A foam material for food packaging and its preparation method

Abstract

The present invention relates to the field of foam materials, in particular to a foam material for food packaging and a preparation method thereof. The method comprises the following steps: S1, weighing raw materials according to a proportion; S2, using a mixer to mix various raw materials and stirring them evenly; S3, extruding the mixed raw materials into a sheet-forming device to prepare sheet-shaped foam through the sheet-forming device; S4, using a thermoforming machine to perform thermoforming processing on the sheet-shaped foam to obtain a foam food packaging container; the sheet-forming device includes an outer tube with an injection tube provided at the upper end, an outlet provided below the outer tube, an inner ring tube coaxially arranged inside the outer tube, and a forming turntable rotatably arranged between the outer tube and the inner ring tube. Forming holes are evenly arranged circumferentially on the forming turntable; the present invention can prepare foam for packaging food.

Description

Technical Field

[0001] The present invention relates to the field of foam materials, and particularly to a foam material for food packaging and a preparation method thereof. Background Art

[0002] Foam materials are materials with a wide range of uses, mainly used for building walls, roof insulation, composite board insulation, cold storage, air conditioners, vehicles, ship insulation, floor heating, decoration carving, packaging, etc. They have very wide uses. At present, the foam materials used more in the market are mostly polystyrene foam materials and phenolic foam materials. However, polystyrene foam boards and phenolic foam boards have poor corrosion resistance, are easy to age, are easy to break, and are prone to generating toxic substances, and cannot be used for food packaging. Therefore, a foam material capable of packaging food is needed. Summary of the Invention

[0003] The purpose of the present invention is to provide a foam material for food packaging and a preparation method thereof, which can prepare foam for food packaging.

[0004] The purpose of the present invention is achieved through the following technical solutions:

[0005] A preparation method of a foam material for food packaging, the method comprising the following steps:

[0006] S1. Weigh raw materials according to a ratio;

[0007] S2. Use a mixer to mix various raw materials and stir them evenly;

[0008] S3. Squeeze the mixed raw materials into a sheet-forming device and prepare sheet-shaped foam through the sheet-forming device;

[0009] S4. Use a thermoforming machine to perform thermoforming processing on the sheet-shaped foam to obtain a foam food packaging container.

[0010] The sheet-forming device includes an outer tube with an injection pipe at the upper end, an outlet arranged below the outer tube, an inner ring tube coaxially arranged inside the outer tube, and a forming turntable rotating between the outer tube and the inner ring tube. Forming holes are evenly arranged circumferentially on the forming turntable.

[0011] The forming turntable includes two toothed rings and arc plates evenly fixed between the two toothed rings. A plurality of arc plates rotate between the outer tube and the inner ring tube. Brief Description of the Drawings

[0012] Figure 1 is a process schematic diagram of the preparation method of the foam material for food packaging;

[0013] Figure 2 is the overall structural schematic of the sheet-forming device Figure 1 ;

[0014] Figure 3 It is a schematic diagram of the overall structure of the sheet-forming device Figure 2 ;

[0015] Figure 4 It is a schematic diagram of the structure of the outer tube;

[0016] Figure 5 It is a schematic diagram of the structure of the connection between the forming turntable and the semi-circular plate;

[0017] Figure 6 It is a schematic diagram of the structure of the forming turntable;

[0018] Figure 7 It is a schematic diagram of an embodiment for adjusting the spacing of the semi-circular plates;

[0019] Figure 8 It is a schematic diagram of the structure of the inner ring tube;

[0020] Figure 9 It is a schematic diagram of the structure of the ejecting wheel;

[0021] Figure 10 It is a schematic diagram of the structure of an embodiment for the guide plate to guide out the sheet-shaped foam.

[0022] In the figure:

[0023] Outer tube 101; Outlet 102; Leg plate 103; Injection tube 104; Cross plate 105;

[0024] Tooth ring 201; Arc plate 202; Semi-circular plate 203; Linking ring 204; Limit frame 205; Bidirectional screw 206;

[0025] Inner ring tube 301; Support frame 302; Blowing tube 303; Long hole 304; Support plate 305;

[0026] Ejecting wheel 401; Avoidance groove 402; Slide block 403; Spring 404;

[0027] Drive shaft 501; Shoveling plate 502; Guide plate 503; Linking plate 504. Specific implementation method

[0028] As Figure 1 shown:

[0029] A method for preparing a foam material for food packaging, characterized in that: the method comprises the following steps: S1. Weigh raw materials in proportion;

[0030] S2. Use a mixer to mix various raw materials and stir them evenly;

[0031] S3. Extrude the mixed raw materials into a sheet-forming device and prepare sheet-shaped foam through the sheet-forming device;

[0032] S4. Use a thermoforming machine to perform thermoforming on the sheet-shaped foam to obtain a foam food packaging container.

[0033] As Figures 2 - 8 shown:

[0034] The sheet forming device includes an outer tube 101, an outlet 102, an injection tube 104, an inner ring tube 301 and a forming turntable. The upper end of the outer tube 101 is provided with the injection tube 104. The outlet 102 is arranged below the outer tube 101. The inner ring tube 301 is coaxially arranged inside the outer tube 101. The forming turntable rotates between the outer tube 101 and the inner ring tube 301. A plurality of forming holes are evenly arranged circumferentially on the forming turntable.

[0035] During use, first drive the forming turntable to rotate inside the inner ring tube 301 and the outer tube 101, so that the forming holes on the forming turntable are sequentially communicated with the injection tube 104; then connect the injection tube 104 to the device for supplying the mixed raw material, so that the raw material enters the forming holes communicated with it from the injection tube 104, filling the forming holes with the raw material. As the forming turntable rotates, the forming holes are sequentially communicated with the injection tube 104 and filled with the raw material. After being separated from the injection tube 104, the raw material in the forming holes rotates with the forming turntable between the inner ring tube 301 and the outer tube 101, and cools and forms during the rotation. Until it rotates to be communicated with the outlet 102, the formed raw material drops from the outlet 102 under the influence of its own gravity and separates from the forming holes, thus obtaining sheet-shaped foam; the forming holes from which the formed raw material detaches continue to rotate with the forming turntable until they are communicated with the injection tube 104 again and are filled with the raw material again, thereby repeating the above process to form a cycle of preparing sheet-shaped foam, improving the efficiency of preparing sheet-shaped foam;

[0036] Among them, during the process that the forming holes are filled with the raw material and rotate to the outlet 102, a cooling device (not shown in the figure) is provided on the inner ring tube 301 in contact with the forming holes to cool the raw material and improve the cooling efficiency.

[0037] Further, as Figure 6 shown:

[0038] The forming turntable includes a toothed ring 201 and arc plates 202. There are two toothed rings 201, and a plurality of arc plates 202 are evenly fixed between the two toothed rings 201. The plurality of arc plates 202 rotate between the outer tube 101 and the inner ring tube 301.

[0039] A plurality of arc plates 202 are evenly fixed between the two toothed rings 201 to form a rotating ring between the outer tube 101 and the inner ring tube 301, and the gap between two adjacent arc plates 202 forms a forming hole, cooperating with the two toothed rings 201 and the inner wall of the outer tube 101 and the outer wall of the inner ring tube 301 to hold the raw material;

[0040] By driving the two gear rings 201 to rotate, the multiple arc plates 202 can be driven, so that multiple forming holes are formed. As the two gear rings 201 rotate, they rotate between the outer tube 101 and the inner ring tube 301.

[0041] Further, such as Figure 4 and 10 As shown:

[0042] The two leg plates 103 are symmetrically fixed on the outer tube 101 , and the transmission shaft 501 rotates on one of the leg plates 103 . The transmission shaft 501 is meshed and transmission-connected with the two gear rings 201 .

[0043] The two leg plates 103 form a support for the device. The driving motor is installed on the leg plates 103 and is used to drive the transmission shaft 501 to rotate the transmission shaft 501, and then mesh and drive the two gear rings 201 to rotate.

[0044] Further, such as Figure 10 As shown:

[0045] The guide plate 503 is obliquely arranged below the outer tube 101, one end of the guide plate 503 rotates on the leg plate 103 away from the transmission shaft 501, and the other end of the guide plate 503 passes through another leg plate 103, the lower ends of the two linking plates 504 rotate on both sides of the guide plate 503 respectively, and the upper ends of the two linking plates 504 rotate symmetrically at the eccentric positions at both ends of the transmission shaft 501.

[0046] The guide plate 503 is used to receive the flake foam dropped from the outlet 102. At the same time, through its inclined setting, the flake foam dropped on the guide plate 503 slides downward along the inner side thereof until it passes through the leg plate 103, thereby the flake foam is collected on the outer side of the leg plate 103.

[0047] When the transmission shaft 501 transmits the two gear rings 201, it will eccentrically transmit the two linkage plates 504, and then drive the guide plate 503 to reciprocate and rise and fall on the leg plate 103 through the two linkage plates 504, thereby vibrating the sheet foam on the guide plate 503, so that the sheet foam quickly slides off the guide plate 503, and the centralized collection efficiency of the sheet foam is improved;

[0048] Baffles are provided on both sides of the guide plate 503 to prevent the flake foam from sliding down from both sides during vibration, thereby affecting the centralized collection of the flake foam.

[0049] Further, such as Figure 8 As shown:

[0050] An air blowing pipe 303 is provided on the inner side of the lower end of the inner ring tube 301 .

[0051] By connecting the blowing pipe 303 to an air pump, the air pump delivers air into the blowing pipe 303, so that the blowing pipe 303 blows air towards the lower end of the inner ring pipe 301. When the forming hole filled with the forming raw material moves to the lower end of the inner ring pipe 301, at this time the forming hole communicates with the outlet 102, and the air flow of the blowing pipe 303 directly blows towards the forming raw material, causing the forming raw material to quickly break away from the forming hole and fall onto the guide plate 503 through the outlet 102, improving the efficiency of the forming raw material breaking away from the forming hole and at the same time preventing the forming raw material from staying in the forming hole and being unable to fall due to its own gravity;

[0052] And after the air flow blown out by the blowing pipe 303 blows the forming raw material onto the guide plate 503, the air flow will continue to flow along the inclined inner side of the guide plate 503, thereby further forming a push on the forming raw material, causing the forming raw material to quickly slide down on the guide plate 503 and further improving the centralized collection efficiency of the sheet-shaped foam.

[0053] Further, as Figure 7 shown:

[0054] Two semi-arc plates 203 are slidably arranged in the forming holes between two adjacent arc plates 202. Multiple semi-arc plates 203 on the same side penetrate through the toothed ring 201 on the same side and are all fixed on the linkage ring 204. The inner rings of the two linkage rings 204 are both slidably provided with limit frames 205, and the two limit frames 205 are respectively threadedly connected to both ends of a bidirectional screw 206.

[0055] Through the semi-arc plates 203 on both sides of the forming hole, the two sides of the forming hole are joined together, so that the forming hole is composed of two semi-arc plates 203 and two arc plates 202;

[0056] By rotating the bidirectional screw 206, the bidirectional screw 206 simultaneously drives the two limit frames 205 through threaded transmission, so that the two limit frames 205 move away from or close to each other simultaneously, and then drives the two linkage rings 204 to move away from or close to each other simultaneously, and then drives the semi-arc plates 203 on both sides to move away from or close to each other simultaneously, so as to achieve the purpose of changing the size of the forming hole; thus enabling the device to prepare sheet-shaped foams of different sizes.

[0057] Further, as Figure 8 shown:

[0058] The support frame 302 is fixed inside the inner ring pipe 301. The two limit frames 205 are both slidably arranged on the support frame 302. The bidirectional screw 206 is rotatably connected to the support frame 302. The cross plate 105 is fixed on the injection pipe 104. The upper ends of the two limit frames 205 are respectively slidably limited at both ends of the cross plate 105.

[0059] The support frame 302 is used to limit and install the two limit frames 205, and at the same time, it is used to install the bidirectional screw 206. At the same time, through the settings of the two limit frames 205 and the cross plate 105, relative limitation between the inner ring pipe 301 and the outer pipe 101 is formed.

[0060] Further, as Figures 8 - 10 shown:

[0061] The long hole 304 is arranged at the lower end of the inner ring pipe 301 away from the transmission shaft 501 end. Two support plates 305 are respectively fixed on both sides of the long hole 304. Two sliders 403 respectively slide in the two support plates 305. The ejecting wheel 401 rotates between the two sliders 403. The avoiding groove 402 is arranged in the middle of the ejecting wheel 401. A spring 404 is arranged between the slider 403 and the support plate 305 to make the ejecting wheel 401 slide out of the long hole 304. The shovel plate 502 is fixed on the leg plate 103 away from the transmission shaft 501 end.

[0062] When the sheet-like foam in the forming hole has not yet separated after passing through the blowing pipe 303 as the forming turntable rotates, the sheet-like foam moves to the long hole 304 along with the forming hole. Driven by the ejecting wheel 401, the middle part of the sheet-like foam bends outwards beyond the outer pipe 101. As the forming turntable continues to rotate, it will drive the sheet-like foam with the middle part bent outwards to move, so that the tip at the lower end of the shovel plate 502 is inserted into the outward-bent part of the sheet-like foam, and as the sheet-like foam continues to move along with the forming turntable, the sheet-like foam is blocked by the shovel plate 502 and slides out of the forming hole, completing the separation of the sheet-like foam from the forming hole;

[0063] The setting of the avoiding groove 402 is used to avoid the tip at the lower end of the shovel plate 502 and prevent the tip at the lower end of the shovel plate 502 from interfering with the ejecting wheel 401;

[0064] When the ejecting wheel 401 contacts the arc plate 202, the ejecting wheel 401 will be squeezed, so that the ejecting wheel 401 drives the slider 403 to squeeze the spring 404, and the ejecting wheel 401 slides into the long hole 304. After passing over the arc plate 202, it comes out again, forming an outward extrusion of the sheet-like foam that has not separated from the forming hole.

[0065] The foam material prepared by the method for preparing a foam material for food packaging described above, the foam material comprises the following raw materials in parts by weight: 25 - 35 parts of starch, 70 - 80 parts of polypropylene, 15 - 20 parts of fatty acid glyceride, 3 - 5 parts of p-toluenesulfonyl semicarbazide, 1 - 2 parts of sodium benzoate, and 2 - 3 parts of dicumyl peroxide.

Claims

1. A preparation method of a foam material for food packaging, characterized in that: The method includes the following steps: S1. Weigh the raw materials in proportion; S2. Use a mixer to mix various raw materials and stir them evenly; S3. Squeeze the mixed raw materials into a sheet forming device and prepare sheet-shaped foam through the sheet forming device; S4. Use a thermoforming machine to perform thermoforming processing on the sheet-shaped foam to obtain a foam food packaging container; The sheet forming device includes an outer tube (101) with an injection pipe (104) provided at the upper end, an outlet (102) provided below the outer tube (101), an inner ring tube (301) coaxially arranged inside the outer tube (101), and a forming turntable rotatably arranged between the outer tube (101) and the inner ring tube (301). A plurality of forming holes are circumferentially and evenly arranged on the forming turntable; The forming turntable includes two toothed rings (201), and a plurality of arc plates (202) evenly fixed between the two toothed rings (201). The plurality of arc plates (202) are rotatably arranged between the outer tube (101) and the inner ring tube (301); Two support leg plates (103) are symmetrically fixed on the outer tube (101). A transmission shaft (501) is rotatably arranged on one of the support leg plates (103). The transmission shaft (501) is meshed and drivingly connected with the two toothed rings (201); A guide plate (503) is obliquely arranged below the outer tube (101). One end of the guide plate (503) is rotatably connected to the support leg plate (103) away from the transmission shaft (501). The other end of the guide plate (503) penetrates through the other support leg plate (103). Linking plates (504) are rotatably arranged on both sides of the guide plate (503). The upper ends of the two linking plates (504) are symmetrically rotatably arranged at the eccentric positions at both ends of the transmission shaft (501); An air blowing pipe (303) is arranged inside the lower end of the inner ring tube (301); Two half arc plates (203) are slidably arranged in the forming holes between two adjacent arc plates (202). The plurality of half arc plates (203) on the same side penetrate through the toothed ring (201) and are fixed on a linking ring (204). Limiting frames (205) are slidably arranged on the inner circles of the two linking rings (204). The two limiting frames (205) are respectively threadedly connected to both ends of a bidirectional screw rod (206); A long hole (304) is arranged at the end of the lower end of the inner ring tube (301) away from the transmission shaft (501). Support plates (305) are fixed on both sides of the long hole (304). Sliders (403) are slidably arranged in the two support plates (305). A top-out wheel (401) is rotatably arranged between the two sliders (403). An avoidance groove (402) is arranged in the middle of the top-out wheel (401). A spring (404) is arranged between the slider (403) and the support plate (305) to make the top-out wheel (401) slide out of the long hole (304). A shovel plate (502) is fixed on the support leg plate (103) at the end away from the transmission shaft (501); 2. The preparation method of a foam material for food packaging according to claim 1, characterized in that: A support frame (302) is fixed inside the inner ring tube (301). The two limiting frames (205) are slidably arranged on the support frame (302). The bidirectional screw rod (206) is rotatably arranged on the support frame (302). A cross plate (105) is fixed on the injection pipe (104). The upper ends of the two limiting frames (205) are respectively slidably limited at both ends of the cross plate (105).

3. A foam material prepared by using the preparation method of a foam material for food packaging according to claim 1, characterized in that: The foam material comprises the following raw materials in parts by weight: 25-35 parts of starch, 70-80 parts of polypropylene, 15-20 parts of fatty acid glyceride, 3-5 parts of p-toluenesulfonyl semicarbazide, 1-2 parts of sodium benzoate, and 2-3 parts of dicumyl peroxide.

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