Antistatic polyolefin packaging film and processing method thereof

Abstract

The invention discloses an antistatic polyolefin packaging film and a processing method thereof, and relates to the technical field of packaging films.According to the prepared packaging film, an antistatic inner-layer material, a core-layer material and an outer-layer material are loaded into extruders corresponding to a three-layer co-extrusion film blowing machine respectively and plasticized and extruded to form an antistatic inner-layer film, a core-layer film and an outer-layer film respectively; and drawing and rolling after blowing. Wherein the antistatic inner-layer film is prepared from the following raw materials in parts by mass: 50 to 60 parts of linear low-density polyethylene, 20 to 25 parts of metallocene polyethylene, 20 to 30 parts of ethylene-alpha olefin copolymer and 2 to 5 parts of antistatic agent; the antistatic agent is obtained by compounding and combining aluminum-doped zinc oxide powder and polyion modified attapulgite; the antistatic polyolefin packaging film prepared by the invention has a good application effect.

Description

Technical Field

[0001] The invention relates to the technical field of packaging films, in particular to an antistatic polyolefin packaging film and a processing method thereof. Background Art

[0002] In the field of packaging materials, especially in plastic film products, static electricity accumulation is a common and thorny problem. Plastics (such as polyethylene, polypropylene, etc.) are widely used due to their excellent insulation and low cost, but their high surface resistivity makes them prone to static electricity due to friction, peeling, etc. during production, transportation and use. The hazards caused by static electricity accumulation include but are not limited to adsorption pollution affecting the appearance quality of products, static electricity discharge causing fire and explosion and other safety hazards; in order to deal with the above problems caused by static electricity, antistatic packaging film came into being.

[0003] Antistatic packaging film reduces its surface resistivity by adding antistatic agents or surface treatment technology to the material, thereby effectively preventing static electricity accumulation; the current production of antistatic packaging film usually adopts the following processes: 1) the antistatic agent is blended with the substrate to form an antistatic masterbatch, and then processed to obtain a film; 2) an antistatic coating is applied to the surface of the film to achieve an antistatic effect; 3) the substrate material is irradiated with gamma rays or beta rays to obtain antistatic properties on its surface. Although antistatic packaging film technology has made certain progress, there are still some shortcomings. For example, in the above process 1), the antistatic agent is blended with the substrate, and the antistatic agent is easy to migrate, resulting in a significant attenuation of the antistatic performance over time; the addition of the antistatic agent reduces the mechanical properties of the material, etc. Therefore, it is urgent to find an antistatic packaging film to deal with the above problems. Summary of the invention

[0004] The object of the present invention is to provide an antistatic polyolefin packaging film and a processing method thereof to solve the problems raised in the prior art.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] An antistatic polyolefin packaging film, characterized in that the antistatic polyolefin packaging film is composed of an antistatic inner film, a core film and an outer film stacked in sequence;

[0007] The antistatic inner film is composed of the following raw materials in parts by weight: 50-60 parts of linear low-density polyethylene, 20-25 parts of metallocene polyethylene, 20-30 parts of ethylene-α-olefin copolymer and 2-5 parts of antistatic agent;

[0008] The core layer film is composed of the following raw materials in parts by weight: 50-60 parts of linear low-density polyethylene and 40-50 parts of low-density polyethylene;

[0009] The outer film is composed of the following raw materials in parts by weight: 50-60 parts of linear low-density polyethylene and 40-50 parts of low-density polyethylene.

[0010] Preferably, the antistatic agent in the raw materials used for the above-mentioned antistatic inner layer film is a composite combination of aluminum-doped zinc oxide powder and polyion-modified attapulgite, and the mass ratio of aluminum-doped zinc oxide powder to polyion-modified attapulgite is 1:(1-4).

[0011] Preferably, the preparation steps of the polyion-modified attapulgite are as follows:

[0012] Step s1: Take nano-attapulgite, grind it through a 400-mesh sieve, and then treat it with acid. Place it in a hydrochloric acid solution, ultrasonically disperse it for 30 minutes, then heat it to 60°C and stir it for 6-8 hours, let it stand overnight, filter it and wash it, dry it, place it in isopropanol, ultrasonically disperse it for 30 minutes under a nitrogen atmosphere, add γ-methacryloxypropyltrimethoxysilane, stir it at 60-70°C for 4 hours, then centrifuge it for alcohol washing, and dry it to obtain pretreated attapulgite;

[0013] Step s2: Mix the pretreated attapulgite prepared in step s1 with methacryloyloxyethyltrimethylammonium chloride, place them in isopropanol, introduce nitrogen, heat to 60-70°C, and stir to react for 1 hour, add azobisisobutyronitrile, continue stirring to react for 20-24 hours, centrifuge and wash with alcohol, dry and place in deionized water, stir until the system is dissolved to obtain solution a, place sodium tetrafluoroborate in warm water, stir and dissolve to obtain solution b, slowly add to solution a, stir for 10-12 hours, filter, wash with water, and dry to obtain polyion-modified attapulgite.

[0014] Preferably, the dosage ratio of γ-methacryloxypropyltrimethoxysilane and nano-attapulgite is 1 mL:(0.5-1) g; the mass ratio of pretreated attapulgite and methacryloyloxyethyltrimethylammonium chloride in step s2 is 1:(2-3); the mass of azobisisobutyronitrile accounts for 0.4-1% of methacryloyloxyethyltrimethylammonium chloride; the concentration ratio of solution a and solution b is 1:(0.6-2) g / mL.

[0015] Preferably, the preparation steps of the aluminum-doped zinc oxide powder are: placing zinc chloride and aluminum nitrate nonahydrate in deionized water, adding polyethylene glycol, stirring for 20-30 minutes, slowly adding sodium bicarbonate solution dropwise while stirring continuously, reacting at 40-60°C for 2-3 hours, standing and aging overnight, then filtering out the solid, washing alternately with alcohol water 2-3 times, drying at 100-120°C for 12 hours, calcining, and keeping warm at 800-1000°C for 2-3 hours to obtain aluminum-doped zinc oxide powder; wherein the dosage ratio of zinc chloride, aluminum nitrate nonahydrate and polyethylene glycol is 1:(0.05-0.25):(0.02-0.04).

[0016] Preferably, the processing method of the above antistatic polyolefin packaging film is as follows:

[0017] Step 1: linear low-density polyethylene, metallocene polyethylene and half of the antistatic agent are mixed, melt-blended at 180° C. to obtain intermediate a for standby use; ethylene-α-olefin copolymer and the remaining antistatic agent are mixed, melt-blended at 170-200° C. to obtain intermediate b, which is mixed with intermediate a to obtain an antistatic inner layer material; linear low-density polyethylene and low-density polyethylene are mixed to obtain core layer material and outer layer material, respectively, for standby use;

[0018] Step 2: Load the antistatic inner layer material, core layer material and outer layer material prepared in step 1 into the corresponding extruders of the three-layer co-extrusion film blowing machine respectively, plasticize and extrude at 200-210°C to form an antistatic inner layer film, a core layer film and an outer layer film respectively, and then pull and roll them up after inflation to obtain a packaging film.

[0019] Preferably, the thickness of the prepared packaging film is 120-200 μm, wherein the thickness ratio of the antistatic inner film, the core film and the outer film is 1:1:1.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1. The present invention adopts three-layer co-extrusion blown film processing to obtain the packaging film, wherein the inner layer adopts linear low-density polyethylene, metallocene polyethylene, ethylene-α-olefin copolymer and antistatic agent in a certain ratio to achieve the functionalization of the inner layer; the outer layer and the core layer both adopt a composite combination of linear low-density polyethylene and low-density polyethylene to maintain the overall performance of the packaging film, balance the cost while achieving high performance of the inner layer, and adapt to market demand.

[0022] 2. The inner layer material selected during the processing is obtained by mixing an intermediate a obtained by melt blending linear low-density polyethylene, metallocene polyethylene and part of the antistatic agent with an intermediate b obtained by melt blending ethylene-α-olefin copolymer and the remaining antistatic agent, so as to improve the compatibility of the antistatic agent in the polyolefin film and reduce agglomeration; the antistatic agent is a composite combination of aluminum-doped zinc oxide powder and polyion-modified attapulgite, wherein the aluminum-doped zinc oxide powder is a transparent conductive oxide with good conductivity; the polyion-modified attapulgite is grafted and polymerized onto the silane-pretreated attapulgite using a quaternary ammonium salt polyionic liquid to achieve hybridization of the polyionic liquid and the inorganic carrier, thereby improving the thermal stability of the polyionic liquid, and at the same time, the introduction of attapulgite improves the agglomeration of the polyionic liquid; furthermore, the migration of the quaternary ammonium salt polyionic liquid to the substrate surface is effectively delayed to achieve long-term antistatic performance; the antistatic performance is synergistically improved by using the composite combination of aluminum-doped zinc oxide powder and polyion-modified attapulgite.

[0023] 3. Add the antistatic agent in a certain ratio to achieve high antistatic performance while ensuring the high transparency of the polyolefin packaging film as much as possible; in addition, aluminum-doped zinc oxide has certain antibacterial properties, which expands the application field of the prepared polyolefin packaging film. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] In the experiment, linear low-density polyethylene DFDA-7042 and low-density polyethylene 951-000 were purchased from Maoming Petrochemical; metallocene polyethylene 2018.RA was purchased from ExxonMobil; ethylene-α-olefin copolymer POE-DF710 came from Mitsui Chemicals; and attapulgite 400 mesh was purchased from Lingshou Yanguo Mineral Products Processing Plant.

[0026] The preparation steps of aluminum-doped zinc oxide powder are as follows: 4.28g zinc chloride and 1.05g aluminum nitrate nonahydrate are placed in 100mL deionized water, 0.12g polyethylene glycol is added, and after stirring for 30min, 200mL 1M sodium bicarbonate solution is slowly added dropwise under constant stirring, and after reacting at 60°C for 2h, it is allowed to stand and age overnight, and then the solid is filtered out, washed alternately with alcohol and water for 3 times, and then dried at 100°C for 12h, and then calcined, and kept warm at 900°C for 3h to obtain aluminum-doped zinc oxide powder.

[0027] Embodiment 1: This embodiment provides a method for processing an antistatic polyolefin packaging film, and the specific steps are as follows:

[0028] Step 1: 53 parts of linear low-density polyethylene, 23 parts of metallocene polyethylene and 2 parts of antistatic agent are mixed, melt-blended at 180°C to obtain intermediate a, which is set aside; 20 parts of ethylene-α-olefin copolymer and 2 parts of antistatic agent are mixed, melt-blended at 200°C to obtain intermediate b, which is mixed with intermediate a to obtain an antistatic inner layer material; 50 parts of linear low-density polyethylene and 50 parts of low-density polyethylene are mixed to obtain a core layer material and an outer layer material, respectively, which are set aside;

[0029] Step 2: The antistatic inner layer material, core layer material and outer layer material prepared in step 1 are respectively loaded into the corresponding extruders of the three-layer co-extrusion film blowing machine in a mass ratio of 1:1:1, and plasticized and extruded at 200° C. to form an antistatic inner layer film, a core layer film and an outer layer film, respectively, and then pulled and rolled after inflation to obtain a packaging film with a thickness of 200 μm;

[0030] The antistatic agent is obtained by mixing aluminum-doped zinc oxide powder and polyion-modified attapulgite in a mass ratio of 1:3;

[0031] The preparation steps of polyion-modified attapulgite are as follows:

[0032] Step s1: 5.02 g of nano-attapulgite was crushed and ground through a 400-mesh sieve, and then treated with acid. The mixture was placed in 50 mL of 1 mol / L hydrochloric acid solution, and ultrasonically dispersed for 30 min, then heated to 60° C. and stirred for 6 h. After standing overnight, the mixture was filtered and washed. After drying, the mixture was placed in 100 mL of isopropanol, and ultrasonically dispersed for 30 min under a nitrogen atmosphere. After that, 5 mL of γ-methacryloxypropyltrimethoxysilane was added. The mixture was stirred at 60° C. for 4 h, and then centrifuged and washed with alcohol. After drying, the pretreated attapulgite was obtained.

[0033] Step s2: Take 3.01g of the pretreated attapulgite prepared in step s1 and mix it with 8.48g of methacryloyloxyethyltrimethylammonium chloride, place it in 100mL of isopropanol, introduce nitrogen, heat to 70°C and stir to react for 1h, add 0.08g of azobisisobutyronitrile and continue to stir to react for 20h, then centrifuge and wash with alcohol, dry and place it in 80mL of deionized water, stir until the system is dissolved to obtain solution a, place 13.50g of sodium tetrafluoroborate in 100mL of warm water, stir and dissolve to obtain solution b, slowly add it to solution a, stir for 10h, filter, wash with water, and dry to obtain polyion-modified attapulgite.

[0034] Embodiment 2: This embodiment provides a method for processing an antistatic polyolefin packaging film, and the specific steps are as follows:

[0035] Step 1: 50 parts of linear low-density polyethylene, 25 parts of metallocene polyethylene and 2.5 parts of antistatic agent are mixed, melt-blended at 180°C to obtain intermediate a, which is set aside; 20 parts of ethylene-α-olefin copolymer and 2.5 parts of antistatic agent are mixed, melt-blended at 200°C to obtain intermediate b, which is mixed with intermediate a to obtain an antistatic inner layer material; 50 parts of linear low-density polyethylene and 50 parts of low-density polyethylene are mixed to obtain a core layer material and an outer layer material, respectively, which are set aside;

[0036] Step 2: The antistatic inner layer material, core layer material and outer layer material prepared in step 1 are respectively loaded into the corresponding extruders of the three-layer co-extrusion film blowing machine in a mass ratio of 1:1:1, and plasticized and extruded at 200° C. to form an antistatic inner layer film, a core layer film and an outer layer film, respectively, and then pulled and rolled after inflation to obtain a packaging film with a thickness of 200 μm;

[0037] The antistatic agent is obtained by mixing aluminum-doped zinc oxide powder and polyion-modified attapulgite in a mass ratio of 1:4;

[0038] The preparation steps of polyion-modified attapulgite are as follows:

[0039] Step s1: 5 g of nano-attapulgite was crushed and ground through a 400-mesh sieve, and then treated with acid. The mixture was placed in 50 mL of 1 mol / L hydrochloric acid solution, and ultrasonically dispersed for 30 min, then heated to 60° C. and stirred for 6 h. After standing overnight, the mixture was filtered and washed. After drying, the mixture was placed in 100 mL of isopropanol, and ultrasonically dispersed for 30 min under a nitrogen atmosphere. After that, 5 mL of γ-methacryloxypropyltrimethoxysilane was added. The mixture was stirred at 70° C. for 4 h, and then centrifuged and washed with alcohol. After drying, the pretreated attapulgite was obtained.

[0040] Step s2: Take 3.01g of the pretreated attapulgite prepared in step s1 and mix it with 8.25g of methacryloyloxyethyltrimethylammonium chloride, place it in 100mL of isopropanol, introduce nitrogen, heat to 70°C and stir to react for 1h, add 0.08g of azobisisobutyronitrile and continue to stir to react for 20h, then centrifuge and wash with alcohol, dry and place it in 80mL of deionized water, stir until the system is dissolved to obtain solution a, place 13.48g of sodium tetrafluoroborate in 100mL of warm water, stir and dissolve to obtain solution b, slowly add it to solution a, stir for 12h, filter, wash with water, and dry to obtain polyion-modified attapulgite.

[0041] Embodiment 3: This embodiment provides a method for processing an antistatic polyolefin packaging film, and the specific steps are as follows:

[0042] Step 1: 58 parts of linear low-density polyethylene, 20 parts of metallocene polyethylene and 1 part of antistatic agent are mixed, melt-blended at 180°C to obtain intermediate a, which is set aside; 20 parts of ethylene-α-olefin copolymer and 1 part of antistatic agent are mixed, melt-blended at 200°C to obtain intermediate b, which is mixed with intermediate a to obtain an antistatic inner layer material; 50 parts of linear low-density polyethylene and 50 parts of low-density polyethylene are mixed to obtain core layer material and outer layer material, respectively, which are set aside;

[0043] Step 2: The antistatic inner layer material, core layer material and outer layer material prepared in step 1 are respectively loaded into the corresponding extruders of the three-layer co-extrusion film blowing machine in a mass ratio of 1:1:1, and plasticized and extruded at 200° C. to form an antistatic inner layer film, a core layer film and an outer layer film, respectively, and then pulled and rolled after inflation to obtain a packaging film with a thickness of 200 μm;

[0044] The antistatic agent is obtained by mixing aluminum-doped zinc oxide powder and polyion-modified attapulgite in a mass ratio of 1:2;

[0045] The preparation steps of polyion-modified attapulgite are as follows:

[0046] Step s1: 5 g of nano-attapulgite was crushed and ground through a 400-mesh sieve, and then treated with acid. The mixture was placed in 50 mL of 1 mol / L hydrochloric acid solution, and ultrasonically dispersed for 30 min, then heated to 60° C. and stirred for 6 h. After standing overnight, the mixture was filtered and washed. After drying, the mixture was placed in 100 mL of isopropanol, and ultrasonically dispersed for 30 min under a nitrogen atmosphere. After that, 5 mL of γ-methacryloxypropyltrimethoxysilane was added. The mixture was stirred at 60° C. for 4 h, and then centrifuged and washed with alcohol. After drying, the pretreated attapulgite was obtained.

[0047] Step s2: Take 3g of the pretreated attapulgite prepared in step s1 and mix it with 6.49g of methacryloyloxyethyltrimethylammonium chloride, place it in 100mL of isopropanol, introduce nitrogen, heat to 70°C and stir to react for 1h, add 0.08g of azobisisobutyronitrile and continue to stir to react for 20h, then centrifuge and wash with alcohol, dry and place it in 80mL of deionized water, stir until the system is dissolved to obtain solution a, place 13.47g of sodium tetrafluoroborate in 100mL of warm water, stir and dissolve to obtain solution b, slowly add it to solution a, stir for 10h, filter, wash with water, and dry to obtain polyion-modified attapulgite.

[0048] Comparative Example 1: As a control experiment of Example 1, the composition of the raw materials in the antistatic inner layer material is adjusted according to Example 1, and the other parameters remain unchanged. The steps are as follows:

[0049] Step 1: 51 parts of linear low-density polyethylene, 23 parts of metallocene polyethylene and 3 parts of antistatic agent are mixed, melt-blended at 180°C to obtain intermediate a, which is set aside; 20 parts of ethylene-α-olefin copolymer and 3 parts of antistatic agent are mixed, melt-blended at 200°C to obtain intermediate b, which is mixed with intermediate a to obtain an antistatic inner layer material; 50 parts of linear low-density polyethylene and 50 parts of low-density polyethylene are mixed to obtain a core layer material and an outer layer material, respectively, which are set aside;

[0050] Step 2: The antistatic inner layer material, core layer material and outer layer material prepared in step 1 are respectively loaded into the corresponding extruders of the three-layer co-extrusion film blowing machine in a mass ratio of 1:1:1, and plasticized and extruded at 200° C. to form an antistatic inner layer film, a core layer film and an outer layer film, respectively, and then pulled and rolled after inflation to obtain a packaging film with a thickness of 200 μm;

[0051] The antistatic agent is obtained by mixing aluminum-doped zinc oxide powder and polyion-modified attapulgite in a mass ratio of 1:3;

[0052] The preparation steps of polyion-modified attapulgite are as follows:

[0053] Step s1: 5.02 g of nano-attapulgite was crushed and ground through a 400-mesh sieve, and then treated with acid. The mixture was placed in 50 mL of 1 mol / L hydrochloric acid solution, and ultrasonically dispersed for 30 min, then heated to 60° C. and stirred for 6 h. After standing overnight, the mixture was filtered and washed. After drying, the mixture was placed in 100 mL of isopropanol, and ultrasonically dispersed for 30 min under a nitrogen atmosphere. After that, 5 mL of γ-methacryloxypropyltrimethoxysilane was added. The mixture was stirred at 60° C. for 4 h, and then centrifuged and washed with alcohol. After drying, the pretreated attapulgite was obtained.

[0054] Step s2: Take 3.01g of the pretreated attapulgite prepared in step s1 and mix it with 8.48g of methacryloyloxyethyltrimethylammonium chloride, place it in 100mL of isopropanol, introduce nitrogen, heat to 70°C and stir to react for 1h, add 0.08g of azobisisobutyronitrile and continue to stir to react for 20h, then centrifuge and wash with alcohol, dry and place it in 80mL of deionized water, stir until the system is dissolved to obtain solution a, place 13.50g of sodium tetrafluoroborate in 100mL of warm water, stir and dissolve to obtain solution b, slowly add it to solution a, stir for 10h, filter, wash with water, and dry to obtain polyion-modified attapulgite.

[0055] Comparative Example 2: As a control experiment of Example 1, the antistatic agent is adjusted to a single polyion-modified attapulgite according to Example 1, and the other parameters remain unchanged. The specific steps are as follows:

[0056] Step 1: Mix 53 parts of linear low-density polyethylene, 23 parts of metallocene polyethylene and 2 parts of polyion-modified attapulgite, melt-blend at 180°C to obtain intermediate a for later use; mix 20 parts of ethylene-α-olefin copolymer and 2 parts of polyion-modified attapulgite, melt-blend at 200°C to obtain intermediate b, and mix with intermediate a to obtain an antistatic inner layer material; mix 50 parts of linear low-density polyethylene and 50 parts of low-density polyethylene to obtain a core layer material and an outer layer material, respectively, for later use;

[0057] Step 2: The antistatic inner layer material, core layer material and outer layer material prepared in step 1 are respectively loaded into the corresponding extruders of the three-layer co-extrusion film blowing machine in a mass ratio of 1:1:1, and plasticized and extruded at 200° C. to form an antistatic inner layer film, a core layer film and an outer layer film, respectively, and then pulled and rolled after inflation to obtain a packaging film with a thickness of 200 μm;

[0058] The preparation steps of polyion-modified attapulgite are as follows:

[0059] Step s1: 5.02 g of nano-attapulgite was crushed and ground through a 400-mesh sieve, and then treated with acid. The mixture was placed in 50 mL of 1 mol / L hydrochloric acid solution, and ultrasonically dispersed for 30 min, then heated to 60° C. and stirred for 6 h. After standing overnight, the mixture was filtered and washed. After drying, the mixture was placed in 100 mL of isopropanol, and ultrasonically dispersed for 30 min under a nitrogen atmosphere. After that, 5 mL of γ-methacryloxypropyltrimethoxysilane was added. The mixture was stirred at 60° C. for 4 h, and then centrifuged and washed with alcohol. After drying, the pretreated attapulgite was obtained.

[0060] Step s2: Take 3.01g of the pretreated attapulgite prepared in step s1 and mix it with 8.48g of methacryloyloxyethyltrimethylammonium chloride, place it in 100mL of isopropanol, introduce nitrogen, heat to 70°C and stir to react for 1h, add 0.08g of azobisisobutyronitrile and continue to stir to react for 20h, then centrifuge and wash with alcohol, dry and place it in 80mL of deionized water, stir until the system is dissolved to obtain solution a, place 13.50g of sodium tetrafluoroborate in 100mL of warm water, stir and dissolve to obtain solution b, slowly add it to solution a, stir for 10h, filter, wash with water, and dry to obtain polyion-modified attapulgite.

[0061] Comparative Example 3: As a control experiment of Example 1, the antistatic agent is adjusted to a single aluminum-doped zinc oxide powder according to Example 1, and the specific steps are as follows:

[0062] Step 1: 53 parts of linear low-density polyethylene, 23 parts of metallocene polyethylene and 2 parts of aluminum-doped zinc oxide powder are mixed, melt-blended at 180°C to obtain intermediate a, which is set aside; 20 parts of ethylene-α-olefin copolymer and 2 parts of aluminum-doped zinc oxide powder are mixed, melt-blended at 200°C to obtain intermediate b, which is mixed with intermediate a to obtain an antistatic inner layer material; 50 parts of linear low-density polyethylene and 50 parts of low-density polyethylene are mixed to obtain a core layer material and an outer layer material, respectively, which are set aside;

[0063] Step 2: Load the antistatic inner layer material, core layer material and outer layer material prepared in step 1 into the corresponding extruders of the three-layer co-extrusion film blowing machine in a mass ratio of 1:1:1, plasticize and extrude at 200°C to form an antistatic inner layer film, a core layer film and an outer layer film, respectively, and then pull and roll them up after inflation to obtain a packaging film with a thickness of 200 μm.

[0064] Detection test

[0065] 1. Antistatic performance: According to GB / T 31838.3, the inner surface resistivity of the packaging films prepared in Examples 1-3 and Comparative Examples 1-3 was measured using a high insulation resistance tester at a test voltage of 500V.

[0066] 2. Optical properties: The transparency and haze of the packaging films prepared in Examples 1-3 and Comparative Examples 1-3 were measured according to GB / T 2410.

[0067] 3. Mechanical properties: The tensile strength and elongation at break of the packaging films prepared in Examples 1-3 and Comparative Examples 1-3 were tested in accordance with GB / T 13022.

[0068]

[0069] Conclusion: From the above data, it can be seen that the comprehensive performance of the packaging film made by the raw material ratio of Example 1 is better than that of the other embodiments; three groups of comparative experiments were conducted on Example 1, among which Comparative Example 1 increased the usage of the antistatic agent, although the antistatic performance was slightly improved, but the optical performance and mechanical properties decreased; Comparative Example 2 The antistatic agent was replaced with a single component, and aluminum-doped zinc oxide (conductive filler) was not added. Although the mechanical properties were improved, the antistatic performance and optical properties decreased; Comparative Example 3 did not add polyion-modified attapulgite, and the antistatic performance and mechanical properties were significantly reduced; It can be seen from the above that the composite combination of aluminum-doped zinc oxide and polyion-modified attapulgite can exert better antistatic performance than a single component; and the ratio combination between the raw materials is crucial.

[0070] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

Claims

1. An antistatic polyolefin packaging film, characterized in that: The antistatic polyolefin packaging film is composed of an antistatic inner film, a core film and an outer film which are stacked in sequence; wherein the antistatic inner film is composed of the following raw materials in parts by weight: 50-60 parts of linear low-density polyethylene, 20-25 parts of metallocene polyethylene, 20-30 parts of ethylene-α-olefin copolymer and 2-5 parts of antistatic agent; the core film is composed of the following raw materials in parts by weight: 50-60 parts of linear low-density polyethylene and 40-50 parts of low-density polyethylene; and the outer film is composed of the following raw materials in parts by weight: 50-60 parts of linear low-density polyethylene and 40-50 parts of low-density polyethylene.

2. The antistatic polyolefin packaging film according to claim 1, characterized in that: The antistatic agent is a composite of aluminum-doped zinc oxide powder and polyion-modified attapulgite, and the mass ratio of the aluminum-doped zinc oxide powder to the polyion-modified attapulgite is 1:(1-4).

3. The antistatic polyolefin packaging film according to claim 2, characterized in that: The preparation steps of polyion-modified attapulgite are as follows: Step s1: Take nano-attapulgite, grind it through a 400-mesh sieve, and then treat it with acid. Place it in a hydrochloric acid solution, ultrasonically disperse it for 30 minutes, then heat it to 60°C and stir it for 6-8 hours, let it stand overnight, filter it and wash it, dry it, place it in isopropanol, ultrasonically disperse it for 30 minutes under a nitrogen atmosphere, add γ-methacryloxypropyltrimethoxysilane, stir it at 60-70°C for 4 hours, then centrifuge it for alcohol washing, and dry it to obtain pretreated attapulgite; Step s2: The pretreated attapulgite prepared in step s1 is mixed with methacryloyloxyethyltrimethylammonium chloride, placed in isopropanol, introduced with nitrogen, heated to 60-70°C and stirred for reaction for 1 hour, azobisisobutyronitrile is added, and the stirring reaction is continued for 20-24 hours, followed by centrifugal alcohol washing, dried, placed in deionized water, stirred until the system is dissolved, to obtain solution a, sodium tetrafluoroborate is placed in warm water, stirred and dissolved to obtain solution b, slowly added to solution a, stirred for 10-12 hours, filtered, washed with water, and dried to obtain polyion-modified attapulgite.

4. The antistatic polyolefin packaging film according to claim 3, characterized in that: The dosage ratio of γ-methacryloxypropyltrimethoxysilane and nano-attapulgite is 1mL:(0.5-1)g; the mass ratio of pretreated attapulgite and methacryloyloxyethyltrimethylammonium chloride in step s2 is 1:(2-3); the mass of azobisisobutyronitrile accounts for 0.4-1% of methacryloyloxyethyltrimethylammonium chloride; the concentration ratio of solution a and solution b is 1:(0.6-2)g / mL.

5. The antistatic polyolefin packaging film according to claim 2, characterized in that: The preparation steps of aluminum-doped zinc oxide powder are as follows: zinc chloride and aluminum nitrate nonahydrate are placed in deionized water, polyethylene glycol is added, and the mixture is stirred for 20-30 minutes, and then a sodium bicarbonate solution is slowly added dropwise under continuous stirring, and the mixture is reacted at 40-60° C. for 2-3 hours, and then aged overnight, and then the solid is filtered out by suction, and then washed alternately with alcohol water for 2-3 times, and then dried at 100-120° C. for 12 hours, and then calcined, and kept warm at 800-1000° C. for 2-3 hours to obtain aluminum-doped zinc oxide powder.

6. The antistatic polyolefin packaging film according to claim 5, characterized in that: The dosage ratio of zinc chloride, aluminum nitrate nonahydrate and polyethylene glycol is 1:(0.05-0.25):(0.02-0.04).

7. A method for processing the antistatic polyolefin packaging film according to claim 1, characterized in that: The specific processing methods are as follows: Step 1: linear low-density polyethylene, metallocene polyethylene and half of the antistatic agent are mixed, melt-blended at 180° C. to obtain intermediate a for standby use; ethylene-α-olefin copolymer and the remaining antistatic agent are mixed, melt-blended at 170-200° C. to obtain intermediate b, which is mixed with intermediate a to obtain an antistatic inner layer material; linear low-density polyethylene and low-density polyethylene are mixed to obtain core layer material and outer layer material, respectively, for standby use; Step 2: Load the antistatic inner layer material, core layer material and outer layer material prepared in step 1 into the corresponding extruders of the three-layer co-extrusion film blowing machine respectively, plasticize and extrude at 200-210°C to form an antistatic inner layer film, a core layer film and an outer layer film respectively, and then pull and roll them up after inflation to obtain a packaging film.

8. A processing method according to claim 7, characterized in that: The thickness of the packaging film is 120-200 μm, wherein the thickness ratio of the antistatic inner film, the core film and the outer film is 1:1:1.

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