A method for improving the forming process of plastic container articles

Abstract

The application discloses a kind of improving plastic container product forming processing method, steps are as follows: S1, the way of bottom glue injection is used to injection molding container bottom;S2, the way of side glue injection is used to injection molding container wall, and container bottom is combined together with the container wall of injection molding as insert;The side wall of container wall cavity is provided with at least 1 side glue injection point.The application not only reduces the requirement to equipment locking force, but also reduces the pressure to injection mold, prolongs the life of mold, and the reduction of flow length ratio makes the mold specific volume smaller, saves mold cost and space;Mold cooling waterway is closer to mold inner wall, to save cooling time, improve the effect of unit time capacity.It can also reduce material processing temperature, the lower the processing temperature, the faster the time of reducing to solidification forming, both reduce energy consumption, and reduce cooling time, shorten the forming cycle, and improve single point glue injection to cause bottom over-thickness waste material, save material and strengthen the pressure capacity of product.

Description

Technical Field

[0001] This invention belongs to the field of container injection molding technology, and specifically relates to an improved method for molding and processing plastic container products. Background Technology

[0002] Currently, most plastic packaging containers on the market are made with thin walls and materials with a large flow length in order to save costs. However, such materials with a large flow length have poor impact resistance and cannot meet the requirements of complex environments such as handling and movement. Moreover, the injection molding method, which usually uses a bottom center injection, requires a large clamping force, and the injection mold is subjected to high pressure. Consequently, the mold life is relatively short and the production efficiency is low. Furthermore, the bottom injection method also has the drawback of being too thick at the bottom, resulting in material waste. Summary of the Invention

[0003] This invention provides an improved molding and processing method for plastic container products. The container injection molding adopts a two-step injection molding method, which reduces the flow length ratio and allows the use of materials with good impact resistance. The two-step injection molding method also solves the problem of the inability to vent air from the side wall injection mold.

[0004] The technical solution adopted in this invention is as follows: An improved method for molding and processing plastic container products includes the following steps: S1, the container bottom is injection molded using a bottom injection method; First, the container bottom is injection molded, and the container bottom cavity used has at least one bottom injection point; the number of bottom injection points is designed according to the actual product, which can be one or more. S2 uses a side injection molding method to mold the container wall, and the container bottom is integrated with the injection-molded container wall as an insert; The container bottom is placed as an insert into the container wall cavity, and the side wall of the container wall cavity has at least 3 side glue injection points.

[0005] The container wall is directly integrated with the container bottom during the injection molding process, serving as the second step in the two-step injection molding process to form the container. Furthermore, since the container bottom acts as an insert, the injection mold used for the container wall can effectively achieve venting.

[0006] In a preferred embodiment of the present invention, the side injection points are distributed on the inner or outer side wall of the container wall cavity. When the side injection points are distributed on the inner side wall of the container wall cavity, the injection molding process is equivalent to starting from the inner side of the container wall; when the side injection points are distributed on the outer side wall of the container wall cavity, the injection molding process is equivalent to starting from the outer side of the container wall.

[0007] As a preferred embodiment of the present invention, there are at least three side injection points, and the specific number is set according to the actual product. An appropriate number of side injection points can speed up the injection molding process.

[0008] In a preferred embodiment of the present invention, the injection mold used for side injection includes a male mold for the container wall and a female mold for the container wall, and the gap between the mating parts of the male mold and the female mold is a container wall cavity, and there is at least one container wall cavity. Because of the separate injection molding of the container bottom and the multi-point injection method on the container sidewalls, the requirements for the clamping force of the equipment are greatly reduced, allowing the original one-cavity mold to be changed to two-cavity or even more-cavity molds, improving production efficiency. Furthermore, the flow length ratio is greatly reduced, allowing the use of materials with good impact resistance and low flow length ratios, thus reducing production costs.

[0009] In a preferred embodiment of the present invention, a hot runner is pre-installed within the container wall mold. The outlet point of the hot runner is located on the side wall of the container wall mold, which is also the side injection point of the container wall cavity. The hot runner has a main runner and branch runners. The outlet point of the branch runner is the side injection point, which communicates with the container wall cavity, allowing the molten material to be injected into the container wall cavity.

[0010] In a preferred embodiment of the present invention, a hot runner is pre-installed within the container wall mold. The outlet point of the hot runner is located on the side wall of the container wall mold, which is also the side injection point of the container wall cavity. The hot runner has a main runner and branch runners. The outlet point of the branch runner is the side injection point, which communicates with the container wall cavity, allowing the molten material to be injected into the container wall cavity.

[0011] As a preferred embodiment of the present invention, the injection-molded container wall has an open end and a larger top and smaller bottom structure. The container wall has a cavity structure and the cross-section can be circular or polygonal. It is particularly suitable for injection molding of wide-mouth containers, such as buckets and square boxes.

[0012] As a preferred embodiment of the present invention, the plastic material used for injection molding includes, but is not limited to, PP, PE, and PC. This material has good toughness and strong impact resistance, thereby improving the overall impact resistance of the injection molded product.

[0013] In a preferred embodiment of the present invention, a cooling structure is provided on the male mold and / or female mold of the container wall near the container wall cavity. By changing the flow length ratio, the cooling water channel can be brought closer to the inner wall of the mold, saving cooling time and increasing the production capacity per unit time.

[0014] As a preferred embodiment of the present invention, the side injection points are distributed in the middle of the container wall cavity. Because conventional containers do not have high requirements for bottom load-bearing and pressure resistance, but have high requirements for the pressure resistance of the container wall, and containers are usually stacked during transportation, the sides of the container are weak points, especially the middle of the side wall. Therefore, in order to improve the overall pressure resistance, multiple injection points on the side can be set in the middle of the side wall. As can be seen from the injection molding principle, the thickness at the injection point position is thicker than other positions, which increases the thickness of the middle of the side wall.

[0015] Compared with the existing technology of traditional bottom single-gate injection, the present invention has the following advantages: 1. It greatly reduces the requirements for clamping force in the equipment, saving on equipment investment.

[0016] By reducing the projected area, the required clamping force for the equipment is significantly reduced. Furthermore, by freeing up the clamping force, the original single-cavity mold can be converted to a single-cavity mold with two or more cavities, further improving production efficiency.

[0017] 2. It significantly reduces the pressure on injection molds, extends mold life, and creates more value for enterprises.

[0018] A reduced flow-to-length ratio can reduce the size of the mold, saving mold costs and space; at the same time, it allows the mold cooling water channel design to be closer to the inner wall of the mold, thereby saving cooling time and increasing the output per unit time.

[0019] 3. It can reduce the material processing temperature and save energy.

[0020] Since the thermal conductivity of injection molding materials is constant, under the premise of ensuring product quality, the lower the processing temperature, the faster the time to solidify and form, which reduces energy consumption, reduces cooling time, and shortens the molding cycle.

[0021] 4. Solving the flow-to-length ratio problem allows for a significant change in the raw materials used in the product, enabling the use of materials with good toughness and high impact resistance.

[0022] 5. Improves the material waste caused by excessive bottom thickness due to single-point glue injection, improves sidewall thickness to increase pressure resistance, greatly improves the overall mechanical properties of the product, and saves materials (approximately 3% to 8% reduction in material).

[0023] Because typical packaging containers do not have high requirements for bottom load-bearing capacity, but require high strength from the sides. Traditional single-point bottom injection systems resulted in excessive bottom thickness due to the filling process, while the sides, subjected to pressure, were weakest due to reinforcing support rings and surface supports at the top and bottom. This invention, with multi-point side injection, thickens the sidewalls at the injection points, thereby increasing the thickness at the center of the sidewall. This conforms to injection molding principles and mechanical principles, achieving both material savings and enhanced product pressure resistance. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a front view of the injection mold for the bottom of the injection molding barrel of the present invention.

[0026] Figure 2 This is a top view of the injection mold for the bottom of the injection molding barrel of the present invention.

[0027] Figure 3 This is a front view of the injection mold for the side-mounted injection molding barrel wall of the present invention.

[0028] Figure 4 This is a top-view cross-sectional view of the injection mold for the side-mounted injection molding barrel wall of the present invention.

[0029] Figure 5 This diagram shows the distribution relationship between the glue injection points on the upper side of the container wall mold and the container wall cavity of the present invention.

[0030] Figure 6 This diagram shows the distribution relationship between the glue injection points on the upper side of the container wall mold and the container wall cavity of the present invention. Detailed Implementation

[0031] 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.

[0032] Example: Taking the injection molding of buckets and containers as an example, this paper illustrates an improved molding process for plastic container products, including the following steps: S1, the container bottom is injection molded using a bottom injection method; First, the container bottom is injection molded, and the container bottom cavity used has at least one bottom injection point; the number of bottom injection points is designed according to the actual product, which can be one or more. The injection mold used for container bottom injection molding includes a container bottom male mold 1 and a container bottom female mold 2. A container bottom cavity 10 is formed between the container bottom male mold 1 and the container bottom female mold 2. Multiple bottom injection hot runners 3 are provided on the container bottom male mold 1. The outlet points of the bottom injection hot runners are the bottom injection points 11 of the container bottom cavity. The molten material enters from the bottom injection hot runners 3 and is injected into the container bottom cavity through the bottom injection points, cooling to form the bottom of the container. In this embodiment, four bottom injection points are used, such as... Figure 1 and 2 As shown.

[0033] S2 uses a side injection molding method to mold the container wall, and the container bottom is integrated with the injection-molded container wall as an insert; The container bottom 12 is placed as an insert into the container wall cavity, and the side wall of the container wall cavity is provided with at least 3 side glue injection points.

[0034] The container wall is directly integrated with the container bottom during the injection molding process, serving as the second step in the two-step injection molding process to form the container. Furthermore, since the container bottom acts as an insert, the injection mold used for the container wall can effectively achieve venting.

[0035] like Figure 3 and 4 As shown, the injection mold used for side injection includes a male mold 4 and a female mold 5 for the container wall, and the gap between the mating parts of the male mold 4 and the female mold 5 is the container wall cavity. In this embodiment, there is one container wall cavity, but there can also be multiple cavities, depending on the actual setup.

[0036] The bottom of the bucket is placed as an insert into the container wall cavity, and the container wall cavity is injection molded using side injection.

[0037] The location of the side injection points can be on the inner or outer wall of the container cavity. When the side injection points are located on the inner wall of the container cavity, the injection process is equivalent to starting from the inner side of the container wall; when the side injection points are located on the outer wall of the container cavity, the injection process is equivalent to starting from the outer side of the container wall.

[0038] Whether the injection point is on the outer or inner side of the container wall cavity depends on the male and female molds of the container wall. In other words, the injection point can be set on either the male or female mold of the container wall, depending on the actual design.

[0039] Furthermore, at least three side injection points are used, with the specific number set according to the actual product. A suitable number of side injection points can speed up the injection molding process. In this embodiment, four side injection points are used.

[0040] Furthermore, the container wall male mold used is a protrusion, and the container wall female mold is a groove. The protrusion inserts into the groove and forms a container wall cavity. A hot runner is pre-installed within the container wall male mold. The outlet point of the hot runner is located on the side wall of the container wall male mold; this outlet point is the side injection point 8 of the container wall cavity. The hot runner has a main runner 6 and four branch runners 7. The outlet points of the branch runners 7 are the side injection points, communicating with the container wall cavity 9. The distribution relationship between the side injection points and the container wall cavity is shown in the diagram below. Figure 5 As shown, the molten material is injected into the cavity of the container wall.

[0041] Alternatively, a hot runner system can be pre-installed within the container wall mold. The outlet point of the hot runner is located on the side wall of the container wall mold, which is also the side injection point of the container wall cavity. The hot runner system has a main runner and branch runners. The outlet point of the branch runner is the side injection point, which communicates with the container wall cavity. The molten material is injected into the container wall cavity. The distribution relationship between the side injection points and the container wall cavity is shown in the diagram below. Figure 6 As shown.

[0042] The hot-melted material enters from the main channel 6 and is distributed to the side of the container wall cavity from the branch channels 7. It is injected into the container wall cavity from the side injection point and, after cooling, is directly integrally formed with the bottom of the barrel.

[0043] After injection molding, the barrel wall is a cavity structure with open ends and a larger top and smaller bottom, and the cross-section is circular. Of course, other wide-mouth containers can also be injection molded, and the cross-section of the container wall is polygonal, such as a square box.

[0044] The change in flow length ratio allows for the use of materials with good toughness and impact resistance, such as PP, PE, and PC, during injection molding. This improves the overall impact resistance of the injection molded product and allows the cooling water channels to be closer to the inner wall of the mold, saving cooling time and increasing the production capacity per unit time.

[0045] Two-step split injection molding can effectively solve the air venting problem of side-entry molds, and also reduce the clamping force of the equipment and the pressure on the mold.

[0046] This invention changes the flow length ratio, divides the container into two parts, sidewall and bottom, and performs injection molding in two steps. Because multi-point injection on the sidewall cannot solve the mold venting problem, and the venting point of this type of mold can only be vented at the bottom of the side, the one-step multi-point injection process on the sidewall cannot be realized. Therefore, the product is divided into two steps, sidewall and bottom, for molding.

[0047] The bottom is processed first, and then it is used as an insert in the secondary molding process along with the container wall. The process is divided into two parts. During the side wall molding, multiple glue injection points can be used in the middle of the side wall. This significantly reduces the flow length ratio and allows for the design of multiple glue injection points according to product requirements, thereby greatly shortening the molding cycle.

[0048] Similarly, in the bottom molding process, one or more injection points can be designed depending on the size of the bottom. This method can save equipment clamping force, make it easier to arrange the cooling water channels of the mold to improve the cooling effect, shorten the molding cycle, and shorten the injection time.

[0049] In this specification, the terms "an embodiment," "example," "specific example," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0050] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. An improved method for molding and processing plastic container products, characterized in that, Includes the following steps: S1, the container bottom is injection molded using a bottom injection method; The container bottom cavity has at least one bottom injection point; S2 uses a side injection molding method to mold the container wall, and the container bottom is placed as an insert into the container wall cavity and combined with the injection molded container wall. The container wall is directly integrated with the container bottom during the injection molding process, serving as the second step in the split injection molding process, thus achieving a two-step injection molding of the container; moreover, the container bottom exists as an insert, so the injection mold used for the container wall can fully achieve venting. The injection mold used for bottom injection molding of the container includes a container bottom male mold (1) and a container bottom female mold (2). A container bottom cavity (10) is formed between the container bottom male mold (1) and the container bottom female mold (2). Multiple bottom injection hot runners (3) are provided on the container bottom male mold (1). The outlet of the bottom injection hot runner is the bottom injection point (11) of the container bottom cavity. The injection mold used for side injection includes a container wall male mold (4) and a container wall female mold (5). The gap between the mating parts of the container wall male mold (4) and the container wall female mold (5) is the container wall cavity. The side injection point can be set on the container wall male mold or on the container wall female mold.

2. The improved molding and processing method for plastic container products according to claim 1, characterized in that: The side glue inlet points are distributed on the inner or outer side walls of the container wall cavity.

3. The improved molding and processing method for plastic container products according to claim 2, characterized in that: The container wall cavity has at least three side glue inlet points.

4. The improved molding and processing method for plastic container products according to claim 1, 2, or 3, characterized in that: The injection mold used for side injection includes a male mold for the container wall and a female mold for the container wall, and the gap between the mating parts of the male mold for the container wall and the female mold for the container wall is a container wall cavity, and there is at least one container wall cavity.

5. The improved molding and processing method for plastic container products according to claim 4, characterized in that: A hot runner is pre-installed inside the container wall mold. The outlet of the hot runner is located on the side wall of the container wall mold, which is the side injection point of the container wall cavity.

6. The improved molding and processing method for plastic container products according to claim 4, characterized in that: A hot runner is pre-installed inside the container wall mold. The outlet of the hot runner is located on the side wall of the container wall mold, which is the side injection point of the container wall cavity.

7. The improved molding and processing method for plastic container products according to claim 4, characterized in that: The injection-molded container has a structure with open ends and a larger top and smaller bottom.

8. The improved molding and processing method for plastic container products according to claim 4, characterized in that: The plastic materials used in injection molding include, but are not limited to, PP, PE, and PC.

9. The improved molding and processing method for plastic container products according to claim 4, characterized in that: Cooling structures are provided on the male mold and / or female mold of the container wall near the container wall cavity.

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