Preparation process of degradable polyglycolic acid tableware

Abstract

The invention discloses a preparation technology of degradable polyglycolic acid tableware. The preparation technology comprises the following steps of raw material pretreatment, melt blending, injection molding, storage, automatic stacking and placing, drying agent placing and packaging. PGA and PBAT are blended according to the proportion of 50: 50-70: 30, and 10%-30% of talcum powder, 0.3%-0.8% of epoxy chain extender and 0.5%-1% of calcium stearate are added, so that the material performance is remarkably improved. The talcum powder enhances rigidity and heat resistance, the epoxy chain extender improves molecular weight and inhibits hydrolysis, and the calcium stearate optimizes processing fluidity. According to the formula, the blending material has the high strength of PGA and the toughness of PBAT, meanwhile, the heat stability and the processing efficiency are improved, further, the protection scheme of a drying agent and an HDP film is adopted in the packaging process, the internal humidity is effectively controlled, PGA hydrolysis is delayed, and it is ensured that tableware keeps good use performance in the storage period.

Description

Technical Field

[0001] The invention relates to the field of degradable polyglycolic acid tableware, and in particular to a preparation process of the degradable polyglycolic acid tableware. Background Art

[0002] Traditional disposable tableware is often made from non-degradable plastics like polypropylene (PP) or polystyrene (PS), leading to serious white pollution. Polyglycolic acid (PGA), a biodegradable material, exhibits excellent biodegradability, but its high brittleness and narrow processing window make it difficult to meet the mechanical performance requirements of tableware when used alone. Polybutylene adipate / terephthalate (PBAT) offers excellent flexibility and processing properties, but lacks strength when used alone and degrades slowly.

[0003] In the existing technology, blending PGA and PBAT can improve the comprehensive performance of the material, but there are the following problems: (1) The PGA / PBAT blend system has poor compatibility, which easily leads to interfacial peeling; (2) PGA is easy to absorb moisture and is prone to hydrolysis and degradation during processing and storage, affecting the performance of the product; (3) Traditional packaging methods (such as single PE film) cannot effectively block moisture, resulting in the deterioration of the performance of tableware during storage. Therefore, it is necessary to propose a preparation process for degradable polyglycolic acid tableware. Summary of the Invention

[0004] The purpose of the present invention is to solve the problems in the background technology and provide a preparation process of degradable polyglycolic acid tableware.

[0005] The above technical objectives of the present invention are achieved through the following technical solutions: A preparation process for degradable polyglycolic acid tableware comprises the following steps: S1, raw material pretreatment: PGA and PBAT are mixed in a mass ratio of 50:50 to 70:30, 10%-30% talc, 0.3%-0.8% epoxy chain extender and 0.5%-1% calcium stearate are added, and the mixture is dried at 80°C for 4 hours until the moisture content is less than 0.05%; S2, melt blending, melt blending by using a screw extruder at a temperature of 160-200°C in stages, a screw speed of 200-300 rpm, a vacuum degree of ≥-0.095 MPa, devolatilization, and granulation to obtain a composite material; S3, injection molding, inject the compound into the injection molding machine with a mold temperature of 40-60°C, an injection pressure of 60-100 MPa, a holding pressure of 30-50 MPa, and a cooling time of 20-40 seconds; S4, storage, transporting the stacked tableware after forming to the tableware dropping mechanism of the tableware assembly mechanism for storage; S5, automatic stacking and placing, bowls, plates, and cups are sequentially dropped onto the conveyor belt through their respective tableware dropping mechanisms for automatic stacking and placement; S6, placing desiccant, the tableware that has been automatically stacked is placed in the dryer through the desiccant automatic conveying mechanism of the tableware assembly mechanism. S7, packaging, the tableware with desiccant is packaged with HDP packaging film.

[0006] The present invention significantly improves material properties by blending PGA and PBAT in a ratio of 50:50 to 70:30, and adding 10%-30% talc, 0.3%-0.8% epoxy chain extender, and 0.5%-1% calcium stearate. Talc enhances rigidity and heat resistance, epoxy chain extender increases molecular weight and inhibits hydrolysis, and calcium stearate optimizes processing fluidity. This formula enables the blended material to combine the high strength of PGA with the toughness of PBAT, while also improving thermal stability and processing efficiency. Furthermore, a desiccant + HDP film protective solution is used during the packaging process to effectively control internal humidity, delay PGA hydrolysis, and ensure that the tableware maintains good performance during storage. This technical solution is environmentally friendly, practical, and economical, and is suitable for large-scale industrial production.

[0007] Preferably, the injection molding machine includes a barrel, a screw structure arranged in the barrel, an automatically adjustable opening nozzle connected to the front end of the barrel, and a clamping system consisting of a solid mold and a movable mold. The axis of the automatically adjustable opening nozzle is coaxially arranged with the injection inlet of the solid mold, and the movable mold forms a sliding fit with the solid mold through a guide rail. When the two are clamped, a cavity matching the shape of the product is formed.

[0008] The present invention can accurately control the melt flow and dynamically adjust the melt flow rate by automatically adjusting the nozzle opening, avoid jet flow or short shot, improve filling uniformity, reduce high-temperature retention of materials, and reduce the risk of PGA degradation.

[0009] Preferably, the automatically adjustable opening nozzle includes a nozzle, a needle valve, a needle valve moving push rod, and a sliding seal. A fluid channel is provided in the nozzle, and the needle valve is slidingly provided in the fluid channel. The sliding seal is provided on the outer wall of the needle valve and is always tightly fitted with the inner wall of the fluid channel. The sliding seal divides the fluid channel into a fluid conduction area and a fluid blocking area. The needle valve moving push rod is provided at the starting end of the needle valve and is located in the fluid blocking area. The side wall of the nozzle located in the fluid conduction area is provided with a feed port, and the feed port is connected to the outlet of the barrel. A melt pressure sensor is also provided in the nozzle for detecting the pressure of the fluid. A displacement sensor is provided on the electric push rod for detecting the position of the needle valve. This is a relatively mature technology currently available, so it will not be described in detail in this case.

[0010] The pressure sensor of the present invention monitors the changes in melt pressure in real time. When it detects that the injection pressure exceeds the set threshold, the PLC issues an instruction to drive the needle valve to move the push rod to open the needle valve; at the same time, the displacement sensor accurately feeds back the actual position of the needle valve and performs a closed-loop comparison with the target opening, so that the opening always matches the melt rheology requirements and achieves opening control accuracy.

[0011] Preferably, a push rod end of the needle valve moving push rod is provided with an electromagnet, a limiting ring is provided on the side wall of the fluid blocking area, and a compression spring is provided between the limiting ring and the sliding seal.

[0012] The invention uses an electromagnet to automatically control the nozzle opening by moving a push rod through a needle valve when power is on. When power is suddenly cut off, the needle valve is disengaged from the electromagnet, and the nozzle can be quickly closed by compressing a spring through a mechanical structure to prevent the melt from flowing out and put an end to drooling.

[0013] Preferably, the tableware assembly mechanism includes a frame, and a tableware falling mechanism, a desiccant automatic conveying mechanism, a tableware delivery mechanism, and a multi-tableware converging conveyor belt arranged on the frame. The tableware falling mechanism and the desiccant automatic conveying mechanism are arranged in sequence in the conveying direction, and the tableware delivery mechanism is arranged above the tableware falling mechanism.

[0014] The present invention uses a tableware dropping mechanism to enable different types of tableware to automatically drop from their respective tableware dropping mechanisms into a tableware feeding mechanism, and then enter a multi-tableware converging conveyor belt through the tableware feeding mechanism in sequence. Finally, the desiccant automatic conveying mechanism puts the desiccant into the assembled tableware, and then sends it to the automatic packaging device, thereby realizing automatic assembly of the tableware, reducing manual participation, and improving the hygiene of the tableware.

[0015] The tableware delivery mechanisms in this case are, in order of conveying direction of the multi-tableware converging conveyor belt, a plate tableware delivery mechanism, a bowl tableware delivery mechanism, and a cup tableware delivery mechanism.

[0016] Preferably, the tableware delivery mechanism includes a delivery conveyor belt, a baffle, a bottom baffle, a side baffle, and a delivery electric push rod. The two bottom baffles are symmetrically arranged at the end of the delivery conveyor belt. The two bottom baffles are close to each other on the side with an inwardly concave arc surface. The two arc surfaces are combined to cooperate with the shape of the tableware. The delivery electric push rod is arranged on the outside of the bottom baffle, and the two side baffles are respectively arranged on both sides of the two bottom baffles. The baffle rod is arranged between the two side baffles and at the end of the bottom baffle.

[0017] The present invention places the injection-molded products on the delivery conveyor belt through a robot arm, and then transports them to the end of the delivery conveyor belt and enters between two bottom baffles. The delivery electric push rod drives the bottom baffle to open, so that the tableware falls into the tableware falling mechanism, and then closes the bottom baffle to carry out the next delivery, realizing automatic delivery without manual labor, ensuring the hygiene of the tableware, and improving production efficiency.

[0018] Preferably, the tableware falling mechanism includes a fixed plate, a spiral column, a drive motor, a transmission mechanism, and a discharge cover. The discharge cover is arranged above the fixed plate, a tableware discharge port is opened in the middle of the discharge cover, an adjustment port is opened in the middle of the fixed plate, a number of spiral columns are arranged on the fixed plate and located around the tableware discharge port, the spiral columns rotate to separate the tableware, the drive motor is arranged on the fixed plate to drive the transmission mechanism, and the transmission mechanism is used to drive the spiral columns to rotate.

[0019] The present invention drives a transmission mechanism through a driving motor and then drives a plurality of spiral columns to rotate. The threaded structure on the spiral columns enables the stacked tableware to be automatically separated, thereby realizing automatic unloading.

[0020] Preferably, the transmission mechanism includes a driving wheel, a synchronous wheel, a synchronous belt, and a tensioning bearing. The synchronous wheel is provided at the top of each spiral column. The driving wheel is located at the top of the drive motor. The synchronous belt passes around the driving wheel, the synchronous wheel, and the tensioning bearing. The tensioning bearing and the synchronous wheel located at the top of the spiral column are provided with an adjustable discharge port plate at the bottom. The adjustable discharge port plate is located below a fixed plate. Two adjustable discharge ports are symmetrically provided. The fixed plate is provided with a first waist-shaped adjustment hole located above the adjustable discharge port plate. The adjustable discharge port plate is provided with a first fixing hole corresponding to the first waist-shaped adjustment hole. A screw is provided in the first fixing hole. The fixed plate is also provided with a limiting groove to facilitate the movement of the tensioning bearing. The drive motor is also provided with a waist-shaped adjustment hole to enable the drive motor to move. The two adjustable discharge ports are formed with arc-shaped openings on opposite sides.

[0021] The present invention arranges the first waist-shaped adjustment hole so that the position of the discharge port plate can be adjusted, thereby driving the position change of the spiral column, thereby being able to separate tableware of different diameters and enhancing the applicability of the product.

[0022] Preferably, four guide posts are further provided on the tableware discharge port, two guide posts forming a group symmetrically distributed around the adjustment port and not on the same side as the adjustment discharge port plate, an adjustment plate is provided on the back of the guide post, a second waist-shaped hole is provided on the adjustment plate, and a second fixing hole 263 that cooperates with the second waist-shaped hole is provided on the fixing plate).

[0023] The second waist-shaped hole makes the position of the guide column adjustable, so that different diameter tableware can be clamped.

[0024] Preferably, the desiccant automatic conveying mechanism comprises a vibrating disc, a dryer conveying belt, L-shaped blocking plates, blocking electric push rods, an infrared reflection sensor and a discharge cylinder, the dryer conveying belt is arranged at a discharge port of the vibrating disc, the discharge cylinder is arranged at the end of the dryer conveying belt and above the multi-tableware combined conveying belt, the dryer conveying belt is sequentially arrayed with a plurality of L-shaped blocking plates in the conveying direction, the horizontal plate of the L-shaped blocking plate is above the dryer conveying belt, a detection hole is formed in the horizontal plate of the L-shaped blocking plate, the infrared reflection sensor is arranged above the detection hole, and the blocking electric push rod is arranged at the end of the L-shaped blocking plate and used for pushing the L-shaped blocking plate to reciprocate up and down.

[0025] The present application realizes full-automatic quantitative feeding of the desiccant through efficient sorting of the vibrating disc, accurate positioning of the conveying belt and real-time detection of the infrared sensor, linkage of the L-shaped blocking plate and the electric push rod ensures that only one quantity of desiccant passes through at a time, and the quantitative feeding is realized on the multi-tableware combined conveying belt, so that the automatic conveying of the desiccant is completed.

[0026] In summary, the present application has the following advantages: 1. The present application significantly improves the material performance by blending PGA and PBAT at a ratio of 50:50 to 70:30, and adding 10%-30% talcum powder, 0.3%-0.8% epoxy chain extender and 0.5%-1% calcium stearate. The talcum powder enhances rigidity and heat resistance, the epoxy chain extender increases molecular weight and inhibits hydrolysis, and the calcium stearate optimizes processing fluidity. The formula makes the blended material have high strength of PGA and toughness of PBAT, while improving thermal stability and processing efficiency. Further, in the packaging process, the protection scheme of desiccant + HDP film is adopted to effectively control the internal humidity, delay the hydrolysis of PGA, and ensure that the tableware maintains good use performance during the storage period. This technical solution is environmentally friendly, practical and economical, and is suitable for large-scale industrial production. 2. The present application can accurately control the melt flow by automatically adjusting the opening degree of the nozzle, dynamically adjust the melt flow rate, avoid jet flow or short jet, improve filling uniformity, reduce high-temperature retention of materials, and reduce the risk of PGA degradation. 3. The present invention uses a tableware drop mechanism to automatically drop different types of tableware from their respective drop mechanisms into the tableware delivery mechanism. The tableware then passes through the delivery mechanism and sequentially enters the multi-tableware converging conveyor. Finally, an automatic desiccant delivery mechanism deposits desiccant into the assembled tableware, which is then fed into an automatic packaging device, achieving automatic tableware assembly. During the packaging process, a desiccant + HDP film protection solution is used to effectively control internal humidity, delay PGA hydrolysis, and ensure that the tableware maintains good performance during storage. 4. The present invention uses an electromagnet so that when power is on, the opening of the nozzle can be automatically controlled by moving the push rod through the needle valve. When the power is suddenly cut off, the needle valve is disengaged from the electromagnet, and the nozzle can be quickly closed by compressing the spring through the mechanical structure to prevent the melt from flowing out and put an end to drooling. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a schematic diagram of an injection molding machine of the present invention; Figure 2 It is a schematic diagram of the needle valve retracted in the present invention; Figure 3 It is an overall schematic diagram of the tableware assembly mechanism of the present invention; Figure 4 Schematic diagram of the automatic desiccant delivery mechanism of the present invention; Figure 5 is a schematic diagram of the tableware dispensing mechanism of the present invention; Figure 6 is a schematic diagram of the tableware dropping mechanism of the present invention; Figure 7 This is a schematic diagram of the tableware dropping mechanism of the present invention without the discharge cover; Figure 8 1 is a top view schematic diagram of the tableware dropping mechanism of the present invention; Figure 9 is a schematic diagram of a fixing plate of the present invention; Figure 10 It is a schematic diagram of adjusting the discharge port plate of the present invention.

[0028] Description of the drawings: 1. Injection molding machine; 2. Tableware assembly mechanism; 21. Tableware dropping mechanism; 22. Automatic desiccant delivery mechanism; 11. Barrel; 12. Screw structure; 13. Automatically adjustable nozzle opening; 14. Fixed mold; 15. Moving mold; 131. Nozzle; 132. Needle valve; 133. Needle valve moving push rod; 134. Sliding seal; 135. Fluid channel; 136. Fluid conduction area; 137. Fluid blocking area; 130. Feeding port; 138. Electromagnet; 121. Limiting ring; 139. Compression spring; 20. Frame; 23. Tableware delivery mechanism; 24. Multi-tableware converging conveyor belt; 231. Delivery conveyor belt; 232. Stop rod; 233. Bottom baffle; 234. Side baffle; 235 , feeding electric push rod; 211, fixed plate; 212, spiral column; 213, drive motor; 214, transmission mechanism; 220, discharge cover; 215, tableware discharge port; 210, adjustment port; 216, driving wheel; 217, synchronous wheel; 218, synchronous belt; 219, tensioning bearing; 25, adjustment discharge port plate; 251, first waist-shaped adjustment hole; 252, first fixing hole; 253, limiting groove; 26, guide column; 261, adjustment plate; 262, second waist-shaped hole; 263, second fixing hole; 221, vibration plate; 222, dryer conveyor belt; 223, L-shaped blocking plate; 224, blocking electric push rod; 225, infrared reflection sensor; 226, discharge barrel; 227, detection hole. DETAILED DESCRIPTION

[0029] The following specific embodiments are merely explanations of the present invention and are not limitations of the present invention. After reading this specification, those skilled in the art may make non-creative modifications to the embodiments as needed. However, as long as they are within the scope of the claims of the present invention, they are protected by patent law.

[0030] The present invention will be described in detail below with reference to the accompanying drawings using embodiments.

[0031] Example 1

[0032] S1, raw material pretreatment: PGA and PBAT were mixed in a mass ratio of 60:40, 20% talc, 0.6% epoxy chain extender and 0.75% calcium stearate were added, and the mixture was dried at 80°C for 4 hours until the moisture content was less than 0.05%; S2, melt blending, using screw extruder 3 at a staged temperature of 180°C, a screw speed of 200-300 rpm, a vacuum degree of ≥-0.095 MPa for devolatilization, and granulation to obtain a composite material; S3, injection molding: inject the compound into the injection molding machine 1 at a mold temperature of 50°C, an injection pressure of 80 MPa, a holding pressure of 40 MPa, and a cooling time of 30 seconds; S4, storage, transporting the formed and stacked tableware to the tableware dropping mechanism 21 of the tableware assembly mechanism 2 for storage; S5, automatic stacking and placing, the bowls, plates, and cups are sequentially dropped onto the conveyor belt through their respective tableware dropping mechanisms 21 for automatic stacking and placing; S6, placing the desiccant, and the automatically stacked tableware is placed into the stacked tableware by the desiccant automatic conveying mechanism 22 of the tableware assembly mechanism 2; S7, packaging, the tableware with desiccant is packaged with HDP packaging film.

[0033] like Figure 1-Figure 2 As shown, the injection molding machine 1 includes a barrel 11, a screw structure 12 arranged in the barrel 11, an automatically adjustable opening nozzle 13 connected to the front end of the barrel 11, and a clamping system consisting of a solid mold 14 and a movable mold 15. The axis of the automatically adjustable opening nozzle 13 is coaxially arranged with the injection inlet of the solid mold 14. The movable mold 15 forms a sliding fit with the solid mold 14 through a guide rail 16. When the two are clamped, a cavity matching the shape of the product is formed. The automatically adjustable opening nozzle 13 includes a nozzle 131, a needle valve 132, a needle valve moving push rod 133, and a sliding seal 134. The sliding seal can adopt a piston structure in a hydraulic push rod. The side wall of the needle valve is also provided with a cooling coil and a heating coil to facilitate temperature control. A fluid channel 135 is provided in the nozzle 131. The needle valve 132 is slidably arranged in the fluid channel 135, and the sliding seal 134 is arranged on the outer wall of the needle valve 132 and is always tightly fitted with the inner wall of the fluid channel 135. The sliding seal 134 divides the fluid channel 135 into a fluid conduction area 136 and a fluid blocking area 137. The needle valve moving push rod 133 is arranged at the starting end of the needle valve 132 and is located in the fluid blocking area 137. The nozzle 131 is located on the side wall of the fluid conduction area 136 and is provided with a feed port 130. The feed port 130 is connected to the outlet of the barrel 11. The push rod end of the needle valve moving push rod 133 is provided with an electromagnet 138. A limiting ring 121 is provided on the side wall of the fluid blocking area 137. A compression spring 139 is provided between the limiting ring 121 and the sliding seal 134.

[0034] like Figure 3 As shown, the tableware assembly mechanism 2 includes a frame 20, and a tableware dropping mechanism 21, a desiccant automatic conveying mechanism 22, a tableware feeding mechanism 23, and a multi-tableware converging conveyor belt 24 arranged on the frame 20. The tableware dropping mechanism 21 and the desiccant automatic conveying mechanism 22 are arranged in sequence along the conveying direction of the multi-tableware converging conveyor belt 24, and the tableware feeding mechanism 23 is arranged above the tableware dropping mechanism 21.

[0035] like Figure 5As shown, the tableware delivery mechanism 23 includes a delivery conveyor belt 231, a baffle 232, a bottom baffle 233, a side baffle 234, and a delivery electric push rod 235. The two bottom baffles 233 are symmetrically arranged at the end of the delivery conveyor belt 231. The two bottom baffles 233 are close to each other on the side with an inwardly concave arc surface. The two arc surfaces are combined to cooperate with the shape of the tableware. The delivery electric push rod 235 is arranged on the outside of the bottom baffle 233, and the two side baffles 234 are respectively arranged on both sides of the two bottom baffles 233. The baffle rod 232 is arranged between the two side baffles 234 and at the end of the bottom baffle 233.

[0036] like Figures 6-10As shown, the tableware falling mechanism 21 includes a fixed plate 211, a spiral column 212, a driving motor 213, a transmission mechanism 214, and a discharge cover 220. The discharge cover 220 is arranged above the fixed plate 211, and a tableware discharge port 215 is provided in the middle of the discharge cover 220. An adjustment port 210 is provided in the middle of the fixed plate 211. Several spiral columns 212 are provided on the fixed plate 211 and are located around the tableware discharge port 215. The spiral columns 212 rotate to separate the tableware. The driving motor 213 is provided on the fixed plate 211 to drive the transmission mechanism 214. The transmission mechanism 214 is used to drive the spiral columns 212 to rotate. The transmission mechanism 214 includes a driving wheel 216, a synchronous wheel 217, a synchronous belt 218, and a tensioning bearing 219. The top of the spiral column 212 is provided with the synchronous wheel 217. The driving wheel 216 is provided at the At the top, the synchronous belt 218 passes around the driving wheel 216, the synchronous wheel 217 and the tensioning bearing 219. The synchronous belt can be detachably connected and can be connected by buckles so that the synchronous belt is always in a tensioned state. The tensioning bearing 219 and the bottom of the synchronous wheel 217 located at the top of the spiral column 212 are provided with an adjusting discharge port plate 25. The adjusting discharge port plate 25 is located below the fixed plate 211. There are two adjusting discharge port plates 25 symmetrically arranged. The fixed plate 211 is located above the adjusting discharge port plate 25 and is provided with a first waist-shaped adjusting hole 251. The adjusting discharge port plate 25 is provided with a first fixing hole 252 corresponding to the first waist-shaped adjusting hole 251. A screw is provided on the first fixing hole 252. The fixed plate 211 is also provided with a limiting groove 253 for facilitating the movement of the tensioning bearing 219. A waist-shaped adjusting hole is also provided on the drive motor, so that the drive motor can also move. An arc-shaped opening is formed on the opposite side of the two adjustment discharge port plates 25. Four guide columns 26 are also provided on the tableware discharge port 215. The two guide columns 26 are a group of symmetrically distributed around the adjustment port 210 and are not on the same side as the adjustment discharge port plate 25. An adjustment plate 261 is provided on the back of the guide column 26, and a second waist-shaped hole 262 is provided on the adjustment plate. A second fixing hole 263 that cooperates with the second waist-shaped hole 262 is provided on the fixing plate 211.

[0037] like Figure 4As shown, the automatic desiccant conveying mechanism 22 includes a vibration plate 221, a dryer conveyor belt 222, an L-shaped blocking plate 223, a blocking electric push rod 224, an infrared reflection sensor 225, and a discharge cylinder 226. The dryer conveyor belt 222 is arranged at the discharge port of the vibration plate 221, and the discharge cylinder 226 is arranged at the end of the dryer conveyor belt 222 and is located above the multi-tableware confluence conveyor belt 24. The dryer conveyor belt 222 is arranged with a plurality of L-shaped blocking plates 223 in sequence along the conveying direction. The horizontal plate of the L-shaped blocking plate 223 is located above the dryer conveyor belt 222. A detection hole 227 is opened on the horizontal plate of the L-shaped blocking plate 223. The infrared reflection sensor 225 is arranged above the detection hole 227. The blocking electric push rod 224 is arranged at the end of the L-shaped blocking plate 223 for pushing the L-shaped blocking plate 223 to perform reciprocating movement up and down.

[0038] Working principle: Figure 1-10 As shown, when in use, the compound material is injected into the injection molding machine with a mold temperature of 40-60°C, the compound material is melted in the barrel 11, and then transported to the nozzle 131, and transported to the solid mold 14 through the nozzle, and then cooperated with the movable mold to injection mold the required tableware. The injection-molded tableware, the injection-molded plates, bowls, and cups are transported to their respective delivery conveyor belts 231 by a manipulator, and then the tableware is transported to the end of the delivery conveyor belt 231 and enters between the two bottom baffles. The delivery electric push rod 235 drives the bottom baffle 233 to open, so that the tableware falls into the tableware falling mechanism 21, and then the bottom baffle is closed for the next delivery. The drive motor 213 of the tableware falling mechanism 21 drives the transmission mechanism 214 and then drives multiple spiral columns 212 to rotate. The threaded structure on the spiral column enables the stacked tableware to be automatically separated, Automatic unloading is now performed, with plates, bowls, and cups unloaded in sequence from the multi-tableware converging conveyor belt 24 for assembly. The desiccant automatic conveying mechanism achieves fully automatic quantitative delivery of desiccant through efficient sorting by the vibrating plate 221, precise positioning of the dryer conveyor belt 222, and real-time detection by the infrared reflection sensor 225. The L-shaped blocking plate 223 and the blocking electric push rod 224 are linked to ensure that only a single amount of desiccant passes through, so that the desiccant is quantitatively delivered to the multi-tableware converging conveyor belt and falls into the assembled plates, bowls, and cups. It is then packaged with HDP packaging film and adopts a desiccant + HDP film protection solution to effectively control the internal humidity, delay PGA hydrolysis, and ensure that the tableware maintains good performance during the storage period. This technical solution is both environmentally friendly, practical, and economical, and is suitable for large-scale industrial production.

[0039] Example 2

[0040] Different from Example 1, a process for preparing degradable polyglycolic acid tableware includes the following steps: S1, raw material pretreatment: PGA and PBAT were mixed in a mass ratio of 50:50, 10% talc, 0.3% epoxy chain extender and 0.5% calcium stearate were added, and dried at 80°C for 4 hours until the moisture content was less than 0.05%; S2, melt blending, using screw extruder 3 at a staged temperature of 160°C, a screw speed of 200 rpm, a vacuum degree of ≥-0.095 MPa for devolatilization, and granulation to obtain a composite material; S3, injection molding, injecting the composite material into the injection molding machine 1, with an injection pressure of 60 MPa, a holding pressure of 30 MPa, and a cooling time of 20 seconds; S4, storage, transporting the formed and stacked tableware to the tableware dropping mechanism 21 of the tableware assembly mechanism 2 for storage; S5, automatic stacking and placing, the bowls, plates, and cups are sequentially dropped onto the conveyor belt through their respective tableware dropping mechanisms 21 for automatic stacking and placing; S6, placing the desiccant, and the automatically stacked tableware is placed into the stacked tableware by the desiccant automatic conveying mechanism 22 of the tableware assembly mechanism 2; S7, packaging, the tableware with desiccant is packaged with HDP packaging film.

[0041] Example 3

[0042] Different from Example 1, a process for preparing degradable polyglycolic acid tableware includes the following steps: S1, raw material pretreatment: PGA and PBAT were mixed in a mass ratio of 70:30, 30% talc, 0.8% epoxy chain extender and 1% calcium stearate were added, and the mixture was dried at 80°C for 4 hours until the moisture content was less than 0.05%; S2, melt blending, using screw extruder 3 to melt blend at a segmented temperature of 200°C, a screw speed of 300 rpm, a vacuum degree of ≥-0.095 MPa, and devolatilization, and granulation to obtain a composite material; S3, injection molding, injecting the compound into the injection molding machine 1 at a mold temperature of 60°C, an injection pressure of 100 MPa, a holding pressure of 50 MPa, and a cooling time of 40 seconds; S4, storage, transporting the formed and stacked tableware to the tableware dropping mechanism 21 of the tableware assembly mechanism 2 for storage; S5, automatic stacking and placing, the bowls, plates, and cups are sequentially dropped onto the conveyor belt through their respective tableware dropping mechanisms 21 for automatic stacking and placing; S6, placing the desiccant, and the automatically stacked tableware is placed into the stacked tableware by the desiccant automatic conveying mechanism 22 of the tableware assembly mechanism 2; S7, packaging, the tableware with desiccant is packaged with HDP packaging film.

[0043] The following are the mechanical properties test methods and comparative results of the PGA / PBAT blended materials and pure PGA materials used in Examples 1, 2, and 3:

[0044] 1. Test method

[0045] 2. Comparison of test results

[0046] Conclusion: Although pure PGA has high strength, it is also very brittle (elongation at break <10%). Through the synergistic effect of PBAT and additives, PGA / PBAT blends significantly improve toughness and impact resistance while maintaining sufficient strength, which is more in line with the actual use needs of tableware.

Claims

1. A process for preparing degradable polyglycolic acid tableware, characterized in that: The following steps are involved: S1, raw material pretreatment: PGA and PBAT are mixed in a mass ratio of 50:50 to 70:30, 10%-30% talc, 0.3%-0.8% epoxy chain extender and 0.5%-1% calcium stearate are added, and the mixture is dried at 80°C for 4 hours until the moisture content is less than 0.05%; S2, melt blending, melt blending by screw extruder at a temperature of 160-200°C in stages, a screw speed of 200-300 rpm, a vacuum degree of ≥-0.095 MPa, devolatilization, and granulation to obtain a composite material; S3, injection molding, injecting the composite material into the injection molding machine (1), with an injection pressure of 60-100 MPa, a holding pressure of 30-50 MPa, and a cooling time of 20-40 seconds; S4, storage, transporting the formed and stacked tableware to the tableware dropping mechanism (21) of the tableware assembly mechanism (2) for storage; S5, automatic stacking and placing, the bowls, plates, and cups are sequentially dropped onto the conveyor belt through their respective tableware dropping mechanisms (21) for automatic stacking and placing; S6, placing the desiccant, and the automatically stacked tableware is placed into the stacked tableware through the desiccant automatic conveying mechanism (22) of the tableware assembly mechanism (2); S7, packaging, the tableware with desiccant is packaged with HDP packaging film.

2. The process for preparing degradable polyglycolic acid tableware according to claim 1, characterized in that: The injection molding machine (1) includes a barrel (11), a screw structure (12) arranged in the barrel (11), an automatically adjustable opening nozzle (13) connected to the front end of the barrel (11), and a mold clamping system consisting of a solid mold (14) and a movable mold (15). The axis of the automatically adjustable opening nozzle (13) is coaxially arranged with the injection inlet of the solid mold (14). The movable mold (15) forms a sliding fit with the solid mold (14) through a guide rail (16). When the two are clamped, a cavity matching the shape of the product is formed.

3. The process for preparing degradable polyglycolic acid tableware according to claim 1, characterized in that: The automatically adjustable opening nozzle (13) comprises a nozzle (131), a needle valve (132), a needle valve movable push rod (133), and a sliding seal (134). A fluid channel (135) is provided in the nozzle (131). The needle valve (132) is slidably provided in the fluid channel (135). The sliding seal (134) is provided on the outer wall of the needle valve (132) and is always in close contact with the inner wall of the fluid channel (135). The sliding seal (134) divides the fluid channel (135) into a fluid conduction area (136) and a fluid blocking area (137). The needle valve movable push rod (133) is provided at the starting end of the needle valve (132) and is located in the fluid blocking area (137). A feed inlet (130) is provided on the side wall of the nozzle (131) located in the fluid conduction area (136). The feed inlet (130) is connected to the outlet of the barrel (11).

4. The process for preparing degradable polyglycolic acid tableware according to claim 1, wherein: The push rod end of the needle valve moving push rod (133) is provided with an electromagnet (138), a limiting ring (121) is provided on the side wall of the fluid blocking area (137), and a compression spring (139) is provided between the limiting ring (121) and the sliding seal (134).

5. The process for preparing degradable polyglycolic acid tableware according to claim 3, characterized in that: The tableware assembly mechanism (2) comprises a frame (20), a tableware dropping mechanism (21) arranged on the frame (20), an automatic desiccant conveying mechanism (22), a tableware delivery mechanism (23), and a multi-tableware converging conveyor belt (24); the tableware dropping mechanism (21) and the automatic desiccant conveying mechanism (22) are arranged in sequence along the conveying direction of the multi-tableware converging conveyor belt (24); and the tableware delivery mechanism (23) is arranged above the tableware dropping mechanism (21).

6. The process for preparing degradable polyglycolic acid tableware according to claim 3, characterized in that: The tableware delivery mechanism (23) comprises a delivery conveyor belt (231), a baffle (232), a bottom baffle (233), a side baffle (234), and a delivery electric push rod (235). The two bottom baffles (233) are symmetrically arranged at the ends of the delivery conveyor belt (231). The two bottom baffles (233) are formed with an inwardly concave arc surface on the side close to each other. The two arc surfaces are combined to match the shape of the tableware. The delivery electric push rod (235) is arranged on the outside of the bottom baffle (233). The two side baffles (234) are respectively arranged on both sides of the two bottom baffles (233). The baffle (232) is arranged between the two side baffles (234) and at the ends of the bottom baffles (233).

7. The process for preparing degradable polyglycolic acid tableware according to claim 6, characterized in that: The tableware dropping mechanism (21) comprises a fixed plate (211), a spiral column (212), a driving motor (213), a transmission mechanism (214), and a discharge cover (220). The discharge cover (220) is arranged above the fixed plate (211). A tableware discharge port (215) is provided in the middle of the discharge cover (220). An adjustment port (210) is provided in the middle of the fixed plate (211). A plurality of spiral columns (212) are arranged on the fixed plate (211) and are located around the tableware discharge port (215). The spiral columns (212) rotate to separate the tableware. The driving motor (213) is arranged on the fixed plate (211) and is used to drive the transmission mechanism (214). The transmission mechanism (214) is used to drive the spiral columns (212) to rotate.

8. The process for preparing degradable polyglycolic acid tableware according to claim 7, characterized in that: The transmission mechanism (214) includes a driving wheel (216), a synchronous wheel (217), a synchronous belt (218), and a tensioning bearing (219). The top of the spiral column (212) is provided with the synchronous wheel (217). The bottom of the tensioning bearing (219) and the synchronous wheel (217) located at the top of the spiral column (212) is provided with an adjusting discharge port plate (25). The adjusting discharge port plate (25) is located below the fixed plate (211). Two adjusting discharge port plates (25) are symmetrically arranged. The fixed plate (211) is provided with a first waist-shaped adjusting hole (251) located above the adjusting discharge port plate (25). The adjusting discharge port plate (25) is provided with a first fixing hole (252) corresponding to the first waist-shaped adjusting hole (251). A screw is provided on the first fixing hole (252). The fixed plate (211) is also provided with a limiting groove (253) for facilitating the movement of the tensioning bearing (219).

9. The process for preparing degradable polyglycolic acid tableware according to claim 8, characterized in that: The tableware discharge port (215) is further provided with four guide posts (26), two guide posts (26) forming a group symmetrically distributed around the adjustment port (210) and not on the same side as the adjustment discharge port plate (25), an adjustment plate (261) being provided on the back of the guide posts (26), a second waist-shaped hole (262) being provided on the adjustment plate (261), and a second fixing hole 263 cooperating with the second waist-shaped hole (262) being provided on the fixing plate (211).

10. The process for preparing degradable polyglycolic acid tableware according to claim 5, characterized in that: The automatic desiccant conveying mechanism (22) comprises a vibration plate (221), a dryer conveyor belt (222), an L-shaped blocking plate (223), a blocking electric push rod (224), an infrared reflection sensor (225), and a discharge cylinder (226). The dryer conveyor belt (222) is arranged at the discharge port of the vibration plate (221). The discharge cylinder (226) is arranged at the end of the dryer conveyor belt (222) and is located above the multi-tableware converging conveyor belt (24). The dryer conveyor belt (222) ) A plurality of L-shaped blocking plates (223) are arranged in sequence along the conveying direction, the transverse plate of the L-shaped blocking plate (223) is located above the dryer conveyor belt (222), a detection hole (227) is opened on the transverse plate of the L-shaped blocking plate (223), the infrared reflection sensor (225) is located above the detection hole (227), and the blocking electric push rod (224) is located at the end of the L-shaped blocking plate (223) for pushing the L-shaped blocking plate (223) to perform up and down reciprocating motion.

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