A PBT composite material, its preparation method and application

Abstract

This invention relates to a PBT composite material, its preparation method, and its applications. The PBT composite material comprises the following components in parts by weight: 39-91 parts PBT resin, 5-15 parts PETG resin, 5-15 parts PCTA resin, and 3-6 parts toughening agent. The PETG resin and PCTA resin of this invention can synergistically and effectively improve the thermal shock resistance and gasoline resistance of the PBT composite material.

Description

Technical Field

[0001] This invention relates to the field of polymer material processing technology, and more specifically, to a PBT composite material, its preparation method, and its application. Background Technology

[0002] Polybutylene terephthalate (PBT) is an important thermoplastic engineering plastic that is widely used in electronics, automobiles and other fields.

[0003] When PBT material is used in automotive engine components (such as connectors and housings), these components are often combined with metal inserts. The operating environment of an automotive engine or the vehicle's usage environment causes these components to frequently experience drastic temperature changes within a short period. The difference in the coefficients of thermal expansion between the metal and PBT material during this process makes PBT material prone to cracking, shortening its lifespan and leading to connection failure between components. Therefore, it is necessary to improve the thermal shock resistance of PBT material. Furthermore, these components often come into contact with gasoline due to their usage scenarios. Existing PBT materials are prone to cracking when in contact with gasoline, which also affects the lifespan of the components and leads to connection failure between components.

[0004] Existing technologies typically add fluorinated processing aids to improve the thermal shock resistance of PBT materials, but this does not significantly improve the material's gasoline resistance and also raises environmental issues. Summary of the Invention

[0005] The primary objective of this invention is to overcome the problems existing in the current PBT materials and to provide a PBT composite material.

[0006] A further objective of this invention is to provide a method for preparing the above-mentioned PBT composite material.

[0007] A further objective of this invention is to provide the application of the above-mentioned PBT composite material in the manufacture of automotive engine parts.

[0008] The above-mentioned objective of the present invention is achieved through the following technical solution: A PBT composite material comprises the following components in parts by weight: 39-91 parts of PBT resin, 5-15 parts of PETG resin, 5-15 parts of PCTA resin 3-6 parts toughening agent.

[0009] In this invention, PBT resin refers to a copolymer of terephthalic acid and butanediol; PETG resin refers to a copolymer of terephthalic acid, ethylene glycol, and 1,4-cyclohexanediethanol (wherein, the molar content of 1,4-cyclohexanediethanol in the glycol is ≤50%); PCTA resin refers to an acid-modified copolymer of terephthalic acid and 1,4-cyclohexanediethanol, wherein the acid-modified acid includes, but is not limited to, isophthalic acid.

[0010] The inventors discovered that both PETG resin and PCTA resin can reduce the crystallinity of PBT composites; and PETG resin can improve the processing performance of PBT composites, making the components more uniformly dispersed. Compared to PETG resin, PCTA resin can better reduce the stress concentration of PBT composites and prevent gasoline penetration. Therefore, PETG resin and PCTA resin can synergistically and effectively improve the thermal shock resistance and gasoline resistance of PBT composites.

[0011] In the PBT composite material of the present invention, the amount of PBT resin can be 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, or 90 parts by weight or a range formed by any two of the above values; the amount of PETG resin can be 5, 6, 8, 10, 12, 14, or 15 parts by weight or a range formed by any two of the above values; the amount of PCTA resin can be 5, 6, 8, 10, 12, 14, or 15 parts by weight or a range formed by any two of the above values; and the amount of toughening agent can be 3, 4, 5, or 6 parts by weight or a range formed by any two of the above values.

[0012] In this invention, PBT resin is used as the main resin, and its content accounts for at least 30 wt% of the PBT composite material.

[0013] Preferably, the PBT composite material comprises the following components in parts by weight: 40-65 parts of PBT resin, 10-15 parts of PETG resin, 10-15 parts of PCTA resin, Toughening agent 4.2~6 parts.

[0014] By adjusting the amount of each component within this range, the PBT composite material exhibits better resistance to thermal shock and gasoline.

[0015] Preferably, the intrinsic viscosity of the PBT resin is 0.7~1.2 dl / g; specifically, it can be 0.7, 0.8, 0.9, 1.0, 1.1, 1.2 dl / g or a range formed by any two of the above values.

[0016] In this invention, the intrinsic viscosity of PBT resin can be tested according to GB / T14190-2017. The test solvent is a mixture of phenol and 1,1,2,2-tetrachloroethane, with a mass ratio of phenol to 1,1,2,2-tetrachloroethane of 50:50, and the test temperature is 25°C.

[0017] Preferably, the mass ratio of PETG resin to PCTA resin is (3~7):(3~7).

[0018] More preferably, the mass ratio of PETG resin to PCTA resin is (5~6):(4~6). Adjusting the mass ratio within this range results in better thermal shock resistance and gasoline resistance in the PBT composite material.

[0019] Preferably, the intrinsic viscosity of the PETG resin is 0.7~1.1 dl / g; specifically, it can be 0.7, 0.76, 0.78, 0.80, 0.85, 0.90, 1.00, 1.10 dl / g or a range formed by any two of the above values.

[0020] In this invention, the intrinsic viscosity of PETG resin can be tested according to GB / T14190-2017. The test solvent is a mixture of phenol and 1,1,2,2-tetrachloroethane, with a mass ratio of phenol to 1,1,2,2-tetrachloroethane of 50:50, and the test temperature is 25°C.

[0021] Preferably, the molar amount of CHDM (1,4-cyclohexanediethanol) in the PETG resin accounts for 12-35% of the total molar amount of diols; more preferably, it is 18-20%.

[0022] In this invention, the molar amount of PETG resin as a percentage of the total molar amount of glycol can be determined by 1H NMR spectroscopy. Specifically, the hydrogen atoms of -OCH2CH2O- (ethylene glycol unit) and the hydrogen atoms of the ester group in -CH2OOC- (CHDM) are integrated and then calculated.

[0023] Preferably, the intrinsic viscosity of the PCTA resin is 0.60~1.1 dl / g; specifically, it can be 0.60, 0.65, 0.70, 0.75, 0.80, 0.85, 0.88, 0.90, 0.95, 1.00, 1.10 dl / g or a range formed by any two of the above values.

[0024] In this invention, the intrinsic viscosity of PCTA resin can be tested according to ISO1628-5-2015. The test solvent is a mixture of phenol and 1,1,2,2-tetrachloroethane, with a mass ratio of phenol to 1,1,2,2-tetrachloroethane of 50:50, and the test temperature is 23°C.

[0025] Preferably, the toughening agent includes, but is not limited to, at least one of ethylene copolymer toughening agents, styrene copolymer toughening agents, and thermoplastic polyester elastomers.

[0026] More preferably, the ethylene copolymer toughening agent includes, but is not limited to, at least one of ethylene-methyl acrylate copolymer and ethylene-vinyl acetate copolymer.

[0027] More preferably, the ethylene copolymer toughening agent is an ethylene-methyl acrylate copolymer. Using this toughening agent, the PBT composite material exhibits better resistance to thermal shock.

[0028] More preferably, the styrene-based copolymer toughening agent includes, but is not limited to, methyl methacrylate-butadiene-styrene terpolymer.

[0029] More preferably, the thermoplastic polyester elastomer includes, but is not limited to, TPEE.

[0030] Preferably, the PBT composite material further includes 10-30 parts of reinforcing fiber, 12-16 parts of flame retardant, and 0.1-3 parts of other additives.

[0031] More preferably, the PBT composite material further includes 22-30 parts of reinforcing fiber, 12-14 parts of flame retardant, and 0.8-2 parts of other additives.

[0032] More preferably, the reinforcing fiber includes, but is not limited to, glass fiber.

[0033] More preferably, the average length of the reinforcing fiber is 6-12 mm and the average diameter of the cross-section is 10-15 μm.

[0034] The average length and average diameter of the reinforcing fiber can be measured by optical microscopy.

[0035] More preferably, the flame retardant includes, but is not limited to, halogen-free flame retardants.

[0036] More preferably, the halogen-free flame retardant includes, but is not limited to, at least one of phosphates, phosphonates, and organophosphates.

[0037] More preferably, the other additives include, but are not limited to, at least one of lubricants or antioxidants.

[0038] Typically, the amount of lubricant used is 0.5 to 1 part, and the amount of antioxidant used is 0.3 to 1 part.

[0039] Optionally, the lubricant is at least one of pentaerythritol stearate, aliphatic carboxylic acid ester, erucamide, ethylene bis-stearamide, montan ester, polyethylene wax, or oxidized polyethylene wax.

[0040] Optionally, the antioxidant is at least one of hindered phenolic antioxidants, phosphite antioxidants, or organosulfur antioxidants.

[0041] The preparation method of the above-mentioned PBT composite material includes the following steps: mixing the components, melt extruding, and granulating to obtain the PBT composite material.

[0042] Preferably, the temperature of the melt extrusion is 200~250℃; the screw speed of the extruder for melt extrusion is 300~550 rpm, and the length-to-diameter ratio of the screw is 30~50:1.

[0043] The application of the above-mentioned PBT composite material in the manufacture of automotive engine parts (such as automotive connectors, plugs, and controller housing parts) is also within the scope of protection of this invention.

[0044] An injection molded part is made from the above-mentioned PBT composite material.

[0045] Preferably, the injection molded part is an automotive engine component (such as an automotive connector, plug, or controller housing component).

[0046] Compared with the prior art, the beneficial effects of the present invention are: In this invention, both PETG resin and PCTA resin can reduce the crystallinity of PBT composite materials. Furthermore, PETG resin can improve the processing performance of PBT composite materials, resulting in more uniform blending of the components. Compared to PETG resin, PCTA resin can better enhance the flexibility of PBT composite materials and reduce stress concentration. Therefore, PETG resin and PCTA resin can synergistically and effectively improve the thermal shock resistance and gasoline resistance of PBT composite materials. Consequently, the PBT composite material of this invention exhibits excellent thermal shock resistance and gasoline resistance, making it highly suitable for manufacturing related components for automotive engines. Detailed Implementation

[0047] To more clearly and completely describe the technical solution of the present invention, the present invention will be further described in detail below through specific embodiments. It should be understood that the specific embodiments described herein are only for explaining the present invention and are not intended to limit the present invention. Various changes can be made within the scope of the claims of the present invention.

[0048] The reagents used in the various embodiments and comparative examples of this invention are described below: PBT resin 1#: PBT GX112, Yizheng Chemical Fiber, intrinsic viscosity is 0.8 dl / g; PBT resin 2#: PBT GX121, Yizheng Chemical Fiber, intrinsic viscosity is 1dl / g; PETG resin #1: SKYGREEN K2012, SK chemicals, intrinsic viscosity 0.78 dl / g, CHDM content 20%; PETG resin #2: Eastar 6763, Eastman, intrinsic viscosity 0.76 dl / g, CHDM content 30%; PETG resin #3: Eastar™ GN071, Eastman, intrinsic viscosity 1 dl / g, CHDM content 18%; PCTA Resin 1#: Cristal™ CN005, Eastman, intrinsic viscosity is 0.65 dl / g; PCTA resin #2: Eastar AN014, Eastman, intrinsic viscosity is 0.85 dl / g; PCTA resin #3: Eastar AN004, Eastman, intrinsic viscosity is 1 dl / g; PCTG resin #1: Tritan TX1501HF, Eastman, intrinsic viscosity is 0.65 dl / g; Toughening agent 1#: Ethylene-methyl acrylate copolymer, brand name LOTRYL 24MA005, Arkema; Toughening agent #2: Ethylene-vinyl acetate copolymer, brand name EVA 1828, HANWHA Corporation; Reinforcing fiber: Glass fiber, ECS11-4.5-534A, Jushi; Flame retardant: hypophosphite, OP1230, Clariant; Other additives #1: Lubricant, pentaerythritol stearate, commercially available; Other additives #2: Antioxidant 1010, commercially available; Unless otherwise specified, all components used in the parallel embodiments and comparative examples (e.g., reinforcing fibers, flame retardants, other additives 1#, other additives 2#) are the same commercially available products.

[0049] The performance of the PBT composite materials provided in the embodiments and comparative examples of this invention was determined according to the following test methods: (1) Thermal shock resistance: The test piece was injection molded and assembled with the metal insert into a combination. The combination was placed in an environmental chamber and subjected to the following thermal cycles: after being placed at 120℃ for 20 min, it was switched to -20℃ for 20 min, and then switched back to 120℃ for 20 min. The switching time was ≤10 s. One cycle consisted of 120℃×20 min and -20℃×20 min. The number of cycles when the test piece cracked was recorded to evaluate its thermal shock resistance performance.

[0050] (2) Gasoline resistance: According to ISO 175:2010 standard, the sample was bent to the specified strain (2%) and immersed in E10 gasoline (23℃, 72h). Then the maximum length of the crack on the sample surface was observed: The crack condition on the surface of the maximum bending stress area was carefully observed with an optical microscope. Among all the observed cracks, the longest crack was found and the size of the longest crack was measured and recorded as “maximum length” in millimeters (mm). If there are no visible cracks on the sample surface, the maximum crack length is 0 mm.

[0051] The preparation process of the PBT composite materials in the embodiments and comparative examples of the present invention is as follows: First, the PBT resin is dried at 130°C for 3 hours; then, each component is weighed according to the formula, mixed, and then melt-extruded in a twin-screw extruder and granulated to obtain the PBT composite material. The temperatures of the twin-screw extruder are as follows: Zone 1: 210°C; Zone 2: 210°C; Zone 3: 220°C; Zone 4: 220°C; Zone 5: 230°C; Zone 6: 230°C; Zone 7: 240°C; Zone 8: 250°C; Zone 9: 240°C; Die head temperature: 240°C; Main extruder speed: 500 rpm; Screw length-to-diameter ratio: 40:1.

[0052] Examples 1-12 Examples 1-12 provide a series of PBT composite materials, the formulations of which are shown in Table 1.

[0053] Table 1. Formulations (parts by weight) for Examples 1-12

[0054] Comparative Examples 1-6 Comparative Examples 1-6 provide a series of PBT composite materials, the formulations of which are shown in Table 2.

[0055] Table 2. Formulations (parts by weight) for Comparative Examples 1-6

[0056] The properties of the PBT composite materials of each embodiment and comparative example were determined according to the test methods mentioned above, and the test results are shown in Table 3.

[0057] Table 3 Performance test results of PBT composite materials in each embodiment and comparative example

[0058] As can be seen from Table 3: The PBT composite materials in Examples 1-12 all had more than 285 cycles in the thermal shock resistance test, and the maximum crack length in the gasoline resistance test was ≤1.5mm, indicating that the PBT composite materials of the present invention have good thermal shock resistance and gasoline resistance.

[0059] Comparative Example 1 included PETG resin but not PCTA resin; Comparative Example 2 included PETG resin but not PCTA resin, with an equal amount of PETG resin used instead; Comparative Example 3 included PCTA resin but not PETG resin; Comparative Example 4 included PCTA resin but not PETG resin, with an equal amount of PCTA resin used instead; Comparative Example 6 used PCTG resin instead of PETG resin. All of these comparisons resulted in poor thermal shock resistance and gasoline resistance. Comparative Example 5, using PCTG resin instead of PCTA resin, showed poor gasoline resistance.

[0060] 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 PBT composite material, characterized in that, The components include the following parts by weight: 39-91 parts of PBT resin, 5-15 parts of PETG resin, 5-15 parts of PCTA resin 3-6 parts toughening agent.

2. The PBT composite material according to claim 1, characterized in that, The intrinsic viscosity of the PBT resin is 0.7~1.2 dl / g.

3. The PBT composite material according to claim 1, characterized in that, The intrinsic viscosity of the PETG resin is 0.7~1.1 dl / g.

4. The PBT composite material according to claim 1, characterized in that, The intrinsic viscosity of the PCTA resin is 0.60~1.1 dl / g.

5. The PBT composite material according to claim 1, characterized in that, The mass ratio of PETG resin to PCTA resin is (3~7):(3~7); preferably (5~6):(4~6).

6. The PBT composite material according to claim 1, characterized in that, The toughening agent includes at least one of ethylene copolymer toughening agents, styrene copolymer toughening agents, and thermoplastic polyester elastomers.

7. The PBT composite material according to claim 1, characterized in that, The PBT composite material also includes 10-30 parts of reinforcing fiber, 12-16 parts of flame retardant, and 0.1-3 parts of other additives.

8. A method for preparing the PBT composite material according to any one of claims 1 to 7, characterized in that, The process includes the following steps: mixing the components, melt extrusion, and granulation to obtain the PBT composite material.

9. The use of the PBT composite material according to any one of claims 1 to 7 in the manufacture of automotive engine parts.

10. An injection molded part, characterized in that, It is prepared from the PBT composite material described in any one of claims 1 to 7.

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