PC composite material and low-temperature rapid forming process thereof

Abstract

The invention relates to a PC composite material and a low-temperature rapid forming process thereof, and belongs to the technical field of PC composite materials. The invention provides a low-temperature rapid molding process of a PC composite material, which comprises the following steps: adding PC and hydroxyl-terminated hyperbranched polyester in the front section of extrusion of a twin-screw extruder, carrying out melt blending, injecting pentaerythritol tetraacrylate in the middle section of extrusion, mixing, adding chopped glass fiber, Exoit OP 1240 and an antioxidant in the rear section of extrusion, mixing, carrying out extrusion granulation to obtain PC composite particles, and carrying out injection molding and cooling molding to obtain the low-temperature rapid molding PC composite material. And the obtained injection molding product can be applied to a new energy automobile battery shell. According to the invention, a double-screw extruder is used for adding different raw materials in sections, controlling the temperature of section treatment and performing grafting treatment on the PC material, so that the compatibility and low-temperature fluidity among the components are improved, meanwhile, the injection molding process is controlled, the curing efficiency is improved, the cooling period is shortened, and low-temperature rapid molding is realized.

Description

Technical Field

[0001] The invention belongs to the technical field of PC composite materials and relates to a PC composite material and a low-temperature rapid prototyping process thereof. Background Art

[0002] Amid the rapid growth of the new energy vehicle industry, demands for lightweight, safe, and cost-effective battery housings are becoming increasingly urgent. This trend is driven not only by improving vehicle range and energy efficiency but also by addressing increasingly stringent environmental regulations and market competition. Against this backdrop, research into low-temperature injection molding processes for polycarbonate (PC) materials is of significant practical significance.

[0003] First, traditional injection molding processes are usually carried out at higher temperatures, which will to some extent cause thermal degradation of PC materials and damage their mechanical properties. This has a greater impact on certain structures that require precision performance but are easily subjected to external environmental shock and vibration, such as new energy vehicle battery housings. Secondly, in order to improve the performance of PC materials, processing requirements are currently met by introducing additives and modification treatments, but high temperature conditions may affect the expression of the performance of these components, and ultimately fail to achieve efficient performance conversion. Finally, traditional high-temperature injection molding will produce higher energy consumption, which not only increases costs but also easily has adverse effects on the environment, which is not in line with environmental protection concepts. Summary of the Invention

[0004] The present invention aims to provide a PC composite material and a low-temperature rapid prototyping process thereof. The present invention uses a twin-screw extruder to add different raw materials in sections, controls the temperature of the sectioned treatment, and performs a grafting treatment on the PC material to improve the compatibility and low-temperature fluidity between the components. At the same time, the injection molding process is controlled to improve the curing efficiency, reduce the cooling cycle, and achieve low-temperature rapid prototyping.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A low-temperature rapid prototyping process for PC composite materials, comprising the following steps:

[0007] S1, adding PC and hydroxyl-terminated hyperbranched polyester to the front section of a twin-screw extruder, melt blending, injecting pentaerythritol tetraacrylate into the middle section of the extrusion and mixing, and finally adding chopped glass fiber, Exolit OP 1240, and an antioxidant to the back section of the extrusion, mixing, and extruding and granulating to obtain PC composite particles;

[0008] S2. Injection molding the PC composite particles and cooling them to form a mold.

[0009] Furthermore, the raw materials of the PC composite particles in step S1 include, by weight, 80-88 parts of PC, 4-6 parts of hydroxyl-terminated hyperbranched polyester, 2-4 parts of pentaerythritol tetraacrylate, 4-6 parts of chopped glass fibers, 1.5-2.5 parts of Exolit OP 1240, and 0.1-0.3 parts of an antioxidant.

[0010] Furthermore, the shear rate of the twin-screw extruder in step S1 is 400-600s -1 ; The die head temperature during extrusion is 180-190°C.

[0011] Furthermore, in step S1, the temperature of the front section of the extrusion is 240-260° C.; and the time of the melt blending is 11-15 seconds.

[0012] Furthermore, in step S1, the temperature of the middle section of the extrusion is 261-265° C.; and the mixing time is 25-35 seconds.

[0013] Furthermore, in step S1, the temperature of the latter section of the extrusion is 210-220° C.; and the mixing time is 8-12 s.

[0014] Furthermore, the injection molding in step S2 refers to setting the shear rate to 100-500s -1 , put the PC composite particles into the barrel of the injection molding machine and then inject them into the mold.

[0015] Furthermore, the barrel temperature of the injection molding machine is set to 195-205°C in the front section, 200-210°C in the middle section, and 205-215°C in the rear section.

[0016] Furthermore, the parameters when injecting into the mold are: injection pressure of 80-100 MPa, injection speed of 70-90 mm / s; the surface layer of the mold is high-frequency heated to a temperature of 115-125°C, and the inner layer temperature is 75-85°C; the high frequency refers to 60-100 kW.

[0017] Furthermore, the PC composite material is applied to battery housings of new energy vehicles.

[0018] Beneficial effects of the present invention:

[0019] The present invention adds PC and hydroxyl-terminated hyperbranched polyester in the front section of extrusion. The terminal hydroxyl groups of the hyperbranched polyester form hydrogen bonds with the ester groups of the PC, thereby improving the compatibility of the two phases. In addition, the branched structure of the hydroxyl-terminated hyperbranched polyester can break the rigid arrangement of the PC linear chains and form entanglements with the PC linear chains, thereby reducing friction between the molecular chains, further reducing the melt viscosity, and imparting low-temperature fluidity to the material. Then, pentaerythritol tetraacrylate is added in the middle section of extrusion. The multifunctional groups of the pentaerythritol tetraacrylate undergo a grafting reaction with the PC / hydroxyl-terminated hyperbranched polyester molecular chains to form a cross-linked network on the surface layer, thereby improving the structural strength and resisting external collision and extrusion deformation. Finally, chopped glass fibers, Exolit OP 1240, and an antioxidant are added in the back section of extrusion. At the same time, a relatively low temperature is used to uniformly disperse the various phases, thereby avoiding high-temperature decomposition or fracture of the material and further improving the performance of the material. Finally, low-temperature and relatively high-pressure injection is used to compensate for the melt fluidity. By dynamically controlling the mold temperature, the outer layer is accelerated to be cured at a high temperature, while the inner layer is controlled at a relatively low temperature to maintain the molecular chain fluidity, thereby ensuring filling integrity, thereby improving curing efficiency, reducing the cooling cycle, and achieving low-temperature rapid molding. DETAILED DESCRIPTION

[0020] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, the specific implementation methods, structures, features and effects of the present invention are described in detail below in combination with the embodiments.

[0021] The PC in all the embodiments and comparative examples of the present invention were purchased directly from the market, and were purchased from Guangdong Xinlong New Materials Co., Ltd.; the terminal hydroxyl hyperbranched polyester and pentaerythritol tetraacrylate were purchased directly from the market, and were purchased from Guangdong Fangxin Biotechnology Co., Ltd.; the chopped glass fibers were purchased directly from the market, and were purchased from Tai'an Yilin New Materials Co., Ltd.; Exolit OP 1240 were purchased directly from the market, and were purchased from Suzhou Jingyan New Materials Co., Ltd.; and the antioxidants 1010 were purchased directly from the market, and were purchased from Sigma-Aldrich (Shanghai) Trading Co., Ltd.

[0022] Example 1

[0023] A low-temperature rapid prototyping process for PC composite materials, comprising the following steps:

[0024] S1, adding PC and hydroxyl-terminated hyperbranched polyester to the front section of a twin-screw extruder, melt blending, injecting pentaerythritol tetraacrylate into the middle section of the extrusion and mixing, and finally adding chopped glass fiber, Exolit OP 1240, and antioxidant 1010 to the back section of the extrusion and mixing, extruding and granulating to obtain PC composite particles;

[0025] S2. Injection molding the PC composite particles and cooling them to form a mold.

[0026] The raw materials of the PC composite particles in step S1 include, by weight, 80 parts of PC, 4 parts of hydroxyl-terminated hyperbranched polyester, 2 parts of pentaerythritol tetraacrylate, 4 parts of chopped glass fibers, 1.5 parts of Exolit OP 1240, and 0.1 parts of antioxidant 1010.

[0027] The shear rate of the twin-screw extruder in step S1 is 400s -1 ; The die head temperature during extrusion is 180°C.

[0028] In step S1, the temperature of the front section of the extrusion is 240° C.; and the time of the melt blending is 11 s.

[0029] In step S1, the temperature of the middle section of the extrusion is 261° C.; and the mixing time is 25 s.

[0030] The temperature of the latter section of the extrusion in step S1 is 210° C.; and the mixing time is 8 s.

[0031] The injection molding in step S2 refers to setting the shear rate to 100s -1 , put the PC composite particles into the barrel of the injection molding machine and then inject them into the mold.

[0032] The injection molding machine barrel temperature was set to 195°C in the front section, 200°C in the middle section, and 205°C in the rear section.

[0033] The parameters when injecting into the mold are: injection pressure of 80 MPa, injection speed of 70 mm / s; the surface layer of the mold is heated to a temperature of 115°C at high frequency, and the inner layer temperature is 75°C; the high frequency refers to 60kW.

[0034] The PC composite material is applied to battery casings of new energy vehicles.

[0035] Example 2

[0036] A low-temperature rapid prototyping process for PC composite materials, comprising the following steps:

[0037] S1, adding PC and hydroxyl-terminated hyperbranched polyester to the front section of a twin-screw extruder, melt blending, injecting pentaerythritol tetraacrylate into the middle section of the extrusion and mixing, and finally adding chopped glass fiber, Exolit OP 1240, and antioxidant 1010 to the back section of the extrusion and mixing, extruding and granulating to obtain PC composite particles;

[0038] S2. Injection molding the PC composite particles and cooling them to form a mold.

[0039] The raw materials of the PC composite particles in step S1 include, by weight, 81 parts of PC, 4.7 parts of hydroxyl-terminated hyperbranched polyester, 2.6 parts of pentaerythritol tetraacrylate, 4.5 parts of chopped glass fibers, 1.8 parts of Exolit OP 1240, and 0.18 parts of antioxidant 1010.

[0040] The shear rate of the twin-screw extruder in step S1 is 480s -1 ; The die head temperature during the extrusion was 182°C.

[0041] The temperature of the front section of the extrusion in step S1 is 246° C.; the time of the melt blending is 12 s.

[0042] The temperature of the middle section of the extrusion in step S1 is 262° C.; and the mixing time is 28 s.

[0043] The temperature of the latter section of the extrusion in step S1 is 212° C.; and the mixing time is 9 s.

[0044] The injection molding in step S2 refers to setting the shear rate to 200s -1 , put the PC composite particles into the barrel of the injection molding machine and then inject them into the mold.

[0045] The barrel temperature of the injection molding machine was set to 197°C in the front section, 203°C in the middle section, and 208°C in the rear section.

[0046] The parameters when injecting into the mold are: injection pressure of 85 MPa, injection speed of 75 mm / s; the surface layer of the mold is high-frequency heated to a temperature of 118°C, and the inner layer temperature is 78°C; the high frequency refers to 70kW.

[0047] The PC composite material is applied to battery casings of new energy vehicles.

[0048] Example 3

[0049] A low-temperature rapid prototyping process for PC composite materials, comprising the following steps:

[0050] S1, adding PC and hydroxyl-terminated hyperbranched polyester to the front section of a twin-screw extruder, melt blending, injecting pentaerythritol tetraacrylate into the middle section of the extrusion and mixing, and finally adding chopped glass fiber, Exolit OP 1240, and antioxidant 1010 to the back section of the extrusion and mixing, extruding and granulating to obtain PC composite particles;

[0051] S2. Injection molding the PC composite particles and cooling them to form a mold.

[0052] The raw materials of the PC composite particles in step S1 include, by weight, 84 parts of PC, 5 parts of hydroxyl-terminated hyperbranched polyester, 3 parts of pentaerythritol tetraacrylate, 5 parts of chopped glass fibers, 2 parts of Exolit OP 1240, and 0.2 parts of antioxidant 1010.

[0053] The shear rate of the twin-screw extruder in step S1 is 500s -1 ; The die head temperature during the extrusion is 185°C.

[0054] The temperature of the front section of the extrusion in step S1 is 250° C.; the time of the melt blending is 13 s.

[0055] In step S1, the temperature of the middle section of the extrusion is 263° C.; and the mixing time is 30 s.

[0056] The temperature of the latter section of the extrusion in step S1 is 215° C.; and the mixing time is 10 s.

[0057] The injection molding in step S2 refers to setting the shear rate to 300s -1 , put the PC composite particles into the barrel of the injection molding machine and then inject them into the mold.

[0058] The injection molding machine barrel temperature was set to 200°C in the front section, 205°C in the middle section, and 210°C in the rear section.

[0059] The parameters when injecting into the mold are: injection pressure of 90 MPa, injection speed of 80 mm / s; the surface layer of the mold is heated to a temperature of 120°C at high frequency, and the inner layer temperature is 80°C; the high frequency refers to 80kW.

[0060] The PC composite material is applied to battery casings of new energy vehicles.

[0061] Example 4

[0062] A low-temperature rapid prototyping process for PC composite materials, comprising the following steps:

[0063] S1, adding PC and hydroxyl-terminated hyperbranched polyester to the front section of a twin-screw extruder, melt blending, injecting pentaerythritol tetraacrylate into the middle section of the extrusion and mixing, and finally adding chopped glass fiber, Exolit OP 1240, and antioxidant 1010 to the back section of the extrusion and mixing, extruding and granulating to obtain PC composite particles;

[0064] S2. Injection molding the PC composite particles and cooling them to form a mold.

[0065] The raw materials of the PC composite particles in step S1 include, by weight, 86 parts of PC, 5.5 parts of hydroxyl-terminated hyperbranched polyester, 3.5 parts of pentaerythritol tetraacrylate, 5.5 parts of chopped glass fibers, 2.2 parts of Exolit OP 1240, and 0.25 parts of antioxidant 1010.

[0066] The shear rate of the twin-screw extruder in step S1 is 550s -1 ; The die head temperature during the extrusion is 188°C.

[0067] The temperature of the front section of the extrusion in step S1 is 255° C.; the time of the melt blending is 14 s.

[0068] The temperature of the middle section of the extrusion in step S1 is 264° C.; and the mixing time is 32 seconds.

[0069] The temperature of the latter section of the extrusion in step S1 is 218° C.; and the mixing time is 11 s.

[0070] The injection molding in step S2 refers to setting the shear rate to 400s -1 , put the PC composite particles into the barrel of the injection molding machine and then inject them into the mold.

[0071] The injection molding machine barrel temperature was set to 202°C in the front section, 208°C in the middle section, and 212°C in the rear section.

[0072] The parameters when injecting into the mold are: injection pressure of 95 MPa, injection speed of 85 mm / s; the surface layer of the mold is heated to a temperature of 123°C at high frequency, and the inner layer temperature is 82°C; the high frequency refers to 90kW.

[0073] The PC composite material is applied to battery casings of new energy vehicles.

[0074] Example 5

[0075] A low-temperature rapid prototyping process for PC composite materials, comprising the following steps:

[0076] S1, adding PC and hydroxyl-terminated hyperbranched polyester to the front section of a twin-screw extruder, melt blending, injecting pentaerythritol tetraacrylate into the middle section of the extrusion and mixing, and finally adding chopped glass fiber, Exolit OP 1240, and antioxidant 1010 to the back section of the extrusion and mixing, extruding and granulating to obtain PC composite particles;

[0077] S2. Injection molding the PC composite particles and cooling them to form a mold.

[0078] The raw materials of the PC composite particles in step S1 include, by weight, 88 parts of PC, 6 parts of hydroxyl-terminated hyperbranched polyester, 4 parts of pentaerythritol tetraacrylate, 6 parts of chopped glass fibers, 2.5 parts of Exolit OP 1240, and 0.3 parts of antioxidant 1010.

[0079] The shear rate of the twin-screw extruder in step S1 is 600s -1 ; The die head temperature during the extrusion is 190°C.

[0080] In step S1, the temperature of the front section of the extrusion is 260° C.; and the time of the melt blending is 15 s.

[0081] In step S1, the temperature of the middle section of the extrusion is 265° C.; and the mixing time is 35 seconds.

[0082] The temperature of the latter section of the extrusion in step S1 is 220° C.; and the mixing time is 12 s.

[0083] The injection molding in step S2 refers to setting the shear rate to 500s -1 , put the PC composite particles into the barrel of the injection molding machine and then inject them into the mold.

[0084] The injection molding machine barrel temperature was set to 205°C in the front section, 210°C in the middle section, and 215°C in the rear section.

[0085] The parameters when injecting into the mold are: injection pressure of 100 MPa, injection speed of 90 mm / s; the surface layer of the mold is heated to a temperature of 125°C at high frequency, and the inner layer temperature is 85°C; the high frequency refers to 100 kW.

[0086] The PC composite material is applied to battery casings of new energy vehicles.

[0087] Comparative Example 1

[0088] On the basis of Example 3, keeping other conditions the same, the low-temperature rapid prototyping process is changed to the following steps:

[0089] S1, adding PC to the front section of the twin-screw extruder, melt blending, injecting terminal hydroxyl hyperbranched polyester and pentaerythritol tetraacrylate into the middle section of the extrusion and mixing, and finally adding chopped glass fiber, Exolit OP 1240, and antioxidant 1010 into the rear section of the extrusion and mixing, extruding and granulating to obtain PC composite particles;

[0090] S2. Injection molding the PC composite particles and cooling them to form a mold.

[0091] Comparative Example 2

[0092] On the basis of Example 3, keeping other conditions the same, the low-temperature rapid prototyping process is changed to the following steps:

[0093] S1. Add PC, hydroxyl-terminated hyperbranched polyester, and pentaerythritol tetraacrylate into a twin-screw extruder and melt blend at a temperature of 250° C. for 43 seconds. Then add chopped glass fiber, Exolit OP 1240, and antioxidant 1010 and mix. Then, add chopped glass fiber, Exolit OP 1240, and antioxidant 1010 and mix at a temperature of 215° C. for 10 seconds. Then, extrude and granulate to obtain PC composite particles.

[0094] S2. Injection molding the PC composite particles and cooling them to form a mold.

[0095] Comparative Example 3

[0096] On the basis of Example 3, keeping other conditions the same, the low-temperature rapid prototyping process is changed to the following steps:

[0097] S1. Add PC, hydroxyl-terminated hyperbranched polyester, and pentaerythritol tetraacrylate into a twin-screw extruder and melt blend at a temperature of 263° C. for 43 seconds. Then add chopped glass fiber, Exolit OP 1240, and antioxidant 1010 and mix. Then, extrude and granulate at a temperature of 215° C. for 10 seconds to obtain PC composite particles.

[0098] S2. Injection molding the PC composite particles and cooling them to form a mold.

[0099] Comparative Example 4

[0100] On the basis of Example 3, keeping other conditions the same, the low-temperature rapid prototyping process is changed to the following steps:

[0101] S1. Add PC, hydroxyl-terminated hyperbranched polyester, pentaerythritol tetraacrylate, chopped glass fiber, Exolit OP 1240, and antioxidant 1010 into a twin-screw extruder, mix at 250°C for 13 seconds, then at 263°C for 30 seconds, and finally at 215°C for 10 seconds, and extrude and granulate to obtain PC composite particles.

[0102] S2. Injection molding the PC composite particles and cooling them to form a mold.

[0103] Comparative Example 5

[0104] On the basis of Example 3, other conditions were kept the same, and the surface temperature of the mold was changed to 110°C.

[0105] Comparative Example 6

[0106] On the basis of Example 3, other conditions were kept the same, and the surface temperature of the mold was changed to 130°C.

[0107] Comparative Example 7

[0108] On the basis of Example 3, other conditions were kept the same, and the inner layer temperature of the mold was changed to 70°C.

[0109] Comparative Example 8

[0110] On the basis of Example 3, other conditions were kept the same, and the inner layer temperature of the mold was changed to 90°C.

[0111] The PC composite materials prepared in Examples 1-5 and Comparative Examples 1-8 were used as samples, and the cooling molding time of the samples was recorded as shown in Table 1 below. The glossiness of the samples was tested with reference to ASTM D523-2014. The glossiness reflects whether the properties of the samples are uniform and flat. The test results are recorded in Table 1 below. The notched impact strength of the samples was tested according to GB / T 1843-2008. The test results are recorded in Table 1 below.

[0112] Table 1

[0113]

[0114]

[0115] As can be seen from Table 1, the PC composite material prepared by the present invention can achieve rapid molding at a relatively low temperature, and the obtained finished product has a smooth and uniform appearance, good glossiness, and good impact resistance.

[0116] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment as above, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to equivalent embodiments using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any indirect modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A low-temperature rapid prototyping process for PC composite materials, characterized by: The low-temperature rapid prototyping process comprises the following steps: S1, adding PC and hydroxyl-terminated hyperbranched polyester to the front section of a twin-screw extruder, melt blending, injecting pentaerythritol tetraacrylate into the middle section of the extrusion and mixing, and finally adding chopped glass fiber, Exolit OP 1240, and an antioxidant to the back section of the extrusion, mixing, and extruding and granulating to obtain PC composite particles; S2. Injection molding the PC composite particles and cooling them to form a mold.

2. The low-temperature rapid prototyping process for PC composite materials according to claim 1, characterized in that: The raw materials of the PC composite particles in step S1 include, by weight, 80-88 parts of PC, 4-6 parts of hydroxyl-terminated hyperbranched polyester, 2-4 parts of pentaerythritol tetraacrylate, 4-6 parts of chopped glass fibers, 1.5-2.5 parts of Exolit OP 1240, and 0.1-0.3 parts of an antioxidant.

3. The low-temperature rapid prototyping process of a PC composite material according to claim 1, characterized in that: The shear rate of the twin-screw extruder in step S1 is 400-600s -1 ; The die head temperature during extrusion is 180-190°C.

4. The low-temperature rapid prototyping process for PC composite materials according to claim 1, characterized in that: In step S1, the temperature of the front section of the extrusion is 240-260° C.; and the time of the melt blending is 11-15 seconds.

5. The low-temperature rapid prototyping process for PC composite materials according to claim 1, characterized in that: In step S1, the temperature of the middle section of the extrusion is 261-265° C.; and the mixing time is 25-35 seconds.

6. The low-temperature rapid prototyping process for PC composite materials according to claim 1, characterized in that: In step S1, the temperature of the latter section of the extrusion is 210-220° C.; and the mixing time is 8-12 seconds.

7. The low-temperature rapid prototyping process for PC composite materials according to claim 1, characterized in that: The injection molding in step S2 refers to setting the shear rate to 100-500s -1 , put the PC composite particles into the barrel of the injection molding machine and then inject them into the mold.

8. The low-temperature rapid prototyping process for PC composite materials according to claim 7, characterized in that: The injection molding machine barrel temperature is set to 195-205°C in the front section, 200-210°C in the middle section, and 205-215°C in the rear section.

9. The low-temperature rapid prototyping process for PC composite materials according to claim 7, characterized in that: The parameters when injecting into the mold are: injection pressure of 80-100MPa, injection speed of 70-90mm / s; the surface layer of the mold is high-frequency heated to a temperature of 115-125°C, and the inner layer temperature is 75-85°C; the high frequency refers to 60-100kW.

10. An application of the PC composite material prepared by the low-temperature rapid prototyping process of the PC composite material according to claims 1 to 8, characterized in that: The PC composite material is applied to battery casings of new energy vehicles.

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