High-barrier recyclable aluminized co-extruded film and preparation method thereof

Abstract

The invention belongs to the technical field of packaging materials, and particularly relates to a high-barrier recyclable aluminum-plated co-extruded film and a preparation method thereof. The packaging film comprises an aluminized layer, a secondary outer layer, a first bonding layer, a blocking layer, a second bonding layer, a secondary inner layer and a heat sealing layer which are connected in sequence, the aluminum-plated layer comprises 20-40 parts by mass of polar resin and 60-80 parts by mass of first metallocene polyethylene, the secondary outer layer comprises 30-40 parts by mass of low-density polyethylene and 60-70 parts by mass of second metallocene polyethylene, and the first bonding layer and the second bonding layer are both 100 parts by mass of modified bonding resin. After the aluminum plating process, the high-barrier packaging film has the advantages of high barrier property, low-temperature heat sealing and high heat sealing strength, and can meet the requirements of high-barrier packaging made of single recyclable materials.

Description

Technical Field

[0001] The invention belongs to the field of packaging materials, and in particular relates to a high-barrier recyclable aluminum-plated co-extruded film and a preparation method thereof. Background Art

[0002] Among the current flexible packaging composite films, films that increase barrier properties are generally: aluminum foil, VMPET, ALOx-PET, SiOx-PET, etc. Since these non-polyolefin films do not have the ability to heat seal alone, they need to be composited with heat-sealing films to complete product packaging or make bags. There are also some small-weight products using VMBOPP. Although they have the ability to heat seal, the heat sealing strength of such films is relatively low. Secondly, environmentally friendly packaging is currently being promoted all over the world, and these non-polyolefin composite films are not recyclable and have no recycling value.

[0003] In addition, after aluminum plating, ordinary polyolefin film has average barrier properties and low heat sealing strength; while the high barrier polyolefin co-extruded with EVOH (ethylene / vinyl alcohol copolymer) generally has a moisture permeability higher than 1.0g / (m 2 d), oxygen permeability is also higher than 1.0cc / m 2 d. Failure to meet barrier requirements.

[0004] Therefore, there is an urgent need for a high-barrier recyclable aluminum-coated co-extruded film and a preparation method thereof to solve the above problems. Summary of the invention

[0005] In order to overcome the defects in the prior art, the present invention provides a high barrier and recyclable aluminum-plated co-extruded film and a preparation method thereof. The co-extruded film of the present invention has good high barrier and is recyclable.

[0006] To achieve one of the above purposes, the present invention adopts the following technical solution:

[0007] A high-barrier recyclable aluminum-plated co-extruded film, the co-extruded film comprises an aluminum-plated layer, a sub-outer layer, a first adhesive layer, a barrier layer, a second adhesive layer, a sub-inner layer and a heat-sealing layer connected in sequence; the aluminum-plated layer comprises 20-40 parts by mass of a polar resin and 60-80 parts by mass of a first metallocene polyethylene, the sub-outer layer comprises 30-40 parts by mass of a low-density polyethylene and 60-70 parts by mass of a second metallocene polyethylene, the first adhesive layer and the second adhesive layer are both 100 parts by mass of a modified adhesive resin, the barrier layer comprises 99-99.5 parts by mass of EVOH resin (ethylene / vinyl alcohol copolymer) and 0.5-1 parts by mass of modified kaolin, the sub-inner layer comprises 20-30 parts by mass of low-density high-pressure polyethylene and 70-80 parts by mass of the second metallocene polyethylene, and the heat-sealing layer comprises 52-59 parts by mass of low-density high-pressure polyethylene, 40-45 parts by mass of a third metallocene polyethylene and 1-3 parts by mass of an anti-blocking agent.

[0008] Preferably, the aluminum-plated layer includes 30 parts by mass of a polar resin and 70 parts by mass of a first metallocene polyethylene, the sub-outer layer includes 35 parts by mass of a low-density polyethylene and 65 parts by mass of a second metallocene polyethylene, the barrier layer includes 99 parts by mass of an EVOH resin and 1 part by mass of modified kaolin, the sub-inner layer includes 25 parts by mass of a low-density high-pressure polyethylene and 75 parts by mass of a second metallocene polyethylene, and the heat-sealing layer includes 53 parts by mass of a low-density high-pressure polyethylene, 43 parts by mass of a third metallocene polyethylene, 2 parts by mass of an opening agent and 2 parts by mass of a non-migrating silicone lubricant.

[0009] Preferably, the modified kaolin is composed of a silane coupling agent and kaolin in a mass ratio of 1:50;

[0010] Preferably, the preparation method of modified kaolin is: placing the silane coupling agent and kaolin in a stirrer, heating and stirring at high speed to mix evenly; the heating temperature cannot be higher than the calcination temperature of kaolin, and the stirring speed is greater than 200 rpm.

[0011] Preferably, the polar resin is an ethylene-methacrylic acid-acrylate terpolymer, and its brand is NucrelAE produced by DuPont of the United States; the brand of the first metallocene polyethylene is 4009MC produced by Exxon, the brand of the low-density polyethylene is 7042 produced by Zhejiang Petrochemical Company, the brand of the second metallocene polyethylene is SP2040 produced by Priman, the brand of the modified adhesive resin is PX3060 produced by LyondellBasell, the brand of the EVOH resin is ET3803RB produced by Japan Synthetic Chemical Company, the brand of the low-density high-pressure polyethylene is 150BW produced by Exxon, the brand of the third metallocene polyethylene is PL1881 produced by Dow Chemical Company of the United States, the brand of the anti-blocking agent is EZA-10 produced by Mitsui Company of Japan, and the brand of the non-migrating silicone slip agent is MBSI-002P produced by DuPont.

[0012] Preferably, the co-extruded film has a thickness of 50-180 μm, wherein the thickness ratio of the aluminum-plated layer, the thickness of the sub-outer layer, and the thickness of the first adhesive layer is 6:8:4:5:4:8:15.

[0013] Preferably, the side of the aluminum-plated layer facing away from the secondary outer layer is plated with an aluminum layer, and the thickness of the aluminum layer is 0.7 μm.

[0014] To achieve the second purpose above, the present invention provides a method for preparing a high-barrier recyclable aluminum-plated co-extruded film, comprising the following steps:

[0015] S1. Weigh the raw materials of each layer of the co-extruded film, mix them in proportion and put them into a mixer to mix evenly, and then send them into an extruder to melt respectively;

[0016] S2, according to the arrangement order of the aluminum-plated layer, the secondary outer layer, the first adhesive layer, the barrier layer, the second adhesive layer, the secondary inner layer and the heat-sealing layer, using an extruder to co-extrude and blow film to obtain a high-barrier co-extruded film;

[0017] S3. Use low-temperature plasma to bombard the surface of the high-barrier co-extruded film, and then evaporate aluminum on the surface of the aluminum-plated layer of the high-barrier co-extruded film to obtain a high-barrier aluminum-plated co-extruded film.

[0018] Preferably, in step S2, the co-extrusion blown film uses the blowing traction, splint bubble elimination, corona treatment, edge trimming and film winding steps in the prior art, and the traction speed of the blowing traction is 2m / min.

[0019] Preferably, when the extruder co-extrudes the blown film, the extruder temperature of the aluminum-plated layer, the sub-outer layer, the sub-inner layer and the heat-sealing layer is (185-190) ± 5°C; the extruder temperature of the first adhesive layer and the second adhesive layer is (210-220) ± 5°C, and the extruder temperature of the barrier layer is (215-220) ± 5°C.

[0020] The advantages of the present invention are:

[0021] (1) The present invention designs a formula of aluminum-plated polyolefin (VMEVE), which, after the aluminum plating process, has high barrier properties, low-temperature heat sealing and high heat sealing strength, and can meet the needs of high barrier packaging of a single recyclable material.

[0022] (2) The present invention adds modified kaolin and ethylene / vinyl alcohol copolymer to blend, so that the water vapor permeability can reach 0.4-1.0g / (m 2 ·d) to achieve an oxygen permeability of 0.1-0.5cc / (m 2 ·d). The barrier property of polyolefin film is improved; the film thickness can be flexibly adjusted from 50μm to 180μm, and the heat sealing strength can reach 35N / 15mm-85N / 15mm after compounding with printed film MDOPE.

[0023] (3) The kaolin of the present invention is a natural layered silicate mineral, and its nano-scale layer structure contains many Si 4+ , AL 3+ The cations can undergo ion exchange reactions with organic or inorganic cations in the solution, introducing Na + Mg 2+ , Ca 2+The present invention modifies kaolin, introduces a hydrophobic structure, and changes its surface tension. Then, a silane coupling agent is used to melt-mix the modified kaolin. The modified kaolin can form a network structure with the resin. Through graft copolymerization, a branched polymer compound is obtained, which can effectively control the movement of water molecules. At the same time, some side chains react with the cross-linking agent, and a network structure is formed by the cross-linking structure and hydrogen bonds, thereby enhancing some mechanical properties.

[0024] (4) The aluminum-plated layer of the present invention: a modified resin (brand name NucrelAE) is blended with metallocene polyethylene (brand name 4009MC). NucrelAE resin is an ethylene-methacrylic acid-acrylate terpolymer resin. Although it is a polar resin, it has good compatibility with non-polar polyethylene resin, especially good adhesion with aluminum, which can greatly improve the adhesion strength of the aluminum layer and improve the surface energy of the film;

[0025] Second outer layer: low-density polyethylene (brand 7042) and metallocene polyethylene (brand SP2040) are blended. Compared with traditional low-density resins, the low-density polyethylene used has higher toughness, crack resistance and tear resistance, and can effectively protect the aluminum layer from impact cracking;

[0026] The first adhesive layer and the second adhesive layer: both use modified adhesive resin (brand name PX3060), which has good compatibility with polyethylene and EVOH resin, thus forming high bonding strength between the layers;

[0027] Barrier layer: EVOH resin (brand name ET3803RB) and modified kaolin are used as a blend. The resin is an ethylene-vinyl alcohol copolymer resin with a molar ratio of 38% of vinyl alcohol. The resin has excellent oxygen barrier properties. The addition of modified kaolin can significantly increase the moisture barrier properties of the film.

[0028] Second inner layer: low-density high-pressure polyethylene resin (brand 150BW) and metallocene polyethylene resin (brand SP2040) are used. The low-density high-pressure polyethylene has excellent processing performance, and the metallocene polyethylene resin has good toughness and stiffness, which supports the film and has excellent heat-sealing properties, improving the heat-sealing strength of the overall film;

[0029] Heat seal layer: low-density high-pressure polyethylene resin (brand name 150BW) is blended with low-melting-point metallocene polyethylene resin (brand name PL1881), and anti-blocking agent and non-migrating silicone lubricant are added. Low-melting-point metallocene polyethylene resin can provide excellent low-temperature heat sealing ability and high heat sealing strength.

[0030] (5) The aluminum-plated co-extruded film product of the present invention not only has excellent barrier properties, but can also be dry-compounded with BOPE, MDOPE, etc. to form a single-material packaging composite film. The heat-sealing performance of the composite film has the low-temperature anti-pollution heat-sealing performance and high heat-sealing strength of polyethylene, and can be used in the packaging of various types of snack foods, inflatable packaging, and daily chemical products. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a comparison chart of the heat sealing strength of the composite film of the co-extruded film (VMEVE) of Example 2 of the present invention and 25 μm MDOPE and the composite film of Comparative Example 1-2 and 25 μm MDOPE. DETAILED DESCRIPTION

[0032] Example 1

[0033] A high barrier recyclable aluminum-plated co-extruded film, and a preparation method thereof is as follows:

[0034] S1. Weigh the raw materials of each layer of the co-extruded film, mix them in proportion and put them into a mixer to mix evenly, and then send them into an extruder to melt respectively;

[0035] S2, according to the arrangement order of the aluminum-plated layer, the secondary outer layer, the first adhesive layer, the barrier layer, the second adhesive layer, the secondary inner layer and the heat-sealing layer, using an extruder to co-extrude and blow film to obtain a high-barrier co-extruded film;

[0036] S3. Use low-temperature plasma to bombard the surface of the high-barrier co-extruded film, and then evaporate aluminum on the surface of the aluminum-plated layer of the high-barrier co-extruded film to obtain a high-barrier aluminum-plated co-extruded film. The thickness of the co-extruded film is 50 μm, wherein the thickness of the aluminum-plated layer, the thickness of the second outer layer, and the thickness of the first adhesive layer are 6 μm, 8 μm, 4 μm, 5 μm, 4 μm, 8 μm, and 15 μm, respectively.

[0037] Among them, in step S1, the aluminum plating layer includes 20 parts by mass of polar resin and 80 parts by mass of the first metallocene polyethylene, the sub-outer layer includes 30 parts by mass of low-density polyethylene and 70 parts by mass of the second metallocene polyethylene, the first adhesive layer and the second adhesive layer are both 100 parts by mass of modified adhesive resin, the barrier layer includes 99 parts by mass of EVOH resin and 1 part by mass of modified kaolin, the sub-inner layer includes 20 parts by mass of low-density high-pressure polyethylene and 80 parts by mass of the second metallocene polyethylene, the heat-sealing layer includes 52 parts by mass of low-density high-pressure polyethylene, 42 parts by mass of the third metallocene polyethylene, 3 parts by mass of an opening agent and 3 parts by mass of a non-migrating silicone lubricant; the modified kaolin is composed of a silane coupling agent and kaolin in a mass ratio of 1:50.

[0038] Example 2

[0039] A high-barrier recyclable aluminum-plated co-extruded film, the preparation method of which is the same as that of Example 1, except that in step S1, the aluminum-plated layer includes 30 parts by mass of a polar resin and 70 parts by mass of a first metallocene polyethylene, the sub-outer layer includes 35 parts by mass of a low-density polyethylene and 65 parts by mass of a second metallocene polyethylene, the barrier layer includes 99 parts by mass of an EVOH resin and 1 part by mass of modified kaolin, the sub-inner layer includes 25 parts by mass of a low-density high-pressure polyethylene and 75 parts by mass of a second metallocene polyethylene, the heat-sealing layer includes 53 parts by mass of a low-density high-pressure polyethylene, 43 parts by mass of a third metallocene polyethylene, 2 parts by mass of an anti-blocking agent and 2 parts by mass of a non-migrating silicone lubricant; and the modified kaolin consists of a silane coupling agent and kaolin in a mass ratio of 1:50.

[0040] Example 3

[0041] A high-barrier recyclable aluminum-plated co-extruded film, the preparation method of which is the same as that of Example 1, except that in step S1, the aluminum-plated layer includes 40 parts by mass of a polar resin and 60 parts by mass of a first metallocene polyethylene, the sub-outer layer includes 40 parts by mass of a low-density polyethylene and 60 parts by mass of a second metallocene polyethylene, the first adhesive layer and the second adhesive layer are both 100 parts by mass of a modified adhesive resin, the barrier layer includes 99.5 parts by mass of an EVOH resin and 0.5 parts by mass of modified kaolin, the sub-inner layer includes 30 parts by mass of a low-density high-pressure polyethylene and 70 parts by mass of a second metallocene polyethylene, the heat-sealing layer includes 58 parts by mass of a low-density high-pressure polyethylene, 40 parts by mass of a third metallocene polyethylene, 1 part by mass of an anti-blocking agent and 1 part by mass of a non-migrating silicone lubricant; and the modified kaolin is composed of a silane coupling agent and kaolin in a mass ratio of 1:50.

[0042] The parameters of each particle used in the formulation of Examples 1-3 are shown in Table 1 below:

[0043] Table 1

[0044]

[0045] Comparative Example 1

[0046] 50μm VMPE (manufacturer: Yongxin Co., Ltd. (Huangshan) Packaging Co., Ltd.).

[0047] Comparative Example 2

[0048] 50μm VMCPP (manufacturer: Yongxin Co., Ltd. (Huangshan) Packaging Co., Ltd.).

[0049] The performance of the films of Example 2 and Comparative Examples 1-2 was tested, and the results are shown in Table 2 below:

[0050] Table 2

[0051]

[0052] As shown in Table 2, the moisture permeability of the co-extruded film prepared by the present invention is lower than 1.0 g / (m 2 d) and the oxygen permeability is less than 1.0cc / m 2 ·d, and are all lower than the values ​​of Comparative Examples 1-2, with better barrier properties and better peel strength.

[0053] The films of Example 2 and Comparative Examples 1-2 were then compounded with 25 μm MDOPE to obtain composite films, and the heat sealing strength of the composite films was tested. The results are as follows: Figure 1 As shown, from Figure 1 It can be seen that after the aluminum-plated co-extruded film prepared by the present invention is dry-compounded with the printed film MDOPE, the heat sealing strength of the co-extruded film can reach more than 30N / 15mm at above 120°C, and its heat sealing performance is significantly higher than the co-extruded film of Comparative Examples 1-2. It is found through testing that the heat sealing strength of the aluminum-plated co-extruded film of the present invention can reach 35N / 15mm-85N / 15mm.

[0054] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A high barrier recyclable aluminum-plated co-extruded film, characterized by: The co-extruded film comprises an aluminum-plated layer, a secondary outer layer, a first adhesive layer, a barrier layer, a second adhesive layer, a secondary inner layer and a heat-sealing layer which are connected in sequence; the aluminum-plated layer comprises 20-40 parts by mass of a polar resin and 60-80 parts by mass of a first metallocene polyethylene, the secondary outer layer comprises 30-40 parts by mass of a low-density polyethylene and 60-70 parts by mass of a second metallocene polyethylene, the first adhesive layer and the second adhesive layer are both 100 parts by mass of a modified adhesive resin, the barrier layer comprises 99-99.5 parts by mass of an EVOH resin and 0.5-1 parts by mass of modified kaolin, the secondary inner layer comprises 20-30 parts by mass of a low-density high-pressure polyethylene and 70-80 parts by mass of a second metallocene polyethylene, and the heat-sealing layer comprises 52-58 parts by mass of a low-density high-pressure polyethylene, 40-45 parts by mass of a third metallocene polyethylene, 1-3 parts by mass of an anti-blocking agent and 1-3 parts by mass of a non-migrating silicone lubricant.

2. The high barrier recyclable aluminum-plated co-extruded film according to claim 1, characterized in that: The aluminum-plated layer includes 30 parts by mass of a polar resin and 70 parts by mass of a first metallocene polyethylene, the sub-outer layer includes 35 parts by mass of a low-density polyethylene and 65 parts by mass of a second metallocene polyethylene, the barrier layer includes 99 parts by mass of an EVOH resin and 1 part by mass of modified kaolin, the sub-inner layer includes 25 parts by mass of a low-density high-pressure polyethylene and 75 parts by mass of a second metallocene polyethylene, and the heat-sealing layer includes 53 parts by mass of a low-density high-pressure polyethylene, 43 parts by mass of a third metallocene polyethylene, 2 parts by mass of an anti-blocking agent, and 2 parts by mass of a non-migrating silicone lubricant.

3. The high barrier recyclable aluminum-plated co-extruded film according to claim 1, characterized in that: The modified kaolin is composed of a silane coupling agent and kaolin in a mass ratio of 1:50; 4. The high barrier recyclable aluminum-plated co-extruded film according to claim 3, characterized in that: The preparation method of the modified kaolin is as follows: placing a silane coupling agent and kaolin in a stirrer, heating and stirring at a high speed to mix them uniformly, and the stirring speed is greater than 200 revolutions / min.

5. The high barrier recyclable aluminum-plated co-extruded film according to claim 1, characterized in that: The polar resin is an ethylene-methacrylic acid-acrylate terpolymer, and its brand is NucrelAE produced by DuPont of the United States; the brand of the first metallocene polyethylene is 4009MC produced by Exxon, the brand of the low-density polyethylene is 7042 produced by Zhejiang Petrochemical Company, the brand of the second metallocene polyethylene is SP2040 produced by Primen, the brand of the modified adhesive resin is PX3060 produced by LyondellBasell, the brand of the EVOH resin is ET3803RB produced by Japan Synthetic Chemical Company, the brand of the low-density high-pressure polyethylene is 150BW produced by Exxon, the brand of the third metallocene polyethylene is PL1881 produced by Dow Chemical Company of the United States, the brand of the anti-blocking agent is EZA-10 produced by Mitsui Company of Japan, and the brand of the non-migrating silicone lubricant is MBSI-002P produced by DuPont.

6. The high barrier recyclable aluminum-plated co-extruded film according to claim 1, characterized in that: The thickness of the co-extruded film is 50-180 μm, wherein the thickness ratio of the aluminum-plated layer, the thickness of the secondary outer layer, and the thickness of the first adhesive layer is 6:8:4:5:4:8:

15.

7. The high barrier recyclable aluminum-plated co-extruded film according to claim 1, characterized in that: The aluminum-plated layer has an aluminum layer on one side facing away from the secondary outer layer, and the thickness of the aluminum layer is 0.7 μm.

8. A method for preparing a high barrier recyclable aluminum-plated co-extruded film according to any one of claims 1 to 7, characterized in that: The steps include: S1. Weigh the raw materials of each layer of the co-extruded film, mix them in proportion and put them into a mixer to mix evenly, and then send them into an extruder to melt respectively; S2, according to the arrangement order of the aluminum-plated layer, the secondary outer layer, the first adhesive layer, the barrier layer, the second adhesive layer, the secondary inner layer and the heat-sealing layer, using an extruder to co-extrude and blow film to obtain a high-barrier co-extruded film; S3, bombarding the surface of the high-barrier co-extruded film with low-temperature plasma, and then vapor-depositing aluminum on the surface of the aluminum-plated layer of the high-barrier co-extruded film to obtain a high-barrier aluminum-plated co-extruded film.

9. The method for preparing a high barrier recyclable aluminum-plated co-extruded film according to claim 8, characterized in that: In step S2, the co-extrusion blown film uses the blowing traction, clamping bubble elimination, corona treatment, edge cutting and film winding steps in the prior art, and the traction speed of the blowing traction is 2m / min.

10. The method for preparing a high barrier recyclable aluminum-plated co-extruded film according to claim 9, characterized in that: When the extruder co-extrudes the blown film, the extruder temperature of the aluminum-plated layer, the secondary outer layer, the secondary inner layer and the heat-sealing layer is (185-190)±5°C; the extruder temperature of the first adhesive layer and the second adhesive layer is (210-220)±5°C, and the extruder temperature of the barrier layer is (215-220)±5°C.

Images