Preparation method of a degradable food packaging box

Abstract

The present invention discloses a preparation method of a degradable food packaging box, which comprises the following steps: S1, taking the packaging box raw materials; S2, feeding the above-mentioned packaging box raw materials into a twin-screw extruder for melt blending, and extruding them into an injection molding machine for injection molding; S3, forming transverse tearing grooves when the packaging box blank is injection molded in the injection molding machine; S4, after the injection molding is completed, taking out the packaging box blank from the injection molding machine; S5, processing a plurality of first through holes on the inner surface of each packaging box blank; S6, inserting and fixing a partition plate with the packaging box blank to form a food packaging box. Compared with the prior art, the present invention prepares an easily tearable food packaging box based on a degradable PLA / PBS composite material. The food packaging box is convenient to be degraded by composting, combining chemical and physical methods, fully improving the degradation efficiency of the packaging box, and at the same time, the packaging box is easy to be demolded during injection molding.

Description

Technical Field

[0001] The present invention relates to the technical field of packaging box manufacturing, and particularly to a preparation method of a degradable food packaging box. Background Art

[0002] In order to improve environmental protection, existing food packaging boxes are usually made of degradable materials. For example, Chinese Patent CN201710943616.6 discloses a degradable food packaging box and its preparation method, which is made of the following raw materials in parts by weight: 70-80 parts of straw powder, 30-40 parts of soybean skin, 20-30 parts of bagasse powder, 8-10 parts of natural resin glue, 5-7 parts of additive, 4-5 parts of fatty acid ester, 4-5 parts of carboxymethyl cellulose, 3-4 parts of glycerol, 14-17 parts of adhesion promoter, 20-25 parts of calcium carbonate powder, 4-6 parts of traditional Chinese medicine antibacterial agent, 1-3 parts of edible pigment, and appropriate amount of water.

[0003] Existing degradable food packaging boxes mainly improve the degradation effect of the packaging box by improving the degradability of raw materials, and improve the degradation effect through a single chemical method. Summary of the Invention

[0004] The purpose of the present invention is to provide a preparation method of a degradable food packaging box, to prepare an easily tearable food packaging box based on a degradable PLA / PBS composite material, the food packaging box is convenient to be degraded by the composting method, the chemical method and the physical method are combined to fully improve the degradation efficiency of the packaging box, and at the same time, the packaging box is easy to be demolded during injection molding.

[0005] In order to achieve the above purpose, the present invention adopts the following technical scheme: A preparation method of a degradable food packaging box includes the following steps:

[0006] S1. Take the packaging box raw materials including the following components in parts by weight: 80-90 parts of polylactic acid (PLA), 5-10 parts of polybutylene succinate (PBS), 1.2-3.2 parts of compatibilizer, 0.8-2.0 parts of chain extender, 0.5-1.5 parts of plasticizer;

[0007] S2. Feed the above packaging box raw materials into a twin-screw extruder, carry out melt blending, and extrude them into an injection molding machine for injection molding;

[0008] S3. The injection molding machine includes a fixed mold and a movable mold. A convex mold is arranged on the fixed mold, convex ribs are arranged on the convex mold, a concave mold is arranged in the movable mold, a cavity for cooperating with the convex mold is arranged on the concave mold, a demolding ejector pin penetrates through the bottom surface of the cavity, the convex mold and the concave mold are combined to form a molding cavity, the molding cavity is used for molding the packaging box blank, and the convex ribs form transverse tearing grooves on the packaging box blank;

[0009] S4. After injection molding, take out the packaging box blank from the injection molding machine;

[0010] S5. Process a plurality of first through holes on the inner surface of each packaging box blank, and the plurality of first through holes are arranged along the width direction of the packaging box blank;

[0011] S6. Insert and fix the partition plate with the packaging box blank, and insert the insertion joints provided at the edge of the partition plate into the first through holes to form a food packaging box.

[0012] As a further description of the above technical solution:

[0013] In step S1, the packaging box raw material includes the following components in parts by weight: 87 parts of polylactic acid, 8 parts of polybutylene succinate, 2.5 parts of compatibilizer, 1.5 parts of chain extender, and 1 part of plasticizer.

[0014] As a further description of the above technical solution:

[0015] In step S5, the first through hole 12 is a tapered hole with a wider upper part and a narrower lower part, and the cross section of the first through hole 12 is a trapezoidal structure with a wider upper part and a narrower lower part. The shape of the insertion joint matches the first through hole 12. On the one hand, it is convenient for the partition plate to be inserted and fixed. On the other hand, since the bottom of the first through hole 12 is narrow (i.e., the outer end of the food packaging box), it can effectively prevent the liquid contained in the food packaging box from leaking along the first through hole 12.

[0016] As a further description of the above technical solution:

[0017] A longitudinal tearing groove 13 is further provided on the packaging box blank 1, and the longitudinal tearing groove 13 is arranged along the width direction of the packaging box blank 1. The plurality of first through holes 12 are arranged along the length direction of the longitudinal tearing groove 13, and the longitudinal tearing groove 13 is also formed by the rib 31. When the food packaging box is discarded, the longitudinal tearing groove 13 cooperates with the transverse tearing groove 11 to further facilitate tearing the packaging box blank 1 and improve the degradation effect. At the same time, under normal conditions, since the longitudinal tearing groove 13 is blocked by the partition plate 2, it will not cause the deformation and tearing of the food packaging box.

[0018] As a further description of the above technical solution:

[0019] The cross section of the longitudinal tearing groove is in a "V" shape.

[0020] As a further description of the above technical solution:

[0021] The cross section of the transverse tearing groove is in a "V" shape.

[0022] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0023] 1. In the present invention, a food packaging box made of a degradable PLA / PBS composite material can be effectively degraded by composting on the one hand; on the other hand, the toughness and hydrolysis resistance of the food packaging box are improved, effectively ensuring the reliability of the food packaging box during use.

[0024] 2. In the present invention, transverse tearing grooves are provided on the blank of the packaging box, and the cross-section of the transverse tearing grooves is in a "V" shape, so that when the food packaging box is discarded, it can be easily torn along the length direction of the blank of the packaging box through the transverse tearing grooves. The packaging box is easy to tear and break, increasing the contact area with the external environment, thereby improving the degradation effect by physical means. The partition is used on the one hand to separate the internal accommodation space of the blank of the packaging box to facilitate the classified storage of food, and on the other hand to form a support during the normal use of the packaging box to prevent the blank of the packaging box from being squeezed and deformed inward. The partition can be specifically formed by injection molding with the same material as the blank of the packaging box for easy degradation.

[0025] 3. In the present invention, during the forming process of the blank of the packaging box, the ribs on the convex mold are used on the one hand to facilitate the formation of the tearing grooves, and on the other hand to make the combination of the convex mold and the blank of the packaging box closer, facilitating the demolding of the blank of the packaging box. Specifically: if the blank of the packaging box is more closely combined with the concave mold (compared with the convex mold), since the ribs make the combination of the convex mold and the blank of the packaging box closer, when the fixed mold and the moving mold are separated, the convex mold can make the connection between the blank of the packaging box and the concave mold loose, facilitating the ejector pin to eject the blank. Conversely, if the blank of the packaging box is more closely combined with the convex mold, through the edge of the blank of the packaging box, it is also convenient for the blank of the packaging box to be demolded from the convex mold. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the embodiments. It should be understood that the following drawings only show some embodiments of the present invention, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can also be obtained based on these drawings without creative efforts.

[0027] Figure 1 Structural schematic of the blank of the packaging box in a preparation method of a degradable food packaging box Figure 1 。

[0028] Figure 2 Structural schematic of the blank of the packaging box in a preparation method of a degradable food packaging box Figure 2 。

[0029] Figure 3 Cross-sectional view of the blank of the packaging box in a preparation method of a degradable food packaging box.

[0030] Figure 4 For Figure 3Partial enlarged view at A in the figure.

[0031] Figure 5 It is a schematic diagram of the cooperation between the male die and the female die in the preparation method of a degradable food packaging box.

[0032] Legend:

[0033] 1. Packaging box blank; 11. Transverse tearing groove; 12. First through hole; 13. Longitudinal tearing groove; 2. Partition board; 3. Male die; 31. Convex rib; 4. Female die; 41. Cavity; 5. Stripping ejector pin. Detailed implementation manners

[0034] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Usually, the components of the embodiments of the present invention described and illustrated herein can be arranged and designed in various different configurations.

[0035] Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0036] Embodiment 1

[0037] A preparation method of a degradable food packaging box includes the following steps:

[0038] S1. Take the packaging box raw materials including the following components in parts by weight: 87 parts of polylactic acid (PLA), 8 parts of polybutylene succinate (PBS), 2.5 parts of compatibilizer, 1.5 parts of chain extender, and 1 part of plasticizer;

[0039] S2. Feed the above packaging box raw materials into a twin-screw extruder for melt blending, and extrude them into an injection molding machine for injection molding;

[0040] S3. The injection molding machine includes a fixed mold and a moving mold. A male die 3 is provided on the fixed mold, and a convex rib 31 is provided on the male die 3. A female die 4 is provided in the moving mold, and a cavity 41 for cooperating with the male die 3 is provided on the female die 4. A stripping ejector pin 5 penetrates through the bottom surface of the cavity 41. The male die 3 and the female die 4 are assembled to form a molding cavity for molding the packaging box blank 1, and the convex rib 31 forms a transverse tearing groove 11 on the packaging box blank 1;

[0041] S4. After injection molding, take out the packaging box blank 1 from the injection molding machine;

[0042] S5. Process a number of first through - holes 12 on the inner surface of each packaging box blank 1. The first through - holes 12 are tapered holes with a wider upper part and a narrower lower part, and the number of first through - holes 12 is arranged along the width direction of the packaging box blank 1.

[0043] S6. Insert and fix the partition 2 to the packaging box blank 1. The insertion joints provided at the edge of the partition 2 are inserted into the first through - holes 12 to form a food packaging box.

[0044] Embodiment 2

[0045] A preparation method of a degradable food packaging box includes the following steps:

[0046] S1. Take packaging box raw materials including the following weight - fraction components: 85 parts of polylactic acid (PLA), 10 parts of polybutylene succinate (PBS), 2.5 parts of compatibilizer, 1.5 parts of chain extender, and 1 part of plasticizer.

[0047] S2. Feed the above - mentioned packaging box raw materials into a twin - screw extruder for melt blending, and then extrude them into an injection molding machine for injection molding.

[0048] S3. The injection molding machine includes a fixed mold and a moving mold. A convex mold 3 is provided on the fixed mold, and a convex rib 31 is provided on the convex mold 3. A concave mold 4 is provided inside the moving mold, and a cavity 41 for cooperating with the convex mold 3 is provided on the concave mold 4. A stripping ejector pin 5 penetrates through the bottom surface of the cavity 41. The convex mold 3 and the concave mold 4 are combined to form a molding cavity for molding the packaging box blank 1. The convex rib 31 forms a transverse tearing groove 11 and a longitudinal tearing groove 13 on the packaging box blank 1. The cross - section of the transverse tearing groove 11 is in a "V" shape, and the longitudinal tearing groove 13 is arranged along the width direction of the packaging box blank 1, and the cross - section of the longitudinal tearing groove 13 is in a "V" shape.

[0049] S4. After injection molding, take out the packaging box blank 1 from the injection molding machine.

[0050] S5. Process a number of first through - holes 12 on the inner surface of each packaging box blank 1. The first through - holes 12 are tapered holes with a wider upper part and a narrower lower part. The number of first through - holes 12 is arranged along the width direction of the packaging box blank 1, and the number of first through - holes 12 is arranged along the length direction of the longitudinal tearing groove 13.

[0051] S6. Insert and fix the partition 2 to the packaging box blank 1. The insertion joints provided at the edge of the partition 2 are inserted into the first through - holes 12 to form a food packaging box.

[0052] As mentioned above, it is only the preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitution or change, and all should be covered within the protection scope of the present invention.

Claims

1. A preparation method of a degradable food packaging box, characterized in that, it comprises the following steps: S1. Take the packaging box raw materials including the following components in parts by weight: 80 - 90 parts of polylactic acid, 5 - 10 parts of polybutylene succinate, 1.2 - 3.2 parts of compatibilizer, 0.8 - 2.0 parts of chain extender, 0.5 - 1.5 parts of plasticizer; S2. Feed the above-mentioned packaging box raw materials into a twin-screw extruder, carry out melt blending, and extrude them into an injection molding machine for injection molding; S3. The injection molding machine includes a fixed mold and a moving mold. A convex mold (3) is arranged on the fixed mold, and a convex rib (31) is arranged on the convex mold (3). A concave mold (4) is arranged in the moving mold, and a cavity (41) for cooperating with the convex mold (3) is arranged on the concave mold (4). A stripping ejector pin (5) penetrates through the bottom surface of the cavity (41). The convex mold (3) and the concave mold (4) are combined to form a molding cavity, and the molding cavity is used for molding the packaging box blank (1). The convex rib (31) forms a transverse tearing groove (11) on the packaging box blank (1). During the molding process of the packaging box blank, on the one hand, the convex rib on the convex mold is convenient for forming the tearing groove, and on the other hand, it makes the combination of the convex mold and the packaging box blank tighter, facilitating the demolding of the packaging box blank; S4. After injection molding, take out the packaging box blank (1) from the injection molding machine; S5. Process a number of first through holes (12) on the inner surface of each packaging box blank (1), and the number of first through holes (12) is arranged along the width direction of the packaging box blank (1); S6. Insert and fix the partition plate (2) with the packaging box blank (1), and the insertion joints arranged at the edge of the partition plate (2) are inserted into the first through holes (12) to form a food packaging box.

2. The preparation method of a degradable food packaging box according to claim 1, characterized in that, in the step S1, the packaging box raw materials include the following components in parts by weight: 87 parts of polylactic acid, 8 parts of polybutylene succinate, 2.5 parts of compatibilizer, 1.5 parts of chain extender, 1 part of plasticizer.

3. The preparation method of a degradable food packaging box according to claim 1, characterized in that, in the step S5, the first through hole (12) is a tapered hole with a "wider upper part and narrower lower part".

4. The preparation method of a degradable food packaging box according to claim 1, characterized in that, a longitudinal tearing groove (13) is further arranged on the packaging box blank (1), the longitudinal tearing groove (13) is arranged along the width direction of the packaging box blank (1), and a number of the first through holes (12) are arranged along the length direction of the longitudinal tearing groove (13).

5. The preparation method of a degradable food packaging box according to claim 4, characterized in that, the cross-section of the longitudinal tearing groove (13) is in a "V" shape.

6. The preparation method of a degradable food packaging box according to claim 1, characterized in that, the cross-section of the transverse tearing groove (11) is in a "V" shape.

Images