Preparation method and device of plastic film for packaging

Abstract

The invention relates to the technical field of packaging plastic film production, in particular to a preparation method and device of a packaging plastic film, and the preparation method comprises the steps of film cutting, heating, pulling and extending and demolding and cooling. The preparation device comprises a main stand, a mold base fixed to the top face of the main stand, a plate frame arranged above the main stand through a double-shaft moving set and a long plate arranged below the plate frame through a driving mechanism, the mold base is in a hollow shape with a downward opening, a heating mechanism is arranged in the mold base, the double-shaft moving set is arranged above the main stand, and the long plate is arranged below the plate frame. The four long plates are used for driving the plate frame to move left and right and up and down, the four long plates are evenly distributed on the four sides of the lower portion of the plate frame, and extension lines of the four long plates intersect to form a rectangular shape matched with the die holder. The rectangular film sections are heated, pulled and extended to form the cylindrical film body, and compared with a traditional plastic packaging bag body formed by hot-pressing and bonding bag pieces, the plastic packaging bag is high in tensile strength, good in tear resistance and high in cracking and damage resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of packaging plastic film production, in particular to a method and device for preparing packaging plastic film. Background Art

[0002] Plastic film for packaging is a kind of packaging material with the characteristics of lightness, transparency, flexibility, moisture-proof and strong barrier properties, which is made of high polymer materials such as polyethylene, polypropylene and polyester through processes such as cast film and blow molding. It is widely used in food, medicine, daily necessities, industrial products and other fields. It can not only protect the contents from pollution, moisture and physical damage, but also achieve aesthetic display and functional expansion through printing, compounding and other processes. It occupies an important position in the modern packaging industry due to its advantages such as low cost, excellent performance and easy processing.

[0003] Packaging film bags are a common type of packaging product on the market, made from plastic film, such as popcorn bags. They are made by cutting the plastic film into bag sheets according to specifications, then applying heat and pressure to bond the edges together to form the bag body, leaving one side open for access. However, these bags only fuse the edges briefly through heat and pressure, creating a physical bond limited to the intermolecular forces at the surface layer, resulting in insufficient mechanical strength. This limited bond can easily break when subjected to external forces or repeated opening and closing, leading to cracking and damage, resulting in poor packaging performance. Summary of the Invention

[0004] The object of the present invention is to provide a method and device for preparing a plastic film for packaging, so as to solve the technical problems raised in the above background technology.

[0005] To achieve the above objectives, the present invention provides the following technical solutions.

[0006] A method for preparing a plastic film for packaging, comprising the following steps: Step 1: Cut the processed plastic film into rectangular film segments; Step 2: Transfer the rectangular film segment to the preparation device for heating; Step 3: Using a preparation device to stretch the preheated rectangular film segment into a cylindrical film body; Step 4: demoulding the cylindrical film body and cooling it to form a shape; The thickness of the rectangular film segment in step 1 is 1.5-2 mm, the heating temperature in step 2 is 120-150° C., and the pulling speed in step 3 is 1-1.5 m / min.

[0007] The present invention also provides a device for preparing plastic film for packaging, comprising a main frame, a mold base fixed on the top surface of the main frame, a plate frame arranged above the main frame through a double-axis moving group, and a long plate arranged below the plate frame through a driving mechanism. The mold base is hollow with an opening facing downward, and a heating mechanism is provided in the mold base. The double-axis moving group is arranged above the main frame for driving the plate frame to move left and right and up and down. There are four long plates, which are evenly distributed on the four sides below the plate frame. The extension lines of the four long plates intersect to form a rectangular shape that is adapted to the mold base. Several second suction cups are installed on each long plate. The driving mechanism is arranged below the plate frame for driving the four long plates to converge closer or diffuse farther away. The rectangular film segment is sucked by the second suction cup and, in cooperation with the mold base, the rectangular film segment can be pulled and formed into a cylindrical film body. A fourth electric push cylinder is also vertically provided between the four long plates below the plate frame, and a third suction cup is installed on the telescopic end of the fourth electric push cylinder.

[0008] Preferably, the driving mechanism includes a threaded rod, a nut seat and a driving device. Four brackets are evenly fixed under the plate frame, and a threaded rod is rotatably installed on each bracket. A sliding rod is fixed on each bracket, and a nut seat is threadedly matched on each threaded rod. Each nut seat is slidably mounted on the corresponding sliding rod. A vertical rod extending vertically downward is fixed on the lower end face of each nut seat, and each long plate is installed under the corresponding nut seat. The driving device is arranged under the plate frame and between the four brackets, and is used to drive the four threaded rods to rotate synchronously. A mounting plate is commonly fixed to the bottom ends of the four brackets, and the fourth electric push cylinder is fixed on the lower end face of the mounting plate.

[0009] Preferably, the driving device includes a driving motor, which is fixed on the lower surface of the plate frame. A first bevel gear is fixed on the output shaft of the driving motor, and a second bevel gear is fixed on the end of each threaded rod close to each other, and each second bevel gear is meshed with the first bevel gear.

[0010] Preferably, a first U-shaped seat is fixed to the bottom end of each vertical rod, and an axis rod is rotatably mounted on the first U-shaped seat. Each axis rod extends horizontally and remains parallel to the long board. A hinge seat is fixed on the axis rod, and the long board is fixed on the end of the hinge seat. An adjustment mechanism is provided under the board frame for driving the four axis rods to rotate and adjust synchronously.

[0011] Preferably, the adjusting mechanism includes a driven gear, a rack and a third electric push cylinder, two vertically extending third electric push cylinders are fixed under the plate frame, the telescopic ends of the two third electric push cylinders are commonly fixed with a rectangular frame, guide rods are fixed on the four outer surfaces of the rectangular frame, each guide rod is parallel to the threaded rod on the same side, each guide rod is slidably fitted with a connecting plate extending vertically downward, a rack is fixed on the bottom end of each connecting plate, and a driven gear is fixed on one end of each shaft rod, and the driven gear is meshed with the rack on the same side, and a limiting rod is fixed on the side of each first U-shaped seat, and the limiting rod is correspondingly limited and clamped in the limiting groove on the rack on the same side, when the third electric push cylinder retracts to the limit position, the openings of each second suction cup are facing downward, and when the third electric push cylinder extends to the limit position, the openings of each second suction cup are horizontally inward.

[0012] Preferably, the heating mechanism includes an air duct, an electric heating net and a fan module, the air duct is fixed in the mold base through a connecting arm, an annular gap is present between the outer peripheral wall of the air duct and the inner wall of the mold base, the top end of the air duct does not contact the inner top wall of the mold base, and the bottom end does not contact the upper surface of the main frame, a circulation groove is provided in the main frame, the circulation groove runs through the front and rear sides of the main frame, and a connecting cavity connecting the interior of the mold base and the circulation groove is provided on the upper surface of the main frame, an electric heating net is installed in the air duct, and a fan module is installed in the air duct above the electric heating net, for forming an upward airflow in the air duct; A blowing hole communicating with the inside of the mold base is provided at the top of the mold base corresponding to the position of the wind tube. A slide groove extending horizontally and passing through the blowing hole is provided on the top of the mold base. A sealing plate for sealing the blowing hole is slidably installed in the slide groove. A first electric push cylinder extending horizontally is fixed on the inner wall of one side of the slide groove. The telescopic end of the first electric push cylinder is fixed to the side of the sealing plate, and is used to drive the sealing plate to perform horizontal opening and closing adjustment.

[0013] Preferably, the dual-axis moving group includes a second power guide rail and a second electric push cylinder. Two vertically upward extending upright frames are fixed on both sides above the main frame. The second power guide rail is commonly fixed on the top of the two upright frames on the same side. A suspension is commonly fixed on the moving ends of the two second power guide rails. The second electric push cylinder is vertically fixed on the suspension. The telescopic rod of the second electric push cylinder extends through and extends to the bottom of the suspension and is fixedly connected to the plate frame located below the suspension.

[0014] Preferably, a first conveying mechanism is provided on one side of the main frame, and a second conveying mechanism is provided on the other side. The first conveying mechanism includes a first power guide rail and a first suction cup. A side frame is provided on the side of the main frame. Two first power guide rails are symmetrically arranged on the side frame. A conveying seat is commonly fixed on the movable seats of the two first power guide rails, and a number of first suction cups are evenly distributed on the conveying seat.

[0015] Preferably, a second U-shaped seat is fixed on the telescopic end of the fourth electric push cylinder, a horizontally extending rotating shaft is rotatably installed on the second U-shaped seat, a connecting arm is fixedly mounted on the rotating shaft, the connecting arm and the rotating shaft remain perpendicular, the third suction cup is installed on the end of the connecting arm, a driving motor is fixed on the side of the second U-shaped seat, and the output shaft of the driving motor is fixedly connected to one end of the rotating shaft.

[0016] Compared with the prior art, the present invention has the following beneficial effects.

[0017] This preparation method heats and stretches a rectangular film segment into a cylindrical film body. Compared with traditional plastic packaging bags formed by hot-pressing and bonding bag sheets, it has high tensile strength, good tear resistance, and strong resistance to cracking and breakage.

[0018] This preparation device uses a driving device to drive the threaded rod to rotate synchronously, so that the nut seat drives the long plate to achieve gathering or spreading movement. Combined with the biaxial movement of the biaxial moving group, it can accurately control the tension distribution during the pulling process of the rectangular film segment, avoiding film thickness deviation or local rupture caused by uneven tension, and improving the forming quality of the cylindrical film body. By turning the opening direction of the second suction cup from downward to horizontally inward, the four sides of the rectangular film segment are ensured to be tightly attached to the outer surface of the mold base during the stretching process. This not only ensures uniform heating of the edges, but also prevents the opening of the cylindrical film from forming a trumpet shape, effectively improving the film forming accuracy and appearance quality. After demoulding, the upward airflow blown out by the fan module is used to expand and fill the cylindrical film body, which not only accelerates the cooling and forming of the inner side of the film, but also eliminates the wrinkling and deformation of the cylindrical film body when it is separated from the mold base through internal air pressure support, thereby ensuring the dimensional stability and structural integrity of the film.

[0019] The driving motor drives the rotating shaft to drive the third suction cup to rotate and adjust, which can turn the cylindrical film body from a vertical state to a horizontal state after demolding, so as to avoid the cylindrical film body opening facing downward, which may cause the suction cup of the second conveying mechanism to fail to hold normally, ensure that the posture of the film is controllable during transfer, and prevent damage or conveying failure caused by posture deviation. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic flow chart of the specific steps of the method for preparing the plastic film for packaging; Figure 2 This is a schematic diagram of the overall structure of the plastic film preparation device for packaging; Figure 3 It is a schematic diagram of the local structure of the main platform in the present invention; Figure 4 Schematic diagram of the structure of the dual-axis moving group in the present invention; Figure 5 Schematic diagram of the heating mechanism structure of the present invention; Figure 6 for Figure 5 A schematic diagram of the structure at center A; Figure 7 It is a schematic diagram of the structure below the plate rack in the present invention; Figure 8 This is a schematic diagram of the installation of the second suction cup structure in the present invention; Figure 9 It is a schematic diagram of the local structure below the plate frame in the present invention; Figure 10 Schematic diagram of the driving mechanism structure of the present invention; Figure 11 Schematic diagram of the structure of the first conveying mechanism in the present invention; Figure 12 This is a schematic structural diagram of Example 5 of the present invention; Figure 13 Schematic diagram of the second suction cup holding the rectangular film segment with its opening facing downward; Figure 14 Schematic diagram of the structure for calendering a rectangular film segment using a die base; Figure 15 It is a schematic diagram of cooling the formed cylindrical film body; Figure 16 Schematic diagram of using the third suction cup to adjust the cylindrical film body to a horizontal state.

[0021] In the figure: 01, first conveying mechanism; 011, side frame; 012, first power guide rail; 0121, moving seat; 013, conveying seat; 014, first suction cup; 02, second conveying mechanism; 03, rectangular film segment; 04, cylindrical film body; 1, main frame; 11, vertical frame; 12, mold base; 121, blowing hole; 122, slide; 123, sealing plate; 124, first electric push cylinder; 13, heating mechanism; 131, connecting arm; 132, air duct; 133, electric heating network; 134, fan module; 135, circulation slot; 136, connecting cavity; 2, two-axis moving group; 21, second power guide rail; 211, moving end; 22, suspension; 23, second electric Push cylinder; 3. Plate rack; 4. Driving mechanism; 41. Bracket; 411. Sliding rod; 412. Mounting plate; 42. Threaded rod; 43. Nut seat; 431. Vertical rod; 44. Driving device; 441. Driving motor; 442. First bevel gear; 443. Second bevel gear; 5. Long plate; 6. Second suction cup; 7. First U-shaped seat; 71. Shaft; 72. Articulated seat; 73. Driven gear; 74. Rack; 741. Limiting groove; 742. Limiting rod; 75. Connecting plate; 76. Guide rod; 77. Rectangular frame; 78. Third electric push cylinder; 8. Fourth electric push cylinder; 9. Third suction cup; 91. Second U-shaped seat; 92. Rotating shaft; 93. Interconnecting arm; 94. Driving motor. DETAILED DESCRIPTION

[0022] The embodiments of the present invention are described below with reference to the accompanying drawings.

[0023] In the description of the embodiments of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms, "connection", and "installation" should be understood in a broad sense. For example, "connection" can be a detachable connection or a non-detachable connection; it can be a direct connection or an indirect connection through an intermediate medium. In addition, "communication" can be a direct connection or an indirect connection through an intermediate medium. Here, "fixed" means that the two are connected to each other and the relative position relationship after connection remains unchanged. The directional terms mentioned in the embodiments of the present invention, such as "inside", "outside", "top", "bottom", etc., are only reference to the directions of the accompanying drawings. Therefore, the directional terms used are for better and clearer explanation and understanding of the embodiments of the present invention, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present invention.

[0024] In the embodiments of the present invention, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Therefore, features defined as "first" or "second" may explicitly or implicitly include one or more of the features.

[0025] In the embodiments of the present invention, "and / or" is simply a description of the association relationship between associated objects, indicating that three possible relationships exist. For example, "A and / or B" can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone. Furthermore, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0026] References to "one embodiment" or "some embodiments" in this specification mean that a particular feature, structure, or characteristic described in connection with that embodiment is included in one or more embodiments of the present invention. Thus, phrases such as "in one embodiment," "in some embodiments," "in other embodiments," and "in yet other embodiments" appearing in various places in this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "including," "comprising," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized. Example 1

[0027] See also Figure 1 The present invention provides a method for preparing a plastic film for packaging, which specifically comprises the following steps: Step 1: Cut the processed plastic film into rectangular film segments 03, each of which has a thickness of 2 mm; Step 2: Transfer the rectangular film segment 03 to a preparation device and heat it to 130° C. to soften the rectangular film segment 03 and make it easily ductile and deformable; Step 3: Using a preparation device, the preheated rectangular film segment 03 is stretched into a cylindrical film body 04 at a speed of 1 m / min; Step 4: Demolding the cylindrical film body 04 and cooling it to obtain a cylindrical packaging film.

[0028] Compared with the traditional plastic packaging bag body formed by hot-pressing and bonding bag sheets, the tubular packaging film prepared by the preparation method of the present invention has high tensile strength, good tear resistance and strong crack and breakage resistance. Example 2

[0029] See also Figure 2-Figure 16 The present invention also provides a device for preparing plastic film for packaging, which participates in steps 2 to arrangement 4 in Example 1. The device includes a main frame 1, a mold base 12 fixed to the top surface of the main frame 1, a plate frame 3 arranged above the main frame 1 through a biaxial moving group 2, and a long plate 5 arranged below the plate frame 3 through a driving mechanism 4. The mold base 12 is hollow with an opening facing downward, and a heating mechanism 13 is provided in the mold base 12. The mold base 12 is made of aluminum to facilitate heat transfer. The biaxial moving group 2 is arranged above the main frame 1 and is used to drive the plate frame 3 to move left and right and up and down. There are four long plates 5, which are evenly distributed on the four sides below the plate frame 3. The extension lines of the four long plates 5 intersect to form a rectangular shape that is adapted to the mold base 12. Each long plate 5 is installed with a plurality of second suction cups 6. Specifically, in this application, each long plate 5 is preferably provided with three second suction cups 6. The driving mechanism 4 is provided below the plate frame 3 and is used to drive the four long plates 5 to converge or diverge; By sucking the rectangular film segment 03 with the second suction cup 6 and cooperating with the mold base 12, the rectangular film segment 03 can be pulled and formed into a cylindrical film body 04. A fourth electric push cylinder 8 is vertically provided between the four long plates 5 below the plate frame 3, and a third suction cup 9 is installed on the telescopic end of the fourth electric push cylinder 8.

[0030] The specific principle of using this device to prepare plastic film for packaging is as follows: The heating mechanism 13 generates heat, which is transferred to the mold base 12 to heat the mold base 12. The dual-axis moving group 2 drives the plate frame 3 to move to the loading area on one side above the main frame 1. The driving mechanism 4 drives the long plates 5 away from each other until the second suction cups 6 on each long plate 5 correspond to the four side edges of the adjacent rectangular film segment 03. The plate frame 3 is driven downward by the biaxial moving group 2 until each second suction cup 6 is in contact with the upper surface of the rectangular film segment 03. Figure 13 As shown, the rectangular film segment 03 is held by the second suction cup 6, and the plate frame 3 is moved upward and reset by the operation of the biaxial moving group 2, and then moved parallel to the top of the mold base 12; The biaxial moving group 2 drives the plate frame 3 downward until the rectangular film segment 03 is attached to the top surface of the mold base 12. Then, the biaxial moving group 2 drives the plate frame 3 to continue to move downward, so that the rectangular film segment 03 is bent downward on the four sides of the top of the mold base 12. At the same time, the driving mechanism 4 drives the four long plates 5 to move closer to each other to adapt to the horizontal position change of the rectangular film segment 03 due to the bending. The heated die base 12 heats the rectangular film segment 03, softening it and enabling it to stretch and deform. Subsequently, the biaxial moving group 2 drives the plate frame 3 to continue moving downward, causing the rectangular film segment 03 to stretch and deform under the extrusion of the die base 12. Finally, the rectangular film segment 03 is rolled and deformed into a cylindrical film body 04 that is sleeved on the die base 12. Next, the plate frame 3 is driven upward by the biaxial moving group 2, and under the suction force of the second suction cup 6, the cylindrical film body 04 is driven to separate from the mold base 12 to achieve demoulding; The fourth electric push cylinder 8 moves downward to push the third suction cup 9 downward to fit the cylindrical film body 04 and hold the cylindrical film body 04. At the same time, the second suction cup 6 releases the cylindrical film body 04 so that the cylindrical film body 04 can be transferred later.

[0031] like Figure 3 and Figure 4 As shown, the biaxial moving group 2 includes a second power guide rail 21 and a second electric push cylinder 23. Two vertically upward extending vertical frames 11 are fixed on both sides above the main frame 1. The second power guide rail 21 is commonly fixed on the top of the two vertical frames 11 on the same side. A suspension 22 is commonly fixed on the moving ends 211 of the two second power guide rails 21. The second electric push cylinder 23 is vertically fixed on the suspension 22. The telescopic rod of the second electric push cylinder 23 extends through and extends to the bottom of the suspension 22 and is fixedly connected to the plate frame 3 located below the suspension 22. The second power guide rail 21 drives the movable end 211 to move along its length direction, which can then drive the suspension 22, the second electric push cylinder 23 and the plate frame 3 to perform left and right translation adjustment as a whole, so as to realize the position adjustment of the plate frame 3 in the horizontal direction. The second electric push cylinder 23 can be extended and retracted to drive the plate frame 3 and the components below the plate frame 3 to rise and fall, so as to realize the upward and downward adjustment of the plate frame 3 and the components below the plate frame 3.

[0032] See also Figure 7 and Figure 9As shown, the driving mechanism 4 includes a threaded rod 42, a nut seat 43 and a driving device 44. Four brackets 41 are evenly fixed under the plate frame 3. A threaded rod 42 is rotatably installed on each bracket 41. A sliding rod 411 is fixed on each bracket 41. A nut seat 43 is threadedly matched on each threaded rod 42. Each nut seat 43 is slidably mounted on the corresponding sliding rod 411. A vertical rod 431 extending vertically downward is fixed on the lower end face of each nut seat 43. Each long plate 5 is respectively installed under the corresponding nut seat 43. The driving device 44 is arranged under the plate frame 3 and between the four brackets 41, and is used to drive the four threaded rods 42 to rotate synchronously. The bottom ends of the four brackets 41 are commonly fixed with a mounting plate 412, and the fourth electric push cylinder 8 is fixed on the lower end face of the mounting plate 412.

[0033] Among them, such as Figure 10 As shown, the driving device 44 includes a driving motor 441, which is fixed on the lower surface of the plate frame 3. A first bevel gear 442 is fixed on the output shaft of the driving motor 441, and a second bevel gear 443 is fixed on the end of each threaded rod 42 close to each other, and each second bevel gear 443 is meshed with the first bevel gear 442.

[0034] The specific working principle of the driving mechanism 4 is as follows: By driving the motor 441 to rotate forward, its output shaft drives the first bevel gear 442 to rotate forward, and the rotating first bevel gear 442 engages to drive the four second bevel gears 443 to rotate synchronously, thereby driving the corresponding threaded rod 42 to rotate. The rotating threaded rod 42 can threadably drive the nut seat 43 to move along the slide rod 411 to the side away from the slide rod 411, thereby driving the four long plates 5 to spread away. Conversely, by the reverse rotation of the first bevel gear 442, the four long plates 5 can be driven to converge, providing stable drive for the spacing adjustment of the second suction cups 6 at the four positions. Example 3

[0035] See also Figure 8 and Figure 9 The difference between this embodiment and embodiment 2 is that: A first U-shaped seat 7 is fixed to the bottom end of each vertical rod 431, and a shaft rod 71 is rotatably mounted on the first U-shaped seat 7. Each shaft rod 71 extends horizontally and remains parallel to the long board 5. A hinge seat 72 is fixedly mounted on the shaft rod 71, and the long board 5 is fixed to the end of the hinge seat 72. This design enables the long board 5 to have the ability to be rotatably adjusted. An adjustment mechanism is provided under the plate frame 3 for driving the four shaft rods 71 ​​to rotate and adjust synchronously.

[0036] See also Figure 8 and Figure 9The adjusting mechanism includes a driven gear 73, a rack 74 and a third electric push cylinder 78. Two vertically extending third electric push cylinders 78 are fixed under the plate frame 3. The telescopic ends of the two third electric push cylinders 78 are commonly fixed with a rectangular frame 77. Guide rods 76 are fixed on the four outer surfaces of the rectangular frame 77. Each guide rod 76 is kept parallel to the threaded rod 42 on the same side. A connecting plate 75 extending vertically downward is slidably sleeved on each guide rod 76. A rack 74 is fixed to the bottom end of each connecting plate 75, and a driven gear 73 is fixedly mounted on one end of each shaft 71. The driven gear 73 meshes with the rack 74 on the same side. A limiting rod 742 is fixed to the side of each first U-shaped seat 7. The limiting rod 742 is correspondingly fixed in the limiting groove 741 on the rack 74 on the same side. The cooperation between the limiting groove 741 and the limiting rod 742 ensures that the rack 74 can be adjusted synchronously with the nut seat 43 and that the rack 74 has the ability to be adjusted in the vertical direction. Among them, the connecting plate 75 is slidably mounted on the guide rod 76, so that the rack 74 has the ability to slide and adjust in the length direction of the threaded rod 42, so that the rack 74 can move synchronously with the corresponding nut seat 43 in the horizontal direction.

[0037] Specifically, through the extension and retraction of the third electric push cylinder 78, under the connection of the rectangular frame 77, the guide rod 76 and the connecting plate 75, the rack 74 can be driven to rise and fall synchronously, and the rack 74 engages to drive the driven gear 73 and drives the shaft 71, the hinge seat 72 and the long plate 5 to rotate, so as to adjust the opening direction of the second suction cup 6. Among them, when the third electric push cylinder 78 retracts to the extreme position, the openings of each second suction cup 6 are facing downward, which is used to horizontally hold the rectangular film segment 03. When the third electric push cylinder 78 extends to the extreme position, the openings of each second suction cup 6 are horizontally inward, ensuring that the rectangular film segment 03 can fit the mold base 12 when pulling.

[0038] When the rectangular film segment 03 is pulled downward and extended, Figure 14 As shown, by adjusting the second suction cup 6 to open horizontally inward, the four sides of the rectangular film segment 03 can be tightly attached to the outer surface of the mold base 12 when being formed into the cylindrical film body 04. On the one hand, it ensures that the four side edges of the rectangular film segment 03 can be tightly attached to the mold base 12 for effective heating, ensuring that the drawing deformation of the plate frame 3 is uniform and thorough. On the other hand, it can prevent the opening of the cylindrical film body 04 from being trumpet-shaped, thereby effectively ensuring the molding quality of the cylindrical film body 04. Example 4

[0039] See also Figure 5 and Figure 6 The difference between this embodiment and embodiment 3 is that: Specifically, the heating mechanism 13 includes an air duct 132, an electric heating net 133, and a fan module 134. The air duct 132 is fixed in the mold base 12 via a connecting arm 131. An annular gap exists between the outer peripheral wall of the air duct 132 and the inner wall of the mold base 12. The top end of the air duct 132 does not contact the inner top wall of the mold base 12, and the bottom end does not contact the upper surface of the main frame 1, so that the hot air flow can fill the mold base 12, thereby improving the heating effect on the mold base 12. A flow groove 135 is provided in the main frame 1, and the flow groove 135 runs through the front and rear sides of the main frame 1. A connecting cavity 136 is provided on the upper surface of the main frame 1, which connects the interior of the mold base 12 and the flow groove 135. The flow groove 135 and the connecting cavity 136 form an air inlet and outlet channel; An electric heating net 133 is installed in the air duct 132 . There are at least three electric heating nets 133 arranged in multiple layers. A fan module 134 is installed above the electric heating nets 133 in the air duct 132 to form an upward airflow in the air duct 132 .

[0040] The fan module 134 works to draw external air into the air duct 132 through the circulation groove 135 and the connecting cavity 136, and blow it out from the top of the air duct 132 to the inner top wall of the mold base 12. The inner top wall of the mold base 12 blocks the airflow and diverts it to the mold base 12 at the outer periphery of the air duct 132, and finally discharges it through the connecting cavity 136 and the circulation groove 135 to form a flowing airflow. In this process, the electric heating net 133 is energized to generate heat, which can heat the airflow. The heated airflow can fill the interior of the mold base 12, heat the mold base 12, and then enable the mold base 12 to heat the rectangular film segment 03. The heating coverage area is large and the heating effect is good.

[0041] In addition, the air intake and outlet share the same channel, and heat exchange is formed when the hot air flow meets the incoming cold air flow, which can preheat the incoming cold air, not only increasing the heating rate, but also improving the heat utilization rate.

[0042] like Figure 6 As shown, a blowing hole 121 communicating with the inside of the mold base 12 is provided at the position of the top of the mold base 12 corresponding to the position of the air cylinder 132, and a slide groove 122 extending horizontally and passing through the blowing hole 121 is provided on the top of the mold base 12. A sealing plate 123 for blocking the blowing hole 121 is slidably installed in the slide groove 122, and a first electric push cylinder 124 extending horizontally is fixed on the inner wall of one side of the slide groove 122. The telescopic end of the first electric push cylinder 124 is fixed to the side of the sealing plate 123. The first electric push cylinder 124 is telescopically operated to drive the sealing plate 123 to be horizontally opened and closed. Specifically, when the first electric push cylinder 124 retracts, it can drive the sealing plate 123 to move to the position corresponding to the blowing hole 121, and the blowing hole 121 can be blocked. When the first electric push cylinder 124 extends, it pushes the sealing plate 123 to move to one side in the slide groove 122, so that the sealing plate 123 and the blowing hole 121 are misaligned, and the blocking of the blowing hole 121 can be cancelled.

[0043] After the cylindrical film body 04 is pulled upward and separated from the mold base 12 for demoulding, the cylindrical film body 04 is in a wrinkled shape due to the friction between the inner side of the cylindrical film body 04 and the outer surface of the mold base 12. In order not to affect the molding quality of the cylindrical film body 04, after the cylindrical film body 04 is demoulded to the top of the mold base 12, the first electric push cylinder 124 is extended to push the sealing plate 123 to one side to cancel the blockage of the blowing hole 121. At the same time, the electric heating net 133 does not stop heating, and the outside air is sucked into the wind tube 132 through the fan module 134 and blown out vertically upward, as shown in FIG. Figure 15 As shown, the airflow is finally blown upward through the blowing hole 121, and the opening of the cylindrical film body 04 is located at the bottom. The upward airflow enters the cylindrical film body 04, causing the cylindrical film body 04 to expand and fill. In addition, the airflow can cool the cylindrical film body 04 from the inside, accelerating the cooling and molding of the cylindrical film body 04 while ensuring high molding quality of the cylindrical film body 04. In addition, when the fourth electric push cylinder 8 pushes the third suction cup 9 downward to hold the cylindrical film body 04, the airflow expands and stretches the cylindrical film body 04, so that the cylindrical film body 04 and the third suction cup 9 can fit tightly and be sucked normally, avoiding the cylindrical film body 04 from being deformed too much and unable to fit tightly on the third suction cup 9.

[0044] The ports on both sides of the flow channel 135 and the blowing hole 121 may be equipped with filter screens to prevent external dust from entering the interior of the mold base 12 and causing pollution. Example 5

[0045] See also Figure 2 、 Figure 11 and Figure 12 The difference between this embodiment and embodiment 4 is that: A first conveying mechanism 01 is provided on one side of the main frame 1, and a second conveying mechanism 02 is provided on the other side, wherein the first conveying mechanism 01 includes a first power guide rail 012 and a first suction cup 014, and a side frame 011 is provided on the side of the main frame 1. Two first power guide rails 012 are symmetrically arranged on the side frame 011, and a conveying seat 013 is fixed on the moving seat 0121 of the two first power guide rails 012, and a number of first suction cups 014 are evenly distributed on the conveying seat 013.

[0046] The rectangular film segment 03 is placed on the conveying seat 013, and the rectangular film segment 03 is sucked by the first suction cup 014. Then, the first power guide rail 012 is operated to drive the movable seat 0121 to move toward the side of the main frame 1, which can drive the conveying seat 013 and the rectangular film segment 03 to move closer to the side of the main frame 1, thereby realizing the loading of the rectangular film segment 03. The specific structure of the second conveying mechanism 02 is consistent with that of the first conveying mechanism 01, so as to convey the formed cylindrical film body 04 downstream.

[0047] Among them, the first suction cups 014 are all arranged on the conveying seat 013, which can perform multi-point suction on the rectangular film segment 03, and can stretch the rectangular film segment 03 to ensure that the second suction cups 6 can fit tightly with the rectangular film segment 03 to generate suction.

[0048] In addition, both ends of the second power guide rail 21 extend to both sides of the main platform 1 so that the adjustment space of the plate rack 3 can cover the first conveying mechanism 01 and the second conveying mechanism 02.

[0049] like Figure 12 As shown, a second U-shaped seat 91 is fixed on the telescopic end of the fourth electric push cylinder 8, and a horizontally extending rotating shaft 92 is rotatably installed on the second U-shaped seat 91. A connecting arm 93 is fixedly sleeved on the rotating shaft 92, and the connecting arm 93 remains perpendicular to the rotating shaft 92. The third suction cup 9 is installed on the end of the connecting arm 93, and a driving motor 94 is fixed on the side of the second U-shaped seat 91. The output shaft of the driving motor 94 is fixedly connected to one end of the rotating shaft 92. When the driving motor 94 works, its output shaft can drive the rotating shaft 92, the connecting arm 93 and the third suction cup 9 to rotate and adjust as a whole, so as to adjust the opening direction of the third suction cup 9. After demoulding and cooling, the third suction cup 9 opens downward to suck the cylindrical film body 04. When the cylindrical film body 04 is transferred to the top of the second conveying mechanism 02, as shown in FIG. Figure 16 As shown, the driving motor 94 drives the third suction cup 9 to rotate ninety degrees, so that the cylindrical film body 04 is placed horizontally, preventing the cylindrical film body 04 from opening downward and being unable to be normally sucked by the suction cup on the second conveying mechanism 02.

[0050] The control method of the present invention is automatic control through a controller. The control circuit of the controller can be implemented by simple programming by technicians in this field. The provision of power is also common knowledge in this field. The present invention will not explain the control method and circuit connection in detail.

[0051] In addition, it is worth noting that all types of suction cups in this application are connected to the air distribution system, and the air distribution system controls the suction and discharge of air for suction and release, which is consistent with the existing technology and will not be described in detail.

[0052] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention.

Claims

1. A method for preparing a plastic film for packaging, characterized in that: The specific steps include: Step 1: Cut the processed plastic film into rectangular film segments (03); Step 2: transferring the rectangular film segment (03) to a preparation device for heating; Step 3: Using a preparation device to stretch the preheated rectangular film segment (03) into a cylindrical film body (04); Step 4: demoulding the cylindrical film body (04) and cooling it to form; The thickness of the rectangular film segment (03) in step 1 is 1.5-2 mm, the heating temperature in step 2 is 110-150° C., and the pulling speed in step 3 is 1-1.5 m / min.

2. A device for preparing a plastic film for packaging, applied to the method for preparing a plastic film for packaging according to claim 1, characterized in that: It comprises a main frame (1), a die base (12) fixed on the top surface of the main frame (1), a plate frame (3) arranged above the main frame (1) via a biaxial moving group (2), and a long plate (5) arranged below the plate frame (3) via a driving mechanism (4); The mold base (12) is hollow with an opening facing downward, and a heating mechanism (13) is provided inside the mold base (12); The biaxial moving group (2) is arranged above the main frame (1) and is used to drive the plate frame (3) to move left and right and up and down; There are four long plates (5) evenly distributed on the four sides below the plate frame (3); the extension lines of the four long plates (5) intersect to form a rectangular shape that is compatible with the mold base (12); and a plurality of second suction cups (6) are installed on each of the long plates (5); The driving mechanism (4) is arranged below the plate frame (3) and is used to drive the four long plates (5) to move closer together or farther apart in a diffused manner; The rectangular film segment (03) is sucked and held by the second suction cup (6), and in cooperation with the mold base (12), the rectangular film segment (03) can be pulled and formed into a cylindrical film body (04); A fourth electric push cylinder (8) is vertically provided between the four long plates (5) below the plate rack (3), and a third suction cup (9) is installed on the telescopic end of the fourth electric push cylinder (8).

3. The device for preparing a plastic film for packaging according to claim 2, characterized in that: The driving mechanism (4) comprises a threaded rod (42), a nut seat (43) and a driving device (44); Four brackets (41) are evenly distributed and fixed below the plate frame (3); a threaded rod (42) is rotatably installed through each bracket (41); and a sliding rod (411) is fixed to each bracket (41); Each threaded rod (42) is provided with a nut seat (43) with matching threads, and each nut seat (43) is slidably mounted on the corresponding sliding rod (411); A vertical rod (431) extending vertically downward is fixed to the lower end surface of each nut seat (43), and each long plate (5) is respectively installed below the corresponding nut seat (43); The driving device (44) is arranged below the plate frame (3) and between the four brackets (41), and is used to drive the four threaded rods (42) to rotate synchronously; A mounting plate (412) is commonly fixed to the bottom ends of the four brackets (41), and the fourth electric push cylinder (8) is fixed on the lower end surface of the mounting plate (412).

4. The device for preparing a plastic film for packaging according to claim 3, characterized in that: The driving device (44) includes a driving motor (441); The driving motor (441) is fixed on the lower surface of the plate frame (3), and a first bevel gear (442) is fixed on the output shaft of the driving motor (441); A second bevel gear (443) is fixed to one end of each threaded rod (42) that is close to each other, and each second bevel gear (443) is correspondingly engaged with the first bevel gear (442).

5. The device for preparing a plastic film for packaging according to claim 4, characterized in that: A first U-shaped seat (7) is fixed to the bottom end of each vertical rod (431), and a shaft (71) is rotatably mounted on the first U-shaped seat (7). Each shaft (71) extends horizontally and remains parallel to the corresponding long board (5); The shaft rods (71) are all fixedly sleeved with hinged seats (72), and the long plates (5) are correspondingly fixed on the ends of the hinged seats (72); An adjustment mechanism is provided below the plate frame (3) for driving the four shafts (71) to rotate and adjust synchronously.

6. The device for preparing a plastic film for packaging according to claim 5, characterized in that: The adjustment mechanism includes a driven gear (73), a rack (74) and a third electric push cylinder (78); Two vertically extending third electric push cylinders (78) are fixed below the plate frame (3), and a rectangular frame (77) is fixed to the telescopic ends of the two third electric push cylinders (78). Guide rods (76) are fixed to the four outer surfaces of the rectangular frame (77), and each guide rod (76) remains parallel to the threaded rod (42) on the same side; A connecting plate (75) extending vertically downward is slidably mounted on each guide rod (76), and a rack (74) is fixed to the bottom end of each connecting plate (75); The driven gear (73) is fixedly mounted on one end of each shaft (71), and the driven gear (73) is meshed with the rack (74) on the same side. A limiting rod (742) is fixed to the side of each first U-shaped seat (7), and the limiting rod (742) is correspondingly fixed in the limiting groove (741) on the rack (74) on the same side; When the third electric push cylinder (78) retracts to the extreme position, the openings of each of the second suction cups (6) face downward; When the third electric push cylinder (78) is extended to the extreme position, the openings of each of the second suction cups (6) are all horizontally inward.

7. The device for preparing a plastic film for packaging according to claim 2, characterized in that: The heating mechanism (13) includes a wind tube (132), an electric heating network (133) and a fan module (134); The wind tube (132) is fixed in the mold base (12) through the connecting arm (131), and an annular gap exists between the outer peripheral wall of the wind tube (132) and the inner wall of the mold base (12), and the top end of the wind tube (132) does not contact the inner top wall of the mold base (12), and the bottom end does not contact the upper surface of the main frame (1); A circulation groove (135) is provided in the main frame (1), and the circulation groove (135) passes through the front and rear sides of the main frame (1); The upper surface of the main frame (1) is provided with a communication cavity (136) communicating with the interior of the mold base (12) and the circulation groove (135); The electric heating net (133) is installed in the air duct (132); A fan module (134) is installed in the air duct (132) above the electric heating network (133) and is used to form an upward airflow in the air duct (132).

8. The device for preparing a plastic film for packaging according to claim 7, characterized in that: A blowing hole (121) communicating with the interior of the mold base (12) is provided at a position corresponding to the position of the air cylinder (132) on the top of the mold base (12); A sliding groove (122) extending horizontally and communicating with the blowing hole (121) is provided on the top of the mold base (12); a sealing plate (123) for sealing the blowing hole (121) is slidably installed in the sliding groove (122); A first electric push cylinder (124) extending horizontally is fixed on an inner wall of one side of the slide groove (122); a telescopic end of the first electric push cylinder (124) is fixed to a side of the sealing plate (123) for driving the sealing plate (123) to perform horizontal opening and closing adjustment; The main frame (1) is provided with a first conveying mechanism (01) on one side and a second conveying mechanism (02) on the other side; The first conveying mechanism (01) comprises a first power guide rail (012) and a first suction cup (014); A side frame (011) is provided on the side of the main frame (1), and two first power guide rails (012) are symmetrically provided on the side frame (011). A conveying seat (013) is fixed on the movable seats (0121) of the two first power guide rails (012), and a plurality of first suction cups (014) are evenly distributed on the conveying seat (013).

9. The device for preparing a plastic film for packaging according to claim 2, characterized in that: The dual-axis moving group (2) includes a second power guide rail (21) and a second electric push cylinder (23); Two vertically upwardly extending upright frames (11) are fixed on both sides above the main frame (1), and a second power guide rail (21) is commonly fixed on the tops of the two upright frames (11) on the same side; A suspension (22) is commonly fixed on the movable ends (211) of the two second power guide rails (21), and the second electric push cylinder (23) is vertically fixed on the suspension (22); The telescopic rod of the second electric push cylinder (23) extends through and to the bottom of the suspension (22), and is fixedly connected to the plate frame (3) located below the suspension (22).

10. The device for preparing a plastic film for packaging according to claim 2, characterized in that: A second U-shaped seat (91) is fixed to the telescopic end of the fourth electric push cylinder (8), and a horizontally extending rotating shaft (92) is rotatably mounted on the second U-shaped seat (91); A connecting arm (93) is fixedly mounted on the rotating shaft (92), and the connecting arm (93) is kept perpendicular to the rotating shaft (92); The third suction cup (9) is mounted on the end of the connecting arm (93); A driving motor (94) is fixed to the side of the second U-shaped seat (91), and an output shaft of the driving motor (94) is fixedly connected to one end of the rotating shaft (92).

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