Air valve film material, air valve film and inflatable bag

Abstract

The present invention discloses a valve film material, which is a multi-layer co-extruded film structure, including a first polyolefin functional layer, a second polyolefin functional layer and an intermediate barrier layer, the two sides of the intermediate barrier layer are respectively combined with the first polyolefin functional layer and the second polyolefin functional layer by an adhesive resin layer, and the intermediate barrier layer is a nylon barrier layer and / or an ethylene-vinyl alcohol copolymer barrier layer. The present invention also protects the valve film and the inflatable bag made of the valve film material, the inflatable bag includes an upper and lower bottom film and a valve film, the valve film is arranged at the opening between the upper and lower bottom films, and the upper and lower bottom films are made of a film material containing a nylon barrier layer or an ethylene-vinyl alcohol copolymer barrier layer. The product of the present invention has better barrier properties, significantly improved gas retention, and has the advantages of high strength, puncture resistance, low cost, etc.

Description

Technical Field

[0001] The invention belongs to the field of organic packaging film materials and products thereof, and in particular relates to an air valve film material and products thereof. Background Art

[0002] The traditional way to cushion packaging items is to have a plurality of protruding small air bubbles on a plastic sheet, and then wrap the plastic film around the outer periphery of the item, so that the small air bubbles can absorb shock and cushion the items to prevent them from breaking or being damaged during transportation. However, the shock absorbing capacity of the small air bubbles is limited, and they can barely provide a cushioning effect for smaller impacts, but cannot achieve the purpose of cushioning and absorbing shocks for larger vibrations or impact loads, which can easily cause the items to break or be damaged.

[0003] Figure 1 Another inflatable bag with a conventional air valve is provided, the inflatable bag comprises an upper bottom film 110 and a lower bottom film 120, which overlap each other to form an opening. The inflatable bag also contains an air valve film, the air valve film comprises a first air valve film layer 210 and a second air valve film layer 220, which overlap each other and are fixed between the upper bottom film 110 and the lower bottom film 120 and are located at the opening, thereby forming a four-layer structure. In particular, the first air valve film layer 210 is overlapped and bonded to the inner side of the upper bottom film 110, and the second air valve film layer 220 is overlapped and bonded to the inner side of the lower bottom film 120. When the inflatable bag is inflated, air is guided into a channel formed between the first air valve film layer 210 and the second air valve film layer 220. When the air bag is filled with air, the first air valve film layer 210 and the second air valve film layer 220 are bonded to each other to seal the opening of the inflatable bag. The air pressure in the inflatable bag acts on the first air valve film layer 210 and the second air valve film layer 220, thereby ensuring that the first air valve film layer 210 and the second air valve film layer 220 are tightly bonded together to prevent air from leaking out of the air valve. The air valve composed of the first air valve film layer 210 and the second air valve film layer 220 is a one-way valve that only allows gas to enter the inflatable bag. However, the existing air valve film material for inflatable bags is mostly made of PE (polyethylene) film, while the base film is mostly made of ordinary PA (nylon) film. Since the material at the air-closing port is PE film, the oxygen permeability of the PE air valve film is between 3000-10000 (cm 3 / m 2 *24h*23℃.atm.50%RH), the bottom film is PE / NYLON / PE, the oxygen permeability is 50-500(cm 3 / m 2*24h*23℃.atm.50%RH), due to the material of the upper bottom film 110, the lower bottom film 120, the first air valve film layer 210 and the second air valve film layer 220, after the manufactured inflatable bag has been used for a period of time, especially when it is continuously squeezed, the air will still slowly leak from the channel, the film body, etc., resulting in the inflatable bag's air retention effect not being long-lasting. Under a pressure of 0.1-0.4MPa, the gas will be reduced by 10% to 30% after 1 month.

[0004] When existing inflatable bags are used for export products with long transportation cycles such as the electronics industry or products with a shelf life of more than 3 months, the poor gas barrier effect of the PE air valve film can easily cause damage to the products during later transportation, limiting the application scope of the inflatable bag products. For example, it is difficult to promote the use of heavy objects with high added value such as refrigerators, washing machines, panels, electronic products, and furniture. In addition, during the production process of inflatable bags made of this material, the scrap rate is high, and it is not easy to detect products with leaks, which brings great uncertainty to the quality of the inflatable bags and easily causes damage to the packaged items.

[0005] The base film and valve film of traditional inflatable bags mainly ensure their air tightness by increasing the viscosity of the material, but this method also leads to slow inflation speed and low inflation efficiency, and cannot adapt to high-speed inflation equipment; the film has low strength and poor impact resistance, and is easily affected by environmental factors during use, resulting in film rupture and leakage, generating waste, polluting the environment, and increasing costs; the production and processing performance is poor, and the film is prone to wrinkling and burring during processing, and cannot adapt to various bag-making equipment, resulting in a high scrap rate. Summary of the invention

[0006] The object of the present invention is to overcome at least one or more of the deficiencies mentioned in the above background technology and to provide a complete solution of an air valve film material, an air valve membrane and an inflatable bag.

[0007] In order to solve the above technical problems, the present invention provides an air valve membrane material, which is a multi-layer co-extruded film structure, including a first polyolefin functional layer, a second polyolefin functional layer and an intermediate barrier layer, and the two sides of the intermediate barrier layer are respectively bonded to the first polyolefin functional layer and the second polyolefin functional layer through an adhesive resin layer (TIE), and the intermediate barrier layer includes a nylon (PA) barrier layer or an ethylene-vinyl alcohol copolymer (EVOH) barrier layer.

[0008] The above technical solution of the present invention adopts a nylon (PA) barrier layer or an ethylene-vinyl alcohol copolymer (EVOH) barrier layer to replace the existing pure polyethylene (PE) structure of the air valve film. The existing air valve film is very thin, generally not more than 50 microns, and based on the limitations of process conditions and simplification requirements, and the conventional thinking of people in this field that the air valve film is mainly a functional film, rather than relying mainly on it for air barrier (air barrier mainly depends on other parts of the product, such as the substrate or bottom film), there are few references to the use of air valve film products containing a nylon (PA) barrier layer or an ethylene-vinyl alcohol copolymer (EVOH) barrier layer. In addition, the film material used for the valve film generally needs to add a small amount of POE to the outermost polyolefin functional layer to increase the viscosity and facilitate the self-adhesion of the valve film. This makes people in the field generally believe that such a high-viscosity polyolefin functional layer is difficult to bond firmly with the PA layer or EVOH layer. In addition, the valve film material is generally thin, difficult to prepare in terms of technology and high cost. Therefore, the prior art basically does not use a multi-film layer structure of a nylon (PA) barrier layer and / or an ethylene-vinyl alcohol copolymer (EVOH) barrier layer for the valve film. The present invention proposes for the first time to use a nylon (PA) barrier layer or an ethylene-vinyl alcohol copolymer (EVOH) barrier layer in the valve film product, which not only breaks the conventional prejudice, but can also be prepared by a co-extrusion molding process, and various air retention products such as air column bags made by combining with the base film have an improvement in air retention rate that exceeds our imagination and has an unexpected air barrier effect.

[0009] In the above-mentioned air valve film material, preferably, the first polyolefin functional layer and the second polyolefin functional layer contain polyethylene or polypropylene, but polyethylene is more preferred.

[0010] The above-mentioned valve film material is preferably added with a sticky resin in the first polyolefin functional layer, preferably polyolefin elastomer (POE) or sticky resin EVA, so as to better bond to the adjacent substrate or base film.

[0011] In the above-mentioned air valve membrane material, preferably, the first polyolefin functional layer includes a first polyethylene outer layer located on the outside and a first polyethylene inner layer close to the bonding resin layer, and the polyolefin elastomer is added to the first polyethylene outer layer.

[0012] In the above-mentioned air valve membrane material, preferably, the second polyolefin functional layer includes a second polyethylene outer layer located on the outside and a second polyethylene inner layer close to the bonding resin layer.

[0013] In the above-mentioned valve membrane material, preferably, the main components of the first polyolefin functional layer and the second polyolefin functional layer are both metallocene linear low-density polyethylene (mLLDPE), and the second polyolefin functional layer is added with low-density, medium-density or high-density polyethylene. More preferably, the density of the low-density polyethylene is 0.910-0.93 kg / cm 3 The density of the medium density polyethylene is 0.930-0.940 kg / cm 3 The density of the high-density polyethylene is 0.940 kg / cm 3 or above (preferably 0.940-0.970).

[0014] The above-mentioned air valve membrane material, preferably, has a total thickness of less than 50 microns, preferably 20-41 microns. Unless otherwise specified in the present invention, the film material thickness or film layer thickness generally referred to refers to the average thickness, and only the thickness measurement value shown in the attached figure is the actual measured thickness of the test point. The thickness of the macro film can be measured according to the national standard (GB / T 6672-2001) and its average thickness. N points (for example, 20 points in different parts) can be selected from the electron microscope photo of each component film layer in the film, and then the thickness of each point is measured and the average value can be taken as the film layer thickness. These test methods are all common knowledge that can be mastered and known by those skilled in the art.

[0015] In the above-mentioned valve film, the nylon barrier layer and the ethylene-vinyl alcohol copolymer barrier layer can be one or more layers with high content, but our experiments show that barrier layers with higher content and more layers cannot bring products with better cost performance. Preferably, the layer thickness ratio of the nylon barrier layer in the valve film is less than 20%, and the layer thickness ratio of the ethylene-vinyl alcohol copolymer barrier layer in the valve film is less than 5%. Furthermore, the intermediate barrier layer contains only one layer of ethylene-vinyl alcohol copolymer barrier layer or nylon barrier layer; or contains two layers of nylon barrier layer; or contains a sandwich structure with an ethylene-vinyl alcohol copolymer barrier layer sandwiched between two layers of nylon barrier layer.

[0016] In the above-mentioned valve film, preferably, the thickness ratio of the first polyolefin functional layer and the second polyolefin functional layer in the valve film is controlled at 30% to 45%.

[0017] As a general technical concept, the present invention also provides a gas valve membrane, which is prepared using the gas valve membrane material of the present invention.

[0018] The prior art generally does not mention the use of air valve membranes containing ethylene-vinyl alcohol copolymer barrier layers or nylon barrier layers. In addition to technical prejudice, cost and other reasons, the threshold of the production process is also a major limiting factor. Existing air valve membranes are generally three-layer PE structures with a relatively thin thickness. Such air valve membranes are generally made by casting or lamination. After pressing, they are cooled. The cooled film material is corona treated, cut with a ceramic scraper, rolled up, and aged to obtain the air valve membrane. Since the existing air valve membranes are all three-layer PE structures, they are rarely prepared using the co-extrusion blown film process. However, in the present invention, since the sandwich structure of the PA layer or EVOH layer is used, if this type of film structure is to be processed into an air valve membrane, the process needs to be greatly improved. Co-extrusion film preparation is the first technical route for air valve membranes that we tried. If the blown film-lamination co-extrusion film preparation technology is used to make a film such as Figure 2 The film material shown in the figure has a large production process loss (2% to 3% waste in the film blowing process and 4% to 6% waste in the film coating process), and the PA or EVOH co-extruded film needs to be blown separately and then bonded to the PE layers on the inner and outer sides through the film coating layer, which leads to a complex process flow, low efficiency, high processing cost, and difficulty in preparing film materials with a thickness of less than 50 microns. Another optional technical route is to directly blow and laminate the film to form a high barrier valve film material, such as Figure 3 As shown, the valve film generally contains at least two layers of EVOH material. In the blown film production, ethylene vinyl acetate copolymer (EVA) is placed as a heat-sealing layer on the inner layer of the blown film, and the two layers of the film bubble are squeezed and heat-sealed by a traction roller to form a thickened film. The cost of the valve film produced by this process is 30% to 60% higher, which is not conducive to market promotion, and it is also difficult to process a film with a thickness of less than 50 microns.

[0019] However, the present invention breaks the conventional thinking and improves the existing processing design scheme, so that each layer of material can be directly blow-molded in a film blowing machine at one time, and the functional layers of the prepared composite film are tightly bonded into a whole through the adhesive resin layer, and the layers are not easy to peel off and are firmly bonded, which can better maintain the high barrier properties of the valve film, and realize full plastic composite, which can be recycled. In addition, the one-time blow molding method can not only process high-barrier film materials with large thickness, but also process ultra-thin high-barrier film materials, while the existing process mainly prepares film materials with a thickness of 60-150 microns, which has no advantages in preparing ultra-thick or ultra-thin film materials.

[0020] The above-mentioned air valve membrane, preferably, comprises a first air valve membrane layer and a second air valve membrane layer which are closely attached to each other, and both the first air valve membrane layer and the second air valve membrane layer comprise the air valve membrane material, and the sides of the first air valve membrane layer and the second air valve membrane layer which are close to each other are set as the first polyolefin functional layer of the air valve membrane material.

[0021] As a general technical concept, the present invention also provides an inflatable bag, comprising an upper base film, a lower base film and the above-mentioned air valve film of the present invention, the air valve film adopts the above-mentioned air valve film material of the present invention, the air valve film is arranged at the opening between the upper base film and the lower base film, and the upper base film and the lower base film both adopt film materials containing nylon barrier layer or ethylene-vinyl alcohol copolymer barrier layer.

[0022] The improvement of the above-mentioned inflatable bag of the present invention not only lies in the use of the air valve film material of the present invention, but also the improvement of the upper bottom film and the lower bottom film. Compared with the existing nylon co-extruded film material used for the bottom film, it has the characteristics of green environmental protection, high barrier and high strength, so that the entire inflatable bag is produced and processed with recyclable all-plastic composite sheet materials, which is of great significance in environmental protection production and recycling.

[0023] The above-mentioned inflatable bag, preferably, the upper base film or the lower base film is made of recyclable high-barrier film material, the high-barrier film material comprises a first polyethylene functional layer, a second polyethylene functional layer, and an ethylene-vinyl alcohol copolymer-type intermediate barrier layer, and the two sides of the ethylene-vinyl alcohol copolymer-type intermediate barrier layer are respectively bonded to the first polyethylene functional layer and the second polyethylene functional layer through an adhesive resin layer.

[0024] In the above-mentioned inflatable bag, preferably, the first polyethylene functional layer, the ethylene-vinyl alcohol copolymer intermediate barrier layer and the second polyethylene functional layer are tightly bonded into a whole by an adhesive resin layer, and each film layer included in the high barrier film material is obtained by co-extrusion molding in one time through a film blowing process. Since each film layer is obtained by blow molding in one time, the composite strength between the layers (above 15N / 15mm) can be very high.

[0025] For the above-mentioned inflatable bag, preferably, the film layer structure of the high-barrier film material displayed under a microscope includes and only has one layer of ethylene-vinyl alcohol copolymer-type intermediate barrier layer, and the layer thickness ratio of the ethylene-vinyl alcohol copolymer-type intermediate barrier layer in the high-barrier film material displayed under a microscope is less than 5%, preferably less than 4%.

[0026] When the total thickness of the high barrier film is about 100 microns, the layer thickness ratio of the intermediate barrier layer in the high barrier film shown under a microscope is less than 5%, preferably less than 4%. The layer thickness ratio described here is basically equivalent to its volume ratio, because when the areas of each film layer are the same, the volume ratio is reflected in the thickness ratio. When the total thickness of the film layer is kept at about 100 microns, the volume ratio of the ethylene-vinyl alcohol copolymer intermediate barrier layer should be significantly smaller than the volume ratio of the intermediate barrier layer in the existing products. In existing products, due to the limitations of process conditions and product requirements, the volume content of the ethylene-vinyl alcohol copolymer intermediate barrier layer is generally controlled at 6% to 20% to maximize its barrier properties. However, in the present invention, through comprehensive control of the film layer structure and components, it is proposed to limit the volume content of the intermediate barrier layer to no more than 5%. This is a breakthrough in conventional operations, because the purpose of the present invention is to significantly increase the thickness of the first polyolefin functional layer and the second polyolefin functional layer in the high-barrier film material, and to make the EVOH layer as low as possible to improve the environmental protection grade standard of the product and reduce costs. This is of great significance for the subsequent recycling and utilization of the product and the expansion of overseas markets.

[0027] For the above-mentioned inflatable bag, preferably, the total thickness of the high barrier film is 30 to 150 microns, the adhesive resin layer is maleic anhydride grafted linear polyethylene, or a blend of maleic anhydride grafted linear polyethylene and linear polyethylene, and the layer thickness ratio of the single-layer adhesive resin layer in the high barrier film displayed under an electron microscope is 3% to 10%.

[0028] In the above-mentioned inflatable bag, preferably, the first polyethylene functional layer and / or the second polyethylene functional layer include an outer PE layer and an inner PE layer close to the adhesive resin layer, and the outer PE layer is a composite of metallocene linear low-density polyethylene and low-density polyethylene. More preferably, under a micro-electron microscope, the outer PE layers on both sides of the ethylene-vinyl alcohol copolymer intermediate barrier layer have a layer thickness ratio of 10% to 30% in the high-barrier film material; the layer thickness ratio of each adhesive resin layer in the high-barrier film material is 3% to 10%, and the rest is occupied by the inner PE layer. The inner PE layer can be composed of a single PE layer or a composite of multiple PE single layers superimposed under a micro-electron microscope. Compared with the film materials of the prior art, by reducing the content of EVOH and significantly increasing the content of the inner PE layer, the sheet can be made stiffer and stiffer, and the total cost of the high-barrier film material can be saved. More preferably, under a micro-electron microscope, the single-side thickness of the inner PE layer contained in the high-barrier film material accounts for 10% to 30%. By nearly equalizing the thickness of the inner PE layer on both sides of the ethylene-vinyl alcohol copolymer intermediate barrier layer, the EVOH layer can be better guaranteed to function and prevent it from contacting moisture in the air.

[0029] The high barrier film material used in the above-mentioned air valve film material and the inflatable bag can be compounded with a layer of PE printed film.

[0030] The present invention improves the film forming process and system so that each film layer included in the valve film material and the high barrier film material can be obtained by one-time co-extrusion molding through the film blowing process, thereby greatly improving the microstructure and connection relationship of the film material and significantly improving the quality of the film material.

[0031] The preparation method of the film material of the present invention comprises a plurality of steps including feeding, heating and melting, coextrusion, film blowing, cooling and shaping, traction and winding. The film blowing and cooling and shaping stage is a one-time film blowing molding to obtain all the film layers, and a thick film stretching and extending operation is added during the traction process. In the case where the total thickness of the film material is thicker or thinner, one-time film blowing molding can greatly reduce costs, improve efficiency, and improve the molding quality of the film material product. More preferably, the film body after the film blowing and cooling and shaping is flattened by a herringbone splint and then traction is performed, and a thick film stretching and extending operation is performed during the traction process through a thick film stretching and extending mechanism, and a film body heating device and a film body cooling device are provided in the thick film stretching and extending mechanism, and the thick film is stretched and extended by repeated alternation of hot and cold.

[0032] In the above-mentioned preparation method, preferably, the film body that has undergone the thick film stretching and extending operation is subjected to a secondary cooling and shaping operation during the transportation process. The secondary cooling and shaping operation is applied to the film body through an air ring cooling device, and the temperature of the film body after the secondary cooling and shaping is controlled at 30°C to 50°C. The secondary cooling and shaping operation is preferably arranged near the upstream or downstream of the slitting operation.

[0033] In the above-mentioned preparation method, preferably, during the feeding process, the raw material particles are directly added into the hopper of the extruder according to the ratio in the set formula in the automatic weighing system, and the material ratio is completed during the transportation process.

[0034] In the above preparation method, preferably, in the film blowing step, the film body is cooled and shaped by an air ring, the film body has a blowing ratio of 1 to 3, and a film body traction ratio of 4 to 6.

[0035] In the above-mentioned preparation method, preferably, the film body that has been cooled and shaped for the second time is pulled by a pulling roller and finally transported to a winding roller for winding. The drum behind the pulling roller may also be provided with a heating roller group for continuing to heat the film material after the second cooling and shaping or a cooling roller group for continuing to cool the film material, and the film material is repeatedly heated and cooled to correct defects before the final winding.

[0036] In the above preparation method, preferably, the two layers of film are separately processed in the secondary cooling, shaping and winding steps.

[0037] The present invention adopts a processing system, including a hopper, a film blowing machine, an extruder, a conveying device, a thick film stretching and extending mechanism, a slitting device and a winding device, wherein the hopper is connected to the extruder, and a plurality of the extruders are connected to the bottom of the film blowing machine. The film material output from the top of the film blowing machine is connected to a thick film stretching and extending mechanism through a conveying device, and the film material output through the thick film stretching and extending mechanism is finally connected to the slitting device and the winding device. The thick film stretching and extending mechanism is provided with a conveying channel of the conveying device, and a film heating device and a film cooling device for repeatedly alternating hot and cold on the film body are provided in the conveying channel. In the existing film blowing machine processing system, no thick film stretching and extending mechanism is used, and the configuration of this set of devices is based on the need for one-time film blowing to process thick films or thin films, ensuring that the intermediate product formed by cooling and forming the film is further extended, preventing the defects of the thick film product generated in the one-time film blowing process from entering the subsequent steps, and ensuring the quality of the thick film product.

[0038] In view of the characteristics of the film blowing processing system of the present invention, we propose to add a hot and cold alternating film stretching and extension mechanism downstream of the top of the film blowing machine, which is not only easy to integrate into the existing processing system, but also low in cost and easy to control the quality of the film. More preferably, the film material output by the thick film stretching and extension mechanism is connected to a secondary cooling and shaping device through a conveying device, and finally connected to a winding device; the secondary cooling and shaping device is arranged near the upstream or downstream of the slitting device. The secondary cooling and shaping device includes an air ring cooling device applied to the film material. The secondary cooling and shaping device also includes a heating roller group and a cooling roller group arranged in front of the air ring cooling device for alternating hot and cold treatment, and the heating roller group and the cooling roller group are arranged to perform horizontal rolling on the film material. This is mainly to consider that if the film quality is still not up to standard before the secondary cooling and shaping, it can be compensated by a hot and cold alternating roller heating before shaping, which is not only low in cost and convenient to operate, but also can further improve the stability of the film material.

[0039] In the above-mentioned processing system, it is more preferred that the number of the extruders corresponds to the number of layers of the film material to be prepared. The configuration of the number of flow channels in the die head of the film blowing machine is consistent with the number of layers of the film material to be prepared. More preferably, the width of a single flow channel located in the die head is larger than the opening size of the single flow channel at the air ring cooling discharge. Designing the width of the flow channel to be larger than the opening size can increase the extrusion force of the discharge near the opening, and make the flow and discharge of the medium in the die head smoother. Based on the need to prepare ultra-thin film materials, we can independently adjust the opening size of a single flow channel at the air ring cooling discharge to be consistent with the thickness of each layer of the film material.

[0040] After the air valve film and high barrier film are processed by the above-mentioned preparation method and processing system, the air valve film and high barrier film are heat-sealed and formed by the existing inflatable bag manufacturing process to obtain the inflatable bag product of the present invention.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] 1. The present invention provides a recyclable high-barrier air valve film material. Compared with the existing PE film material, the barrier property of the present invention is better and the gas retention property is significantly improved.

[0043] 2. The air-holding time of the air-inflating bag of the present invention can be extended by 3 to 20 times compared with the existing air-inflating bag, the air leakage rate is reduced by 15% to 40%, and the maximum bearing pressure is increased by 10% to 50%. The application scope of the air-inflating bag product of the present invention is significantly expanded, and it can replace cartons, polystyrene, pearl cotton, etc. and be applied to the packaging of various household appliances and electronic products, and even the packaging of export products that are in transit for a long time.

[0044] 3. The valve membrane and high barrier membrane of the present invention are preferably high-performance membranes formed by co-extrusion of high barrier materials, polyethylene and other related adhesive materials, and can achieve the high strength, high barrier, puncture resistance and other functions that only traditional NY and PE film composites can have without composite metal materials.

[0045] 4. Further controlling the amount of the intermediate barrier layer through process operation and optimizing the design of other layers can further reduce costs, while achieving better high barrier properties, higher gas retention and aroma retention.

[0046] 5. Further controlling the number of intermediate barrier layers and optimizing the design of other layers through process operation can further simplify the process steps and product thickness of film production, thereby further reducing costs, improving post-processing efficiency of inflatable bags, and improving product quality.

[0047] 6. The film layer structure design of the present invention, especially the design of the content and number of the inner PE layer, can further improve the glossiness, mechanical strength, stiffness and puncture resistance of the film material.

[0048] 7. Through the film layer structure design of the present invention, especially the arrangement of each layer and the position distribution of the PE printing film, the film material of the present invention can have good printing adaptability.

[0049] 8. Through the film material selection, film structure design and parameter optimization control of the present invention, the film material of the present invention can have better environmental stress cracking resistance, flexibility, good heat sealing performance, and meet the requirements of multi-layer heat sealing for bag making.

[0050] 9. The product of the present invention is more environmentally friendly, and the packaging film material can be 100% recycled and reused, which is beneficial to saving resources and protecting the environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 It is a schematic diagram of the membrane layer structure of a local section of an existing inflatable bag.

[0052] Figure 2 Schematic diagram of the film layer structure of the all-plastic composite packaging material prepared by the existing lamination and lamination process.

[0053] Figure 3 The schematic diagram of the film layer structure of the all-plastic composite packaging material prepared by the existing blown film lamination composite process, wherein PE is the polyethylene layer and EVA is the ethylene vinyl acetate copolymer layer.

[0054] Figure 4 It is a schematic diagram of the film layer structure of the cross section of the inflatable bag of the present invention.

[0055] Figure 5 It is a schematic diagram of the structure of the gas valve membrane and the high barrier membrane of the present invention.

[0056] Figure 6 This is a cross-sectional electron microscope photograph of the inflatable bag product prepared in Example 1 of the present invention.

[0057] Figure 7 This is a cross-sectional electron microscope photograph of the inflatable bag product prepared in Example 2 of the present invention.

[0058] Figure 8 This is a cross-sectional electron microscope photograph of the inflatable bag product prepared in Example 3 of the present invention.

[0059] Fig. 9 This is a cross-sectional electron microscope photograph of the inflatable bag product prepared in Example 4 of the present invention.

[0060] Fig.10 This is a cross-sectional electron microscope photograph of the air valve film material of the sandwich-type intermediate barrier layer of the present invention.

[0061] Fig.11 This is a cross-sectional electron microscope photograph of an inflatable bag product prepared in a comparative example of the present invention.

[0062] Fig.12 It is a schematic diagram of the process principle of the method for preparing the gas valve membrane material (base membrane) of the present invention.

[0063] Fig.13 It is a structural schematic diagram of the valve membrane material (base membrane) processing system of the present invention.

[0064] Fig.14 It is the appearance diagram of the die head of the film blowing machine in the air valve film material (base film) processing system of the present invention.

[0065] Fig.15 It is a partial enlarged view of the thick film stretching and extending mechanism of the valve film material (base film) processing system of the present invention.

[0066] Legend:

[0067] 1. Hopper; 2. Film blowing machine; 21. Die head; 22. Flow channel; 23. Flow channel opening; 3. Extruder; 4. Conveying device; 5. Thick film stretching and extending mechanism; 51. Film heating device; 52. Film cooling device; 6. Slitting device; 61. Horizontal vibration mechanism; 62. Vertical vibration mechanism; 7. Winding device; 8. Secondary cooling and shaping device;

[0068] 100, base film; 110, upper base film; 120, lower base film; 200, air valve film; 210, first air valve film layer; 220, second air valve film layer; 300, multi-film layer structure; 310, polyethylene outer layer; 321, adhesive resin layer; 322, polyethylene inner layer; 323, intermediate barrier layer. DETAILED DESCRIPTION

[0069] In order to facilitate the understanding of the present invention, the present invention is described in more comprehensive and detailed manner below, but the protection scope of the present invention is not limited to the following specific embodiments.

[0070] Unless otherwise defined, all professional terms used below have the same meanings as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0071] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0072] Embodiment 1:

[0073] Reference Figure 4 A one-way check valve inflatable bag of the present invention comprises a bottom film 100, the bottom film 100 comprises an upper bottom film 110 and a lower bottom film 120, an opening is arranged between the upper bottom film 110 and the lower bottom film 120; an air valve film 200 is arranged at the opening between the upper bottom film 110 and the lower bottom film 120, the air valve film 200 comprises a first air valve film layer 210 and a second air valve film layer 220, the first air valve film layer 210 is closely attached to the upper bottom film 110, the second air valve film layer 220 is closely attached to the lower bottom film 120, and the air valve film 200 and the bottom film 100 both comprise the following Figure 5The multi-layer film structure 300 shown includes a polyethylene outer layer 310, a polyethylene inner layer 322, an adhesive resin layer 321 and an intermediate barrier layer 323; the multi-layer film structure 300 is prepared by a one-time blown film forming process through a co-extrusion blown film process. The polyethylene outer layer 310 and the polyethylene inner layer 322 located on one side of the intermediate barrier layer 323 constitute a first polyolefin functional layer, and the polyethylene outer layer 310 and the polyethylene inner layer 322 located on the other side of the intermediate barrier layer 323 constitute a second polyolefin functional layer.

[0074] The valve membrane 200 in this embodiment adopts a multi-layer structure 300 as shown in Table 1 below, and the average thickness of the membrane layer is about 30 microns (due to limitations of membrane material processing, the thickness of different parts of the membrane material also has a slight deviation).

[0075] Table 1: Structural parameters of the gas valve membrane layer in this embodiment

[0076]

[0077] The upper base film 110 and the lower base film 120 in this embodiment both adopt a multi-layer structure 300 as shown in Table 2 below, and the average thickness of the film layer is about 50 microns.

[0078] Table 2: Base film layer structure parameter table of this embodiment

[0079]

[0080]

[0081] In this embodiment, PA as the middle barrier layer has the advantages of high strength, low air permeability, and good gas retention performance. It can better isolate the air and prevent gas penetration relative to the polyethylene outer layer 310 and the polyethylene inner layer 322. The inflatable bag gas retention product made by combining the air valve film of this embodiment with the bottom film 100 has a high gas retention rate and good gas barrier effect. After inflation, under a certain pressure, the gas is reduced by 1% to 6%, thereby extending the storage time of the inflatable bag product for gas, and significantly improving the protection level of the goods during storage and transportation.

[0082] In some other embodiments of the present invention, the polyethylene outer layer 310 and the polyethylene inner layer 322 may also be replaced by polypropylene. However, the main base materials of the polyethylene outer layer 310 and the polyethylene inner layer 322 in the air valve membrane material of this embodiment are both MLLDPE metallocene polyethylene, but polyolefin elastomer (POE) is added to the polyethylene outer layer 310 of the first polyolefin functional layer, and low-density polyethylene (LDPE) is added to the polyethylene outer layer 310 of the second polyolefin functional layer. Such a membrane layer structure design not only has good air retention performance, but also facilitates the self-adhesion of the air valve membrane and the base membrane in the later stage, and can control costs.

[0083] In some other embodiments of the present invention, the middle barrier layer 323 can be made of at least one layer of PA6, PA66, or a blend of PA6 and PA66. PA6 and PA66 are flame resistant, wear resistant, heat resistant, have high tensile strength, good electrical insulation, and as core layer materials have good gas retention properties and are relatively reliable.

[0084] In this embodiment, the base film is made of high barrier film material, wherein the main base materials of the polyethylene outer layer 310 and the polyethylene inner layer 322 are both MLLDPE metallocene polyethylene, but low-density polyethylene (LDPE) is added to the polyethylene outer layer 310 of the first and second polyolefin functional layers, and the middle barrier layer 323 can be made of at least one layer of PA6, PA66, or a blend of PA6 and PA66. Such a film layer structure design not only has good gas retention performance, is easy to process and reduce costs, but also has a strong blocking effect on gases, which can further improve the gas retention performance of the base film.

[0085] The cross-sectional electron microscope photo of the inflatable bag product of this embodiment is as follows Figure 6 As shown, after testing, it has at least the following effects: compared with the inflatable bag of the following comparative example, the oxygen permeability of the air valve membrane of this embodiment is low, the air retention time of the inflatable bag of this embodiment can reach 60 days, which is extended by more than 3 times, and the maximum pressure resistance is increased by 20% (the pressure resistance test can refer to GB / T4857.4-2008).

[0086] Air retention time test method: Inflate the bag (pressure: 0.01-0.2MPa), place it under a flat plate and apply a certain pressure (10-100kg), observe the change of pressure over time, when the pressure value drops to 80% of the initial pressure, the time recorded at this time is the air retention time.

[0087] Embodiment 2:

[0088] Reference Figure 4 A one-way check valve inflatable bag of the present invention comprises a bottom film 100, the bottom film 100 comprises an upper bottom film 110 and a lower bottom film 120, an opening is arranged between the upper bottom film 110 and the lower bottom film 120; an air valve film 200 is arranged at the opening between the upper bottom film 110 and the lower bottom film 120, the air valve film 200 comprises a first air valve film layer 210 and a second air valve film layer 220, the first air valve film layer 210 is closely attached to the upper bottom film 110, the second air valve film layer 220 is closely attached to the lower bottom film 120, and the air valve film 200 and the bottom film 100 both comprise the following Figure 5The multi-layer film structure 300 shown includes a polyethylene outer layer 310, a polyethylene inner layer 322, an adhesive resin layer 321 and an intermediate barrier layer 323; the multi-layer film structure 300 is prepared by a one-time blown film forming process through a co-extrusion blown film process. The polyethylene outer layer 310 and the polyethylene inner layer 322 located on one side of the intermediate barrier layer 323 constitute a first polyolefin functional layer, and the polyethylene outer layer 310 and the polyethylene inner layer 322 located on the other side of the intermediate barrier layer 323 constitute a second polyolefin functional layer.

[0089] The air valve membrane 200 in this embodiment adopts a multi-layer structure 300 as shown in Table 3 below, and the average thickness of the membrane layer is about 30 microns.

[0090] Table 3: Valve membrane layer structure parameters of this embodiment

[0091]

[0092] The upper base film 110 and the lower base film 120 in this embodiment both adopt a multi-layer structure 300 as shown in Table 4 below, and the average thickness of the film layer is about 36 microns.

[0093] Table 4: Base film layer structure parameter table of this embodiment

[0094]

[0095] In the air valve film material of this embodiment, the PA as the middle barrier layer has the advantages of high strength, low air permeability, and good air retention performance. It can better isolate the air and prevent gas penetration relative to the polyethylene outer layer 310 and the polyethylene inner layer 322. The inflatable bag air retention product made by combining the air valve film of this embodiment with the bottom film 100 has a high air retention rate and good air barrier effect. After inflation, under a certain pressure, the gas is reduced by 1% to 6%, thereby extending the storage time of the inflatable bag product for gas, and significantly improving the protection level of the product during storage and transportation.

[0096] In some other embodiments of the present invention, the polyethylene outer layer 310 and the polyethylene inner layer 322 may also be replaced by polypropylene. However, the main base materials of the polyethylene outer layer 310 and the polyethylene inner layer 322 in the air valve membrane material of this embodiment are both MLLDPE metallocene polyethylene, but polyolefin elastomer (POE) is added to the polyethylene outer layer 310 of the first polyolefin functional layer, and low-density polyethylene (LDPE) is added to the polyethylene outer layer 310 of the second polyolefin functional layer. Such a membrane layer structure design not only has good air retention performance, but also facilitates the self-adhesion of the air valve membrane and the base membrane in the later stage, and can control costs.

[0097] In some other embodiments of the air valve film material of the present invention, the middle barrier layer 323 can be made of at least one layer of PA6, PA66, or a blend of PA6 and PA66. PA6 and PA66 are flame resistant, wear resistant, heat resistant, have high tensile strength, good electrical insulation, and have good gas retention properties as core layer materials and are relatively reliable.

[0098] In this embodiment, the bottom film is made of high barrier film material, wherein the main base material of the polyethylene outer layer 310 and the polyethylene inner layer 322 is MLLDPE metallocene polyethylene, but low density polyethylene (LDPE) is added to the polyethylene outer layer 310 of the first and second polyolefin functional layers, and EVOH is used as the main component of the middle barrier layer 323. Such a film layer structure design not only has good gas retention performance, is easy to process and reduce costs, but also has a stronger blocking effect on gas, which can further improve the gas retention performance of the bottom film. When using conventional composite film material peeling strength test (such as GB / T 8808-1988 "Soft Composite Plastic Material Peeling Test Method" and other conventional test methods), effective peeling cannot be performed between the first polyolefin functional layer, the EVOH middle barrier layer, and the second polyolefin functional layer. The composite fastness between the first polyolefin functional layer and the ethylene-vinyl alcohol copolymer middle barrier layer, and between the ethylene-vinyl alcohol copolymer middle barrier layer and the second polyolefin functional layer is greater than 15N / 15mm. The film structure of the high barrier film material displayed under a microscope includes only one EVOH middle barrier layer, and the ethylene content in the middle barrier layer is 38wt%.

[0099] The cross-sectional electron microscope photo of the inflatable bag product of this embodiment is as follows Figure 7 As shown, the test shows at least the following effects: compared with the inflatable bag of the following comparative example, the air retention time of the inflatable bag of this embodiment can reach 120 days, and the maximum pressure resistance is increased by 30%.

[0100] Embodiment 3:

[0101] Reference Figure 4 A one-way check valve inflatable bag of the present invention comprises a bottom film 100, the bottom film 100 comprises an upper bottom film 110 and a lower bottom film 120, an opening is arranged between the upper bottom film 110 and the lower bottom film 120; an air valve film 200 is arranged at the opening between the upper bottom film 110 and the lower bottom film 120, the air valve film 200 comprises a first air valve film layer 210 and a second air valve film layer 220, the first air valve film layer 210 is closely attached to the upper bottom film 110, the second air valve film layer 220 is closely attached to the lower bottom film 120, and the air valve film 200 and the bottom film 100 both comprise the following Figure 5The multi-layer film structure 300 shown includes a polyethylene outer layer 310, a polyethylene inner layer 322, an adhesive resin layer 321 and an intermediate barrier layer 323; the multi-layer film structure 300 is prepared by a one-time blown film forming process through a co-extrusion blown film process. The polyethylene outer layer 310 and the polyethylene inner layer 322 located on one side of the intermediate barrier layer 323 constitute a first polyolefin functional layer, and the polyethylene outer layer 310 and the polyethylene inner layer 322 located on the other side of the intermediate barrier layer 323 constitute a second polyolefin functional layer.

[0102] The air valve membrane 200 in this embodiment adopts a multi-membrane layer structure 300 as shown in Table 5 below, and the average thickness of the membrane layer is about 40 microns.

[0103] Table 5: Valve membrane layer structure parameters of this embodiment

[0104]

[0105] The upper base film 110 and the lower base film 120 in this embodiment both adopt a multi-layer structure 300 as shown in Table 6 below, and the average thickness of the film layer is about 75 microns.

[0106] Table 6: Base film layer structure parameter table of this embodiment

[0107]

[0108] In the air valve film material of this embodiment, the EVOH used as the middle barrier layer has the advantages of high strength, low air permeability, and good gas retention performance. It can better isolate the air and prevent gas penetration relative to the polyethylene outer layer 310 and the polyethylene inner layer 322. The inflatable bag gas retention product made by combining the air valve film of this embodiment with the bottom film 100 has a high gas retention rate and good gas barrier effect. After inflation, under a certain pressure, the gas is reduced by 3% to 6%, thereby extending the storage time of the inflatable bag product for gas, and significantly improving the protection level of the product during storage and transportation.

[0109] In some other embodiments of the present invention, the polyethylene outer layer 310 and the polyethylene inner layer 322 may also be replaced by polypropylene. However, the main base materials of the polyethylene outer layer 310 and the polyethylene inner layer 322 in the air valve membrane material of this embodiment are both MLLDPE metallocene polyethylene, but polyolefin elastomer (POE) is added to the polyethylene outer layer 310 of the first polyolefin functional layer, and low-density polyethylene (LDPE) is added to the polyethylene outer layer 310 of the second polyolefin functional layer. Such a membrane layer structure design not only has good air retention performance, but also facilitates the self-adhesion of the air valve membrane and the base membrane in the later stage, and can control costs.

[0110] In this embodiment, the bottom film is made of high barrier film material, wherein the main base materials of the polyethylene outer layer 310 and the polyethylene inner layer 322 are both MLLDPE metallocene polyethylene, but low-density polyethylene (LDPE) is added to the polyethylene outer layer 310 of the first and second polyolefin functional layers, and PA is used as the main component of the middle barrier layer 323. Such a film layer structure design not only has good gas retention performance, is easy to process and reduce costs, but also has a stronger blocking effect on gas, which can further improve the gas retention performance of the bottom film. The middle barrier layer 323 can be made of at least one layer of PA6, PA66, or a blend of PA6 and PA66. PA6 and PA66 are flame retardant, wear resistant, heat resistant, have high tensile strength, and good electrical insulation. As the core layer material, they have good gas retention performance and are relatively reliable.

[0111] The cross-sectional electron microscope photo of the inflatable bag product of this embodiment is as follows Figure 8 As shown, the test shows at least the following effects: compared with the inflatable bag of the following comparative example, the air retention time of the inflatable bag of this embodiment can reach 120 days, which is extended by more than 3 times, and the maximum pressure resistance is increased by 30%.

[0112] Embodiment 4:

[0113] Reference Figure 4 A one-way check valve inflatable bag of the present invention comprises a bottom film 100, the bottom film 100 comprises an upper bottom film 110 and a lower bottom film 120, an opening is arranged between the upper bottom film 110 and the lower bottom film 120; an air valve film 200 is arranged at the opening between the upper bottom film 110 and the lower bottom film 120, the air valve film 200 comprises a first air valve film layer 210 and a second air valve film layer 220, the first air valve film layer 210 is closely attached to the upper bottom film 110, the second air valve film layer 220 is closely attached to the lower bottom film 120, and the air valve film 200 and the bottom film 100 both comprise the following Figure 5 The multi-layer film structure 300 shown includes a polyethylene outer layer 310, a polyethylene inner layer 322, an adhesive resin layer 321 and an intermediate barrier layer 323; the multi-layer film structure 300 is prepared by a one-time blown film forming process through a co-extrusion blown film process. The polyethylene outer layer 310 and the polyethylene inner layer 322 located on one side of the intermediate barrier layer 323 constitute a first polyolefin functional layer, and the polyethylene outer layer 310 and the polyethylene inner layer 322 located on the other side of the intermediate barrier layer 323 constitute a second polyolefin functional layer.

[0114] The air valve film 200 in this embodiment adopts a multi-layer structure 300 as shown in Table 7 below, and the average thickness of the air valve film material is about 40 microns.

[0115] Table 7: Valve membrane layer structure parameters of this embodiment

[0116]

[0117]

[0118] The upper base film 110 and the lower base film 120 in this embodiment both adopt a multi-layer structure 300 as shown in Table 8 below, and the average thickness of the film material is about 36 microns.

[0119] Table 8: Base film layer structure parameter table of this embodiment

[0120]

[0121] In the air valve film material of this embodiment, the EVOH used as the middle barrier layer has the advantages of high strength, low air permeability, and good gas retention performance. It can better isolate the air and prevent gas penetration relative to the polyethylene outer layer 310 and the polyethylene inner layer 322. The inflatable bag gas retention product made by combining the air valve film of this embodiment with the bottom film 100 has a high gas retention rate and good gas barrier effect. After inflation, under a certain pressure, the gas is reduced by 3% to 6%, thereby extending the storage time of the inflatable bag product for gas, and significantly improving the protection level of the product during storage and transportation.

[0122] In some other embodiments of the present invention, the polyethylene outer layer 310 and the polyethylene inner layer 322 may also be replaced by polypropylene. However, the main base materials of the polyethylene outer layer 310 and the polyethylene inner layer 322 in the air valve membrane material of this embodiment are both MLLDPE metallocene polyethylene, but polyolefin elastomer (POE) is added to the polyethylene outer layer 310 of the first polyolefin functional layer, and low-density polyethylene (LDPE) is added to the polyethylene outer layer 310 of the second polyolefin functional layer. Such a membrane layer structure design not only has good air retention performance, but also facilitates the self-adhesion of the air valve membrane and the base membrane in the later stage, and can control costs.

[0123] In this embodiment, the base film is made of high barrier film material, wherein the main base materials of the polyethylene outer layer 310 and the polyethylene inner layer 322 are both MLLDPE metallocene polyethylene, but low-density polyethylene (LDPE) is added to the polyethylene outer layer 310 of the first and second polyolefin functional layers, and EVOH is used as the main component of the middle barrier layer 323. Such a film layer structure design not only has good gas retention performance, is easy to process and reduce costs, but also can present a stronger blocking effect on gas, which can further improve the gas retention performance of the base film.

[0124] The cross-sectional electron microscope photo of the inflatable bag product of this embodiment is as follows Fig. 9 As shown, the test shows at least the following effects: compared with the inflatable bag of the following comparative example, the air retention time of the inflatable bag of this embodiment can reach 360 days, and the maximum pressure resistance is increased by 30%.

[0125] In addition, in other embodiments of the present invention, the middle barrier layer of the valve film material of the present invention can also be processed into a sandwich structure "comprising two nylon barrier layers with an ethylene-vinyl alcohol copolymer barrier layer sandwiched between them" (see Fig.10 ).

[0126] Comparative Example:

[0127] The inflatable bag structure of the above-mentioned embodiment 1 is adopted, but the selected valve film material and bottom film material are shown in the following Table 9, and the average thickness of the film material is about 36 microns.

[0128] Table 9: Comparative Example Valve Membrane Layer Structure Parameters

[0129]

[0130] The upper base film and the lower base film in this embodiment both adopt the multi-layer structure 300 shown in Table 10 below, and the average thickness of the film material is about 50 microns.

[0131] Table 10: Comparative Example Base Film Layer Structure Parameters

[0132]

[0133] The cross-sectional electron microscope photo of the inflatable bag product of this comparative example is as follows Fig.11 As shown, the test shows that the following effects are achieved: the air retention time of the inflatable bag of this comparative example can reach 30 days.

[0134] The performance comparison test data of the membrane materials in the above embodiments and comparative examples are shown in Table 11 below:

[0135] Table 11: Comparative experimental table of performance parameters of high barrier films in various embodiments

[0136]

[0137] like Fig.12 As shown, the preparation method of the film material of this embodiment includes multiple steps of feeding, heating and melting, co-extrusion, film blowing, cooling and shaping, pulling, and winding. The specific operations are as follows:

[0138] S1: The raw material particles of each layer in the multi-layer structure 300 of the above embodiment are transported from their respective storage tanks to the hoppers of each extruder; during the transportation process, the raw material particles pass through an automatic weighing system, and the raw material particles are added to the hoppers of each extruder according to the ratio in the formula in the automatic weighing system. The material ratio is completed during the transportation process, and the metering is accurate, which reduces the weighing process in the processing process.

[0139] S2: In this embodiment, there are seven hoppers, which are used to store the raw material particles of each layer respectively. In other embodiments, the number of hoppers may vary from 9 to 11 depending on the different film layer structures. Some hoppers may also be added to store functional additives. The raw material particles are stored in different hoppers, which is convenient for transportation and adjustment of the ratio of each component. It is suitable for different material ratios and makes the entire processing device more flexible. After the hopper is loaded, the raw material particles are heated, melted, distributed, co-extruded, and shaped by air ring cooling in the extruder to obtain a one-time formed film body.

[0140] S3: When the film is cooled and shaped by the air ring, the blowing ratio of the film is generally 1 to 3, and the traction ratio of the film is 4 to 6, so that the film material reaches the preset thickness.

[0141] S4: After being cooled and shaped by the air ring, the film body is flattened by a herringbone clamp and then pulled to form two layers of film, which enter a thick film stretching and extending mechanism for thick film stretching and extending operation. The thick film stretching and extending mechanism is provided with a film heating device and a film cooling device, and the thick film is stretched and extended by repeated alternation of hot and cold.

[0142] S5: After the thick film stretching operation, the film body can be subjected to a secondary cooling and shaping operation during the conveying process (but this operation is not necessary). The secondary cooling and shaping operation can be applied to the film body through an air ring cooling device, or through multiple groups of horizontally arranged heating rollers and cooling rollers to make the film material smoother and more uniform in performance; and the temperature of the film body after secondary cooling and shaping is controlled at 30℃~50℃. The film material moves in the drum to make the material smoother and more uniform in performance, and the physical function of each component is brought to the extreme.

[0143] S6: The film body after secondary cooling and shaping is pulled by a traction roller, post-processed and cooled, and then transported to the winding roller for winding. Specifically, a heating roller group and a cooling roller group can be set in the roller after the traction roller as needed. The heating roller group and the cooling roller group are alternately set to repeatedly heat and cool the film material, so that the roller can continue to heat or cool the film material after secondary cooling and shaping, so that the hardness of the material is improved and the ductility is better; the post-processing treatment is corona and trimming. After the film is post-processed, the two layers of film are cooled, shaped and rolled up respectively.

[0144] The preparation method of this embodiment realizes the one-time direct molding of high-barrier film materials, and can be used to make packaging tubes such as toothpaste tubes, simplifying the process and reducing costs. The characteristics of high-strength material technology make the material have advantages in the field of tube making, such as uniform tube thickness, smooth tube body, good barrier properties, high processing efficiency, low material cost, and high stiffness.

[0145] like Fig.13The processing system shown in the figure for preparing recyclable high-barrier film materials comprises a hopper 1, a film blowing machine 2, multiple extruders 3, a conveying device 4, a thick film stretching and extending mechanism 5, a slitting device 6 and a winding device 7. The hopper 1 is connected to the extruder 3, and the multiple extruders 3 are connected to the bottom of the film blowing machine 2. The number of the multiple extruders 3 corresponds to the number of layers of the high-barrier film materials to be prepared. The film materials output from the top of the film blowing machine 2 are connected through the conveying device 4 and pass through the thick film stretching and extending mechanism 5. The film materials output through the thick film stretching and extending mechanism 5 are finally connected to the slitting device 6 and the winding device 7.

[0146] Fig.15 This is a partial enlarged view of the thick film stretching and extending mechanism 5 of this embodiment. Fig.15 It can be seen that the thick film stretching and extending mechanism 5 is provided with a conveying channel for accommodating the conveying device 4, and the conveying channel is provided with a film heating device 51 and a film cooling device 52 for performing alternating hot and cold treatment on the film. The thick film stretching and extending mechanism 5 is arranged near the discharge of the film blowing machine 2 (arranged at the top of the film blowing machine 2 in this embodiment), and a plurality of groups of film heating devices 51 and film cooling devices 52 are alternately arranged.

[0147] like Fig.13 As shown, the film material outputted by the thick film stretching and extending mechanism 5 can be selectively connected to a secondary cooling and shaping device 8 through the conveying device 4, and the secondary cooling and shaping device 8 is connected to the slitting device 6 and the winding device 7. The secondary cooling and shaping device includes an air ring cooling device applied to the film material, and also includes a heating roller group and a cooling roller group arranged in front of the air ring cooling device for alternating hot and cold treatments, and the heating roller group and the cooling roller group are arranged to perform horizontal rolling on the film material.

[0148] like Fig.14 As shown, the number of flow channels 22 in the die head 21 of the film blowing machine 2 is configured to be consistent with the number of layers of the film material to be prepared, and the width of a single flow channel 22 in the die head 21 is greater than the size of the flow channel opening 23 of the single flow channel 22 at the air ring cooling discharge. The size of the flow channel opening 23 at the air ring cooling discharge is consistent with the thickness of each film layer, so as to prepare a multi-layer film structure with a corresponding layer thickness ratio.

Claims

1. A valve film, comprising a first valve film layer and a second valve film layer closely attached to each other, wherein both the first valve film layer and the second valve film layer comprise valve film materials, characterized in that: The valve film material is a multi-layer co-extruded film structure, including a first polyolefin functional layer, a second polyolefin functional layer and an intermediate barrier layer. The two sides of the intermediate barrier layer are respectively combined with the first polyolefin functional layer and the second polyolefin functional layer through an adhesive resin layer (TIE). The first polyolefin functional layer is added with a viscous resin, and the viscous resin is a polyolefin elastomer (POE) or a viscous resin EVA; the intermediate barrier layer includes a nylon (PA) barrier layer and / or an ethylene-vinyl alcohol copolymer (EVOH) barrier layer; the total thickness of the valve film material is less than 50 microns; the layer thickness ratio of the nylon barrier layer in the valve film material is less than 20%, and the layer thickness ratio of the ethylene-vinyl alcohol copolymer barrier layer in the valve film material is less than 5%; The side portions of the first air valve film layer and the second air valve film layer close to each other are arranged as the first polyolefin-based functional layer of the air valve film material.

2. The air valve membrane according to claim 1, characterized in that: The first polyolefin-based functional layer and the second polyolefin-based functional layer include polyethylene or polypropylene.

3. The air valve membrane according to claim 2, characterized in that: The first polyolefin-based functional layer and the second polyolefin-based functional layer contain polyethylene.

4. The air valve membrane according to claim 2, characterized in that: The first polyolefin-based functional layer includes a first polyethylene outer layer located on the outside and a first polyethylene inner layer close to the bonding resin layer, and polyolefin elastomer is added into the first polyethylene outer layer.

5. The air valve membrane according to claim 2, characterized in that: The second polyolefin-based functional layer includes a second polyethylene outer layer located on the outside and a second polyethylene inner layer close to the adhesive resin layer.

6. The air valve membrane according to any one of claims 2 to 5, characterized in that: The main components of the first polyolefin functional layer and the second polyolefin functional layer are both metallocene linear low-density polyethylene (mLLDPE), and low-density, medium-density or high-density polyethylene is added to the second polyolefin functional layer.

7. The air valve membrane according to any one of claims 1 to 5, characterized in that: The total thickness of the air valve film is 20-41 microns.

8. The air valve membrane according to any one of claims 1 to 5, characterized in that: The intermediate barrier layer includes only one ethylene-vinyl alcohol copolymer barrier layer or a nylon barrier layer; or includes two nylon barrier layers; or includes a sandwich structure with an ethylene-vinyl alcohol copolymer barrier layer sandwiched between two nylon barrier layers.

9. The air valve membrane according to any one of claims 1 to 5, characterized in that: The thickness ratio of the first polyolefin functional layer and the second polyolefin functional layer in the valve film is controlled at 30%-45%.

10. An inflatable bag, characterized in that: It comprises an upper base film, a lower base film and an air valve film as described in any one of claims 1 to 9, wherein the air valve film is arranged at an opening between the upper base film and the lower base film, and the upper base film and the lower base film are made of film materials containing a nylon barrier layer or an ethylene-vinyl alcohol copolymer barrier layer.

11. The inflatable bag according to claim 10, characterized in that: The upper base film or the lower base film is made of recyclable high-barrier film material, which includes a first polyethylene functional layer, a second polyethylene functional layer, and an ethylene-vinyl alcohol copolymer intermediate barrier layer. The two sides of the ethylene-vinyl alcohol copolymer intermediate barrier layer are respectively bonded to the first polyethylene functional layer and the second polyethylene functional layer through an adhesive resin layer.

12. The inflatable bag according to claim 11, characterized in that: The first polyethylene functional layer, the ethylene-vinyl alcohol copolymer intermediate barrier layer and the second polyethylene functional layer are tightly bonded into a whole through an adhesive resin layer, and the film layers included in the high barrier film material are obtained by one-time co-extrusion molding through a film blowing process.

13. The inflatable bag according to any one of claims 11 to 12, characterized in that: The film structure of the high-barrier film material displayed under a microscope includes and only has one ethylene-vinyl alcohol copolymer-type intermediate barrier layer, and the layer thickness ratio of the ethylene-vinyl alcohol copolymer-type intermediate barrier layer in the high-barrier film material displayed under a microscope is less than 5%.

14. The inflatable bag according to claim 13, characterized in that: The thickness ratio of the ethylene-vinyl alcohol copolymer intermediate barrier layer in the high barrier film material displayed under a microscope is less than 4%.

15. The inflatable bag according to any one of claims 11 to 12, characterized in that: The total thickness of the high barrier film is 30 to 150 microns, the adhesive resin layer is maleic anhydride grafted linear polyethylene, or a blend of maleic anhydride grafted linear polyethylene and linear polyethylene, and the layer thickness ratio of the single-layer adhesive resin layer in the high barrier film displayed under an electron microscope is 3% to 10%.

16. The inflatable bag according to any one of claims 11 to 12, characterized in that: The first polyethylene functional layer and / or the second polyethylene functional layer comprises an outer PE layer and an inner PE layer close to the adhesive resin layer, and the outer PE layer is a composite of metallocene linear low-density polyethylene and low-density polyethylene.

17. The inflatable bag according to claim 16, characterized in that: Under a microscope, the thickness ratio of the outer PE layers on both sides of the ethylene-vinyl alcohol copolymer intermediate barrier layer in the high barrier film is 10% to 30%; the thickness ratio of each adhesive resin layer in the high barrier film is 3% to 10%, and the rest is occupied by the inner PE layer.

18. The inflatable bag according to claim 17, characterized in that: Under an electron microscope, the single-side thickness of the inner PE layer contained in the high-barrier film material accounts for 10% to 30%.

Images