Liquid pesticide composite packaging film without aluminum foil

Abstract

The application discloses a liquid pesticide composite packaging film without aluminum foil, which comprises, from inside to outside, a heat-sealing layer, a composite barrier layer and a balancing layer; the composite barrier layer comprises, from inside to outside, a PE layer, a barrier layer and a PE layer; and the PE layer, the barrier layer and the PE layer are bonded together through a composite PU adhesive. The composite packaging film of the application has a balancing layer as an outer layer, a composite barrier layer as a middle layer and a heat-sealing layer as an inner layer, so that the composite packaging film has good permeation resistance and can effectively prevent organic solvents in liquid pesticides from permeating outward. Specifically, the composite barrier layer has good barrier performance and corrosion resistance, and different barrier layers can be selected according to the properties of the liquid pesticide to be packaged.

Description

Technical Field

[0001] This invention belongs to the field of packaging film technology, and specifically relates to a composite packaging film for liquid pesticides that does not contain aluminum foil. Background Technology

[0002] Because liquid pesticides are packaged using highly corrosive and toxic organic solvents such as toluene and xylene, packaging materials must possess strong corrosion resistance and barrier properties. In rural my country, where household contract responsibility systems are prevalent, the amount of pesticides used each time is relatively small, making smaller-volume packaging of liquid pesticides highly desirable. However, traditional liquid pesticide packaging in the domestic market mostly uses plastic or glass bottles, which have many drawbacks, such as large capacity, fragility, high cost, inconvenient transportation, and difficulty in measurement.

[0003] Furthermore, composite packaging films used for packaging liquid pesticides often contain aluminum, which is expensive and difficult to recycle after disposal. There is an urgent need to develop an economical and convenient composite packaging film that can effectively prevent the penetration and corrosion of liquid pesticides, is easy to carry, and can be applied to small-capacity packaging bags. Summary of the Invention

[0004] The purpose of this invention is to provide a composite packaging film for liquid pesticides that does not contain aluminum foil. This composite packaging film has good impermeability and can effectively prevent organic solvents in liquid pesticides from seeping outwards.

[0005] To achieve the above-mentioned objectives, the technical solution of the present invention includes:

[0006] A liquid pesticide composite packaging film without aluminum foil includes, from the inside out, a heat-sealing layer, a composite barrier layer, and a balancing layer. The composite barrier layer includes, from the inside out, a PE layer, a barrier layer, and another PE layer. The PE layer, barrier layer, and PE layer are bonded together by a composite PU adhesive. The composite PU adhesive includes a polyurethane adhesive and a silane coupling agent. The silane coupling agent is 3-aminopropyltriethoxysilane or (3-mercaptopropyl)trimethoxysilane.

[0007] The composite packaging film of this invention has an outer balancing layer, a middle composite barrier layer, and an inner heat-sealing layer, giving the composite packaging film excellent impermeability and effectively preventing organic solvents in liquid pesticides from seeping out. Specifically, the composite barrier layer has good barrier and corrosion resistance properties, and different barrier layers can be selected according to the properties of the liquid pesticide to be packaged.

[0008] On the one hand, the silanol groups generated from the dehydration of alkoxy groups in the silane coupling agent react with the active groups on the surface of each layer in the composite barrier layer, enhancing the adhesion between the layers. On the other hand, the polyurethane adhesive in the PU adhesive introduces hydrophilic groups, giving the PU adhesive strong water absorption. The silane coupling agent introduced in this invention contains siloxane, which undergoes hydrolytic condensation with the polyurethane adhesive in the composite PU adhesive, increasing the density of crosslinking points between polyurethane molecular chains, thereby improving the water resistance of the composite PU adhesive.

[0009] In the aforementioned aluminum foil-free liquid pesticide composite packaging film, the mass fraction of the silane coupling agent in the composite PU adhesive is 0.5%-2%.

[0010] In the aforementioned aluminum foil-free liquid pesticide composite packaging film, the composite barrier layer comprises, from the inside out, a PE layer, an EVOH layer, and a PE layer, with a thickness ratio of 1:(1-3):(1-3). The composite barrier layer formed by the PE layer, EVOH layer, and PE layer exhibits good performance in blocking benzene and its derivatives.

[0011] In the above-mentioned aluminum foil-free liquid pesticide composite packaging film, the PE layer, EVOH layer and PE layer have the same thickness.

[0012] In the aforementioned aluminum foil-free liquid pesticide composite packaging film, the composite barrier layer comprises, from the inside out, a PE layer, a PA layer, and another PE layer, with a thickness ratio of 1:(1-2.5):(1-2.5). The composite barrier layer formed by the PE, EVOH, and PE layers exhibits good barrier properties against organic solvents such as kerosene, making it suitable for packaging pesticides containing organic solvents such as kerosene.

[0013] In the aforementioned aluminum foil-free liquid pesticide composite packaging film, the heat-sealing layer is a CPP layer or a PE layer. Using a CPP or PE layer for the heat-sealing layer can reduce the temperature required during the heat-sealing process and improve the composite properties of the packaging film. CPP molecules have longer sub-chains and generally higher crystallinity than PE molecules, resulting in better solvent barrier properties compared to PE films.

[0014] In the aforementioned aluminum foil-free liquid pesticide composite packaging film, the balancing layer is a PET layer. Even if a small amount of unblocked solvent permeates through the balancing layer to the outside of the packaging film, a dynamic balance of permeation is achieved, ensuring a relatively small amount of permeation.

[0015] In the above-mentioned aluminum foil-free liquid pesticide composite packaging film, the thickness of the heat-sealing layer is 10-20 μm, the thickness of the composite barrier layer is 30-100 μm, and the thickness of the balancing layer is 10-30 μm.

[0016] In the above-mentioned aluminum foil-free liquid pesticide composite packaging film, a printing layer is also provided on the outside of the balancing layer. The printing layer is a polypropylene film or a polyethylene terephthalate film.

[0017] Compared with the prior art, the beneficial effects of the present invention are reflected in:

[0018] (1) This invention is a high-barrier material without added aluminum. A packaging film is formed by combining a balancing layer, a composite barrier layer, and a heat-sealing layer. It possesses corrosion resistance and functions to block water vapor, oxygen, and ultraviolet rays. Specifically, the outer layer of the composite packaging film is a balancing layer, the middle layer is a composite barrier layer, and the inner layer is a heat-sealing layer. This gives the composite packaging film excellent impermeability, effectively preventing the organic solvents in liquid pesticides from seeping out. In particular, the composite barrier layer has good barrier and corrosion resistance properties, and different barrier layers can be selected according to the properties of the liquid pesticide to be packaged.

[0019] (2) On the one hand, the silanol groups generated by the dehydration of the alkoxy groups in the silane coupling agent react with the active groups on the surface of each layer in the composite barrier layer, enhancing the adhesion between the layers of the composite barrier layer. On the other hand, the polyurethane adhesive in the PU adhesive introduces hydrophilic groups, giving the PU adhesive strong water absorption. The silane coupling agent introduced in this invention contains siloxane, which undergoes hydrolytic condensation with the polyurethane adhesive in the composite PU adhesive, increasing the density of crosslinking points between polyurethane molecular chains, thereby improving the water resistance of the composite PU adhesive.

[0020] (3) The composite barrier layer has ideal impermeability and can effectively prevent organic solvents in liquid pesticides from seeping outwards. The composite barrier layer formed by PE, EVOH, and PE layers exhibits good performance in blocking benzene and its derivatives. Detailed Implementation

[0021] The technical solution of the present invention will be further described in detail below with reference to specific embodiments.

[0022] Example 1

[0023] A composite packaging film for liquid pesticides without aluminum foil comprises, from the inside out, a heat-sealing layer, a composite barrier layer, and a balancing layer. The heat-sealing layer is a CPP layer, and the balancing layer is a PET layer. The thickness of the heat-sealing layer is 10 μm, the thickness of the composite barrier layer is 30 μm, and the thickness of the balancing layer is 10 μm.

[0024] The composite barrier layer consists of a PE layer, an EVOH layer, and a PE layer from the inside out. The PE layer, EVOH layer, and PE layer are bonded together by a composite PU adhesive, and the thickness ratio of the PE layer, EVOH layer, and PE layer is 1:1:1.

[0025] The composite PU adhesive comprises a polyurethane adhesive and a silane coupling agent, wherein the silane coupling agent has a mass fraction of 0.5% in the composite PU adhesive. The silane coupling agent is 3-aminopropyltriethoxysilane. The polyurethane adhesive used in this embodiment is a commercially available product, purchased from Beijing Gaomeng Chemical Co., Ltd., and its model number is YH3640A.

[0026] The manufacturing method of this composite packaging film includes the following steps:

[0027] (1) Apply composite PU adhesive to both sides of the EVOH layer, with the amount of adhesive applied to each side controlled at 4g / m². 2 They are laminated with PE layers, wound up, and cured to obtain composite barrier layers.

[0028] (2) Apply polyurethane adhesive to one side of the composite barrier layer obtained in step (1), wherein the amount of adhesive applied is controlled at 4.2 g / m². 2 And then laminated with CPP, wound up and cured;

[0029] (3) Apply polyurethane adhesive to the other side of the composite barrier layer obtained in step (1), wherein the amount of adhesive applied is controlled at 4 g / m². 2 It is then laminated with PET, wound up, and cured to obtain a composite packaging film.

[0030] Example 2

[0031] This embodiment presents a liquid pesticide composite packaging film without aluminum foil, comprising, from the inside out, a heat-sealing layer, a composite barrier layer, a balancing layer, and a printing layer. The heat-sealing layer is a PE layer, the balancing layer is a PET layer, and the printing layer is a polypropylene film. The thickness of the heat-sealing layer is 20 μm, the thickness of the composite barrier layer is 100 μm, and the thickness of the balancing layer is 30 μm.

[0032] Specifically, the composite barrier layer comprises a PE layer, an EVOH layer, and a PE layer from the inside out. The PE layer, the barrier layer, and the PE layer are bonded together by a composite PU adhesive, and the thickness ratio of the PE layer, the EVOH layer, and the PE layer is 1:3:3.

[0033] The composite PU adhesive comprises a polyurethane adhesive and a silane coupling agent, with the silane coupling agent comprising 2% by mass in the composite PU adhesive. The silane coupling agent is 3-aminopropyltriethoxysilane or (3-mercaptopropyl)trimethoxysilane. The polyurethane adhesive used in this embodiment is a commercially available product, purchased from Beijing Gaomeng Chemical Co., Ltd., and its model number is YH3640A.

[0034] Example 3

[0035] This embodiment presents a liquid pesticide composite packaging film without aluminum foil, comprising, from the inside out, a heat-sealing layer, a composite barrier layer, and a balancing layer. The heat-sealing layer is a CPP layer, and the balancing layer is a PET layer. Furthermore, the thickness of the heat-sealing layer is 15 μm, the thickness of the composite barrier layer is 50 μm, and the thickness of the balancing layer is 20 μm.

[0036] Specifically, the composite barrier layer consists of a PE layer, a PA layer, and a PE layer from the inside out, and the thickness ratio of the PE layer, PA layer, and PE layer is 1:1.5:1.5.

[0037] In addition, the composite PU adhesive used includes a polyurethane adhesive and a silane coupling agent, with the silane coupling agent comprising 1.5% by mass in the composite PU adhesive. The silane coupling agent is (3-mercaptopropyl)trimethoxysilane. The polyurethane adhesive used in this embodiment is a commercially available product, purchased from Beijing Gaomeng Chemical Co., Ltd., and its model number is YH3640B.

[0038] Comparative Example 1

[0039] The difference between Comparative Example 1 and Example 1 is that a PE layer is used instead of the composite barrier layer.

[0040] Comparative Example 2

[0041] The difference between Comparative Example 2 and Example 1 is that the layers of the composite barrier layer are bonded together with PU adhesive.

[0042] The composite packaging films prepared in Examples 1-3 and Comparative Examples 1-2 were used to prepare packaging bags for corrosion resistance and permeability testing. The test results are shown in the table below. The corrosion resistance and permeability test was conducted as follows: 50 ml of pesticide test solution was injected into the packaging bag, which was then sealed and placed in an oven at 60°C for 20 days. After removing the sample, the pesticide residue inside the bag was drained, and the condition of the inner film was observed.

[0043] surface

[0044]

[0045] As can be seen from the table above, no corrosion or delamination occurred in the inner film and heat-sealed areas of the packaging bags prepared in Examples 1-3. Therefore, compared to Comparative Example 1, the composite barrier layers in Examples 1-3 exhibit ideal impermeability and can effectively prevent the organic solvents in liquid pesticides from seeping outwards.

[0046] Compared to Comparative Example 2, the composite PU adhesives in Examples 1-3 enhanced the adhesion between the layers of the composite barrier layer, enabling the composite barrier layer to effectively prevent the organic solvents in liquid pesticides from penetrating outwards. The specific principle is as follows: the silanol groups generated from the dehydration of the alkoxy groups in the silane coupling agent react with the active groups on the surface of each layer of the composite barrier layer, enhancing the adhesion between the layers and ensuring that the composite barrier layer has ideal impermeability.

[0047] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, equivalent changes and alterations made based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A composite packaging film for liquid pesticides without aluminum foil, characterized in that, From the inside out, it includes a heat-sealing layer, a composite barrier layer, and a balancing layer. The composite barrier layer includes a PE layer, a barrier layer, and another PE layer from the inside out. These PE layers are bonded together by a composite PU adhesive. The barrier layer is an EVOH layer or a PA layer. The composite PU adhesive includes a polyurethane adhesive and a silane coupling agent. The silane coupling agent is 3-aminopropyltriethoxysilane or (3-mercaptopropyl)trimethoxysilane. The balancing layer is a PET layer.

2. The aluminum foil-free liquid pesticide composite packaging film as described in claim 1, characterized in that, The mass fraction of this silane coupling agent in the composite PU adhesive is 0.5%-2%.

3. The aluminum foil-free liquid pesticide composite packaging film as described in claim 1, characterized in that, The thickness ratio of the PE layer, EVOH layer and PE layer is 1:(1-3):(1-3).

4. The aluminum foil-free liquid pesticide composite packaging film as described in claim 3, characterized in that, The PE layer, EVOH layer, and PE layer have the same thickness.

5. The aluminum foil-free liquid pesticide composite packaging film as described in claim 1, characterized in that, The thickness ratio of the PE layer, PA layer and PE layer is 1:(1-2.5):(1-2.5).

6. The aluminum foil-free liquid pesticide composite packaging film as described in claim 1, characterized in that, The heat-sealing layer is a CPP layer or a PE layer.

7. The aluminum foil-free liquid pesticide composite packaging film as described in claim 1, characterized in that, The thickness of the heat-sealing layer is 10-20 μm, and the thickness of the composite barrier layer is 30-100 μm.

8. The aluminum foil-free liquid pesticide composite packaging film as described in claim 1, characterized in that, The thickness of the balancing layer is 10-30 μm.

9. The aluminum foil-free liquid pesticide composite packaging film as described in claim 1, characterized in that, The outer side of the balancing layer is also provided with a printing layer, which is a polypropylene film or a polyethylene terephthalate film.

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