PC / PBT (polycarbonate / polybutylene terephthalate) composition as well as preparation method and application thereof

Abstract

The invention discloses a PC / PBT (polycarbonate / polybutylene terephthalate) composition as well as preparation and application thereof. The PC / PBT composition comprises the following components in parts by weight: 18-62 parts of PC resin; 13 to 47 parts of PBT resin; 0.05 to 2.5 parts of a transesterification inhibitor; wherein the ester exchange inhibitor comprises an acidic buffering agent and basic sodium pyrophosphate. In the PC / PBT composition system, the acidic buffer agent and the basic sodium pyrophosphate are added as ester exchange inhibitors, so that the prepared PC / PBT composition has better chemical resistance, fatigue resistance stability and better size stability.

Description

Technical Field

[0001] This invention belongs to the field of engineering plastics technology, specifically relating to a PC / PBT composition, its preparation method, and its application. Background Technology

[0002] Polycarbonate (PC) / polybutylene terephthalate (PBT) alloys possess excellent toughness and good appearance properties, making them widely used in medical and healthcare, clean energy, and kitchen appliances. Industries such as medical devices and clean energy are prone to contact with chemical reagents such as disinfectants and electrolytes. To extend equipment lifespan and improve safety, these industries place high demands on the chemical resistance of the selected plastic shell materials. However, both PC and PBT are polyester materials with a certain degree of reactivity, which can affect the mechanical and chemical resistance properties of the alloy. Furthermore, high-end medical equipment applications (such as quadruped robots) require high dimensional stability to ensure precision. PBT has a low glass transition temperature and, especially at temperatures above 60°C, can still exhibit slow crystallization, leading to significant post-shrinkage and affecting the precision and functionality of the equipment. Additionally, medical robots often come into contact with chemical reagents, necessitating high chemical resistance.

[0003] To ensure the mechanical and solvent resistance properties of PC / PBT alloys, existing technologies typically employ traditional hydrogen phosphate or hydrogen pyrophosphate as inhibitors of transesterification reactions in PC / PBT alloys. This prevents excessive transesterification from affecting the crystallization of the PBT phase. However, this approach has limited effectiveness, and the chemical and mechanical properties of the material still decrease to some extent after repeated thermal histories. Furthermore, this technique cannot inhibit the crystallization behavior of the PBT phase after injection molding, resulting in significant post-molding shrinkage. Reducing the proportion of PBT in PC / PBT alloys can decrease post-molding shrinkage, but it leads to a significant reduction in the material's chemical resistance. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of existing PC / PBT alloy materials in that they cannot simultaneously possess fatigue resistance, chemical resistance, and dimensional stability, and to provide a PC / PBT composition.

[0005] Another object of the present invention is to provide a method for preparing the PC / PBT composition.

[0006] Another object of the present invention is to provide the application of the PC / PBT composition.

[0007] To achieve the above objectives, the present invention employs the following technical solution:

[0008] A PC / PBT composition comprising the following components in parts by weight: 18-62 parts of PC resin; 13-47 parts of PBT resin; Transesterification inhibitor 0.05~2.5 parts; The transesterification inhibitor includes an acidic buffer and basic sodium pyrophosphate.

[0009] This invention provides a PC / PBT composition in which an acidic buffer (providing a weakly acidic environment) and basic sodium pyrophosphate are added as transesterification inhibitors to the PC / PBT system. This can simultaneously ensure the solvent resistance and fatigue resistance of the PC / PBT composition. Specifically, during processing, basic sodium pyrophosphate will generate Na2HPO3 in situ at the PC / PBT processing temperature and in a weakly acidic environment, which can maintain the acid stability of the system, inhibit the transesterification reaction between PC resin and PBT resin, and inhibit the reaction of the end groups of PBT resin, thereby improving fatigue resistance.

[0010] It should be noted that, in the PC / PBT composition described in this invention, the content of PC resin is preferably not less than 30 wt%.

[0011] It should be noted that the PC resin mentioned in this invention is 18 to 62 parts, for example, but not limited to 18 parts, 20 parts, 22 parts, 25 parts, 28 parts, 30 parts, 32 parts, 35 parts, 38 parts, 40 parts, 42 parts, 45 parts, 48 ​​parts, 50 parts, 52 parts, 55 parts, 58 parts, 60 parts, or 62 parts, etc., and the specific values ​​between the above values ​​are not exhaustively listed in this invention due to space limitations and for the sake of brevity.

[0012] Furthermore, the melt flow rate of the PC resin at 300°C and 1.2 kg is 3~20 g / 10 min.

[0013] Specifically, the test standard for the melt flow rate of the PC resin is ISO1133-2012.

[0014] Furthermore, the PC resin includes bisphenol A type PC resin.

[0015] It should be noted that the transesterification inhibitor described in this invention is 0.05~2.5 parts, for example, but not limited to 0.05 parts, 0.06 parts, 0.07 parts, 0.08 parts, 0.09 parts, 0.1 parts, 0.15 parts, 0.2 parts, 0.25 parts, 0.3 parts, 0.35 parts, 0.4 parts, 0.45 parts, 0.5 parts, 0.55 parts, 0.6 parts, 0.65 parts, 0.7 parts, 0.75 parts, 0.8 parts, 0. 85 parts, 0.9 parts, 0.95 parts, 1 part, 1.05 parts, 1 part, 1.1 parts, 1.2 parts, 1.3 parts, 1.4 parts, 1.5 parts, 1.6 parts, 1.7 parts, 1.8 parts, 1.9 parts, 2 parts, 2.1 parts, 2.2 parts, 2.3 parts, 2.4 parts, or 2.5 parts, etc., and the specific point values ​​between the above point values, are not exhaustively listed in this invention due to space limitations and for the sake of brevity.

[0016] Further, the transesterification inhibitor is 0.07 to 1 part.

[0017] Furthermore, the content of transesterification inhibitor in the PC / PBT composition is preferably 0.05~2wt%.

[0018] Furthermore, based on the effective component in the acid buffer, the mass ratio of the acid buffer to the basic sodium pyrophosphate in the transesterification inhibitor is (0.5~1.5):1, for example, but not limited to, 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1 or 1.5:1, and specific values ​​between the above-mentioned values.

[0019] Furthermore, the mass ratio of acid buffer to basic sodium pyrophosphate in the transesterification inhibitor is (0.8~1.5):1.

[0020] Furthermore, the mass ratio of acid buffer to basic sodium pyrophosphate in the transesterification inhibitor is (0.8~1.2):1.

[0021] Furthermore, the acidic buffer includes weak acids and / or acidic salts.

[0022] Furthermore, the weak acid includes organic weak acids and / or inorganic weak acids.

[0023] Furthermore, the organic weak acid includes one or more of acetic acid, benzoic acid, or citric acid; the inorganic weak acid includes phosphoric acid and / or boric acid.

[0024] Furthermore, the acidic salt includes sodium bisulfate and / or disodium dihydrogen pyrophosphate.

[0025] It should be noted that the PBT resin mentioned in this invention is 13 to 47 parts, for example, but not limited to 13 parts, 15 parts, 18 parts, 20 parts, 22 parts, 25 parts, 28 parts, 30 parts, 32 parts, 35 parts, 38 parts, 40 parts, 42 parts, 45 parts, or 47 parts, etc., and the specific values ​​between the above-mentioned values ​​are not exhaustively listed in this invention due to space limitations and for the sake of brevity.

[0026] Furthermore, the intrinsic viscosity of the PBT resin is ≥0.8 dL / g.

[0027] Furthermore, the intrinsic viscosity of the PBT resin is 0.8~1.5 dL / g. Specifically, the intrinsic viscosity of the PBT resin was tested using an Ubbelohde viscometer in accordance with the GB / T 1632.3-2010 standard.

[0028] Furthermore, the PC / PBT composition also includes 4 to 15 parts of toughening agent.

[0029] Furthermore, the toughening agent includes acrylate toughening agents and / or silicone acrylate toughening agents.

[0030] Specifically, the acrylate toughening agent includes one or more of the following: methyl methacrylate-butadiene-styrene copolymer, ethylene-acrylate copolymer, or ethylene-methacrylate-glycidyl methacrylate terpolymer.

[0031] Furthermore, without affecting the chemical resistance and dimensional stability of the PC / PBT composition of the present invention, the PC / PBT composition further includes 0.1 to 5 parts of processing aids.

[0032] Specifically, the processing aids include, but are not limited to, antioxidants and / or lubricants.

[0033] In this invention, commonly used antioxidants can be selected, such as, but not limited to, one or more of hindered phenolic antioxidants, phosphite antioxidants, or thioester antioxidants.

[0034] Specifically, the hindered phenolic antioxidants are N,N'-hexamethylene bis(3,5-di-tert-butyl-4-hydroxyphenylpropionamide) (Irganox 1098), pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (Irganox 1010), 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione (antioxidant 1790), 1,6-hexanediol bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (Irganox 259), and octadecyl β-(4-hydroxy-3,5-di-tert-butylphenyl)propionate (Irganox 1098). 1076) or one or more of 3,9-bis{2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)acrylic acid]-1,1-dimethyl}-2,4,8,10-tetraoxaspirocycloundecane (ADK AO-80).

[0035] The phosphite antioxidant is one or more of tris(2,4-di-tert-butylphenyl) phosphite (antioxidant 168), bis(2,6-di-tert-butyl-4-tolyl) pentaerythritol phosphite (PEP-36), or 627A.

[0036] The thioester antioxidant is one or more of the following: distearate thiodipropionate, dodecyl thiodipropionate (antioxidant DLTDP), dilaurate thiodipropionate, or pentaerythritol-based dodecyl thiopropyl ester.

[0037] The present invention may use commonly used lubricants, such as, but not limited to, one or more of vinyl bis-stearamide, pentaerythritol stearate, polysiloxane, calcium stearate, magnesium stearate, zinc stearate, silicone, PE wax, or PP wax.

[0038] This invention also protects a method for preparing the above-mentioned PC / PBT composition, comprising the following steps: The components are mixed evenly, and then melt-blended and extruded to obtain a PC / PBT composition. Preferably, the preparation method includes the following steps: S1. Mix a portion of PBT resin (5wt%~15wt%) and transesterification inhibitor evenly, and then extrude and granulate to obtain masterbatch; S2. Mix the remaining PBT resin, other components and the masterbatch described in step S1 evenly, and obtain a PC / PBT composition by melt blending and extrusion granulation.

[0039] Furthermore, the extrusion granulation temperature in step S1 is 235~245℃.

[0040] Furthermore, the extrusion temperature in step S2 is 220~280℃.

[0041] Furthermore, the extrusion speed in step S2 is 180~600 rpm.

[0042] This invention also protects the application of the above-mentioned PC / PBT composition in the electronics, new energy, intelligent manufacturing, and medical industries. In particular, the above-mentioned PC / PBT composition can be used to prepare parts with good chemical resistance and dimensional stability. For example, it can be used as a material for battery packs and energy storage device housings in the new energy field; robot body housings and drive connectors in intelligent manufacturing; ventilator housings, quadruped robot housings, anesthetic housings, and imaging equipment housings in the medical field; and kitchenware housings in the electronics and electrical appliance field.

[0043] A housing component is made using the above-mentioned PC / PBT composition.

[0044] Compared with the prior art, the present invention has the following beneficial effects: This invention provides a PC / PBT composition. By adding an acidic buffer that can provide an acidic environment and basic sodium pyrophosphate as a transesterification inhibitor to the PC / PBT composition system, the chemical resistance and fatigue resistance of the composition can be effectively improved, and the resulting composition has good dimensional stability. Detailed Implementation

[0045] The present invention will be further described in detail below with reference to specific embodiments. These embodiments are only used to explain the present invention and are not intended to limit the scope of the present invention. Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods; the materials and reagents used are commercially available unless otherwise specified.

[0046] 1. Raw materials used in each embodiment and comparative example: PC resin: PC resin 1: PC2050, with a melt flow rate of 4.5 g / 10 min at 300℃ and 1.2 kg, purchased from Wanhua Chemical; PC resin 2: 1300-10NP, with a melt flow rate of 10 g / 10 min at 300℃ and 1.2 kg, purchased from LG Chem; PBT resin: PBT resin 1: PBT 1200-211M, intrinsic viscosity of 0.83, purchased from Changchun, Jiangsu; PBT resin 2: PBT GL236, intrinsic viscosity 1.3, purchased from Yizheng Chemical Fiber; Acid buffers: Acid buffer 1: Acetic acid, concentration 4wt%, molecular formula CH3COOH, commercially available; Acidic buffer 2: Citric acid, concentration 4wt%, molecular formula C6H8O7, commercially available; Acidic buffer 3: Boric acid, concentration 4wt%, molecular formula H3BO3, commercially available; Acid buffer 4: Sodium pyrophosphate: molecular formula Na2H2P2O7, commercially available; Basic sodium pyrophosphate: molecular formula Na4P2O7, commercially available; Hydrogen phosphate: Anhydrous disodium hydrogen phosphate, structural formula NaH2PO4, commercially available; Ester exchange inhibitor 1: Acid buffer 1 and basic sodium pyrophosphate are mixed in a mass ratio of 1:1; Ester exchange inhibitor 2: A mixture of acid buffer 1 and basic sodium pyrophosphate in a mass ratio of 0.5:1; Ester exchange inhibitor 3: Acid buffer 1 and basic sodium pyrophosphate are compounded in a mass ratio of 1.5:1; Ester exchange inhibitor 4: Acid buffer 2 and basic sodium pyrophosphate are compounded in a mass ratio of 1:1; Ester exchange inhibitor 5: Acid buffer 3 and basic sodium pyrophosphate are compounded in a mass ratio of 1:1; Ester exchange inhibitor 6: Acid buffer 4 and basic sodium pyrophosphate are compounded in a mass ratio of 1:1; Ester exchange inhibitor 7: Acid buffer 1 and sodium pyrophosphate in a mass ratio of 1:1; Ester exchange inhibitor 8: a mixture of hydrogen phosphate and sodium acid pyrophosphate in a 1:1 mass ratio; Toughening agent: Acrylic toughening agent, methyl methacrylate-butadiene-styrene copolymer, M-521, purchased from Kanekachi, Japan; Processing aids: Antioxidant: A compound of Irganox 1010 and antioxidant 168 in a mass ratio of 1:2, both of which are commercially available; Lubricant: Pentaerythritol stearate, commercially available; It should be noted that the same raw materials were used in the parallel experiments in the examples and comparative examples.

[0047] 2. The PC / PBT compositions in each embodiment and comparative example were prepared according to the formulations in Tables 1-2 and the following preparation methods: S1. Mix a portion of PBT resin (10wt%) and an ester exchange inhibitor evenly, and granulate by extrusion at 240°C to obtain masterbatch; S2. The remaining PBT resin, other components and the masterbatch from step S1 are mixed evenly, and then melt-blended and extruded using a twin-screw extruder to obtain a PC / PBT composition; the extrusion temperature is 220~280℃ and the extrusion speed is 340 rpm.

[0048] Example 11 was prepared by the following method: The components are mixed evenly, and then melt-blended and extruded granulated using a twin-screw extruder to obtain a PC / PBT composition; the extrusion temperature is 220~280℃, and the extrusion speed is 340 rpm.

[0049] 3. Performance Testing: (1) Chemical resistance test: The PC / PBT compositions prepared in each example and comparative example were tested for initial tensile strength using tensile specimens described in ASTM D638-2022. The tensile specimens were fixed on the fixture with a strain rate of 0.5~1.5%, and the chemical reagent Mars Brand composite quaternary ammonium salt was evenly coated on the surface of the specimens. The specimens after coating with the reagent were wrapped with plastic wrap to prevent the rapid volatilization of the chemical reagent. The specimens were placed under constant temperature and humidity conditions for 168 hours, and then the chemical resistance tensile strength was measured. The chemical resistance of the composition was evaluated according to the result calculated by tensile performance retention rate A = chemical resistance tensile strength / initial tensile strength × 100%. (2) Fatigue resistance test: The PC / PBT compositions prepared in each example and comparative example were tested for initial tensile strength using tensile specimens described in ASTM D638-2022 standard; the tensile specimens were placed in an oven at 80°C and baked for 24 hours, and then placed at room temperature for 48 hours to test fatigue tensile strength. The fatigue resistance of the composition was evaluated by the result calculated according to the tensile property retention rate B = fatigue tensile strength / initial tensile strength × 100%. (3) Impact strength test: The PC / PBT compositions prepared in each example and comparative example were tested for 3.2 mm IZOD notched impact strength according to ASTM D256-2010 standard, and the requirement was >400 J / m; (4) Dimensional stability test: The PC / PBT compositions prepared in each example and comparative example were used to make small square test pieces (120mm×80mm obtained by injection molding) as described in GB / T17037.4-2003. The small square test pieces were placed in an oven at 80°C and baked for 4 hours. After being placed at room temperature for 48 hours, the difference in molding shrinkage rate between the examples and comparative examples was tested by two-dimensional measurement.

[0050] Examples 1-11 and Comparative Examples 1-4 Table 1. Amounts (parts by weight) and properties of each component in the PC / PBT compositions of Examples 1-11

[0051] Table 2. Amounts (parts by weight) and properties of each component in the PC / PBT compositions of each comparative example.

[0052] As can be seen from Table 1, the PC / PBT composition prepared by the present invention has good fatigue resistance, chemical resistance and dimensional stability. Specifically, the chemical resistance tensile strength retention rate A is not less than 50%, preferably not less than 70%; the fatigue resistance tensile strength retention rate B is not less than 35%, preferably not less than 70%; the shrinkage rate is not higher than 0.5%; and the impact strength is high, all >410J / m.

[0053] As can be seen from Comparative Examples 1 and 2, although using other substances to replace the transesterification inhibitor in this invention has a certain transesterification inhibition effect, it is easier to form infusible substances during processing, which leads to a decrease in the overall performance of the obtained PC / PBT composition.

[0054] Comparative Examples 3 and 4 show that if too few transesterification inhibitors are used, the transesterification reaction cannot be completely suppressed, resulting in a decrease in the overall performance of the prepared PC / PBT composition. If too many transesterification inhibitors are used, the reaction rate may be too fast, making the reaction process difficult to control. This may lead to the occurrence of side reactions and affect the overall performance of the PC / PBT composition.

[0055] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A PC / PBT composition, characterized in that, Includes the following components, calculated in parts by weight: 18-62 parts of PC resin; 13-47 parts of PBT resin; Transesterification inhibitor 0.05~2.5 parts; The transesterification inhibitor includes an acidic buffer and basic sodium pyrophosphate.

2. The PC / PBT composition according to claim 1, characterized in that, The mass ratio of acid buffer to basic sodium pyrophosphate in the transesterification inhibitor is (0.5~1.5):

1.

3. The PC / PBT composition according to claim 1 or 2, characterized in that, The acidic buffer comprises a weak acid and / or an acidic salt; the weak acid comprises an organic weak acid and / or an inorganic weak acid; preferably, the organic weak acid comprises one or more of acetic acid, benzoic acid, or citric acid; the inorganic weak acid comprises phosphoric acid and / or boric acid; and the acidic salt comprises sodium bisulfate and / or disodium dihydrogen pyrophosphate.

4. The PC / PBT composition according to claim 1, characterized in that, The melt flow rate of the PC resin at 300°C and 1.2 kg is 3~20 g / 10 min.

5. The PC / PBT composition according to claim 1, characterized in that, The intrinsic viscosity of the PBT resin is ≥0.8 dL / g; preferably, the intrinsic viscosity of the PBT resin is 0.8~1.5 dL / g.

6. The PC / PBT composition according to claim 1, characterized in that, It also includes 4 to 15 parts of toughening agent; preferably, the toughening agent includes acrylate toughening agent and / or silicone acrylate toughening agent; preferably, the acrylate toughening agent includes one or more of methyl methacrylate-butadiene-styrene copolymer, ethylene-acrylic acid copolymer or ethylene-methacrylate-glycidyl methacrylate terpolymer.

7. The PC / PBT composition according to claim 1, characterized in that, It also includes 0.1 to 5 parts of processing aids; said processing aids include antioxidants and / or lubricants.

8. A method for preparing the PC / PBT composition according to any one of claims 1 to 7, characterized in that, Includes the following steps: The components are mixed evenly, and then melt-blended and extruded to obtain a PC / PBT composition. Preferably, the preparation method includes the following steps: S1. Mix a portion of PBT resin and transesterification inhibitor evenly, and then extrude and granulate to obtain masterbatch; S2. Mix the remaining PBT resin, other components and the masterbatch described in step S1 evenly, and obtain a PC / PBT composition by melt blending and extrusion granulation.

9. The application of the PC / PBT composition according to any one of claims 1 to 7 in the electronics, new energy, intelligent manufacturing, and medical industries.

10. A housing component, characterized in that, It is prepared using the PC / PBT composition according to any one of claims 1 to 7; preferably, the shell component includes a quadruped robot shell component and a humanoid shell component.

Images