Color-through pet multilayer preform and its injection process and pet multilayer bottle

Abstract

The application provides a color-crossing PET multilayer bottle embryo and an injection molding process thereof and a color-crossing PET multilayer bottle. The injection molding process comprises the following steps: first, injecting an outer layer material containing a colorant into a mold cavity; when the outer layer material is filled to 92-95% of the volume of the mold cavity, start injecting an inner layer material containing a colorant; the inner and outer layer materials have different colors; when the sum of the filling volumes of the inner and outer layer materials reaches 108-115% of the volume of the mold cavity, enter a segmented pressure maintaining; when the sum of the filling volumes of the inner and outer layer materials reaches 115-125% of the volume of the mold cavity, stop injecting the layer materials and the outer layer material, and end the pressure maintaining; after cooling, the color-crossing PET multilayer bottle embryo is obtained. The injection molding process controls the injection molding steps of the inner and outer layer materials with different colors, so that the inner layer is turned outwards to the surface of the bottle embryo outer wall, the two color layers cross and change, and the bottle embryo has a color-crossing effect in appearance.

Description

TECHNICAL FIELD

[0001] The present application relates to a color crossover PET multilayer bottle embryo and its injection molding process and color crossover PET multilayer bottle, and belongs to the packaging technical field. BACKGROUND

[0002] With the development of the beverage industry, PET packaging and aseptic filling equipment have emerged and are maturely used in the dairy and other beverage industries. PET bottles have high mechanical strength, variable shapes, can be repeatedly opened and closed, and are convenient to carry. However, most of the packaging bottles on the market are pure colors, which are relatively simple. Even if the multi-color bottle is double-colored, the color change is single, which affects the appearance of the PET bottle. SUMMARY

[0003] To solve the above technical problems, the purpose of the present application is to provide a color crossover PET multilayer bottle embryo and its injection molding process and color crossover PET multilayer bottle. The inner layer of the bottom of the bottle embryo prepared by the injection molding process is turned outwards to the surface of the outer wall of the bottle embryo, realizing the crossover of different color layers.

[0004] To achieve the above purpose, the present application provides a color crossover PET multilayer bottle embryo and its injection molding process, which comprises the following steps:

[0005] First, the outer layer material containing a colorant is injected into the mold cavity. When the outer layer material is filled to 92-95% of the volume of the mold cavity, the inner layer material containing a colorant is started to be injected. The inner layer material and the outer layer material have different colors;

[0006] When the sum of the filling volumes of the inner layer material and the outer layer material reaches 108-115% of the volume of the mold cavity, the segmented pressure maintaining is entered. When the sum of the filling volumes of the inner layer material and the outer layer material reaches 115-125% of the volume of the mold cavity, the injection of the inner layer material and the outer layer material is stopped, and the pressure maintaining is ended;

[0007] After cooling, the color crossover PET multilayer bottle embryo is obtained.

[0008] During the injection process, the inner layer material and the outer layer material are both in liquid state, so the volume ratio described above is calculated based on the volume of the liquid material.

[0009] The injection molding process of the present application controls the entering of the pressure maintaining state during the simultaneous injection of the inner layer material and the outer layer material, so that the inner layer material at the bottom of the bottle embryo is turned outwards to the surface of the outer wall of the bottle embryo. The inner layer material and the outer layer material of different colors are extruded and mixed to a certain extent, realizing the crossover and transformation of the two colors, which is different from the gradual change effect from solid to light color in the prior art.

[0010] According to the specific embodiment of the present application, in the injection molding process, preferably, the inner layer material and the outer layer material respectively contain PET and a colorant, and more preferably, the inner layer material and the outer layer material respectively contain PET, a colorant and a stabilizer. The colorant can be a color masterbatch, and the amount of the colorant added is determined according to the color requirement. The multi-layer bottle preform of the present application contains two colors, for example, the inner layer is green and the outer layer is white.

[0011] The injection molding process of the present application is suitable for all multi-layer bottle preforms with ABA structure manufactured by a twin-screw one-step injection molding process, and the material of the bottle preform is not limited to PET, and modified PET or other plastics suitable for the injection molding process can also be used to achieve the gradual change effect of the bottle preform.

[0012] According to the specific embodiment of the present application, in the injection molding process, preferably, the temperature of the mold is 185-320°C.

[0013] According to the specific embodiment of the present application, in the injection molding process, preferably, the inner layer material and the outer layer material are injected through an inner layer screw and an outer layer screw respectively, the temperature of the inner layer screw is controlled to be 175-310°C, and the temperature of the outer layer screw is 175-300°C.

[0014] In the injection molding process of the present application, the temperature control of the mold and the 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 a bottle preform product with stable appearance. By controlling the temperature of the mold and the screw within the above-mentioned appropriate range, the present application can ensure that all bottle preform materials can be injected under stable injection molding pressure, thereby ensuring that the colorant is uniformly distributed in the material.

[0015] According to the specific embodiment of the present application, in the injection molding process, preferably, before the inner layer material is injected, the injection rate of the outer layer material is 4.7-13 cm / s; and when the inner and outer layer materials are injected simultaneously, the injection rate of the inner layer material is 1-8.64 cm / s; and the injection rate of the outer layer material is 1-4.7 cm / s. 3 3 3

[0016] According to the specific embodiment of the present application, in the injection molding process, preferably, in the segmented pressure maintaining, the first segment pressure is 25-31 bar, the second segment pressure is 32-38 bar, and the third segment pressure is 45-60 bar.

[0017] According to the specific embodiment of the present application, in the injection molding process, preferably, the total time length of the segmented pressure maintaining is 3-4 s; and more preferably, the time length of the first segment pressure maintaining is 1 s, the time length of the second segment pressure maintaining is 1 s, and the time length of the third segment pressure maintaining is 1.5 s.​​​

[0018] In the injection molding process of the present application, the pressure in the segmented pressure maintaining process gradually increases, and the pressure maintaining process can ensure that the bottle preform product is defect-free and has qualified performance.

[0019] According to the specific embodiment of the present application, in the above injection molding process, preferably, the temperature of the cooling is 13-19℃, and the time is 3-4s.

[0020] The injection molding process of the present application can ensure that the colorant (color) in the bottle preform precisely stays at the set position by controlling the pressure and time of pressure maintaining and the temperature and time of cooling, prevent the color from appearing bleeding and deviation, and ensure the color range of the bottle preform and the stability of the overall weight and shape of the bottle preform.

[0021] According to the specific embodiment of the present application, in the above injection molding process, preferably, the injection molding process is realized by a double-screw ABA one-step injection molding machine.

[0022] The present application also provides a color-through PET multi-layer bottle preform, which is made by the above injection molding process.

[0023] According to the specific embodiment of the present application, in the above color-through PET multi-layer bottle preform, preferably, the inner layer of the bottom of the bottle preform is turned outwards to the outer wall surface of the bottle preform.

[0024] The gradient color PET multi-layer bottle preform of the present application has a three-layer sandwich structure, i.e. ABA structure, the outer layers (A layers) are located on both sides, and the inner layer (B layer, or intermediate layer) is located in the middle and is wrapped by the outer layers, but at the bottom of the bottle preform, the inner layer penetrates the outer layer, forming a color-through effect.

[0025] The present application also provides a color-through PET multi-layer bottle, which is made by blow molding from the color-through PET multi-layer bottle preform.

[0026] The technical solution provided by the present application has the following beneficial effects:

[0027] The injection molding process of the color-through PET multi-layer bottle preform of the present application controls the injection molding steps of the inner layer material and the outer layer material of different colors, turns the inner layer outwards to the outer wall surface of the bottle preform, and makes the two color layers penetrate and change, so that the bottle preform has a color-through effect in appearance. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 Appearance diagram of the bottle preform prepared for Example 1;

[0029] Figure 2 Longitudinal sectional view of the bottle preform prepared for Example 1;

[0030] Figure 3Appearance diagram of the multilayer bottle obtained by blow molding the bottle preform of Example 1. DETAILED DESCRIPTION

[0031] In order to have a clearer understanding of the technical features, objectives and beneficial effects of the present application, the technical solutions of the present application are described in detail as follows, but cannot be understood as limiting the implementable scope of the present application.

[0032] Example 1

[0033] The present example provides an injection molding process of color crossover PET multilayer bottle preform, wherein the inner layer material is 0.6wt% green color masterbatch + 99.4wt% PET, and the outer layer material is 1.5wt% red and white color masterbatch + 98.5wt% PET, and the process is realized by using a double-screw ABA type one-step injection molding machine.

[0034] The process comprises the following steps:

[0035] The temperature of the preheated mold is 285℃, and the temperature of the screws A and B is 285℃, the outer layer material is injected into the mold cavity through the screw A at an injection speed of 4.7-13cm / s, when the outer layer material is filled to 95% of the volume of the mold cavity, the inner layer material is injected through the screw B at an injection speed of 1-8.64cm / s, and the injection speed of the outer layer material is reduced to 1-4.7cm / s. 3 3 / s; 3

[0036] When the sum of the filling volumes of the inner layer material and the outer layer material reaches 108% of the volume of the mold cavity, the following segmented pressure maintaining is entered: first pressure maintaining at 30.8bar for 1s, then pressure maintaining at 33bar for 1s, and finally pressure maintaining at 55.2bar for 1.5s; when the sum of the filling volumes of the inner layer material and the outer layer material reaches 120% of the volume of the mold cavity, the injection of the layer material and the outer layer material is stopped;

[0037] Cooling at 13.9℃ for 3s to obtain the color crossover PET multilayer bottle preform.

[0038] The photo of the multilayer bottle preform obtained by the present example is shown in Figure 1 As can be seen from the photo, the bottom of the bottle preform has a color crossover effect. Figure 1

[0039] The above bottle preform is longitudinally cut open, as shown in Figure 2 As can be seen from the photo, the green inner layer of the bottom of the bottle preform is turned outwards to the outer wall surface of the bottle preform, and the green inner layer and the white outer layer crossover and transform, so that the bottle preform has a color crossover effect in appearance.

[0040] The bottle preform of the present example can also be blow molded into a color crossover PET multilayer bottle, and the appearance diagram thereof is shown in Figure 3 ​​​。

Claims

1. A color-crossing PET multilayer preform injection molding process comprising the following steps: The outer layer material containing the colorant is first injected into the mold cavity of the mold, and when the outer layer material is filled to 92-95% of the volume of the mold cavity, the injection of the inner layer material containing the colorant is started, wherein the inner layer material and the outer layer material have different colors; when the sum of the filling volumes of the inner layer material and the outer layer material reaches 108-115% of the volume of the mold cavity, enter the segmented pressure holding, when the sum of the filling volumes of the inner layer material and the outer layer material reaches 115-125% of the volume of the mold cavity, stop injecting the inner layer material and the outer layer material, and end the pressure holding; in the segmented pressure holding, the first segment pressure is 25-31 bar, the second segment pressure is 32-38 bar, and the third segment pressure is 45-60 bar; the total duration of the segmented pressure holding is 3-4 s; after cooling, the cooling temperature is 13-19℃, and the cooling time is 3-4 s, to obtain the color-crossing PET multilayer preform.

2. The injection molding process of claim 1, wherein, the inner layer material and the outer layer material respectively contain PET and a colorant.

3. The injection molding process of claim 2, wherein, the inner layer material and the outer layer material respectively further contain a stabilizer.

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

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

6. The injection molding process of claim 1, wherein, The outer layer material is injected at a rate of 4.7-13 cm 3 / s; the inner layer material is injected at a rate of 1-8.64 cm 3 / s; and the outer layer material is injected at a rate of 1-4.7 cm 3 / s.

7. The injection molding process of claim 1, wherein, the injection molding process is realized by a double-screw ABA one-step injection molding machine.

8. A color-shifting PET multilayer preform, wherein, the color-crossing PET multilayer preform is made by the injection molding process of any one of claims 1-7.

9. The color-shifting PET multi-layered bottle preform according to claim 8, wherein, the inner layer of the bottom of the preform is everted to the outer surface of the preform.

10. A color-crossing PET multilayer bottle made by blow molding the color-crossing PET multilayer preform of claim 8 or 9.

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