High-transparency pet multilayer bottle blank with glass light effect, injection molding process thereof and pet multilayer bottle

Abstract

The application provides a high-transparency PET multi-layer bottle blank with glass light effect and an injection molding process thereof and a high-transparency PET multi-layer bottle with glass light effect, and the injection molding process comprises the following steps: presetting the filling position of an inner layer material, injecting an outer layer material and the inner layer material, pressure maintaining and cooling, so as to obtain the high-transparency PET multi-layer bottle blank with glass light effect. The injection molding process controls the inner layer of the multi-layer bottle blank to gradually offset radially towards the inner wall inside the blank wall, so that the outer transparent outer layer is thickened accordingly, so that the bottle blank is high-transparency and has glass light effect.

Description

TECHNICAL FIELD

[0001] The application relates to a high-transparency PET multi-layer bottle embryo with a glass light effect, an injection molding process thereof and a high-transparency PET multi-layer bottle with a glass light effect, and belongs to the technical field of packaging. BACKGROUND

[0002] With the development of the beverage industry, PET packaging and aseptic filling equipment emerge as the times require and have been maturely used in the dairy and other beverage industries. The PET bottle has high mechanical strength, can have various shapes, can be repeatedly opened and closed, and is convenient to carry. However, most of the PET bottles on the market are pure colors, are relatively single, and a small amount of multi-layer bottles are not transparent enough in appearance, which affects the visual effect of the PET bottle. SUMMARY

[0003] To solve the above technical problems, the purpose of the application is to provide an injection molding process of a high-transparency PET multi-layer bottle embryo with a glass light effect. The bottle embryo prepared by using the injection molding process has a glass light effect and high color transparency in appearance.

[0004] To achieve the above purpose, the application provides an injection molding process of a high-transparency PET multi-layer bottle embryo with a glass light effect, which comprises the following steps:

[0005] S1: The filling position of the inner layer material is preset, so that the filling position of the inner layer material is gradually offset radially from the inner wall to the outer wall along the embryo opening, the transition area and the embryo body of the mold in turn;

[0006] S2: The outer layer material is injected into the mold cavity, when the outer layer material is filled to 30-57% of the volume of the mold cavity, the inner layer material containing a colorant is started to be injected, and the outer layer material is continuously injected;

[0007] S3: When the filling volume (i.e. the feeding volume) of the inner layer material reaches 10-40% of the volume of the mold cavity, and the sum of the filling volumes of the inner layer material and the outer layer material reaches 102.5-120% of the volume of the mold cavity, the injection of the inner layer material is stopped, and the injection of the outer layer material is continuously maintained;

[0008] S4: When the filling volume of the outer layer material reaches 108-110% of the volume of the mold cavity, the pressure is maintained, until the total filling volume of the outer layer material reaches 119-122.5% of the volume of the mold cavity, the injection of the outer layer material is stopped, the pressure maintaining is ended, and cooling is performed, to obtain the high-transparency PET multi-layer bottle embryo with a glass light effect.

[0009] The mold used in the application corresponds to the product structure of the bottle embryo, including the embryo opening, the transition area and the embryo body. In the injection process of the application, the inner layer material and the outer layer material are both in liquid state, therefore, the volume ratio described above is calculated based on the volume of the liquid material.

[0010] The injection molding process of the present application controls the filling position of the inner layer material, so that the color inner layer of the preform gradually offsets radially (in the radial direction of the preform) from the inner wall to the outer wall of the preform along the preform mouth, transition zone, and preform body, thickens the transparent outer layer of the preform body surface layer, improves the light refraction effect of the preform, and thus makes the preform appearance transparent and has a light effect similar to glass material.

[0011] According to a specific embodiment of the present application, in the above injection molding process, preferably, the filling position of the inner layer material set in S1 is as follows: at the preform mouth of the mold, the filling position of the inner layer material is located at the radial middle position of the inner and outer walls of the mold; at the transition zone of the mold, the filling position of the inner layer material gradually offsets radially from the radial middle position to the inner wall; and at the preform body of the mold, the filling position of the inner layer material is the inner wall surface of the mold.

[0012] According to a specific embodiment of the present application, in the above injection molding process, preferably, the inner layer material comprises PET and a colorant; more preferably, it further comprises a stabilizer. The colorant can be a color masterbatch, and its addition amount is determined according to the appearance color requirement.

[0013] According to a specific embodiment of the present application, in the above injection molding process, preferably, the outer layer material is pure PET.

[0014] The injection molding process of the present application is suitable for all double-screw one-step injection molding of multilayer preforms with ABA structure, and the preform material is not limited to PET material. Modified PET or other plastics suitable for injection molding process can also be used to achieve the gradual change of the preform effect.

[0015] According to a specific embodiment of the present application, in the above injection molding process, preferably, the temperature of the mold is 185-320℃, preferably 235-335℃.

[0016] According to a specific embodiment of the present application, in the above injection molding process, preferably, the inner layer material and the outer layer material are injected through the inner layer screw and the outer layer screw respectively, the temperature of the inner layer screw is controlled to be 175-310℃, and the temperature of the outer layer screw is 175-300℃.

[0017] In the injection molding process of the present application, the temperature control of the mold and screw used for injection molding determines the screw pressure during injection molding. If the temperature is not properly set, the screw pressure will be too high, which will eventually cause instability of the injection molding process and make it impossible to manufacture preform products with stable appearance. By controlling the temperature of the mold and screw within the above appropriate range, the present application can ensure that all preform materials can be injected under stable injection molding pressure, thereby ensuring the uniformity of the color inner layer distribution.

[0018] According to the specific embodiment of the present application, in the injection molding process, preferably, the nozzle temperature of the inner-layer screw and the outer-layer screw is 185-320℃.

[0019] According to the specific embodiment of the present application, in the injection molding process, preferably, the injection speed of the outer-layer material before injecting the inner-layer material in S2 is 1.67-13.36 cm / s. 3 According to the specific embodiment of the present application, in the injection molding process, preferably, the injection speed of the outer-layer material before injecting the inner-layer material in S2 is 1.67-13.36 cm / s. 3 According to the specific embodiment of the present application, in the injection molding process, preferably, the injection speed of the outer-layer material before injecting the inner-layer material in S2 is 1.67-13.36 cm / s. 3 According to the specific embodiment of the present application, in the injection molding process, preferably, the injection speed of the outer-layer material before injecting the inner-layer material in S2 is 1.67-13.36 cm / s. 3

[0020] According to the specific embodiment of the present application, in the injection molding process, preferably, the pressure of the pressure holding is 30.8-35.2 bar, and the duration is 1.33-4 seconds.

[0021] According to the specific embodiment of the present application, in the injection molding process, preferably, the temperature of the cooling is 14-18.3℃, and the duration is 3.49-8 seconds.

[0022] The injection molding process of the present application can ensure that the colorant (color) in the preform precisely stays at the set position, prevent color bleeding, deviation and other problems, and ensure the color range of the preform and the stability of the overall weight and shape of the preform.

[0023] According to the specific embodiment of the present application, preferably, the injection molding process is realized by a double-screw ABA one-step injection molding machine.

[0024] The present application also provides a high-transparency PET multi-layer preform with glass light effect prepared by the above injection molding process, which has a transparent outer layer and a colored inner layer, wherein the inner layer gradually shifts radially towards the inner wall along the preform mouth, transition zone, and preform body.

[0025] The gradient color PET multi-layer preform of the present application has a three-layer sandwich structure, i.e. ABA structure, with outer layers (A layers) on both sides and an inner layer (B layer, or intermediate layer) in the middle, which is wrapped by the outer layers. In the multi-layer preform of the present application, the inner layer refers to the layer located in the inner layer of the preform wall after longitudinal sectioning, and the outer layer refers to the layer located in the inner layer of the preform wall after longitudinal sectioning.

[0026] According to the specific embodiment of the present application, the high-transparency PET multi-layer preform with glass light effect, preferably, Figure 1 ​As shown, at the bottle embryo mouth, the inner layer is located at the radial middle position of the inner and outer walls of the mold; at the transition zone of the bottle embryo, the inner layer is gradually radially offset from the radial middle position to the inner wall; and at the body of the bottle embryo, the inner layer is located at the inner wall.

[0027] In the high-transparency PET multilayer bottle embryo with glass light effect of the present application, the radial deviation of the inner layer is defined as follows: the radial distance between the actual position of the inner layer and the radial middle position of the inner and outer walls of the bottle embryo accounts for 1 / 2 of the thickness of the embryo wall. Thus, when the inner layer is located at the middle of the embryo wall, the radial deviation of the inner layer is 0; and when the inner layer is located at the inner wall of the embryo wall, the radial deviation of the inner layer is 100%.

[0028] The present application also provides a high-transparency PET multilayer bottle with glass light effect, which is made by blow molding the above-mentioned high-transparency PET multilayer bottle embryo with glass light effect.

[0029] The technical solution provided by the present application has the following beneficial effects:

[0030] The injection molding process of the present application controls the gradual radial offset of the inner layer of the multilayer bottle embryo from the inside of the embryo wall to the inner wall, so that the outer transparent outer layer thickens accordingly, thereby making the bottle embryo highly transparent and having a glass light effect. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 The filling position of the inner layer in the bottle embryo of the present application is shown in the figure, wherein 1 is the mouth, 2 is the transition zone, and 3 is the body of the embryo, and B is the inner layer.

[0032] Figure 2 The appearance of the bottle embryo prepared in Example 1 is shown in the figure.

[0033] Figure 3 The longitudinal section of the bottle embryo prepared in Example 1 is shown in the figure.

[0034] Figure 4 The appearance of the multilayer bottle obtained by blow molding the bottle embryo of Example 1 is shown in the figure. DETAILED DESCRIPTION

[0035] In order to have a clearer understanding of the technical features, objectives and beneficial effects of the present application, the technical solution of the present application will be described in detail as follows, but it should not be understood as limiting the scope of the present application.

[0036] Example 1

[0037] The present application provides an injection molding process for a high-transparency PET multilayer bottle embryo with glass light effect, wherein the inner layer material is 4.0% color masterbatch + 96.0% PET, and the outer layer material is pure PET. The process is realized by using a double-screw ABA type one-step injection molding machine.

[0038] The process includes the following steps:

[0039] S1: The filling position of the inner layer material is set as follows: at the mold blank opening, the filling position of the inner layer material is located at the radial midpoint between the inner and outer walls of the mold; in the transition zone of the mold, the filling position of the inner layer material gradually shifts radially from the radial midpoint to the inner wall; at the mold blank body, the filling position of the inner layer material is the inner wall surface of the mold.

[0040] S2: The preheating temperature of the mold is 325℃, and the temperatures of screws A and B are also 325℃; the outer layer material is propelled at a speed of 1.67-13.36cm by screw A. 3 The material is injected into the mold cavity at an injection speed of / s. When the outer layer material fills 30% of the mold cavity volume, it is then injected through screw B at a speed of 1-3.5cm. 3 The inner layer material is injected at an injection speed of / s, while the outer layer material is maintained at a speed of 1.67-13.36cm. 3 / s continuous injection;

[0041] S3: When the filling volume of the inner layer material reaches 10% of the mold cavity volume, and the sum of the filling volumes of the inner and outer layer materials reaches 102.5% of the mold cavity volume, stop injecting the inner layer material and maintain the outer layer material at a position ≤1.67cm. 3 Continuous injection speed of / s;

[0042] S4: When the filling volume of the outer layer material reaches 108% of the mold cavity volume, pressure holding begins. Pressure is maintained at an average of 35 bar for 4 seconds. When the total filling volume of the outer layer material reaches 119% of the mold cavity volume, the injection of the outer layer material is stopped, the pressure holding ends, and the material is cooled at 14°C for 4 seconds to obtain the high-transparency PET multilayer preform with glass luminescence.

[0043] The photograph of the multilayer preform obtained in this embodiment is shown below. Figure 2 As shown, by Figure 2 It can be seen that the bottle preform has a highly transparent color, good light refraction, and a glass-like effect.

[0044] The above preform is cut longitudinally, as follows: Figure 3 As shown, it can be seen that the colored inner layer of the preform shifts towards the inner wall of the preform, making the transparent outer layer of the preform body thicker, thus giving the preform a glassy effect.

[0045] The preform of this embodiment is blow-molded into a high-transparency PET multilayer bottle, as shown below. Figure 4 As shown, it also has the optical effect of glass.

Claims

1. An injection molding process for a high-transparency PET multilayer preform with glass-like gloss, comprising the following steps: S1: Pre-set the filling position of the inner layer material, so that the filling position of the inner layer material gradually shifts radially towards the inner wall from between the inner wall and the outer wall of the mold along the mold blank opening, transition zone, and blank body. S2: Inject the outer layer material into the mold cavity. When the outer layer material fills 30-57% of the mold cavity volume, start injecting the inner layer material containing the colorant, and continue injecting the outer layer material. S3: When the filling volume of the inner layer material reaches 10-40% of the mold cavity volume, and the sum of the filling volumes of the inner layer material and the outer layer material reaches 102.5-120% of the mold cavity volume, stop injecting the inner layer material and keep injecting the outer layer material continuously. S4: When the filling volume of the outer layer material reaches 108-110% of the mold cavity volume, pressure holding begins. The pressure holding pressure is 30.8-35.2 bar, and the duration is 1.33-4 seconds. When the total filling volume of the outer layer material reaches 119-122.5% of the mold cavity volume, the injection of the outer layer material stops, and the pressure holding ends. After cooling, the cooling temperature is 14-18.3℃, and the cooling time is 3.49-8 seconds, to obtain the high-transparency PET multilayer preform with glass luminescence.

2. The injection molding process according to claim 1, wherein, The filling positions of the inner layer material set by S1 are as follows: at the mold blank opening, the filling position of the inner layer material is located at the radial midpoint between the inner and outer walls of the mold; in the transition zone of the mold, the filling position of the inner layer material gradually shifts radially from the radial midpoint to the inner wall; at the mold blank body, the filling position of the inner layer material is the inner wall surface of the mold.

3. The injection molding process according to claim 1, wherein, The inner layer material comprises PET and colorant.

4. The injection molding process according to claim 3, wherein, The inner layer material also contains a stabilizer.

5. The injection molding process according to claim 1, wherein, The temperature of the mold is 185-320℃.

6. The injection molding process according to claim 1, wherein, The inner layer material and the outer layer material are injected through the inner layer screw and the outer layer screw, respectively. The temperature of the inner layer screw is controlled at 175-310℃, and the temperature of the outer layer screw is 175-300℃.

7. The injection molding process according to claim 1, wherein, Before the inner layer material is injected into S2, the injection speed of the outer layer material is 1.67-13.36 cm. 3 / s; When the inner and outer layers of material are injected simultaneously in S3, the injection speed of the inner layer material is 1-3.5cm. 3 The injection speed of the outer layer material is 1.67-13.36 cm / s. 3 / s; After stopping the injection of the inner layer material in S4, the injection speed of the outer layer material is ≤1.67cm. 3 / s.

8. The injection molding process according to claim 1, wherein, The injection molding process is achieved using a twin-screw ABA-type one-step injection molding machine.

9. A high-transparency PET multilayer preform with glassy gloss, prepared by the injection molding process according to any one of claims 1-8, comprising a transparent outer layer and a colored inner layer, wherein, Along the preform opening, transition zone, and body in sequence, the inner layer gradually shifts radially from between the inner and outer walls of the preform towards the inner wall.

10. The high-transparency PET multilayer preform with glassy luminescence according to claim 9, wherein, At the preform opening, the inner layer is located at the radial midpoint between the inner and outer walls of the mold; in the transition zone of the preform, the inner layer gradually shifts radially from the radial midpoint to the inner wall; at the preform body, the inner layer is located on the inner wall.

11. A high-transparency PET multilayer bottle with glass effect, which is made by blow molding from the high-transparency PET multilayer preform with glass effect as described in claim 9 or 10.

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