Vacuum seal bags

Abstract

A vacuum seal bag, characterized in that it comprises: a bag body (10), the bag body (10) comprising a wall (11) made of plastic film, a bag opening (12) on the top side of the wall (11), and a bag bottom (13) axially opposite the bag opening (12), the wall (11) constituting a circumferentially closed, continuous surface structure whose inner surface encloses a vacuum space (15), the inner surface of the wall (11) being provided with functional raised and depressed textures (14), the raised and depressed textures (14) extending continuously from the bag opening (12) along the inner surface of the wall (11) to the bag bottom (13), thereby forming gas escape paths, and the bag opening (12) being a hot-melt sealable bag opening.

Description

TECHNICAL FIELDThe present invention relates to the field of vacuum packaging technology, in particular to a vacuum closure bag having a circumferentially closed continuous surface structure.PRIOR ARTA vacuum packaging machine allows long term preservation of articles by two essential operations: vacuuming and heat sealing. The operation is as follows: Step 1: Vacuuming: A vacuum sealing bag is placed in a sealed slit and a vacuum pump is started to suck the air from the bag to a predetermined pressure or a predetermined time threshold; Step 2: Heat sealing: With heating elements, a double film (e.g., PA / PE composite material) is fused very rapidly at the bag opening to achieve a gas-tight seal.In order to achieve effective venting, conventional vacuum closure bags must be formed with raised and recessed textures in the region of the bag opening in order to prevent sticking between the film layers and thus blocking of the gas channels. In Figures 1 to 3 the structure of an existing closure bag is shown, which consists of the following parts:a smooth plastic film layer 0111 for basic sealing and mechanical strength;a plastic film layer 0112 having raised and recessed textures, wherein raised and recessed textures 04 are provided on an inner wall of the plastic film layer 0112 having raised and recessed textures, and gas escape paths are formed in spaces between the plastic film layer 0112 having raised and recessed textures; andMelting edges 06, which bond the edges of two films to one another by hot pressing to form a bag body, wherein the smooth plastic film layer 0111 and the plastic film layer 0112 having raised and recessed textures enclose a vacuum space 015 with their inner surfaces by means of the melting edges 06.Existing vacuum closure bags have the following deficiencies: 1. complex multistage manufacturing process: smooth films and films with raised and recessed textures must be produced separately and processed further in several operations, e.g. separate cutting, laminating and edge fusion. This requires high investments in plants and personnel. 2. low material utilization: When two foil rolls are processed synchronously, increased material waste at the edges easily occurs due to uneven tension.The above problems result in high production costs for conventional vacuum sealing bags, particularly in mass production, which limits competitiveness on the market.CONTENT OF THE PRESENT INVENTIONIn view of the disadvantages of the prior art, the present invention provides a novel vacuum seal bag structure in which the separate processing and laminating steps are omitted, thereby greatly simplifying the production process and reducing the manufacturing cost.In order to achieve the above object, the technical solution of the present invention provides a vacuum seal bag comprising:a bag body, the bag body comprising a wall of plastic film, a bag opening at the top of the wall, and a bag bottom axially opposite the bag opening.The wall represents a continuous surface structure closed in the circumferential direction, the inner surface of which encloses a vacuum space.The inner surface of the wall is provided with functional raised and recessed textures, the raised and recessed textures extending from the bag opening along the inner surface of the wall continuously to the bag bottom, thereby forming gas escape paths.The bag opening is a hot melt sealable bag opening.It is also provided that the bag bottom has one of the following structures: a) a closed bag bottom which is sealed by hot melting; b) an open bag bottom.It is also provided that the wall is integrally formed by blow molding.It is also provided that the elevation of the raised and recessed texture is formed in the form of straight strips, obliquely running straight strips or wave-shaped profiles or a combination thereof.It is also provided that the elevation of the raised and recessed texture has a height of 0.1 to 0.5 mm.It is also contemplated that the protrusion of the raised and recessed texture 14 is formed in the shape of straight stripes extending axially along the bag body.Furthermore, it is provided that the respective straight strip has a width of 1 to 3 mm and the distance between adjacent textures is 2 to 5 mm.It is further contemplated that the raised and recessed textures 14 will have one of the following distribution manners: a) the entire inner surface of the wall 11; and b) 20% to 90% of the inner surface of the wall 11, with the uncovered areas being smooth.It is also provided that the plastic film has a thickness of 10 to 300 μm.It is also provided that the plastic film is of single-layer construction and consists of polyethylene or polypropylene.The present invention has an advantage that the costs can be significantly reduced by the following measures: 1. process flow simplification: In the vacuum seal bag structure according to the present invention, multiple operations of the existing process, such as the separate production of smooth films and films having raised and recessed textures, the cutting, lamination and edge fusion, can be replaced by the one-piece blow molding, thereby simplifying the process; and 2. cut material cuts reduction: In this process, cut material cuts do not occur, thereby improving material utilization and reducing waste.BRIEF DESCRIPTION OF THE DRAWINGSFIG. 1 is a main view of a vacuum sealing bag according to the prior art; FIG. 2 shows a perspective view of the vacuum closure bag according to the prior art; FIG. 3 shows a schematic sectional structural view of the vacuum closure bag along A-A according to the prior art; FIG. 4 is a schematic structural view of a vacuum seal bag according to Embodiment I of the present invention; FIG. 5 is a perspective view of the vacuum seal bag according to Embodiment I of the present invention; FIG. 6 is a schematic sectional structural view of the vacuum seal bag taken along A-A according to Embodiment I of the present invention; FIG. 7 is a schematic sectional structural view of the vacuum seal bag taken along B-B according to Embodiment I of the present invention; FIG. 8 shows a schematic view of the vacuum closure bag with obliquely running straight strips distributed in regions on the inner surface of the wall according to exemplary embodiment II of the present invention; FIG. 9 shows a schematic view of the vacuum closure bag with wavy profiles distributed in regions on the inner surface of the wall according to exemplary embodiment III of the present invention; FIG. 10 is a perspective view of the vacuum sealing bag according to Embodiment IV of the present invention; FIG. 11 is a schematic structural view of the vacuum seal bag in the form of a roll according to Embodiment IV of the present invention; FIG. 12 shows a structural comparison of the melting edge of the vacuum closure bag according to the prior art and according to the present invention (12a: prior art, 12b: embodiment I, 12c: embodiment V); and FIG. 13 shows a flow diagram of a film blowing process.List of reference numbers:FIGS. 1-3 show prior art representations: smooth plastic film layer 0111; plastic film layer with raised and recessed textures 0112; raised and recessed texture 04; melting edge 06FIGS. 4-12 are illustrations of the embodiments of the present invention: bag body 10; wall 11; bag opening 12; bag bottom 13; raised and recessed texture 14; vacuum space 15DETAILED DESCRIPTIONIn conjunction with the figures in the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be described clearly and fully hereinafter. Obviously, they do not constitute a limitation of the present invention.In the present invention, for the sake of better clarity, it is provided that the observer is directed for observation on FIG. 2, the left rear side of the observer is directed as front, the right front side of the observer is directed as rear, the left front side of the observer is directed as right, the right rear side of the observer is directed as left, the upper side of the observer is directed as top, the underside of the observer is directed as bottom. It should be noted that the terms "front", "rear", "above", "below", "inside", "above", "below", etc. are used herein with reference to the orientation or positional relationship illustrated in the accompanying drawings, respectively, to clearly describe only the present utility model. These terms neither implicitly nor explicitly mean that a structure or an element must be arranged or designed in a specific orientation and therefore do not represent a limitation of the present utility model. It is further understood that the terms "first" and "second" are for clarity and convenience of description only and are not to be understood as expressing or implying relative importance or number.Embodiment I: Closed vacuum closure bags with full-area, rectilinear textures1. Product ConstructionThis embodiment provides a rectangular plate-shaped vacuum seal bag as shown in Figs. 4 to 7.It comprises a bag body 10, wherein the bag body 10 is integrally formed of linear low density polyethylene (LLDPE) by blow molding and has overall dimensions of 300±5 mm length x 200±3 mm width.Construction:a wall 11 having a thickness of 10 μm, said wall 11 constituting a circumferentially closed continuous surface structure;a bag opening 12 at the top of the wall 11;a bag bottom 13 axially opposed to the bag opening 12 and being a closed bag bottom sealed by hot melt; anda vacuum space 15, the vacuum space 15 of the vacuum closure bag being enclosed by surfaces of the wall 11.2. Formation of Surface TexturesAn inner surface of the wall 11 is provided with functional raised and recessed textures 14, the raised and recessed textures being straight stripes extending axially along the bag body.The straight strips have one of the following dimensions: a) the height of the elevation of the strip is 0.1 mm, the width of the strip is 0.5 mm and the distance between adjacent strips is 0.5 mm; and b) the height of the elevation of the strip is 0.5 mm, the width of the strip is 3 mm and the distance between adjacent strips is 5 mm.Distribution: The entire inner surface of the wall is covered.3. Production ProcessAs shown in FIGS. 6 and 7, the production process for the vacuum seal bag according to the present invention includes the following steps:Production of green body: A mature blow molding method using linear low density polyethylene as a raw material is used. Depending on the design requirements for straight strips, annular forming heads are tailored to produce hollow and continuous green bodies for vacuum sealing bags by continuous blow molding. After flattening the produced green body, its width should be in the range of 200±3 mm.Cutting of the blank: The blank for vacuum sealing bags produced is cut in sections to a length of 300±5 mm, so that plate-shaped blank for vacuum sealing bags having a length of 300±5 mm and a width of 200±3 mm are produced.Sealing of the bag bottom and forming of the bag opening: One end of the green body for the plate-shaped vacuum sealing bag is sealed by hot melting into a robust bag bottom 13, while the other end remains open to form a user-friendly bag opening 12.4. Performance Test DataAccording to the performance tests, the vacuum sealing bag of this embodiment has good heat sealing strength and tear strength, the heat sealing strength being in accordance with the industry standard, and the tear strength satisfying the application requirements, thereby ensuring the reliability and durability of the sealing bag.5. Analysis of Technical EffectsAs shown in Fig. 12 (12a: Prior Art, 12b: Present Embodiment), the vacuum seal bag of the present invention is different from the prior art in that the number of the melt edges is reduced from three to one so that the green body can be manufactured in one film extrusion process at a time. a) Process simplification: In the conventional process, five operations are required: Two-times film extrusion (smooth plastic film layer, plastic film layer having raised and recessed textures) → Dicing → Laminating → Heat sealing, while in the present invention, three operations are required:One-time Film Extrusion → Slicing → Heat Sealing.b) Reduction of waste of material waste:In the conventional process, a material cut of approximately 10% is produced during the cutting process,while in the present invention hardly any material waste is produced.Embodiment II: Closed vacuum closure bags with regional, obliquely running straight strips1. Product ConstructionThe vacuum seal bag in this embodiment is constructed as in Embodiment I except that the material was replaced with polypropylene (PP) and the wall 11 has a thickness of 300 μm. The bag body 10 is integrally formed by blow molding, has dimensions of 300±5 mm in length x 200±3 mm in width, and forms a circumferentially closed, continuous surface structure whose inner surface encloses a space 15 of the vacuum sealing bag.2. Formation of Surface TexturesThe inner surface of the wall 11 is provided with functional raised and recessed textures 14 formed as obliquely extending straight stripes. The oblique straight strips have one of the following two dimensions: a) the height of the elevation of the strip is 0.1 mm, the width of the strip is 0.5 mm and the distance between adjacent strips is 0.5 mm; and b) the height of the elevation of the strip is 0.5 mm, the width of the strip is 3 mm and the distance between adjacent strips is 5 mm.As shown in Figure 8, 20% of the inner surface of the wall is covered with obliquely extending straight strips, while the remainder remains smooth.3. Production ProcessThe production process is substantially identical to Embodiment I, however, at the green body manufacturing stage, a particular annular forming head is tailored to obliquely running straight strips according to design requirements to ensure the precise shaping of the obliquely running straight strips during blow molding. The cutting of the blank, the sealing of the bag bottom and the forming of the bag opening correspond to the embodiment I.4. Performance Test DataAccording to the performance tests, the vacuum sealing bag of this embodiment has good heat sealing strength and tear strength, the heat sealing strength being in accordance with the industry standard, and the tear strength satisfying the application requirements, thereby ensuring the reliability and durability of the sealing bag.5. Analysis of Technical EffectsBy using polypropylene material and the formation of obliquely extending straight strips in this embodiment, it is possible to simplify the process, reduce waste of material and optimize the performance of the closure bag. The heat resistance and chemical stability of the polypropylene material ensure that the closure bag retains its good properties under various environmental conditions, which extends the range of application of the product.Embodiment III: Closed vacuum closure bags with regional, wavy profiles1. Product ConstructionThe vacuum seal bag in this embodiment is constructed as in Embodiment II except for the raised and recessed textures. The bag body 10 is made of polypropylene (PP), is integrally molded by blow molding, and has dimensions of 300±5 mm in length x 200±3 mm in width. The wall 11 has a thickness of 300 μm and forms a continuous surface structure closed in the circumferential direction, the inner surface of which encloses a space 15 of the vacuum closure bag.2. Formation of Surface TexturesThe inner surface of the wall 11 is provided with functional raised and recessed textures 14 which are formed as wavy contours. The parameters for the wavy profiling are as follows: a) The wavy profiling is 0.1 mm high, 0.5 mm wide and arranged parallel, wherein the distance between the centers of adjacent wavy profilings is 0.5 mm; and b) The wavy profiling is 0.5 mm high, 3 mm wide and arranged parallel, wherein the distance between the centers of adjacent wavy profilings is 5 mm.As shown in Figure 9, 90% of the inner surface of the wall is covered with wavy contours, the remaining 10% remaining smooth.3. Production ProcessThe production process is substantially identical to Embodiment II, but in the green body production stage a particular annular die head is tailored to wavy profiles depending on design requirements to ensure precise shaping of wavy profiles during blow molding. The cutting of the blank, the sealing of the bag bottom and the forming of the bag opening correspond to the embodiment II.4. Performance Test DataAccording to the performance tests, the vacuum sealing bag of this embodiment has good heat sealing strength and tear strength, the heat sealing strength being in accordance with the industry standard, and the tear strength satisfying the application requirements, thereby ensuring the reliability and durability of the sealing bag.5. Analysis of Technical EffectsBy using the wave-shaped profiling formation in this embodiment, it is possible to simplify the process, reduce waste of material and further optimize the performance of the closure bag. The wavy profile ensures increased flexibility and compressive strength of the bag body.Embodiment IV: Rolled-up vacuum closure bag1. Product ConstructionAs shown in Figs. 10 and 11, the vacuum seal bag of this embodiment is substantially different from that of the embodiment I in that:The bag bottom is open, so that the length can be flexibly adapted to the actual requirements of the user and there are no fixed size requirements.The bag body 10 is integrally molded from linear low density polyethylene (LLDPE) by blow molding and is formed as a whole in the shape of a roll having a width of 200±3 mm.2. Formation of Surface TexturesThe inner surface of the wall 11 is provided with functional raised and recessed textures 14 formed as straight stripes. The parameters of the strips are as follows:The straight strips have one of the following dimensions: a) the height of the elevation of the strip is 0.1 mm, the width of the strip is 0.5 mm and the distance between adjacent strips is 0.5 mm; and b) the height of the elevation of the strip is 0.5 mm, the width of the strip is 3 mm and the distance between adjacent strips is 5 mm.3. Production ProcessThe production process is different from that of the embodiment I as follows:Production of green body: A mature blow molding method using linear low density polyethylene as a raw material is used. Depending on the design requirements for straight strips, annular forming heads are tailored to produce hollow and continuous green bodies for vacuum sealing bags by continuous blow molding. After flattening the produced green body, its width should be in the range of 200±3 mm.Green body forming: The green body is directly continuously extruded and cooled to form a roll without the need for cutting or fusion. Reeling: The shaped green body is rolled up to the desired length to facilitate storage and transport.4. Performance Test DataAccording to the performance tests, the two-opening vacuum-seal wound bag of this embodiment has good heat-seal strength and tear strength, the heat-seal strength being in accordance with the industry standard, and the tear strength satisfying the application requirements, thereby ensuring the reliability and durability of the seal bag.5. Analysis of Technical EffectsAs shown in FIG. 12 ( 12 a:Prior Art, 12 c:Present Embodiment), the vacuum seal bag of the present invention is different from the prior art in that the number of the melt edges has been reduced from three to zero, so that the green body can be manufactured in one film extrusion process at a time.In this embodiment, the use of a roller construction and an open bag bottom simplifies the process, reduces waste of material and simultaneously improves the production efficiency and applicability of the product. The roller shape facilitates mass production and continuous processing, while the open bag bottom meets the requirements of certain applications with regard to rapid removal and flexible lengths. In this embodiment, as compared with Embodiment I, material utilization and process simplification are maintained while the function and performance of the closure bag are further optimized, thereby expanding the range of application of the product.Embodiment V: Film Blowing Process of Vacuum Seal Bag1. OverviewAs shown in FIG. 13, in this embodiment, a film blowing process of a vacuum seal bag based on the design parameters of embodiment I and ensuring high quality and stable performance of the produced vacuum seal bag by precisely controlling all process steps will be described in detail.2. parameters and steps(a) Raw Material ProcessingAs raw material, linear low density polyethylene (LLDPE) is used, which is excellent in flexibility, strength and workability and meets the performance requirements of vacuum sealing bags.(b) Die head structureAn annular forming head is tailored according to the design requirements for straight strips in Embodiment I. The forming head must be designed to produce raised and recessed textures in the form of continuous, uniform, straight stripes during film blowing. Specific parameters:Height of the protrusion of the strip: 0.1 mmWidth of the strip: 0.5 mmDistance between adjacent strips: 0.5 mm(c) Extrusion and inflationThe raw material is heated by a screw extruder to the appropriate temperature for melting and plasticizing.The molten plastic is extruded from a die head and forms a hollow tubular green body.During the extrusion, the green body is inflated with compressed air, as a result of which it expands, cools and assumes its shape.(d) Cooling and TractionThe green body is passed through a cooling device, generally a wind ring, in order to quickly cool it to room temperature.The cooled green body is drawn by a traction device, wherein the speed of movement of the green body is controlled such that uniform cooling and shaping is ensured.(e) ReelingThe cooled and shaped green body is rolled up to facilitate subsequent cutting and further processing. During the winding, care must be taken that the body of material remains flat and uniformly tensioned and no folds or loosening occur.3. Important Points of Quality ControlRaw material quality: The purity and performance of the linear low density polyethylene must meet the requirements for impurities and inferior raw material not to impair the product quality.Temperature control: The temperature of the extruder and die is accurately controlled to ensure the flowability and processability of the molten resin.Inflation ratio: The inflation ratio must be controlled appropriately so that the green body can fully expand during the inflation process and a uniform wall thickness is achieved.Cooling effect: The air amount and air speed of the cooling device must be uniform in order that the green body can be cooled quickly and uniformly and a reduction in performance due to insufficient cooling is avoided.Traction speed: The traction speed is appropriately adjusted according to the cooling and forming state of the green body to ensure dimensional accuracy and optical quality of the green body.4. Performance Testing and Performance ValidationThe vacuum seal bag produced is subjected to a performance test including heat seal strength, tear strength, airtightness, etc. to ensure that it meets the relevant standards and application requirements.The performance of the closure bags is tested in practice, including vacuuming and heat sealing on a vacuum packaging machine to check the tightness and reliability.With such a film blowing process, vacuum seal bags can be produced according to the design requirements of Embodiment I with good tightness, mechanical strength and airtightness suitable for vacuum packaging of foods, medicines and other articles.Only preferred embodiments of the present invention have been described above. It should be noted that those skilled in the art can make further improvements and modifications without departing from the principle of the present invention, and that these improvements and modifications also fall within the scope of the present invention.

Claims

Vacuum closure bag, characterized in that it comprises a bag body (10), the bag body (10) comprising a wall (11) made of plastic film, a bag opening (12) at the top of the wall (11) and a bag bottom (13) axially opposite the bag opening (12), the wall (11) representing a circumferentially closed, continuous surface structure, the inner surface of which encloses a vacuum space (15), the inner surface of the wall (11) being provided with functional raised and recessed textures (14), the raised and recessed textures (14) extending from the bag opening (12) along the inner surface of the wall (11) continuously as far as the bag bottom (13), thereby forming gas escape paths, and the bag opening (12) being a hot melt sealable bag opening.Vacuum closure bag according to one of the preceding claims, characterized in that the bag base (13) has one of the following structures: a) a closed bag base which is sealed by hot melting; b) an open bag base.Vacuum closure bag according to one of the preceding claims, characterized in that the wall (11) is formed in one piece by blow moulding.Vacuum closure bag according to one of the preceding claims, characterized in that the elevation of the raised and recessed texture (14) is designed in the form of straight strips, obliquely running straight strips or wave-shaped profiles or a combination thereof.Vacuum closure bag according to one of the preceding claims, characterized in that the elevation of the raised and recessed texture (14) has a height of 0.1 to 0.5 mm.Vacuum closure bag according to one of the preceding claims, characterized in that the elevation of the raised and recessed texture (14) is formed in the form of straight strips which extend axially along the bag body.Vacuum closure bag according to one of the preceding claims, characterized in that the respective straight strip has a width of 0.5 to 3 mm and the distance between adjacent textures is 0.5 to 5 mm.Vacuum closure bag according to any of the preceding claims, characterized in that the raised and recessed textures (14) have one of the following distribution manners: a) the entire inner surface of the wall (11); and b) 20% to 90% of the inner surface of the wall (11), wherein the uncovered areas are smooth.Vacuum closure bag according to one of the preceding claims, characterized in that the plastic film has a thickness of 10 to 300 μm.Vacuum closure bag according to one of the preceding claims, characterized in that the plastic film is of single-layer construction and consists of polyethylene or polypropylene.

Images