in a high-speed mixer to obtain a premix at a rotation speed of 2000 r / min.

[0061] S2: Add 0.5 part of silane coupling agent-modified nano zinc oxide, 1 part of silane coupling agent-modified mica powder, and 0.1 part of erucamide weighed according to the ratio to the premix for thorough blending at a rotation speed of 2000 r / min.

[0062] According to the steps of S3 in Example 1, the polyethylene mulch film of Comparative Example 1 was prepared.

[0063] Comparative Example 2

[0064] It was carried out according to Example 1, except that in the raw material formula, high-density polyethylene (MFR is 0.25 g / 10 min, density 0.9549 g / cm 3 ) was replaced with high-density polyethylene (MFR is 0.46 g / 10 min, 190 °C / 5 kg; density 0.9559 g / cm 3 ) to obtain the polyethylene film of Comparative Example 2.

[0065] Comparative Example 3

[0066] S1: Weigh 78 parts of metallocene polyethylene (MFR is 3.5 g / 10 min, density 0.9560 g / cm 3 ), 22 parts of high-density polyethylene (MFR is 0.25 g / 10 min, density 0.9549 g / cm 3 ), 0.1 part of primary antioxidant 1790, and 0.15 part of secondary antioxidant 626, and premix them in a high-speed mixer to obtain a premix, with a rotation speed of 2000 r / min.

[0067] S2: Weigh 1 part of silane-coupled nano-zinc oxide, 0.5 part of silane-coupled mica powder, and 0.1 part of erucamide according to the ratio, and add them to the premix for thorough blending. Preferably, the rotation speed is 2000 r / min.

[0068] The polyethylene mulch film of Comparative Example 3 was prepared according to S3 in Example 1.

[0069] Comparative Example 4

[0070] S1: Weigh 78 parts of metallocene polyethylene (MFR is 3.5 g / 10 min, density 0.9560 g / cm 3 ), 22 parts of high-density polyethylene (MFR is 0.25 g / 10 min, density 0.9549 g / cm 3 ), 0.1 part of primary antioxidant 1024, and 0.15 part of secondary antioxidant 168, and premix them in a high-speed mixer to obtain a premix, with a rotation speed of 2000 r / min.

[0071] S2: Weigh 3 parts of silane-coupled nano-zinc oxide, 3 parts of silane-coupled mica powder, and 0.1 part of oleic acid amide according to the ratio, and add them to the premix for thorough blending, with a rotation speed of 2000 r / min.

[0072] The polyethylene mulch film of Comparative Example 4 was prepared according to the S3 step in Example 1.

[0073] Comparative Example 5

[0074] The difference from Example 1 is that the high-density polyethylene in Example 1 is replaced with metallocene polyethylene (MFR is 3.5 g / 10 min, density 0.9560 g / cm 3 ), and the rest are the same as in Example 1, and a polyethylene mulch film of Comparative Example 5 is prepared.

[0075] Comparative Example 6

[0076] The difference from Example 1 is that the metallocene polyethylene in Example 1 is replaced with high-density polyethylene (MFR is 0.25 g / 10 min, density 0.9549 g / cm 3 ), and the rest are the same as in Example 1, and a polyethylene mulch film of Comparative Example 5 is prepared.

[0077] Comparative Example 7

[0078] The difference from Example 1 is that the silane-coupled mica powder in Example 1 is replaced with ordinary mica powder, and the rest are the same as in Example 1.

[0079] The polyethylene film materials prepared by the methods described in Examples 1-4 and Comparative Examples 1-7 were tested according to national standards, and their dart impact strength (g), elongation at break (%), tensile strength (MPa), and oxidation induction time (min) were tested.

[0080] The performance test results are shown in Table 1.

[0081] Table 1 Performance indexes of polyethylene materials prepared in Examples 1-4 and Comparative Examples 1-7

[0082]

[0083]

[0084] As can be seen from the above table, the dart impact strength of Examples 1-4 is 379-390 g, the elongation at break is 785-898%, the tensile strength is 50-55 MPa, and the oxidation induction time is 78.5-79.5 MPa. The prepared material has excellent processing performance, tensile strength, mechanical strength, and excellent aging resistance, and is a metallocene polyethylene mulch film composition.

[0085] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A metallocene polyethylene material, characterized in that: By mass parts, it consists of the following raw materials: 75-85 parts of metallocene polyethylene resin, 15-25 parts of high-density polyethylene, 0.05-0.2 part of a primary antioxidant, 0.1-0.25 part of a secondary antioxidant, 1-2 parts of silane-coupled modified nano-zinc oxide, 1-2 parts of silane-coupled modified mica powder, and 0.05-0.2 part of a slip agent.

2. The metallocene polyethylene material according to claim 1, wherein: The primary antioxidant is at least one of pentaerythritol tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, tris(3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanuric acid, N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexanediamine, n-octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, and bis(3,5-di-tert-butyl-4-hydroxy-benzoyl)hydrazide.

3. The metallocene polyethylene material according to claim 1, characterized in that: The secondary antioxidant is at least one of tris[2,4-di-tert-butylphenyl] phosphite, 3,9-bis(octadecyloxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane, or bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite.

4. The metallocene polyethylene material according to claim 1, characterized in that: The slip agent is oleic acid amide or erucic acid amide; Or, the silane-coupled modified nano-zinc oxide is vinyltriethoxysilane-modified nano-zinc oxide; Preferably, the preparation method of the vinyltriethoxysilane-modified nano-zinc oxide is: spraying a vinyltriethoxysilane solution on the nano-zinc oxide filler, stirring and mixing evenly, and then drying to obtain it. Preferably, the mass ratio of nano-zinc oxide to vinyltriethoxysilane is 1-3:0.01-0.05; Preferably, the stirring time is 10-30 min, and the stirring speed is 600-1000 r / min; Preferably, the drying temperature is 100-120 °C, and the drying time is 1-2 h.

5. The metallocene polyethylene material according to claim 1, wherein: The comonomer of the high-density polyethylene is 1-butene, and the density is 0.944 - 0.959 g / cm 3 ; the melt flow rate is 0.24 - 0.45 g / 10 min, at 190 °C / 5 kg.

6. The metallocene polyethylene material according to claim 1, characterized in that: The comonomer of the metallocene polyethylene resin is 1-hexene, and the density is 0.916 - 0.92 g / cm 3 , the melt flow rate is 3.3 - 3.7 g / 10 min, at 190 °C / 2.16 kg.

7. The metallocene polyethylene material according to claim 1, wherein: The silane-coupled modified mica powder is vinyltriethoxysilane-modified mica powder; Preferably, the preparation method of the vinyltriethoxysilane-modified mica powder is: spraying a vinyltriethoxysilane solution on the mica powder and stirring and mixing to obtain it. Preferably, the temperature of stirring and mixing is 20-30 °C, and the time of stirring and mixing is 10-20 min; Preferably, the mass ratio of mica powder to vinyltriethoxysilane is 1-3:0.01-0.

05.

8. The preparation method of the metallocene polyethylene material according to any one of claims 1-7, characterized in that: It includes the following steps: Mix the primary antioxidant, secondary antioxidant, metallocene polyethylene resin, and high-density polyethylene in proportion and stir for 1-3 min; Then add the slip agent, silane-coupled modified nano-zinc oxide, and silane-coupled modified mica powder in proportion and conduct secondary blending to obtain a mixed material; Melt and knead the obtained mixed material and then extrude and pelletize to obtain it.

9. The preparation method of the metallocene polyethylene material according to claim 8, characterized in that: The temperature of the melt-kneading is 180-200 °C; Preferably, during melt compounding, the screw speed of the extruder is 100 - 300 r / min, the feeding speed is 5 - 10 r / min, and the vacuum negative pressure is above -0.

09.

10. A metallocene polyethylene composite ground film, characterized in that: Prepared from the metallocene polyethylene material according to any one of claims 1 - 7; Preferably, the preparation method of the metallocene polyethylene composite plastic film is: extruding and blowing the metallocene polyethylene material to obtain it.

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