A fresh-keeping atmosphere-modified film and its processing method and processing equipment

Abstract

The present invention belongs to the field of energy conservation and environmental protection, and in particular, relates to a fresh-keeping atmosphere-modifying film, a processing method thereof, and a processing equipment thereof. The fresh-keeping atmosphere-modifying film comprises: a high-barrier middle layer, an outer layer located on the upper side of the high-barrier middle layer, an inner layer located on the lower side of the high-barrier middle layer, and a reinforcing layer located on the lower side of the inner layer, the reinforcing layer and the inner layer are bonded by a first bonding layer, the inner layer and the high-barrier middle layer are bonded by a second bonding layer, the high-barrier middle layer and the outer layer are bonded by a third bonding layer, and the outer layer and the inner layer are a linear low-density polyethylene mixture. The fresh-keeping atmosphere-modifying film of the present application has high barrier properties, good mechanical properties, and good environmental performance.

Description

Technical Field

[0001] The invention belongs to the field of energy conservation and environmental protection, and in particular relates to a fresh-keeping atmosphere-modifying film and a processing method and processing equipment thereof. Background Art

[0002] Nowadays, plastic film products have been widely used in all walks of life in human society. Plastic film is a necessity in daily life, but most products are disposable and thrown away immediately after use. If their environmental performance is poor and they are not easily degraded and recycled, they will cause serious pollution to the environment.

[0003] In order to make the film have gas barrier properties, barrier components such as PA and EVOH are introduced into the raw materials for film preparation in the prior art. However, the addition of the above components often causes problems such as compatibility between the raw materials, which makes the processing of the resulting film not smooth. In particular, problems such as frequent film breakage occur during the preparation of low-thickness films, which seriously affects the preparation efficiency. At the same time, it also causes the physical and chemical properties of the film, such as strength and barrier properties, to decrease, affecting its application. The present invention provides a fresh-keeping gas-conditioning film by adjusting the material formula, which has high barrier properties, good mechanical properties and good environmental performance. Summary of the invention

[0004] The object of the present invention is to provide a method and equipment for processing a fresh-keeping modified atmosphere film, so as to improve the barrier property, mechanical property and environmental protection property of the fresh-keeping modified atmosphere film.

[0005] A fresh-keeping atmosphere-modified film, comprising:

[0006] High barrier middle layer;

[0007] An outer layer located on the upper side of the high barrier middle layer;

[0008] An inner layer located below the high barrier middle layer;

[0009] A reinforcement layer located on the upper side of the outer layer;

[0010] The reinforcing layer and the outer layer are bonded by a first bonding layer;

[0011] The outer layer and the high barrier middle layer are bonded by a second bonding layer;

[0012] The high barrier middle layer and the inner layer are bonded by a third bonding layer;

[0013] Both the outer layer and the inner layer comprise linear low density polyethylene.

[0014] Preferably, the high barrier intermediate layers are, from top to bottom, first reinforcement layer, base layer, and second reinforcement layer.

[0015] Preferably, the first reinforcement layer and the second reinforcement layer are both a mixture of polyamide 66 and polyamide 6, the percentage of polyamide 66 is 70%, and the base layer is an ethylene-vinyl alcohol copolymer layer.

[0016] Preferably, the inner layer is a mixture of linear low-density polyethylene and an anti-fog adhesive, wherein the percentage of the linear low-density polyethylene is 70%.

[0017] Preferably, the outer layer is a blend of linear low density polyethylene.

[0018] Preferably, the reinforcement layer is a mixture of polyamide 66 and polyamide 6, and the percentage of polyamide 66 is 70%.

[0019] Preferably, the melt index of polyamide 66 and polyamide 6 at 190° C. and a load of 2.16 kg is independently selected from 10 to 80 g / 10 min.

[0020] Preferably, the linear low-density polyethylene has a melt index of 0.1-90 g / 10 min at 190° C. and a load of 2.16 kg.

[0021] A method for processing a fresh-keeping atmosphere-modified film, the method comprising the following steps:

[0022] S1: Mix the raw materials according to the formula ratio;

[0023] S2: melt the obtained mixed material according to the weight ratio of each layer and blow it into a tube film using multiple blow molding extruders;

[0024] S3: Post-processing the obtained tubular film to obtain the fresh-keeping atmosphere-modified film.

[0025] A device for processing fresh-keeping atmosphere-modified film using the above processing method, characterized in that the device at least comprises a blow molding extruder and a stretching roller.

[0026] Beneficial technical effects:

[0027] The fresh-keeping modified atmosphere film provided by the present invention has high barrier properties, good mechanical properties and better environmental protection performance by adjusting the material formula, and can extend the preservation time of food. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Moreover, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0029] Figure 1A schematic diagram of a fresh-keeping atmosphere-modifying film according to an embodiment of the present invention is shown;

[0030] Figure 2 A schematic diagram showing a high barrier middle layer of a fresh-keeping atmosphere-modifying film according to an embodiment of the present invention is shown.

[0031] In the figure: 100. reinforcement layer; 200. outer layer; 300. high barrier middle layer; 400. inner layer; 301. first reinforcement layer; 302. base layer; 303. second reinforcement layer. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical scheme and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. All other embodiments obtained by ordinary technicians in the field without creative work in the embodiments of the present invention are within the scope of protection of the present invention.

[0033] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.

[0034] The melt index in the present invention is a value indicating the fluidity of plastic materials during processing. The test method is to melt plastic pellets into plastic fluid within 10 minutes at a certain temperature and pressure, and then measure the number of grams (g) flowing out through a circular tube with a certain diameter. The larger the value, the better the processing fluidity of the plastic material, and vice versa.

[0035] Ethylene-vinyl alcohol copolymer has extremely high gas barrier properties, and its oxygen barrier property is 10,000 times that of polyethylene. It can effectively extend the shelf life and aroma preservation period of food and prevent food from oxidation and deterioration. Ethylene-vinyl alcohol copolymer has excellent barrier properties to oils and organic solvents, and is suitable for packaging food containing oils. The most important thing is that ethylene-vinyl alcohol copolymer has the highest thermal stability among high-performance barrier resins, which means that the waste generated during the processing can be regenerated and reused, and it is a green and environmentally friendly product, does not contain chlorine, and the waste can be recycled. Therefore, in the present invention, ethylene-vinyl alcohol copolymer is used as the base layer.

[0036] However, ethylene-vinyl alcohol copolymer is relatively hard, brittle, and has poor impact resistance at low temperatures. It is also highly hydrophilic, easily absorbs moisture, and is sensitive to ambient humidity, so it is not suitable for use in high humidity environments, and its heat resistance is relatively low.

[0037] In order to solve the above problems, in the present invention, the first strengthening layer and the second strengthening layer are respectively arranged on the upper and lower sides of the ethylene-vinyl alcohol copolymer as the base layer. Since polyamide 66 has good impact resistance, especially under low temperature conditions, the impact resistance is better than other materials, and it has good resistance to ultraviolet rays and atmospheric aging, and its heat resistance and wear resistance are better than ethylene-vinyl alcohol copolymer, in the present invention, the first strengthening layer and the second strengthening layer are both a mixture of polyamide 66. Preferably, since polyamide 6 has better processing performance than polyamide 66, its toughness and performance are better than polyamide 66 at low temperatures, and the transparency of the fresh-keeping atmosphere film can be improved, the first strengthening layer and the second strengthening layer can both be a mixture of polyamide 66 and polyamide 6.

[0038] Furthermore, in order to improve the flexibility and ductility of the fresh-keeping atmosphere-controlled film, reduce the weight of the fresh-keeping atmosphere-controlled film and reduce the cost, the present invention is provided with an outer layer and an inner layer on the upper side of the first strengthening layer and the lower side of the second strengthening layer, respectively, wherein the outer layer and the inner layer are both a mixture of linear low-density polyethylene. Preferably, in order to improve the transparency of the fresh-keeping atmosphere-controlled film, prevent or eliminate the fogging phenomenon on the fresh-keeping atmosphere-controlled film when the temperature changes, maintain the beautiful and professional appearance of the packaging, and reduce the condensation of moisture inside the packaging, thereby maintaining a dry environment for the food in the package and extending the shelf life of the food, a part of the anti-fog adhesive can be mixed into the mixture of the linear low-density polyethylene of the outer layer and the inner layer, so that the fresh-keeping atmosphere-controlled film is more suitable for refrigerated and frozen environments.

[0039] However, the mechanical strength, heat resistance and wear resistance of linear low-density polyethylene are not as good as those of polyamide 66. Preferably, the present invention provides a reinforcing layer on the upper side of the outer layer, and the reinforcing layer can be a mixture of polyamide 66 and polyamide 6.

[0040] Example 1: Combined with reference Figure 1 to Figure 2 As shown, according to one embodiment of the present invention, a fresh-keeping atmosphere-modifying film is provided, and the fresh-keeping atmosphere-modifying film comprises:

[0041] High barrier middle layer 300;

[0042] An outer layer 200 located on the upper side of the high barrier middle layer;

[0043] An inner layer 400 located below the high barrier middle layer;

[0044] A reinforcing layer 100 located on the upper side of the outer layer;

[0045] The reinforcing layer 100 and the outer layer 200 are bonded by a first bonding layer;

[0046] The outer layer 200 and the high barrier middle layer 300 are bonded by a second bonding layer;

[0047] The high barrier middle layer 300 and the inner layer 400 are bonded by a third bonding layer;

[0048] The outer layer 200 and the inner layer 400 both include linear low density polyethylene.

[0049] Preferably, the high barrier intermediate layers are, from top to bottom, first reinforcement layer 301 , base layer 302 , and second reinforcement layer 303 .

[0050] Preferably, the first reinforcement layer and the second reinforcement layer are a mixture of polyamide 66 and polyamide 6, the percentage of polyamide 66 is 50%-70%, and optimally, the percentage of polyamide 66 is 70%, and the base layer is an ethylene-vinyl alcohol copolymer layer.

[0051] Preferably, the inner layer is a mixture of linear low-density polyethylene and an anti-fog adhesive, wherein the percentage of the linear low-density polyethylene is 70%-80%, and optimally, the percentage of the linear low-density polyethylene is 70%.

[0052] Preferably, the outer layer is a blend of linear low density polyethylene.

[0053] Preferably, the reinforcement layer is a mixture of polyamide 66 and polyamide 6, the percentage of polyamide 66 is 50%-70%, and most preferably, the percentage of polyamide 66 is 70%.

[0054] Preferably, the melt index of polyamide 66 and the polyamide 6 at 190° C. and 2.16 kg load is independently selected from 10-80 g / 10 min.

[0055] Preferably, the linear low-density polyethylene has a melt index of 0.1-90 g / 10 min at 190° C. and a load of 2.16 kg.

[0056] In order to ensure the impact resistance of the high barrier intermediate layer and its adaptability to high humidity and low temperature environments, the first reinforcement layer and the second reinforcement layer have the same thickness, and the sum of their thicknesses is greater than the thickness of the base layer.

[0057] Preferably, the sum of the thickness of the first strengthening layer and the second strengthening layer is 1.03-1.13 times the thickness of the base layer.

[0058] Preferably, the sum of the thickness of the first strengthening layer and the second strengthening layer is 1.03-1.15 times the thickness of the base layer.

[0059] Preferably, the sum of the thickness of the first strengthening layer and the second strengthening layer is 1.03-1.17 times the thickness of the base layer.

[0060] Preferably, the sum of the thickness of the first strengthening layer and the second strengthening layer is 1.13-1.23 times the thickness of the base layer.

[0061] Preferably, the sum of the thickness of the first strengthening layer and the second strengthening layer is 1.13-1.25 times the thickness of the base layer.

[0062] Preferably, the sum of the thickness of the first strengthening layer and the second strengthening layer is 1.13-1.27 times the thickness of the base layer.

[0063] In order to ensure the overall impact resistance of the fresh-keeping modified atmosphere film, the thickness of the outermost reinforcement layer is greater than the thickness of the first reinforcement layer or the thickness of the second reinforcement layer.

[0064] Preferably, the thickness of the reinforcement layer is 1.01-1.06 times the thickness of the first reinforcement layer or the thickness of the second reinforcement layer.

[0065] Preferably, the thickness of the reinforcement layer is 1.01-1.11 times the thickness of the first reinforcement layer or the thickness of the second reinforcement layer.

[0066] Preferably, the thickness of the reinforcement layer is 1.01-1.16 times the thickness of the first reinforcement layer or the thickness of the second reinforcement layer.

[0067] In order to ensure the flexibility and ductility of the fresh-keeping modified atmosphere film, the thickness of the outer layer and the inner layer are the same, and the thickness of the outer layer and the inner layer are both greater than the thickness of the first strengthening layer or the thickness of the second strengthening layer, but less than the thickness of the reinforcement layer.

[0068] Preferably, 1.05 times the thickness of the first strengthening layer or the second strengthening layer<the thickness of the outer layer or the thickness of the inner layer<0.95 times the thickness of the reinforcement layer.

[0069] Preferably, 1.1 times the thickness of the first strengthening layer or the second strengthening layer<the thickness of the outer layer or the thickness of the inner layer<0.95 times the thickness of the reinforcement layer.

[0070] Preferably, 1.13 times the thickness of the first strengthening layer or the second strengthening layer<the thickness of the outer layer or the thickness of the inner layer<0.95 times the thickness of the reinforcement layer.

[0071] Embodiment 2: According to another embodiment of the present invention, a fresh-keeping atmosphere-modifying film is provided, and the fresh-keeping atmosphere-modifying film comprises:

[0072] A base layer composed of ethylene vinyl alcohol copolymer;

[0073] A reinforcement layer consisting of a blend of polyamide 66 and polyamide 6;

[0074] The stretching layer consists of linear low-density polyethylene.

[0075] Preferably, since ethylene vinyl alcohol copolymer has poor adhesion to most polymers, but can directly adhere to polyamide 66, a reinforcement layer composed of a mixture of polyamide 66 and polyamide 6 is provided on the upper and lower sides of the base layer composed of ethylene vinyl alcohol copolymer.

[0076] Preferably, in order to improve the mechanical strength, heat resistance and wear resistance of the fresh-keeping atmosphere-controlled film, the number of reinforcing layers composed of a mixture of polyamide 66 and polyamide 6 is not less than three layers. Preferably, the outermost layer of the fresh-keeping atmosphere-controlled film is set to be a reinforcing layer composed of a mixture of polyamide 66 and polyamide 6.

[0077] Preferably, in order to improve its toughness and performance at low temperatures and to improve the transparency of the fresh-keeping atmosphere-controlled film, the percentage of polyamide 66 in the mixture of polyamide 66 and polyamide 6 is 50%-70%, and optimally, the percentage of polyamide 66 is 70%.

[0078] Preferably, in order to ensure the ductility of the fresh-keeping modified atmosphere film, the number of the ductile layers composed of linear low-density polyethylene is not less than two.

[0079] Preferably, at least one expansion layer is arranged on the upper side of the base layer.

[0080] Preferably, the innermost layer of the fresh-keeping atmosphere-modified film is arranged as an extension layer composed of linear low-density polyethylene.

[0081] Preferably, in order to improve the transparency of the fresh-keeping modified atmosphere film, prevent or eliminate the fogging phenomenon on the fresh-keeping modified atmosphere film when the temperature changes, maintain the beautiful and professional appearance of the package, and reduce the condensation of moisture inside the package, thereby maintaining a dry environment for the food in the package and extending the shelf life of the food, the innermost extension layer is set to be a mixture of linear low-density polyethylene and an anti-fog adhesive, wherein the percentage of linear low-density polyethylene is 70%-80%.

[0082] Optimally, the percentage of linear low density polyethylene is 70%.

[0083] Embodiment 3: A method for processing a fresh-keeping modified atmosphere film, the method comprising the following steps:

[0084] S1: Mix the raw materials according to the formula ratio;

[0085] S2: melt the obtained mixed material according to the weight ratio of each layer and blow it into a tube film using multiple blow molding extruders;

[0086] S3: Post-processing the obtained tubular film to obtain the fresh-keeping atmosphere-modified film.

[0087] The stretching ratio during the processing of the fresh-keeping modified atmosphere film of the present application can be 2:1 to 10:1, preferably 3:1.

[0088] A device for processing fresh-keeping atmosphere-modified film using the above processing method, characterized in that the device at least comprises a blow molding extruder and a stretching roller.

[0089] It should be noted that the serial numbers of the embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0090] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A fresh-keeping atmosphere-modified film, characterized in that: include: High barrier middle layer; An outer layer located on the upper side of the high barrier middle layer; An inner layer located below the high barrier middle layer; A reinforcement layer located on the upper side of the outer layer; The reinforcing layer and the outer layer are bonded by a first bonding layer; The outer layer and the high barrier middle layer are bonded by a second bonding layer; The high barrier middle layer and the inner layer are bonded by a third bonding layer; Both the outer and inner layers consist of linear low-density polyethylene. The high barrier intermediate layer is composed of the first strengthening layer, the base layer, and the second strengthening layer from top to bottom. The thickness of the first strengthening layer is the same as that of the second strengthening layer. The sum of the thickness of the first strengthening layer and the second strengthening layer is 1.13-1.27 times the thickness of the base layer. The thickness of the strengthening layer is 1.01-1.06 times the thickness of the first strengthening layer or the thickness of the second strengthening layer. The thickness of the first strengthening layer or the thickness of the second strengthening layer is 1.1 times < the thickness of the outer layer or the thickness of the inner layer < 0.95 times the thickness of the strengthening layer. The thickness of the outer layer is the same as that of the inner layer. The first reinforcement layer and the second reinforcement layer are both a mixture of polyamide 66 and polyamide 6, the percentage of polyamide 66 is 70%, and the base layer is an ethylene-vinyl alcohol copolymer layer. The inner layer is a mixture of linear low-density polyethylene and anti-fog adhesive, wherein the percentage of linear low-density polyethylene is 70%. The outer layer is a mixture of linear low-density polyethylene, The reinforcing layer is a mixture of polyamide 66 and polyamide 6, the percentage of polyamide 66 is 70%, the melting indexes of polyamide 66 and polyamide 6 at 190°C and 2.16kg load are independently selected from 10-80g / 10min, and the melting index of the linear low-density polyethylene at 190°C and 2.16kg load is 0.1-90g / 10min.

2. A method for processing the fresh-keeping atmosphere-modified film according to claim 1, comprising the following steps: S1: Mix the raw materials according to the formula ratio; S2: melt the obtained mixed material according to the weight ratio of each layer using multiple blow molding extruders and blow them into tubular films; S3: Post-processing the obtained tubular film to obtain the fresh-keeping atmosphere-modified film.

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