PP / PE composite bottle cap and preparation method thereof

Abstract

The invention relates to the technical field of composite bottle caps, and discloses a PP / PE composite bottle cap which comprises an outer cap body and an inner cap body, the outer cap body is arranged in the inner cap body, anti-skid lines are arranged on the outer portion of the outer cap body, a bottom end portion is arranged at the bottom of the inner cap body, a top ring is arranged on the inner side of the top of the inner cap body, and the top ring is arranged on the inner side of the top of the inner cap body. The inner side wall of the inner cover body is provided with an internal thread, the top of the inner cover body is provided with a positioning column, the inner side of the top of the outer cover body is provided with a positioning hole, the outer wall of the inner cover body is provided with a staggered convex body, and the inner side wall of the outer cover body is provided with a connecting groove. According to the PP / PE composite bottle cap and the preparation method thereof, the inner cap body is made of a PE material, has excellent flexibility and good elasticity and can be tightly attached to a bottle opening, the top ring on the inner side of the top of the inner cap body is designed to be matched with internal threads on the inner side wall, when the bottle cap is screwed, the top ring can effectively fill a gap between the bottle opening and the bottle cap, a sealing face is formed, and the sealing effect is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of composite bottle caps, and specifically relates to a PP / PE composite bottle cap and a preparation method thereof. Background Art

[0002] A bottle cap is a sealing component used for a bottle body structure, mainly used for sealing the bottle mouth. It is mainly used in the packaging industry. With the increasing market demand for diversified, high-quality and functional packaging, traditional single-material bottle caps have gradually exposed many limitations.

[0003] Traditional bottle caps are made by one-time injection molding with a single material, such as a single-structure bottle cap made of common polyethylene (PE) or polypropylene (PP) materials. During use, the polyethylene (PE) material has good flexibility and a good sealing effect, but poor rigidity and is prone to deformation. While the polypropylene (PP) material has good rigidity and is not easily deformed, but due to its high hardness, its sealing effect is poor and it is prone to liquid leakage. Therefore, it is necessary to invent a PP / PE composite bottle cap and a preparation method thereof to solve the above problems. Summary of the Invention

[0004] The present invention provides the following technical solutions: a PP / PE composite bottle cap, including an outer cover body and an inner cover body. The outer cover body is arranged inside the inner cover body. Anti-slip lines are arranged on the outside of the outer cover body. A bottom end part is arranged at the bottom of the inner cover body. A top ring is arranged on the inner side of the top of the inner cover body. Internal threads are arranged on the inner side wall of the inner cover body. A positioning post is arranged on the top of the inner cover body. A positioning hole is arranged on the inner side of the top of the outer cover body. A misaligned convex body is arranged on the outer wall of the inner cover body. A connecting groove is arranged on the inner side wall of the outer cover body.

[0005] Preferably, a plurality of the positioning posts and the positioning holes are provided, and the positioning posts are fitted inside the positioning holes, which is convenient for positioning and assembling the outer cover body and the inner cover body, and at the same time avoids misalignment between the outer cover body and the inner cover body.

[0006] Preferably, a plurality of the misaligned convex bodies and the connecting grooves are provided, and the misaligned convex bodies are fitted inside the connecting grooves, which is convenient for connecting the outer cover body and the inner cover body, and at the same time avoids misalignment between the outer cover body and the inner cover body.

[0007] Preferably, the outer cover body and the anti-slip lines are integrally injection-molded with PP material, which is convenient for the outer cover body to have good rigidity, can provide stable support, and improve the strength of the bottle cap.

[0008] Preferably, the inner cover body, bottom end, top ring, internal thread, positioning column, and dislocation convex body are integrally injection-molded from PE material, which facilitates the inner cover body to have good toughness and can have a good sealing effect.

[0009] A preparation method of a PP / PE composite bottle cap includes the following steps: S1. Raw material pretreatment Place the PP material in a hot air dryer at 80 - 90 °C and dry it for 2 - 3 hours, and place the PE material at 70 - 80 °C and dry it for 1 - 2 hours until the moisture content of the PP material and the PE material is lower than 0.02%.

[0010] S2. Injection molding Add the dried PP material into the hopper of the injection molding machine. After the material is evenly plasticized in the barrel, start injection. The melt is injected into the mold cavity through the hot runner system. During the holding pressure stage, compensate for the material shrinkage. After fully cooling, open the mold, and the manipulator takes out the product. Then add the dried PE material into the hopper of the injection molding machine. After the material is plasticized, inject it into the mold cavity. During the holding pressure stage, ensure the integrity of the positioning column and the dislocation convex body. After cooling, use a special demolding mechanism to eject the product.

[0011] S3. Surface treatment Remove the flash and burrs generated during the injection molding process, check the integrity of the positioning column and the dislocation convex body, clean the residues in the internal thread part, place the injection-molded parts in a constant temperature environment (23 ± 2 °C) for 24 hours, perform secondary polishing on the anti-slip pattern part of the outer cover body, and clean the appearance of the product.

[0012] S4. Assembly and molding Align the positioning column of the inner cover body with the positioning hole of the outer cover body, apply slight pressure to make the positioning column enter the positioning hole, rotate the outer cover body to align the dislocation convex body with the connecting groove, and use a special pressing equipment to apply a pressure of 50 - 80 N to complete the assembly, and confirm that there is no looseness or dislocation between the outer cover body and the inner cover body.

[0013] S5. Quality inspection Regularly detect the key dimensions using a coordinate measuring instrument, assemble the bottle cap onto a standard bottle mouth, conduct negative pressure and positive pressure tests, measure the torque required for the first opening, which should be in the range of 0.8 - 2.5 N·m, simulate the sealing performance after multiple opening and closing operations, and detect the bonding strength between the outer cover body and the inner cover body.

[0014] S6. Packaging and storage Use an ion blower to remove static electricity and dust, wipe the key parts with alcohol, package them with an anti-static packaging bag, use a corrugated cardboard box for the outer box, line it with bubble film, store them in a dry and clean warehouse, control the temperature at 10 - 30 °C, and the relative humidity does not exceed 60%, and avoid direct sunlight.

[0015] Preferably, in the step S1, the PP material is selected as an injection-grade PP resin with a melt index in the range of 15 - 30 g / 10 min (230 °C / 2.16 kg), and the PE material is selected as high-density polyethylene with a melt index in the range of 8 - 15 g / 10 min (190 °C / 2.16 kg).

[0016] Preferably, in the step S2, a precision injection molding machine with a clamping force of 60 - 100 tons is selected. The barrel temperature is controlled in sections, the temperature of the feeding section is 160 - 170 °C, the temperature of the compression section is 180 - 190 °C, the temperature of the metering section is 190 - 200 °C, the temperature of the nozzle is 180 - 190 °C, the injection pressure is 50 - 70 MPa, the holding pressure is 30 - 40 MPa, the injection speed is medium-speed injection, and the cooling time is 10 - 14 seconds.

[0017] Preferably, in the step S4, a semi-automatic or fully automatic assembly machine is adopted. The equipment is equipped with a vision positioning system to ensure assembly accuracy, a pressure sensor to monitor the pressing process, and a torque tester to check the rotational mating performance.

[0018] Preferably, in the step S5, the key dimensions include the diameter and height of the positioning posts, the diameter and depth of the positioning holes, the pitch and tooth profile of the internal thread, and the mating dimensions of the offset convex bodies and connecting grooves.

[0019] Compared with the prior art, the present invention provides a PP / PE composite bottle cap and its preparation method, having the following beneficial effects: For the PP / PE composite bottle cap and its preparation method, the inner cap body is made of PE material, which has excellent flexibility and good elasticity, and can closely fit the bottle mouth. The top ring design on the inner side of the top of the inner cap body, combined with the internal thread on the inner side wall, can effectively fill the gap between the bottle mouth and the bottle cap when the bottle cap is tightened, forming a sealing surface and improving the sealing effect.

[0020] For the PP / PE composite bottle cap and its preparation method, the outer cap body is integrally injection-molded from PP material. The PP material has good mechanical properties, high strength and rigidity. The anti-slip lines provided on the outer cap body not only increase the friction on the surface of the outer cap body, facilitating users to open and close the bottle cap, but also enhance the structural strength of the outer cap body to a certain extent.

[0021] For the PP / PE composite bottle cap and its preparation method, the outer cap body and the inner cap body are integrally formed by injection molding and then press-fitted and assembled. The processing process is simple and does not require major modifications to the existing production technology. Only by adding press-fitting and assembly equipment can the production and processing of the composite bottle cap be realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1Schematic diagram of the external structure of the present invention; Figure 2 Schematic diagram of the bottom view structure of the present invention; Figure 3 Schematic diagram of the sectional structure of the present invention; Figure 4 Schematic diagram of the disassembled structure of the present invention; Figure 5 Schematic diagram of the disassembled bottom view structure of the present invention; Figure 6 Schematic diagram of the process structure of the present invention.

[0023] In the figure: 1. Outer cover body; 2. Anti-slip pattern; 3. Inner cover body; 4. Bottom end part; 5. Top ring; 6. Internal thread; 7. Positioning column; 8. Positioning hole; 9. Dislocation convex body; 10. Connection groove. Detailed implementation manners

[0024] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention. Embodiment 1

[0025] Please refer to Figures 1 - 5 , the present invention provides a technical solution: a PP / PE composite bottle cap, including an outer cover body 1 and an inner cover body 3. The outer cover body 1 is arranged inside the inner cover body 3. An anti-slip pattern 2 is arranged on the outside of the outer cover body 1. A bottom end part 4 is arranged at the bottom of the inner cover body 3. A top ring 5 is arranged on the inner side of the top of the inner cover body 3. An internal thread 6 is arranged on the inner side wall of the inner cover body 3. A positioning column 7 is arranged on the top of the inner cover body 3. A positioning hole 8 is arranged on the inner side of the top of the outer cover body 1. A dislocation convex body 9 is arranged on the outer wall of the inner cover body 3. A connection groove 10 is arranged on the inner side wall of the outer cover body 1.

[0026] Furthermore, a plurality of positioning columns 7 and positioning holes 8 are provided, and the positioning columns 7 are fitted inside the positioning holes 8, which is convenient for positioning and assembling the outer cover body 1 and the inner cover body 3, and at the same time avoids dislocation between the outer cover body 1 and the inner cover body 3.

[0027] Furthermore, a plurality of dislocation convex bodies 9 and connection grooves 10 are provided, and the dislocation convex bodies 9 are fitted inside the connection grooves 10, which is convenient for connecting the outer cover body 1 and the inner cover body 3, and at the same time avoids dislocation between the outer cover body 1 and the inner cover body 3.

[0028] Furthermore, the outer cover 1 and the anti-slip pattern 2 are integrally injection-molded from PP material, which facilitates the outer cover 1 to have good rigidity, enabling stable support and improving the strength of the bottle cap.

[0029] Furthermore, the inner cover 3, the bottom end, the top ring 5, the internal thread 6, the positioning post 7, and the offset convex body 9 are integrally injection-molded from PE material, which facilitates the inner cover 3 to have good toughness and a good sealing effect. Embodiment 2

[0030] Please refer to Figure 6 and, in combination with Embodiment 1, further obtain a method for preparing a PP / PE composite bottle cap, which includes the following steps: S1. Raw material pretreatment Place the PP material in a hot air dryer at 80 - 90 °C and dry it for 2 - 3 hours, and dry the PE material at 70 - 80 °C for 1 - 2 hours until the moisture content of the PP material and the PE material is lower than 0.02%.

[0031] Select injection-grade PP resin with a melt index in the range of 15 - 30 g / 10 min (230 °C / 2.16 kg) for the PP material, and select high-density polyethylene for the PE material with a melt index in the range of 8 - 15 g / 10 min (190 °C / 2.16 kg).

[0032] S2. Injection molding Add the dried PP material to the hopper of the injection molding machine. After the material is uniformly plasticized in the barrel, start injection. The melt is injected into the mold cavity through the hot runner system. During the holding pressure stage, compensate for the material shrinkage. After fully cooling, open the mold, and the manipulator takes out the product. Then add the dried PE material to the hopper of the injection molding machine. After the material is plasticized, inject it into the mold cavity. During the holding pressure stage, ensure the integrity of the positioning post and the offset convex body structure. After cooling, use a special demolding mechanism to eject the product.

[0033] Select a precision injection molding machine with a clamping force of 60 - 100 tons for the injection molding machine. The barrel temperature is controlled in sections. The temperature of the feeding section is 160 - 170 °C, the temperature of the compression section is 180 - 190 °C, the temperature of the metering section is 190 - 200 °C, the temperature of the nozzle is 180 - 190 °C, the injection pressure is 50 - 70 MPa, the holding pressure is 30 - 40 MPa, the injection speed is medium-speed injection, and the cooling time is 10 - 14 seconds.

[0034] S3. Surface treatment Remove the flash and burrs generated during the injection molding process, check the integrity of the positioning post and the offset convex body, clean the residues in the internal thread part, place the injection-molded parts in a constant temperature environment (23 ± 2 °C) for 24 hours, perform secondary polishing on the anti-slip pattern part of the outer cover, and clean the appearance of the product.

[0035] S4. Assembly and Molding Align the positioning posts of the inner cover body with the positioning holes of the outer cover body. Apply slight pressure to make the positioning posts enter the positioning holes. Rotate the outer cover body to align the misaligned convex bodies with the connecting grooves. Use a special pressing device to apply a pressure of 50 - 80 N to complete the assembly. Confirm that there is no looseness or misalignment between the outer cover body and the inner cover body.

[0036] Adopt a semi-automatic or fully automatic assembly machine. The equipment is equipped with a vision positioning system to ensure assembly accuracy. A pressure sensor monitors the pressing process, and a torque tester checks the rotational mating performance.

[0037] S5. Quality Inspection Regularly detect the key dimensions using a coordinate measuring machine. Assemble the bottle cap onto a standard bottle mouth and conduct negative pressure and positive pressure tests. Measure the torque required for the first opening, which should be in the range of 0.8 - 2.5 N·m. Simulate the sealing performance after multiple opening and closing operations and detect the bonding strength between the outer cover body and the inner cover body.

[0038] The key dimensions include the diameter and height of the positioning posts, the diameter and depth of the positioning holes, the pitch and tooth profile of the internal thread, and the mating dimensions of the misaligned convex bodies and the connecting grooves.

[0039] S6. Packaging and Storage Use an ion blower to remove static electricity and dust. Wipe the key parts with alcohol. Package with an anti-static packaging bag. The outer box uses a corrugated cardboard box lined with bubble film. Store in a dry and clean warehouse with the temperature controlled at 10 - 30 °C and the relative humidity not exceeding 60%. Avoid direct sunlight.

[0040] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A PP / PE composite bottle cap, comprising an outer cover body (1) and an inner cover body (3), characterized in that: The outer cover body (1) is arranged inside the inner cover body (3). The outer part of the outer cover body (1) is provided with anti-slip lines (2). The bottom of the inner cover body (3) is provided with a bottom end part (4). The inner side of the top of the inner cover body (3) is provided with a top ring (5). The inner side wall of the inner cover body (3) is provided with an internal thread (6). The top of the inner cover body (3) is provided with positioning columns (7). The inner side of the top of the outer cover body (1) is provided with positioning holes (8). The outer wall of the inner cover body (3) is provided with offset convex bodies (9). The inner side wall of the outer cover body (1) is provided with connecting grooves (10).

2. The PP / PE composite bottle cap according to claim 1, wherein A plurality of the positioning columns (7) and the positioning holes (8) are provided, and the positioning columns (7) are fitted inside the positioning holes (8).

3. The PP / PE composite bottle cap according to claim 1, characterized in that, A plurality of the offset convex bodies (9) and the connecting grooves (10) are provided, and the offset convex bodies (9) are fitted inside the connecting grooves (10).

4. A PP / PE composite bottle cap according to claim 1, characterized in that, The outer cover body (1) and the anti-slip lines (2) are integrally injection-molded from PP material.

5. A PP / PE composite bottle cap according to claim 1, characterized in that, The inner cover body (3), the bottom end, the top ring (5), the internal thread (6), the positioning columns (7), and the offset convex bodies (9) are integrally injection-molded from PE material.

6. A method for preparing a PP / PE composite bottle cap according to any one of claims 1-5, characterized in that, It includes the following steps: S1. Raw material pretreatment Place the PP material in a hot air dryer at 80 - 90 °C and dry it for 2 - 3 hours. Place the PE material at 70 - 80 °C and dry it for 1 - 2 hours until the moisture content of the PP material and the PE material is lower than 0.02%; S2. Injection molding Add the dried PP material into the hopper of the injection molding machine. After the material is evenly plasticized in the barrel, start injection. The melt is injected into the mold cavity through the hot runner system. In the holding pressure stage, compensate for the material shrinkage. After fully cooling, open the mold, and the manipulator takes out the product. Add the dried PE material into the hopper of the injection molding machine. After the material is plasticized, inject it into the mold cavity. In the holding pressure stage, ensure the integrity of the positioning columns and the offset convex bodies. After cooling, use a special demolding mechanism to eject the product; S3. Surface treatment Remove the flash and burrs generated during the injection molding process, check the integrity of the positioning columns and the offset convex bodies, clean the residues in the internal thread part, place the injection-molded parts in a constant temperature environment (23 ± 2 °C) and store them for 24 hours, perform secondary polishing on the anti-slip line part of the outer cover body, and clean the appearance of the product; S4. Assembly molding Align the positioning columns of the inner cover body with the positioning holes of the outer cover body, apply slight pressure to make the positioning columns enter the positioning holes, rotate the outer cover body to align the offset convex bodies with the connecting grooves, and use a special pressing equipment to apply a pressure of 50 - 80 N to complete the assembly, and confirm that there is no looseness or misalignment between the outer cover body and the inner cover body; S5. Quality inspection Regularly detect the key dimensions using a coordinate measuring machine, assemble the bottle cap to a standard bottle mouth, perform negative pressure and positive pressure tests, measure the torque required for the first opening, which should be in the range of 0.8 - 2.5 N·m, simulate the sealing performance after multiple opening and closing operations, and detect the bonding strength between the outer cover body and the inner cover body; S6. Packaging and storage Use an ion blower to remove static electricity and dust, wipe the key parts with alcohol, pack them with anti-static packaging bags, use corrugated cardboard boxes for the outer boxes, line them with bubble wrap, store them in a dry and clean warehouse, control the temperature at 10 - 30 °C, and the relative humidity not exceeding 60%, and avoid direct sunlight.

7. A method for preparing a PP / PE composite bottle cap according to claim 6, characterized in that, In the step S1, the PP material is selected as an injection - grade PP resin with a melt index in the range of 15 - 30 g / 10 min (230 °C / 2.16 kg), and the PE material is selected as high - density polyethylene with a melt index in the range of 8 - 15 g / 10 min (190 °C / 2.16 kg).

8. A method for preparing a PP / PE composite bottle cap according to claim 6, characterized in that, In the step S2, a precision injection molding machine with a clamping force of 60 - 100 tons is selected. The barrel temperature is controlled in sections. The temperature of the feeding section is 160 - 170 °C, the temperature of the compression section is 180 - 190 °C, the temperature of the metering section is 190 - 200 °C, the temperature of the nozzle is 180 - 190 °C, the injection pressure is 50 - 70 MPa, the holding pressure is 30 - 40 MPa, the injection speed is medium - speed injection, and the cooling time is 10 - 14 seconds.

9. A method for preparing a PP / PE composite bottle cap according to claim 6, characterized in that, In the step S4, a semi - automatic or fully automatic assembly machine is used. The equipment is equipped with a vision positioning system to ensure assembly accuracy, a pressure sensor to monitor the pressing process, and a torque tester to check the rotational mating performance.

10. The preparation method of a PP / PE composite bottle cap according to claim 1, wherein, In the step S5, the key dimensions include the diameter and height of the positioning posts, the diameter and depth of the positioning holes, the pitch and thread profile of the internal thread, and the mating dimensions of the misaligned convex bodies and the connecting grooves.

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