PC / PET alloy material and preparation method and application thereof

Abstract

The invention relates to a PC / PET alloy material as well as a preparation method and application thereof, and belongs to the technical field of high polymer materials. The PC / PET alloy material disclosed by the invention is prepared from the following components in parts by weight: 38 to 57 parts of PC resin, 18 to 32 parts of PET resin, 9 to 16 parts of talcum powder, 1.5 to 8 parts of toughening agent and 0.05 to 0.35 part of ester exchange inhibitor, the pH value of the talcum powder is less than 9, and the D50 particle size is 2-3 [mu] m; the intrinsic viscosity of the PET resin is 0.7 to 0.9 dL / g; the ester exchange inhibitor comprises at least one of sodium pyrophosphate and disodium dihydrogen pyrophosphate. The PC resin and the medium-viscosity PET resin are compounded, and the talcum powder with small pH value and small particle size is selected, so that the degradation of PC can be reduced, the shear heat of a PC / PET system is reduced, and good impact performance and good appearance after heat retention are realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer materials, and particularly relates to a PC / PET alloy material, a preparation method thereof and an application thereof. Background Art

[0002] Polycarbonate (PC) has the characteristics of high heat resistance, high strength, good transparency, etc. PET has good creep resistance, fatigue resistance, abrasion resistance, small wear and high hardness; the PC / PET alloy material has excellent low-temperature impact resistance, chemical resistance, high heat resistance, good sprayability, etc., making it widely used in automotive exterior painted products, such as door handles, luggage racks, grilles, etc. In addition, some large-sized exterior parts have higher requirements for the dimensional stability and rigidity of the PC / PET alloy material. Mineral powder-filled PC / PET alloy materials effectively make up for the deficiencies of the former, making it a major trend for automotive exterior parts such as spoilers, roof racks, and skylight trim panels.

[0003] Restricted by existing technical limitations, at present, in this system of materials on the market, due to the easy occurrence of transesterification reaction between PC and PET, and at the same time, the characteristics of the filler itself also have a negative impact on PC and PET. Specifically, during the subsequent injection molding process of the client, the material is unstable and has poor heat retention performance, mainly manifested as appearance defects such as silver streaks, material flowers, and gate halos, which affect subsequent processes such as painting.

[0004] Therefore, it is of great significance to prepare a PC / PET alloy material with good appearance. Summary of the Invention

[0005] The purpose of the present invention is to overcome the problems existing in the above-mentioned prior art, and provide a PC / PET alloy material, a preparation method thereof and an application thereof.

[0006] The present invention is realized through the following technical solutions:

[0007] In the first aspect, the present invention provides a PC / PET alloy material, which comprises the following components in parts by weight: 38-57 parts of PC resin, 18-32 parts of PET resin, 9-16 parts of talcum powder, 1.5-8 parts of toughening agent, 0.05-0.35 parts of transesterification inhibitor; the pH value of the talcum powder < 9, and the D50 particle size is 2 μm - 3 μm; the intrinsic viscosity of the PET resin is 0.7 dL / g - 0.9 dL / g.

[0008] The research of the present invention has found that the pH value of talcum powder affects the appearance after heat retention of the PC / PET system. Talcum powder with a pH value < 9 has a lower alkalinity and is not likely to cause the degradation of PC and PET. Moreover, talcum powder with a D50 particle size in the range of 2 μm - 3 μm has a small particle size, which can enable the alloy material to have a good appearance after heat retention. When combined with a PET resin having an intrinsic viscosity of 0.7 dL / g - 0.9 dL / g, it helps the dispersion of talcum powder and overall improves the mechanical properties of the material and the good appearance after heat retention. If the intrinsic viscosity of the PET resin is too low, it will lead to poor mechanical properties of the material, uneven dispersion of talcum powder, and poor appearance. If the intrinsic viscosity of the PET resin is too high, it will lead to poor processability of the material, which is not conducive to subsequent injection molding.

[0009] Specifically, D50: The particle size corresponding to when the cumulative particle size distribution percentage of a sample reaches 50%. Its physical meaning is that 50% of the particles have a particle size larger than it, and 50% of the particles have a particle size smaller than it. D50 is also called the median diameter or median particle size. D50 is often used to represent the average particle size of powder. The D50 particle size of the talcum powder is measured by a laser particle size analyzer. The detailed test method is to measure the scattered light intensity of talcum powder particles using a laser particle size analyzer and calculate the particle size distribution through optical principles.

[0010] Specifically, the test method for the pH value of the talcum powder refers to ISO 787 / 9 - 2019 "General methods of test for pigments and extenders - Part 9: Determination of pH value of aqueous suspensions". The detailed test method is as follows: Take 10 g of talcum powder, add 100 mL of deionized water, stir for 5 min, let it stand for 60 min, and measure the pH value of the solution using a pH meter.

[0011] Specifically, the test standard for the specific viscosity of the PET resin refers to EN ISO 1628 - 5 - 2015.

[0012] In the PC / PET alloy material of the present invention, the weight parts of the PC resin are any one or the range value of two of 38 parts, 40 parts, 45 parts, 50 parts, 55 parts, and 57 parts; the weight parts of the PET resin are any one or the range value of two of 18 parts, 20 parts, 25 parts, 30 parts, and 32 parts.

[0013] Preferably, in the PC / PET material, the mass percentage content of the PC resin is not less than 45%.

[0014] Preferably, the PC / PET alloy material further includes 0.4 - 1.5 parts of masterbatch.

[0015] Preferably, the PC / PET alloy material further includes 0.05 - 0.35 parts of antioxidant, 0.05 - 0.35 parts of lubricant, and 0.2 - 0.8 parts of weathering agent.

[0016] Preferably, the pH value of the talcum powder is 7.5 - 8.5.

[0017] Preferably, the PC / PET alloy material, by weight, comprises the following components: 40 - 55 parts of PC resin, 20 - 30 parts of PET resin, 10 - 15 parts of talcum powder, 2 - 7 parts of toughening agent, 0.1 - 0.3 part of transesterification inhibitor, 0.1 - 0.3 part of antioxidant, 0.1 - 0.3 part of lubricant, 0.3 - 0.7 part of weathering agent, and 0.5 - 1.2 parts of color masterbatch.

[0018] Preferably, the mass ratio of the PC resin to the PET resin is (1.3 - 2.75):1.

[0019] More preferably, the mass ratio of the PC resin to the PET resin is (1.5 - 2):1.

[0020] Preferably, the melt index of the PC resin according to ISO 1133 - 2012 at a temperature of 300 °C and a load of 1.2 kg is 8 - 12 g / 10 min.

[0021] In the present invention, the PC resin may be transesterification polycarbonate, phosgene polycarbonate, etc.

[0022] Optionally, the PC resin comprises at least one of bisphenol A polycarbonate and siloxane polycarbonate.

[0023] Preferably, the toughening agent comprises a core - shell rubber - type graft copolymer.

[0024] Preferably, the core - shell rubber - type graft copolymer comprises at least one of methyl methacrylate - butadiene - styrene copolymer and silicone rubber graft copolymer; more preferably, the silicone rubber graft copolymer is an alkyl methacrylate - siloxane / alkyl acrylate graft copolymer.

[0025] Specifically, the toughening agent may be at least one of S - 2001 (Mitsubishi Chemical) or EM500 (LG Korea).

[0026] Preferably, the transesterification inhibitor comprises at least one of sodium pyrophosphate and disodium dihydrogen pyrophosphate (DHPP).

[0027] The transesterification inhibitor can react with the catalyst residues in the polyester alloy, thereby inhibiting the transesterification between PC and polyester.

[0028] Preferably, the antioxidant comprises at least one of pentaerythritol ester antioxidant and phosphite antioxidant.

[0029] Preferably, the lubricant includes at least one of pentaerythritol stearate and polydimethylsiloxane.

[0030] Preferably, the weathering agent includes a hindered amine polymer.

[0031] Preferably, the masterbatch includes a black masterbatch.

[0032] In a second aspect, the present invention provides a method for preparing the PC / PET alloy material, comprising the following steps:

[0033] (1) Mix a part of the talcum powder with all the other components evenly to obtain a premix.

[0034] (2) Place the premix obtained in step (1) at the main feeding port of a twin-screw extruder, feed the remaining talcum powder laterally, melt and extrude, pelletize, and dry to obtain the PC / PET alloy material.

[0035] The method for preparing the PC / PET alloy material of the present invention is simple and suitable for industrial production.

[0036] Preferably, in step (1), the part of the talcum powder is 30%-40% of the total weight of the talcum powder.

[0037] Preferably, in step (2), the conditions for the melt extrusion are: the temperature of the first zone is 80-120°C, the temperature of the second zone is 120-160°C, the temperature of the third zone is 220-250°C, the temperature of the fourth zone is 240-270°C, the temperature of the fifth zone is 240-270°C, the temperature of the sixth zone is 250-270°C, the temperature of the seventh zone is 250-270°C, the temperature of the eighth zone is 250-270°C, the temperature of the ninth zone is 250-270°C, and the temperature of the die head is 250-270°C; the screw speed is 400-500 revolutions per minute, and the length-diameter ratio is (38-50):1.

[0038] In a third aspect, the present invention provides the application of the PC / PET alloy material in an automobile.

[0039] The PC / PET alloy material of the present invention has good appearance after heat retention and impact resistance, and can be used for automobile electric tail wings, antenna covers, lidar covers, etc.

[0040] The present invention has the following beneficial effects: The present invention uses a PC resin and a medium-viscosity PET resin in combination, and then selects talcum powder with a pH value <9 and a specific particle size, which can reduce the degradation of PC, reduce the shear heat of the PC / PET system, and thus achieve good impact performance and good appearance after heat retention. The heat retention result is relatively ideal, there are no obvious material flowers on the product surface, and the thermal stability is good. It can be used for sprayed products such as antenna covers and electric tail wings. Detailed Embodiments

[0041] To better illustrate the purpose, technical solution and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments. Those skilled in the art should understand that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0042] Unless otherwise specified, the test methods used in the examples are all conventional methods; the materials, reagents, etc. used, unless otherwise specified, can all be obtained from commercial channels.

[0043] In the following examples and comparative examples, the test method for the pH value of talcum powder is as follows: Take 10 g of talcum powder, add 100 mL of deionized water, stir for 5 min, let stand for 60 min, and use a pH meter to measure the pH value of the solution.

[0044] Examples 1-9

[0045] The composition of the PC / PET alloy material described in the examples of the present invention is shown in Table 1.

[0046] The preparation method of the PC / PET alloy material described includes the following steps:

[0047] (1) Mix 40 wt% of talcum powder with all the other components evenly to obtain a premix;

[0048] (2) Place the premix obtained in step (1) at the main feeding port of a twin-screw extruder, feed the remaining talcum powder from the side, melt and extrude, pelletize, and dry to obtain the PC / PET alloy material;

[0049] The conditions for the melt extrusion are as follows: the temperature of the first zone is 100 °C, the temperature of the second zone is 140 °C, the temperature of the third zone is 235 °C, the temperature of the fourth zone is 255 °C, the temperature of the fifth zone is 255 °C, the temperature of the sixth zone is 260 °C, the temperature of the seventh zone is 260 °C, the temperature of the eighth zone is 260 °C, the temperature of the ninth zone is 260 °C, and the temperature of the die head is 260 °C; the screw speed is 450 revolutions per minute; the length-diameter ratio of the twin-screw extruder is 40:1.

[0050] Comparative Examples 1-7

[0051] The differences between Comparative Examples 1-7 and the examples are only in the types and ratios of the components, as shown in Table 2.

[0052] Among the components described in each example and comparative example,

[0053] The PC resin-1 is: PC CH8105, Cangzhou Dahua Group Co., Ltd., with a melt index of 10 g / 10 min at 300 °C and a load of 1.2 kg according to ISO 1133-2012;

[0054] The PC resin-2 is: PC CH100-0R-L, China SABIC (Tianjin) Petrochemical, the melt index at 300°C and 1.2kg load according to ISO 1133-2012 is 11g / 10min;

[0055] The PET resin-1 is: PET CB-608S, Shanghai Yuanfang, with an intrinsic viscosity of 0.865 dL / g;

[0056] The PET resin-2 is: PET BG80, Yizheng Chemical Fiber, with an intrinsic viscosity of 0.791 dL / g;

[0057] The PET resin-3 is: PET FG600, Yizheng Chemical Fiber, with an intrinsic viscosity of 0.600 dL / g;

[0058] The talc powder-1 is: Finntalc M05SLC, Hemmings, with a D50 particle size of 2.2 μm and a pH value of 8.32;

[0059] The talc-2 is: STEAMIC 00S CA, Yirui stone, D50 particle size is 2.3 μm, pH value is 8.40;

[0060] The talc-3 is: M550C, Magris Talc, D50 particle size is 2.2 μm, pH value is 7.89;

[0061] The talc-4 is: HTP Ultra 5L, Italian-American, with a D50 particle size of 0.5 μm and a pH value of 9.02;

[0062] The talc powder-5 is: MISTRONCB, Yirui stone, D50 particle size is 2.2μm, pH value is 9.2;

[0063] The talc-6 is: M625C, Magris Talc, D50 particle size is 1.3 μm, pH value is 7.84;

[0064] The talc powder-7 is: SDC-8489, Liaoning Xinda Talc Group Co., Ltd., with a D50 particle size of 4.6 μm and a pH value of 9.36;

[0065] The toughening agent is: organic silicone rubber graft copolymer, S-2001, Mitsubishi Chemical;

[0066] The ester exchange inhibitor-1 is: disodium dihydrogen pyrophosphate, Heitai chemical;

[0067] The transesterification inhibitor-2 is: bisphenol A-bis(diphenyl phosphate), Zhejiang Wansheng Co., Ltd.;

[0068] The antioxidant is: primary antioxidant 1010 and secondary antioxidant 168 mixed in a mass ratio of 1:2, from Ciba Specialty Chemicals Shanghai Co., Ltd.;

[0069] The lubricant: pentaerythritol stearate, commercially available;

[0070] The weathering agent: hindered amine polymer, commercially available;

[0071] The masterbatch: black masterbatch, black species CB5093, from Muil Chemical Co., Ltd., Korea;

[0072] Unless otherwise specified, the component raw materials used in the examples and comparative examples of the present invention are all commercially available raw materials, and the component raw materials used in each parallel experiment are of the same kind.

[0073] Table 1 Component contents (parts) in the materials of Examples 1-9

[0074]

[0075] Table 2 Component contents (parts) in the materials of Comparative Examples 1-7

[0076]

[0077]

[0078] The PC / PET alloy materials prepared in each example and comparative example were subjected to the following performance tests, specifically as follows:

[0079] 1. Charpy impact strength: Tested in accordance with ISO 179-1:2010, injection molded into standard specimens, and the test conditions were 23°C and -30°C;

[0080] 2. Tensile strength: Tested in accordance with ISO 527-1-2012, injection molded into standard specimens, and the test conditions were 23°C and a rate of 50 mm / min;

[0081] 3. Flexural modulus: Tested in accordance with ISO 178-2019, injection molded into standard specimens, and the test conditions were 23°C and a rate of 2 mm / min;

[0082] 4. Appearance: After drying the material particles at 120°C for 6 h, heat retaining at 270°C for 10 min, and then injection molding into a combustion plate of 356 mm × 100 mm × 3 mm, visually observe the surface of the sample for material flowers / silver streaks. The surface without material flowers / silver streaks is rated as grade 5, the surface with slight changes is rated as grade 4, the surface with material flowers / silver streaks area less than one-third is rated as grade 3, the surface with material flowers / silver streaks area from one-third to half is rated as grade 2, and the surface with material flowers / silver streaks area greater than half is rated as grade 1.

[0083] The test results are shown in Tables 3 and 4.

[0084] Table 3 Test Results of Material Properties of Examples 1-9

[0085]

[0086] Table 4 Test Results of Material Properties of Comparative Examples 1-7

[0087]

[0088] From the test results in Tables 3-4, it can be seen that the PC / PET alloy material of the present invention has excellent mechanical properties and good appearance after heat retention. The tensile strength can reach more than 60 MPa, the flexural modulus is not less than 4000 MPa, and the impact strength at room temperature is not less than 8 kJ / m 2 , and the impact strength at -30 °C is not less than 5 kJ / m 2 , and the appearance evaluation is not less than Grade 4.

[0089] It can be seen from Comparative Example 1 that the lack of PET resin will lead to a decrease in impact performance. In Comparative Example 2, the viscosity of the PET resin is too low, resulting in agglomeration of talcum powder in the system and poor appearance. In Comparative Example 3, both the particle size and pH value of the talcum powder are not good, resulting in a decrease in impact performance and poor appearance; in Comparative Example 4, the pH value of the talcum powder is relatively large, resulting in serious PC degradation and very poor appearance. In Comparative Example 5, the particle size of the talcum powder is too small, resulting in low impact, poor appearance, and pinholes on the surface. In Comparative Example 6, the particle size of the talcum powder is too large and the alkalinity is too strong, resulting in serious PC degradation, very poor appearance, and uneven surface. In Comparative Example 7, a phosphate compound is used as an ester exchange inhibitor. Due to the low heat resistance of the phosphate, it will lead to a decrease in modulus, a significant decrease in impact, and average appearance.

[0090] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A PC / PET alloy material, characterized in that, By weight parts, it comprises the following components: 38 - 57 parts of PC resin, 18 - 32 parts of PET resin, 9 - 16 parts of talcum powder, 1.5 - 8 parts of toughening agent, 0.05 - 0.35 parts of transesterification inhibitor; the pH value of the talcum powder < 9, and the D50 particle size is 2 μm - 3 μm; the intrinsic viscosity of the PET resin is 0.7 dL / g - 0.9 dL / g; the transesterification inhibitor comprises at least one of sodium pyrophosphate and disodium dihydrogen pyrophosphate.

2. The PC / PET alloy material according to claim 1, wherein The mass ratio of the PC resin to the PET resin is (1.3 - 2.75):

1.

3. The PC / PET alloy material according to claim 1 or 2, characterized in that, The mass ratio of the PC resin to the PET resin is (1.5 - 2):

1.

4. The PC / PET alloy material according to claim 1, wherein The melt index of the PC resin according to ISO 1133 - 2012 at a temperature of 300 °C and a load of 1.2 kg is 8 - 12 g / 10 min.

5. The PC / PET alloy material according to claim 1, wherein, The PC / PET alloy material further comprises 0.4 - 1.5 parts of color masterbatch; and / or, it further comprises 0.05 - 0.35 parts of antioxidant, 0.05 - 0.35 parts of lubricant, 0.2 - 0.8 parts of weathering agent.

6. The PC / PET alloy material according to claim 1, characterized in that, The toughening agent comprises a core - shell rubber - type graft copolymer.

7. The PC / PET alloy material according to claim 6, characterized in that, The core - shell rubber - type graft copolymer comprises at least one of methyl methacrylate - butadiene - styrene copolymer and silicone rubber graft copolymer.

8. The PC / PET alloy material according to claim 5, characterized in that, The weathering agent comprises a hindered amine polymer; and / or, the antioxidant comprises at least one of pentaerythritol ester antioxidant and phosphite antioxidant; and / or, the lubricant comprises at least one of pentaerythritol stearate and polydimethylsiloxane.

9. The preparation method of the PC / PET alloy material according to any one of claims 1-8, characterized in that, It comprises the following steps: (1) Mix part of the talcum powder with all the other components evenly to obtain a premix. (2) Place the premix obtained in step (1) at the main feeding port of a twin - screw extruder, feed the remaining talcum powder laterally, melt - extrude, pelletize, and dry to obtain the PC / PET alloy material.

10. The application of the PC / PET alloy material according to any one of claims 1 - 8 in an automobile.

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