One-piece molded handle bottle based on one-step injection stretch blow molding process

Abstract

This invention relates to the field of plastic molding technology, specifically to a one-piece molded bottle with a handle based on a one-step injection stretch blow molding process. This process first dries the raw material by removing moisture using a dehumidifying dryer to prevent molecular weight reduction due to hydrolysis during processing. The injection mold cavity consists of a bottle body pre-forming cavity and a handle pre-forming cavity. The preform formed by the injection molding unit is a thick-walled tubular structure with a handle. This one-step injection stretch blow molding process enables the one-piece molding of a bottle with a handle. Compared to processes where the handle and bottle body are manufactured separately, this simplifies assembly, saves energy and costs, and provides better recyclability, eliminating the need for disassembly and sorting for recycling.

Description

Technical Field

[0001] This invention relates to the field of plastic molding technology, specifically to an integrally molded handle bottle based on a one-step injection stretch blow molding process. Background Technology

[0002] Bottles with handles are bottles with handles. The mainstream production model for bottles with handles in the industry still follows the traditional segmented processing technology. From a production process perspective, the manufacturing of bottles with handles generally follows a technical path of separate production followed by post-assembly. Specifically, the bottle body is mainly made using traditional blow molding. This process involves placing a heated and softened plastic preform into a mold, and using compressed air pressure to force the preform to adhere tightly to the inner wall of the mold, thus obtaining a bottle structure with a specific shape and volume. The handle, as an independent component, is usually produced using injection molding. This involves injecting molten plastic raw material into a special mold cavity for the handle using an injection molding machine, and then cooling and solidifying it to obtain the molded handle.

[0003] This separate production process, which involves blow molding the bottle body and injection molding the handle, necessitates a dedicated assembly line to complete the assembly process. This not only results in complex procedures and poor handle stability, but also requires disassembly for recycling if the handle and bottle body are made of different materials, increasing recycling costs. Summary of the Invention

[0004] The purpose of this invention is to provide an integrally molded handle bottle based on a one-step injection stretch blow molding process, so as to solve the problems of the above-mentioned process of separately manufacturing the bottle body and handle, which is complex and has poor handle stability.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a one-step injection stretch blow molding process, which includes the following steps:

[0006] Step 1: Raw material drying treatment. The moisture in the raw materials is removed by a dehumidifying dryer to prevent the molecular weight from decreasing due to hydrolysis during processing, and to control the final moisture content to ≤0.005%.

[0007] Step 2: Injection molding of the preform. The cavity of the injection mold consists of a preform cavity for the bottle body and a preform cavity for the handle. The preform formed by the injection molding unit is a thick-walled tubular structure with a handle. The shape of the handle must match the final product and allow for stretching.

[0008] Step 3: Preform temperature control. The preform temperature control station is equipped with an anti-oxidation heater to control the temperature of different areas of the preform and heat it to the high elasticity range to ensure uniform stress distribution during stretching. During the heating process, inert gas is used to protect the preform and prevent excessive oxidation of the preform surface.

[0009] Step 4: Stretch blow molding, in which the preform is expanded to the shape of the blow molding cavity by the stretch blow molding unit, and finally the handle bottle is formed;

[0010] Step 5: Cooling, shaping, and demolding. Cold water at 5-15℃ is introduced through the cooling water channel built into the blow molding mold to remove the heat from the product. The cooling time partially overlaps with the blow molding time, with a total cooling time of 3-5 seconds. When the surface temperature of the product drops to 50-60℃, the blow molding mold is opened for demolding, completing the preparation.

[0011] In step one, the drying temperature is controlled at 150-180 degrees Celsius, and the drying time is 4-6 hours.

[0012] In step two, the inner wall of the injection mold needs to be polished to Ra≤0.02μm to ensure a smooth surface of the parison. The injection pressure is 80-120MPa, adjusted within the above range according to the parison size to ensure that the melt fills the dead corners of the cavity. The holding pressure is 40-60MPa, and the holding time is 2-5 seconds to compensate for the cooling shrinkage of the melt and avoid shrinkage marks or voids in the parison. The cooling time is 5-10 seconds, cooled by the mold water channel, so that the surface of the parison is solidified but the interior still retains a certain degree of plasticity, which is convenient for subsequent stretching operations.

[0013] In step three, the temperature of the main body of the bottle is controlled at 90-100 degrees Celsius, and the temperature difference between different parts is ≤5 degrees Celsius; the temperature of the handle is 85-95 degrees Celsius. The handle does not participate in the main stretching, and the temperature of the handle is lower than that of the bottle body to maintain structural stability.

[0014] In step four, the cavity of the blow molding mold is completely consistent with the final bottle shape, including handle details. The inner wall is equipped with cooling water channels, and the mold temperature is controlled at 15-30 degrees Celsius to ensure rapid product shaping.

[0015] Stretch blow molding includes axial stretching and radial blow molding. First, axial stretching is performed, with the stretching rod extending rapidly to stretch the preform axially to the target length at a speed of 500-800 mm / s and a stretching pressure of 0.3-0.5 MPa, ensuring the stretching rod remains stable. After the stretching rod is in place, radial blow molding is performed by introducing high-pressure air into the preform. The blow molding pressure is controlled in stages: a pre-blow pressure of 0.2-0.4 MPa initially expands the preform, allowing it to conform to the bottom of the mold and the handle cavity, preventing wrinkles; the main blow pressure is 0.8-1.5 MPa, adjusted according to the bottle wall thickness requirements, ensuring the preform completely conforms to the inner wall of the mold. The blow molding time is 2-4 seconds to ensure the product is fully shaped.

[0016] The antioxidant heater includes a bottle body heating cover and a handle heating cover that are fixed to each other. When the preform enters the antioxidant heater, the bottle body heating cover and the handle heating cover respectively adjust the temperature of the bottle body and handle of the preform in separate zones.

[0017] An inert gas input pipe is connected to the bottom of the bottle body heating cover and the handle heating cover. A sequential action assembly is provided on the outside of the bottle body heating cover. An internal insertion tube is provided in the sequential action assembly. When the preform enters the anti-oxidation heater, the sequential action assembly can control the internal insertion tube to be inserted into the preform. Inert gas is introduced through the inert gas input pipe and the internal insertion tube to provide anti-oxidation protection for the inner and outer surfaces of the preform.

[0018] A fixed wall shell is fixedly installed on the surface of the bottle heating cover. A pneumatically controlled support block is detachably installed on the fixed wall shell. The sequential action assembly includes a first cylinder, a swing arm, and a second cylinder. The first cylinder is fixedly installed on the pneumatically controlled support block. When the first cylinder is filled with positive pressure gas, the swing arm swings first, and then the second cylinder drives the internal insertion tube to extend, so that the internal insertion tube is inserted into the preform. When the first cylinder is under negative pressure, the second cylinder first controls the internal insertion tube to retract, and then the swing arm swings back to reset.

[0019] The second cylinder is provided with a first piston and a second piston. The first piston and the second piston are both fixedly installed at the end of the internal insertion tube. There is a gap between the first piston and the second piston. An insertion tube through hole is opened between the gap between the first piston and the second piston. The gap between the first piston and the second piston communicates with the inner cavity of the internal insertion tube through the insertion tube through hole.

[0020] The side wall of the second cylinder is connected to an inert gas alignment pipe. When the internal insertion pipe is extended into place, the inert gas alignment pipe is aligned and connected with the gap between the first piston and the second piston. Inert gas is input through the inert gas alignment pipe, causing the internal insertion pipe to spray out inert gas.

[0021] A joint gear is fixedly mounted on the swing arm component, a bracket is fixedly mounted at the end of the first cylinder body, a support side plate is fixedly mounted on the bracket, a central shaft tube is fixedly mounted on the support side plate, and the central shaft tube passes through the joint gear, so that the joint gear can rotate around the central shaft tube.

[0022] The bracket platform is symmetrically fixed with limit plates on both sides, which can limit and block the swing arm when it swings. The joint gear is externally meshed with a toothed condition. A rack positioning groove is opened through the bracket platform. The toothed condition is inserted through the rack positioning groove. A switch piston is set inside the first cylinder. The switch piston is fixedly installed with the rack positioning groove. When the switch piston moves axially inside the first cylinder, it can drive the toothed condition to move along its length direction, thereby driving the joint gear to rotate, so that the swing arm swings.

[0023] A permanent magnet is embedded in the swing arm component. When the inside of the first cylinder is filled with positive pressure gas to drive the swing arm component to swing into place, the permanent magnet will magnetically engage with the limiting plate.

[0024] The outer surface of the second cylinder is fixedly provided with an outer wall ridge, and an outer wall cavity is formed in the outer wall ridge. One end of the outer wall cavity is connected to the end of the second cylinder, and the other end of the outer wall cavity is connected to a rocker arm inner cavity. The rocker arm inner cavity is formed inside the rocker arm component and the joint gear.

[0025] The joint gear is also provided with an annular cavity, the inner cavity of the swing arm is connected to the annular cavity, and the surface of the central shaft tube is provided with a shaft tube air groove, and the annular cavity is connected to the inner cavity of the central shaft tube through the shaft tube air groove;

[0026] The bracket platform and the supporting side plate are provided with bracket cavities. One end of the bracket cavity is connected to the central shaft tube, and the other end is connected to the first cylinder. The gas in the first cylinder will not enter the bracket cavity due to the blocking of the switching piston. The gas in the first cylinder will only enter the bracket cavity when the switching piston rises to the limit position and passes through the connection between the bracket cavity and the first cylinder.

[0027] The bottle with one-piece handle is made using a one-step injection stretch blow molding process. It includes a bottle body and a handle, which are made of the same material in one piece.

[0028] Compared with the prior art, the beneficial effects of the present invention are:

[0029] 1. The one-step injection stretch blow molding process of this invention can produce bottles with handles in one piece. Compared with the process of making the handle and bottle body separately, it can simplify the assembly process, save energy and cost, and has better recyclability, eliminating the need for disassembly and sorting for recycling.

[0030] 2. In the one-step injection stretch blow molding process of the present invention, an anti-oxidation heater is used to protect the parison from excessive surface oxidation by using an inert gas during the heating of the parison. Furthermore, the air inside the parison can be actively discharged through the internal tube, so that the inner wall surface of the parison is also fully protected against oxidation, thereby improving production quality.

[0031] 3. The antioxidant heater of the present invention, through the set sequential action components, can realize the sequential control of the internal tube flipping, extending, and first retracting and then resetting flipping by simply switching positive and negative pressure. This makes the antioxidant heater of the present invention, when applied in production line equipment, able to greatly simplify the cost of automation control. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the overall structure of the antioxidant heater.

[0033] Figure 2 This is a partial schematic diagram of an antioxidant heater.

[0034] Figure 3 This is a front view of the antioxidant heater.

[0035] Figure 4 This is a three-dimensional half-section view of the antioxidant heater.

[0036] Figure 5 This is a three-dimensional half-section view of the first piston.

[0037] Figure 6 This is a three-dimensional half-section view of the joint gear.

[0038] Figure 7 This is a three-dimensional half-section view of the pneumatic support block.

[0039] Figure 8 This is a three-dimensional half-section view of the central axis tube.

[0040] In the diagram: 1. Bottle body heating cover; 2. Handle heating cover; 3. Inert gas inlet pipe; 4. Internal insert pipe; 5. Fixed wall shell; 6. Pneumatic control block; 7. First cylinder; 8. Swing arm; 9. Second cylinder; 401. First piston; 402. Second piston; 403. Insert pipe through hole; 404. Inert gas alignment pipe; 801. Joint gear; 802. Support platform; 803. Support side plate; 804. Central shaft tube; 805. Limiting support plate; 806. Gear condition; 807. Rack positioning groove; 808. Switch piston; 809. Permanent magnet; 81. 0. Outer wall edge; 811. Outer wall cavity; 812. Swing arm inner cavity; 813. Annular cavity; 814. Shaft tube air groove; 815. Bracket cavity; 816. Positive and negative pressure air nozzles; 601. Downstream air cavity; 602. Upstream air cavity; 603. Through vertical pipe; 604. First plug shaft; 605. Second plug shaft; 606. Associated shaft; 607. Opening and closing control groove; 608. Normally open air inlet groove; 609. Right angle pressure piece; 610. Lifting spring; 611. Inertial air source pipe; 612. Array dispersion pipe; 101. Infrared heating tube; 501. Assembly hole. Detailed Implementation

[0041] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0042] Please see Figures 1 to 8 This invention provides a technical solution: a one-step injection stretch blow molding process, which includes the following steps:

[0043] Step 1: Select PET chips with an intrinsic viscosity of 0.75-0.85 dL / g as raw material. This type of raw material is suitable for bottle manufacturing, balancing product strength and processing performance. Dry the raw material using a dehumidifying dryer to remove moisture and prevent molecular weight reduction due to hydrolysis during processing. Control the drying temperature within the range of 150-180 degrees Celsius. Too low a temperature will not completely remove moisture, while too high a temperature will easily cause PET pre-crystallization. The drying time is 4.5 hours, adjusted according to the initial moisture content of the raw material, ensuring the final moisture content is ≤0.005%. After drying, the PET must be stored in a sealed hopper to prevent moisture absorption from air exposure, and the ambient humidity must be controlled at ≤40%.

[0044] Step 2: Injection molding of the preform. The cavity of the injection mold consists of a preform cavity for the bottle body and a preform cavity for the handle. The inner wall of the injection mold needs to be polished to Ra≤0.02μm to ensure a smooth surface of the preform. The injection pressure is 80-120MPa, adjusted within the above range according to the size of the preform. In this embodiment, it is 110MPa to ensure that the melt fills the dead corners of the cavity. The holding pressure is 50MPa, and the holding time is 3.5 seconds to compensate for the cooling shrinkage of the melt and avoid shrinkage marks or voids in the preform. The cooling time is 7.5 seconds, which is achieved by cooling through the mold water channel to solidify the surface of the preform while maintaining a certain degree of plasticity inside, facilitating subsequent stretching operations. The preform formed by the injection molding unit is a thick-walled tubular structure with a handle. The shape of the handle needs to match the final product and allow for stretching.

[0045] Step 3: Preform temperature control. The preform temperature control station is equipped with an antioxidant heater to control the temperature of different areas of the preform and heat it to the high elasticity range to ensure uniform stress distribution during stretching.

[0046] In the process of this invention, by utilizing a rotary station to simultaneously connect the injection molding of the preform and the preform temperature control process, the work efficiency is improved. The turntable rotates the empty mold unit to the injection area, and the injection system injects molten plastic into the preform mold under high pressure. After the mold is opened, a complete preform with a handle is formed in one go. At this time, the preform has only undergone preliminary cooling and retains residual heat. The turntable directly sends the preform into the temperature control process by rotating, while the mold on the turntable continues to perform injection molding, realizing efficient connection and uninterrupted production closed loop.

[0047] Furthermore, it makes full use of the residual heat from the injection molding process for temperature regulation, which is more energy-efficient. Compared with reheating, it can reduce the risk of handle deformation, crystallization, and other adverse effects caused by uneven reheating.

[0048] The antioxidant heater includes a bottle body heating cover 1 and a handle heating cover 2 that are fixed to each other. When the preform enters the antioxidant heater, the bottle body heating cover 1 and the handle heating cover 2 respectively adjust the temperature of the bottle body and handle of the preform in separate zones; for example Figure 4As shown, both the bottle body heating cover 1 and the handle heating cover 2 are equipped with infrared heating tubes 101. The bottle body heating cover 1 and the handle heating cover 2 are made of heat-insulating ceramic with a metal protective layer on the outer surface. The infrared heating tubes 101 are embedded in the inner wall of the heat-insulating ceramic. When the infrared heating tubes 101 are powered on, they can emit heating infrared light. The infrared light can directly penetrate the surface of the bottle preform and be absorbed by the interior of the material, avoiding the problem of overheating of the surface and lack of softening inside. It also has low heat loss and fast response speed, which is suitable for the continuous temperature control requirements of the production line. The infrared heating tubes 101 are made of nickel-chromium alloy wire.

[0049] The bottom of the bottle body heating cover 1 and the handle heating cover 2 are connected by an inert gas input pipe 3. There are two inert gas input pipes 3, corresponding to the bottle body heating cover 1 and the handle heating cover 2 respectively. The bottle body heating cover 1 is provided with a sequential action component, which is provided with an internal insertion tube 4. When the preform enters the anti-oxidation heater, the sequential action component can control the internal insertion tube 4 to be inserted into the preform. Inert gas is introduced through the inert gas input pipe 3 and the internal insertion tube 4 to provide anti-oxidation protection for the inner and outer surfaces of the preform.

[0050] The temperature of the main body of the bottle is controlled at 95 degrees Celsius, and the temperature difference between different parts is ≤5 degrees Celsius; the temperature of the handle is 90 degrees Celsius. The handle does not participate in the main stretching. The temperature of the handle is lower than that of the bottle body to maintain structural stability. During the heating process, the preform is protected by inert gas to avoid excessive oxidation of the preform surface.

[0051] Step 4: Stretch blow molding. The preform is expanded into the shape of the blow mold cavity through the stretch blow molding unit. The cavity of the blow mold is completely consistent with the final bottle shape, including the handle details. The inner wall is equipped with cooling water channels, and the mold temperature is controlled at 25 degrees Celsius to ensure rapid product shaping.

[0052] Stretch blow molding includes axial stretching and radial blow molding. First, axial stretching is performed, with the stretching rod extending rapidly to stretch the preform axially to the target length at a speed of 600 mm / s and a stretching pressure of 0.35 MPa, ensuring the stretching rod remains stable. After the stretching rod reaches its position, radial blow molding is performed by introducing high-pressure air into the preform. The blow molding pressure is controlled in stages: a pre-blow pressure of 0.25 MPa initially expands the preform, allowing it to conform to the bottom of the mold and the handle cavity, preventing wrinkles; the main blow pressure is 1.2 MPa, adjusted according to the bottle wall thickness requirements, ensuring the preform completely conforms to the inner wall of the mold. The blow molding time is 2.8 seconds to ensure the product is fully shaped, ultimately forming a handle-equipped bottle.

[0053] Step 5: Cooling, shaping, and demolding. 10°C cold water is introduced through the cooling water channel built into the blow molding mold to remove the heat from the product. The cooling time partially overlaps with the blow molding time, with a total cooling time of 3 seconds. When the surface temperature of the product drops to 50°C, the blow molding mold is opened for demolding, completing the preparation.

[0054] The flow rate of cooling water in blow molding molds varies depending on the thickness of the handle and the bottle wall. For areas with thicker walls, the cooling water channel design can be made more dense, and a mold temperature controller can be used to control the water temperature and flow rate to improve the cooling effect in a targeted manner.

[0055] The surface of the bottle heating cover 1 is fitted with a fixed wall shell 5 by welding, such as... Figure 4 As shown, the surface of the fixed wall shell 5 is provided with an assembly hole 501, through which the anti-oxidation heater is fixed. A pneumatic control block 6 is detachably installed on the fixed wall shell 5, and the pneumatic control block 6 and the fixed wall shell 5 are detachably fixed together by screws.

[0056] The sequential action assembly includes a first cylinder 7, a swing arm 8, and a second cylinder 9. The first cylinder 7 is integrally machined and fixedly mounted on the pneumatic support block 6 using a CNC machine tool. When the first cylinder 7 is filled with positive pressure gas, the swing arm 8 swings first, and then the second cylinder 9 drives the internal insertion tube 4 to extend, so that the internal insertion tube 4 is inserted into the blank. When the first cylinder 7 is under negative pressure, the second cylinder 9 first controls the internal insertion tube 4 to retract, and then the swing arm 8 swings back to its original position. Figure 7 As shown, a positive and negative pressure nozzle 816 is connected to the bottom of the first cylinder 7. The positive and negative pressure nozzle 816 is connected to a gas source that can switch between positive and negative pressure through a gas pipe.

[0057] The second cylinder 9 is internally equipped with a first piston 401 and a second piston 402. Both pistons 401 and 402 are fixedly mounted at the ends of the internal insertion tube 4. A gap exists between the first piston 401 and the second piston 402, and an insertion tube through hole 403 is formed between this gap and the internal cavity of the internal insertion tube 4. Figure 7 As shown, the pneumatic support block 6 has a downstream air chamber 601 and an upstream air chamber 602. The pneumatic support block 6 also has a through-pipe 603, which passes through both the downstream air chamber 601 and the upstream air chamber 602, and both ends of the through-pipe 603 are completely open to the outside. The through-pipe 603 also has a first plug shaft 604 and a second plug shaft 605, both of which are in sealed contact with the inner wall surface of the through-pipe 603. A connecting shaft 606 is integrally formed and fixedly installed at the center of the first plug shaft 604 and the second plug shaft 605, enabling the first plug shaft 604 and the second plug shaft 605 to move axially synchronously.

[0058] A through-hole control groove 607 and a normally open air inlet groove 608 are provided on the surface of the through-hole vertical pipe 603, such as Figure 7As shown, the opening and closing control groove 607 is connected to the upstream air chamber 602, and the normally open air inlet groove 608 is connected to the downstream air chamber 601. The opening and closing of the opening and closing control groove 607 is controlled by the lifting and lowering movement of the first plug shaft 604. When the first plug shaft 604 is at the same height position as the opening and closing control groove 607, the opening and closing control groove 607 is blocked and closed by the first plug shaft 604.

[0059] A right-angle pressure member 609 is fixedly installed at the upper end of the associated shaft 606. A lifting spring 610 is installed between the right-angle pressure member 609 and the pneumatic support block 6. Through the elastic support of the lifting spring 610, the associated shaft 606 and the right-angle pressure member 609 have an elastic upward movement tendency. In the initial state, the first plug shaft 604 and the opening and closing control groove 607 are at the same height position, closing the opening and closing control groove 607. When the swing arm 8 swings to the left and reaches its position, the swing arm 8 will press on the right-angle pressure member 609, causing the right-angle pressure member 609 and the associated shaft 606 to move down synchronously. At this time, the first plug shaft 604 moves down, and the upstream air chamber 602 is connected to the downstream air chamber 601 through the opening and closing control groove 607 and the normally open air inlet groove 608.

[0060] like Figure 8 As shown, an inert gas source pipe 611 is externally connected to the upstream gas chamber 602. The inert gas source pipe 611 is connected to a positive pressure inert gas, such as nitrogen. An array dispersion pipe 612 is externally connected to the downstream gas chamber 601. There are three sets of array dispersion pipes 612. The three sets of array dispersion pipes 612 are respectively connected to the inert gas input pipe 3 at the bottom of the bottle body heating cover 1, the inert gas input pipe 3 at the bottom of the handle heating cover 2, and the inert gas alignment pipe 404.

[0061] By using the structure described above in the pneumatically controlled support block 6, the switching between positive and negative pressures can simultaneously control the sequential control of the internal insertion tube 4's flipping, extension, and retraction followed by reset flipping, while also controlling the timing of inert gas release. When there is positive pressure in the first cylinder 7, the swing arm 8 first swings to the left. After the swing arm 8 is in position, the second cylinder 9 drives the internal insertion tube 4 to extend, allowing it to insert into the blank. At this time, the swing arm 8 also presses against the right-angle pressing piece 609, causing the first plug shaft 604 to move downwards. The positive pressure inert gas source in the upstream air chamber 602 enters the through vertical pipe 603 through the opening and closing control groove 607, and then enters the downstream air chamber 601 through the normally open air inlet groove 608. Finally, it is delivered to the inert gas input pipe 3 and the inert gas alignment pipe 404 through three sets of inert gas source pipes 611, causing the inert gas to be automatically released. When negative pressure is applied within the first cylinder 7, the second cylinder 9 first drives the internal insertion tube 4 to retract, causing the internal insertion tube 4 to be pulled out of the blank. Then, the swing arm 8 swings to the right to reset. At this time, the swing arm 8 moves away from the right-angle pressure member 609. Under the elasticity of the lifting spring 610, the first plug shaft 604 moves upward, closing the opening and closing control groove 607 and cutting off the release of inert gas. The significance of the above structure is that when the antioxidant heater of this invention is applied in production line equipment, it is only necessary to control the positive and negative pressure switching of the gas at the positive and negative pressure nozzle 816 to achieve multi-stage control of the flipping activity of the internal insertion tube 4, without affecting the placement and removal of the blank, and at the same time, to achieve control of the release timing of inert gas, greatly simplifying the cost of automation control.

[0062] The side wall of the second cylinder 9 is connected to an inert gas alignment pipe 404. When the internal insertion pipe 4 is extended into place, the inert gas alignment pipe 404 is aligned and connected with the gap between the first piston 401 and the second piston 402. Inert gas is input through the inert gas alignment pipe 404, causing the internal insertion pipe 4 to spray out inert gas.

[0063] A joint gear 801 is fixedly mounted on the swing arm 8. A bracket platform 802 is fixedly mounted at the end of the first cylinder 7. A support side plate 803 is fixedly mounted on the bracket platform 802. A central shaft tube 804 is fixedly mounted on the support side plate 803. The central shaft tube 804 passes through the joint gear 801, so that the joint gear 801 can rotate around the central shaft tube 804.

[0064] The bracket platform 802 is symmetrically fixed with limit plates 805 on both sides. The limit plates 805 can limit and block the swing arm 8 when it swings. The joint gear 801 is externally meshed with a tooth condition 806. A rack positioning groove 807 is opened through the bracket platform 802. The tooth condition 806 is inserted through the rack positioning groove 807 for limiting. A switch piston 808 is provided inside the first cylinder 7. The switch piston 808 is fixedly installed with the rack positioning groove 807. When the switch piston 808 moves axially inside the first cylinder 7, it can drive the tooth condition 806 to move along its length direction, thereby driving the joint gear 801 to rotate, so that the swing arm 8 swings.

[0065] A permanent magnet 809 is embedded and fixed on the swing arm component 8. When the first cylinder 7 is filled with positive pressure gas and the swing arm component 8 swings to the position, the permanent magnet 809 will magnetically engage with the limiting plate 805.

[0066] An outer wall ridge 810 is fixedly provided on the outer surface of the second cylinder body 9. An outer wall cavity 811 is formed in the outer wall ridge 810. One end of the outer wall cavity 811 is connected to the end of the second cylinder body 9, and the other end of the outer wall cavity 811 is connected to a rocker arm inner cavity 812. The rocker arm inner cavity 812 is formed inside the rocker arm component 8 and the joint gear 801. An annular cavity 813 is also formed in the joint gear 801. The rocker arm inner cavity 812 is connected to the annular cavity 813. A shaft tube air groove 814 is formed through the surface of the central shaft tube 804. The annular cavity 813 is connected to the shaft tube air groove. 814 is connected to the inner cavity of the central shaft tube 804; a bracket cavity 815 is provided in the bracket platform 802 and the support side plate 803. One end of the bracket cavity 815 is connected to the central shaft tube 804, and the other end is connected to the first cylinder 7. The gas in the first cylinder 7 will not enter the bracket cavity 815 due to the blocking of the switch piston 808. The gas in the first cylinder 7 will only enter the bracket cavity 815 after the switch piston 808 rises to the limit position and passes through the communication port between the bracket cavity 815 and the first cylinder 7.

[0067] The bottle with one-piece handle is made using a one-step injection stretch blow molding process. It includes a bottle body and a handle, which are made of the same material in one piece.

[0068] In this invention, when the preform is heated by the bottle body heating cover 1 and the handle heating cover 2, an inert gas, preferably nitrogen, is introduced through the inert gas input pipe 3 and the inert gas alignment pipe 404 for protection. Most plastic bottles are made of PET, a polymer material containing easily oxidized structures such as ester bonds in its molecular chain. During the temperature control stage, the preform needs to be heated to a high-elasticity range of 80-110℃. At this temperature, the molecular chain activity is enhanced. Direct exposure to high temperatures in the air will accelerate the chemical reaction between the preform surface and oxygen, potentially producing chromophores such as carbonyl groups, causing the preform surface to yellow, deteriorate surface properties, and develop microcracks or increased brittleness. This can lead to problems such as breakage from the oxidized area during subsequent stretching. Therefore, nitrogen protection effectively improves production quality.

[0069] In the existing technology, the method of filling nitrogen gas from the bottom for protection has limitations in practical applications. Since the preform has already formed the shape of a tubular container, the inside of the preform will be filled with oxygen-containing air in other process stages. The existing method of filling nitrogen gas from the bottom for protection during heating cannot remove the air inside the preform. When the preform is heated to the high elasticity range, the air inside the preform that has not been removed will still cause a certain amount of oxidation on the inner wall surface of the preform, resulting in insufficient production quality.

[0070] The antioxidant heater in this invention is inserted into the interior of the blank through an internal tube 4, which sprays nitrogen gas. During the heating process, the air inside the blank is actively discharged, so that both the inner and outer surfaces of the blank can be protected, which can effectively improve the production quality.

[0071] For details on the principle of controlling the internal cannula 4 by introducing positive and negative pressure through the positive and negative pressure nozzles 816, please refer to [link / reference needed]. Figure 6 and Figure 7 As shown, positive pressure gas enters the first cylinder 7, driving the switch piston 808 to rise. Before the switch piston 808 rises above the height of the connection between the bracket cavity 815 and the first cylinder 7, the gas in the first cylinder 7 will not enter the bracket cavity 815. The rise of the switch piston 808 will drive the gear condition 806 to rise, causing the joint gear 801 to rotate counterclockwise, which in turn causes the swing arm 8 to swing to the left. When the swing arm 8 swings to the left to a horizontal state, the switch piston 808 rises to its limit height. Only after the switch piston 808 passes through the connection between the bracket cavity 815 and the first cylinder 7 can the positive pressure gas in the first cylinder 7 enter the bracket cavity 815.

[0072] Positive pressure gas enters the bracket cavity 815, passes through the central shaft tube 804 and the shaft tube gas groove 814 into the annular cavity 813, then passes through the swing arm inner cavity 812 into the outer wall cavity 811, and finally enters the interior of the second cylinder 9 through the upper end of the second cylinder 9. The positive pressure gas acts on the upper surface of the first piston 401, driving the first piston 401 to move downward, causing the internal insertion tube 4 to move downward and extend until the internal insertion tube 4 is fully extended. After the internal insertion tube 4 is fully extended, the gap between the inert gas alignment pipe 404 and the first piston 401 and the second piston 402 is correspondingly connected, allowing the internal insertion tube 4 to eject inert gas. The input of the aforementioned positive pressure gas causes the swing arm 8 to rotate into position first before the internal insertion tube 4 moves downward and extends.

[0073] After the swing arm 8 swings to the left to a horizontal position, as Figure 6 As shown, the permanent magnet 809 magnetically engages with the limiting plate 805, increasing the resistance to the rightward swing reset of the swing arm 8. When negative pressure is connected in the first cylinder 7, the negative pressure connects to the interior of the second cylinder 9 through the bracket cavity 815, following the same path principle. Ultimately, the negative pressure attraction acts simultaneously on the upper surface of the first piston 401 and the lower surface of the switch piston 808. By setting the magnetic strength of the permanent magnet 809, the first piston 401 first moves the internal insertion tube 4 upward to reset under the attraction of the negative pressure. When the first piston 401 moves upward to the limit position, since the first piston 401 is stationary, the negative pressure acts entirely on the lower surface of the switch piston 808. At this time, the force generated by the switch piston 808 under the negative pressure must be able to overcome the magnetic attraction of the permanent magnet 809, causing the gear condition 806 to move downward, driving the joint gear 801 to rotate counterclockwise, causing the swing arm 8 to swing to the right to reset.

[0074] When the swing arm 8 swings to the right and returns to a horizontal position, there are no obstructions on the upper part of the bottle heating cover 1, and the mechanical clamps of the production equipment can easily hold the preform in and out.

[0075] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A one-step injection stretch blow molding process, characterized in that, The process comprises the following steps: Step one: raw material drying treatment, remove the moisture in the raw material through the dehumidifying dryer, prevent the molecular weight from decreasing due to hydrolysis during processing, control the final moisture content ≤0.005%; Step two: injection molding preform forming, the cavity of the injection mold is composed of a bottle body preforming cavity and a handle preforming cavity, the preform formed by the injection molding unit is a thick-walled tubular structure with a handle, the handle shape needs to match the final product and leave a stretching allowance; Step three: preform temperature adjustment, the preform temperature adjustment station is equipped with an antioxidant heater, the temperature of different areas of the preform is controlled, the preform is heated to the high elastic state interval, and the stress is uniformly distributed during stretching, inert gas is used to protect the preform during the heating process to avoid excessive oxidation of the surface of the preform; Step four: stretch blow molding, the preform is expanded to the shape of the cavity of the blow molding mold through the stretch blow molding unit, and a handle bottle is finally formed; Step five: cooling, setting and demolding, the product heat is taken away through the cooling water path built in the blow molding mold, the blow molding mold is opened and demolded when the surface temperature of the product decreases to 50-60℃, and the preparation is completed; The antioxidant heater comprises a bottle body heating cover and a handle heating cover which are fixed to each other, when the preform enters the antioxidant heater, the bottle body heating cover and the handle heating cover respectively adjust the temperature of the bottle body and the handle of the preform; an inert gas input pipe is arranged at the bottom of the bottle body heating cover and the handle heating cover, a sequential action assembly is arranged outside the bottle body heating cover, an internal insertion pipe is arranged in the sequential action assembly, when the preform enters the antioxidant heater, the sequential action assembly can control the internal insertion pipe to be inserted into the preform, inert gas is input through the inert gas input pipe and the internal insertion pipe to protect the inner wall and the outer wall surface of the preform from oxidation; A fixed wall shell is fixedly arranged on the surface of the bottle body heating cover, an air control supporting block is detachably mounted on the fixed wall shell, the sequential action assembly comprises a first cylinder body, a swing arm and a second cylinder body, the first cylinder body is fixedly mounted on the air control supporting block, when the inside of the first cylinder body is filled with positive pressure gas, the swing arm swings first, and then the second cylinder body drives the internal insertion pipe to extend, so that the internal insertion pipe is inserted into the preform; when the inside of the first cylinder body is under negative pressure, the second cylinder body controls the internal insertion pipe to retract first, and then the swing arm reversely swings to reset; The inside of the second cylinder body is provided with a first piston and a second piston, the first piston and the second piston are fixedly mounted at the end position of the internal insertion pipe, a gap is arranged between the first piston and the second piston, an insertion pipe through hole is arranged between the gap between the first piston and the second piston, and the gap between the first piston and the second piston is communicated with the inner cavity of the internal insertion pipe through the insertion pipe through hole; an inert gas alignment pipe is arranged in the side wall of the second cylinder body, when the internal insertion pipe extends to the position, the inert gas alignment pipe is aligned and communicated with the gap between the first piston and the second piston, and inert gas is input through the inert gas alignment pipe, so that the internal insertion pipe sprays inert gas.

2. A one-step injection stretch blow molding process according to claim 1, characterized in that: In step one, the drying temperature is controlled at 150-180 degrees Celsius, and the drying time is 4-6 hours.

3. A one-step injection stretch blow molding process according to claim 1, characterized in that: In the second step, the inner wall of the injection mold needs to be polished to Ra≤0.02μm to ensure the smooth surface of the parison, the injection pressure is 80-120MPa; the holding pressure is 40-60MPa, the holding time is 2-5 seconds, which is used to compensate for the cooling shrinkage of the melt to avoid shrinkage marks or cavities on the parison; the cooling time is 5-10 seconds, which is cooled through the mold waterway to make the surface of the parison solidify but the inside still maintain a certain plasticity, which is convenient for subsequent stretching operation.

4. The one-step injection stretch blow molding process according to claim 1, characterized in that: In the third step, the temperature of the bottle body is controlled at 90-100 degrees Celsius, and the temperature difference between different parts is ≤5 degrees Celsius; the temperature of the handle is 85-95 degrees Celsius, the handle does not participate in the main stretching, and the temperature of the handle is lower than that of the bottle body to maintain the structural stability.

5. The one-step injection stretch blow molding process according to claim 1, characterized in that: In the fourth step, the cavity of the blow mold is completely consistent with the shape of the final bottle, including the handle details, the inner wall is provided with a cooling waterway, and the mold temperature is controlled at 15-30 degrees Celsius to ensure that the product is quickly shaped; The stretch blow molding includes axial stretching and radial blow molding. First, axial stretching is performed, the stretching rod is quickly extended, the parison is axially stretched to the target length, the stretching speed is 500-800mm / s, and the stretching pressure is 0.3-0.5MPa to ensure that the stretching rod does not shake; after the stretching rod is in place, radial blow molding is performed, high-pressure air is introduced into the parison, the blow molding pressure is controlled in stages, the pre-blowing pressure is 0.2-0.4MPa to make the parison expand initially, fit the mold bottom and the handle cavity to avoid wrinkles; the main blow pressure is 0.8-1.5MPa, which is adjusted according to the wall thickness requirement of the bottle body to ensure that the parison completely fits the inner wall of the mold, and the blow molding time is 2-4 seconds to ensure that the product is fully shaped.

6. The one-step injection stretch blow molding process according to claim 1, characterized in that: The joint gear is fixedly arranged on the swing arm, the end of the first cylinder body is fixedly arranged with a bracket table, the bracket table is fixedly arranged with a supporting side plate, and the supporting side plate is fixedly arranged with a central shaft tube.

7. A one-step injection stretch blow molding process according to claim 6, characterized in that: The two sides of the bracket table are symmetrically fixedly arranged with limiting support plates, which can limit and block the swing arm when it swings; the outside of the joint gear is engaged with a tooth condition, a rack positioning groove is formed in the bracket table, the tooth condition is inserted through the rack positioning groove, and a switch piston is arranged in the first cylinder body and fixedly installed with the rack positioning groove.

8. A one-step injection stretch blow molding process according to claim 7, characterized in that: When the switch piston moves axially in the first cylinder body, it can drive the tooth condition to move along its length direction, thereby driving the joint gear to rotate and make the swing arm swing.

9. A one-step injection stretch blow molding process according to claim 8, characterized in that: The swing arm is embedded with a permanent magnet, which is magnetically attracted to the limiting support plate when the first cylinder body is filled with positive pressure gas to drive the swing arm to swing into place. The outer surface of the second cylinder body is fixedly provided with an outer wall rib, the outer wall rib is provided with an outer wall cavity, one end of the outer wall cavity is communicated with the end of the second cylinder body, and the other end of the outer wall cavity is communicated with an arm inner cavity. The joint gear is also provided with an annular cavity, the swing arm inner cavity is communicated with the annular cavity, the surface of the central shaft tube is provided with a shaft tube air groove, and the annular cavity is communicated with the inner cavity of the central shaft tube through the shaft tube air groove; The bracket cavity is communicated with the central shaft tube at one end and communicated with the first cylinder body at the other end, and the gas in the first cylinder body cannot enter the bracket cavity due to the blockage of the switch piston. When and only when the switch piston rises to the limit position and passes through the communication port between the bracket cavity and the first cylinder body, the gas in the first cylinder body enters the bracket cavity.

10. A handle bottle integrally formed by a one-step injection stretch blow moulding process according to any one of claims 1 to 9, characterised in that: The bottle body and the handle are integrally formed by the same material.

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