PBT composition, preparation method and application thereof, and electronic circuit component

Abstract

The invention discloses a PBT composition, a preparation method and application thereof, and an electronic circuit component. The PBT composition is prepared from the following components in parts by weight: 42 to 55 parts of PBT resin; 8-18 parts of a brominated flame retardant; 1-7 parts of a synergistic flame retardant; 22 to 38 parts of glass fiber; 0.3 to 2.7 parts of a nucleating agent; wherein the nucleating agent comprises an organic nucleating agent and an inorganic nucleating agent; and the number of the glass fiber points in the unit area of the cross section of the PBT composition extrusion strip is 3300-4300 / mm < 2 >. The high-temperature dimensional stability of the PBT composition can be effectively improved by adopting the compounded organic nucleating agent and inorganic nucleating agent and combining the number of glass fiber points in the unit area of the cross section of a composition extruded strip.

Description

Technical Field

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

[0002] With the rapid development of emerging fields such as robotics, low-altitude economy, 5G communication, and new energy, the performance requirements for electronic and electrical products are becoming increasingly stringent. As key components in electronic circuits, relays, capacitors, connectors, and sensors need to operate stably for extended periods under complex conditions with higher voltages and currents. This places higher demands on the flame retardancy, temperature resistance, and dimensional stability of materials. Taking relays as an example, their operating characteristics (such as pull-in voltage and release voltage) are directly affected by the precision of the distance between the reed and the contacts. Dimensional deformation of materials under high-temperature environments can lead to spacing deviations, resulting in poor contact, abnormal arcing, and ultimately affecting equipment reliability. Furthermore, in scenarios such as high-voltage battery management systems and fast-charging interfaces in the new energy field, and where robots replace humans in high-temperature operations, the thermal shrinkage of internal relays can cause them to detach. The miniaturization trend and increased power density of components further exacerbate the challenges to the dimensional stability of materials under thermal stress.

[0003] Polybutylene terephthalate (PBT), one of the five major general-purpose engineering plastics, is widely used in electronic and electrical components such as relay housings, connector terminals, and sensor bases due to its high heat resistance, excellent electrical insulation properties, chemical corrosion resistance, and rapid prototyping advantages. Through modification with flame retardants and glass fibers, existing PBT materials can meet the basic requirements of UL94 V-0 flame retardancy and mechanical strength. However, with the increasing operating temperatures of electronic equipment (such as temperatures exceeding 150°C in the motor compartment of new energy vehicles), while traditional PBT materials meet application requirements in terms of dimensional stability at room temperature, their excessive dimensional shrinkage at high temperatures is becoming increasingly apparent, making them unable to meet application needs. Summary of the Invention

[0004] The purpose of this invention is to overcome the defects or shortcomings of the poor high-temperature dimensional stability of PBT compositions in the prior art, and to provide a PBT composition.

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

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

[0007] To achieve the above objectives, the present invention employs the following technical solution: A PBT composition comprising the following components in parts by weight: 42-55 parts of PBT resin; 8-18 parts of brominated flame retardant; Synergistic flame retardant 1-7 parts; 22-38 parts glass fiber; Nucleating agent 0.3~2.7 parts; The nucleating agent comprises a compound of organic and inorganic nucleating agents; the number of glass fiber dots per unit area of ​​the cross-section of the PBT composition extrusion strip is 3300-4300 / mm. 2 .

[0008] This invention provides a PBT composition using PBT resin as the matrix resin and incorporating compounded organic and inorganic nucleating agents. This effectively increases the crystallization temperature of the composition and reduces its longitudinal and transverse shrinkage rates under high-temperature conditions. By adjusting the number of glass fiber dots per unit area in the cross-section of the extruded strip, the PBT composition can be prevented from softening and deforming at high temperatures. Simultaneously, interfacial debonding under thermal stress can be avoided, preventing poor dimensional stability at high temperatures. Furthermore, a specific density of glass fiber dots per unit area and the retention length of glass fibers can form thermally conductive channels in the matrix resin, facilitating heat transfer and ensuring that the composition is not easily deformed under high-temperature conditions.

[0009] It should be noted that, in the PBT composition of the present invention, the content of PBT resin is preferably not less than 40 wt%.

[0010] It should be noted that the number of glass fiber dots per unit area of ​​the cross-section of the PBT composition extruder in this invention is 3300~4300 per mm. 2 For example, but not limited to, 3300 pieces / mm 2 3350 pieces / mm 2 3400 pieces / mm 2 3450 pieces / mm 2 3500 pieces / mm 2 3550 pieces / mm 2 3600 pieces / mm 2 3650 pieces / mm 2 3700 pieces / mm 2 3750 pieces / mm 2 3800 pieces / mm 2 3850 pieces / mm 2 3900 pieces / mm 2 3950 pieces / mm 2 4000 pieces / mm 2 4050 pieces / mm 2 4100 pieces / mm 2 4150 pieces / mm2 4200 pieces / mm 2 4250 pieces / mm 2 Or 4300 pieces / mm 2 And so on, as well as the specific point values ​​between the above point values. Due to space limitations and for the sake of brevity, the specific point values ​​included in the range will not be exhaustively listed in this invention.

[0011] Specifically, the number of glass fiber dots per unit area of ​​the PBT composition extrusion strip cross-section is determined by vertically cutting the strip to obtain a flat cross-section; polishing the cross-section and cleaning it to remove debris; using a scanning electron microscope to collect data from multiple regions (at least 5 different locations) of the cross-section; and then counting the number of dots per unit cross-sectional area (mm²). 2 The number of glass fiber dots N (dots) on the cross-section is denoted as D (dots / mm). 2 =N / A, where the average number of glass fiber points per unit area in the cross-section at multiple locations is taken.

[0012] It should be noted that the nucleating agent described in this invention is 0.3 to 2.7 parts, for example, but not limited to 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 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, 2.5 parts, 2.6 parts, or 2.7 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.

[0013] It should be noted that the nucleating agent content in the PBT composition described in this invention is 0.3~3wt%.

[0014] Furthermore, the glass fiber retention length in the PBT composition is 180~420μm.

[0015] Furthermore, the glass fiber retention length in the PBT composition is 200~400μm.

[0016] Furthermore, the glass fiber retention length in the PBT composition is 300~350μm.

[0017] Furthermore, the glass fiber retention length in the PBT composition is 320~340μm.

[0018] Furthermore, the method for testing the retention length of the glass fiber is to place the PBT composition in a muffle furnace and treat it at 800°C for 30 minutes, take a small amount of residual ash and disperse it in water, measure and record the length of 200 glass fibers under a two-dimensional instrument, and take the average value as the retention length.

[0019] It should be noted that the retained length of the glass fiber described in this invention can be controlled by the design and combination of the extruder screw elements, the extruder processing parameters (temperature / feeding / speed), and the glass fiber feeding method (main feeding or side feeding).

[0020] Furthermore, the mass ratio of organic nucleating agent to inorganic nucleating agent in the nucleating agent is 1:(0.13~7), for example, but not limited to, 1:0.13, 1:0.15, 1:0.5, 1:1, 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5, 1:5, 1:5.5, 1:6, 1:6.5 or 1:7, etc., and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the specific values ​​included in the range will not be exhaustively listed in this invention.

[0021] Furthermore, the mass ratio of organic nucleating agent to inorganic nucleating agent in the nucleating agent is 1:(0.5~3).

[0022] Furthermore, the mass ratio of organic nucleating agent to inorganic nucleating agent in the nucleating agent is 1:(0.6~1).

[0023] Furthermore, the brominated flame retardant includes one or more of brominated polystyrene, brominated polycarbonate, brominated epoxy resin, or pentabromobenzene polyacrylate.

[0024] Furthermore, the brominated flame retardant is brominated polystyrene and / or pentabromobenzene polyacrylate.

[0025] Furthermore, the organic nucleating agent includes fatty acid salts and / or ethylene-acrylic acid metal ionomers.

[0026] Specifically, the fatty acid salts include calcium lignite and / or sodium lignite.

[0027] Specifically, the ethylene-acrylic acid metal ionomers include ethylene-zinc acrylate ionomers and / or ethylene-sodium methacrylate ionomers.

[0028] Furthermore, the organic nucleating agent is sodium lignite and / or ethylene-sodium methacrylate ionomer.

[0029] Furthermore, the inorganic nucleating agent includes one or more of talc, calcium oxide, calcium carbonate, mica, or kaolin.

[0030] Furthermore, the inorganic nucleating agent includes talc and / or mica powder.

[0031] In some preferred embodiments, the D50 of the inorganic nucleating agent is 2~25 μm.

[0032] Specifically, the D50 of the talc powder was determined according to standard GB / T 19077-2016.

[0033] Furthermore, the intrinsic viscosity of the PBT resin is 0.5~1.5 dL / g.

[0034] Specifically, the test standard for intrinsic viscosity is GB / T 14190-2017, and the test temperature for intrinsic viscosity is 25℃.

[0035] Furthermore, the synergistic flame retardant includes antimony trioxide.

[0036] Furthermore, without affecting the high-temperature dimensional stability and flame retardancy of the PBT composition, it also includes 0.1 to 5 parts of toughening agent and / or 0.1 to 5 parts of processing aid.

[0037] Furthermore, the toughening agent comprises a methyl acrylate-glycidyl methacrylate block copolymer.

[0038] Furthermore, the processing aids include, for example but not limited to, antioxidants and / or lubricants.

[0039] 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.

[0040] 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).

[0041] 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.

[0042] The thioester antioxidant is one or more of the following: distearate thiodipropionate, dodecyl thiodipropionate (antioxidant DLTDP), dilaurate thiodipropionate, or pentaerythritol-based dodecyl thiopropionate.

[0043] The present invention may use one or more commonly used lubricants, such as, but not limited to, vinyl bis-stearamide, pentaerythritol stearate, polysiloxane, calcium stearate, magnesium stearate, zinc stearate, silicone, PE wax, or PP wax.

[0044] Further, the PBT composition comprises the following components in parts by weight: 45-54 parts of PBT resin; 9-15 parts of brominated flame retardant; Synergistic flame retardant 2-6 parts; 25-35 parts glass fiber; Nucleating agent 0.4~2.5 parts; Toughening agent 0.5-4 parts; Processing aids: 0.5-2 parts.

[0045] This invention also protects a method for preparing the above-mentioned PBT composition, comprising the following steps: S1. Mix all components except glass fiber in proportion to obtain a premix; S2. The premixed material described in step S1 and glass fiber are melt-blended and extruded to obtain a PBT composition.

[0046] Furthermore, the mixing speed in step S1 is 700-900 rpm, and the mixing time is 2-4 minutes.

[0047] Furthermore, the extrusion granulation described in step S2 is carried out in a twin-screw extruder.

[0048] Furthermore, the temperature of the twin-screw extruder is 200-230℃ in zone 1, 240-260℃ in zone 2, 235-255℃ in zone 3, 235-255℃ in zone 4, 235-255℃ in zone 5, 240-260℃ in zone 6, 240-260℃ in zone 7, 220-240℃ in zone 8, 220-240℃ in zone 9, and 240-260℃ in zone 10. The screw speed of the twin-screw extruder is 200-450 rpm.

[0049] This invention also protects the application of the above-mentioned PBT composition in the preparation of materials for robots, low-altitude economy, new energy or 5G communication; especially the application of electronic circuit components in materials for robots, low-altitude economy, new energy or 5G communication.

[0050] The present invention also protects an electronic circuit component made using the above-mentioned PBT composition, such as a relay, sensor, connector, actuator, etc.

[0051] Compared with the prior art, the present invention has the following beneficial effects: This invention provides a PBT composition that effectively improves the high-temperature dimensional stability of the PBT composition by using a compounded organic and inorganic nucleating agent as the nucleating agent, and by combining the distribution of glass fiber dots per unit area in the cross-section of the extruded strip. Detailed Implementation

[0052] 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.

[0053] 1. Raw materials used in each embodiment and comparative example: PBT resin: PBT resin 1: PBT GX112, intrinsic viscosity of 0.82 dL / g, purchased from Sinopec Yizheng Chemical Fiber Co., Ltd. PBT resin 2: PBT GL236, intrinsic viscosity of 1.28 dL / g, purchased from Sinopec Yizheng Chemical Fiber Co., Ltd. Brominated flame retardants: Brominated flame retardant 1: Brominated polystyrene, SAYTEX 621, purchased from Albemarle, USA; Bromine-based flame retardant 2: Brominated epoxy resin, powder-F-2100, purchased from Dead Sea bromine in Israel; Brominated flame retardant 3: Brominated polycarbonate, FG-8500, purchased from Teijin, Japan; Bromine-based flame retardant 4: pentabromobenzyl polyacrylate, powder-FR-1025, purchased from Dead Sea bromine in Israel; Synergistic flame retardant: Antimony trioxide, S-04N, purchased from Yiyang Shengli Materials Technology Co., Ltd.; Fiberglass: Fiberglass 1: ECS10-3.0-T436HK, chopped length 3.0mm, purchased from Taishan Fiberglass Co., Ltd.; Glass fiber 2: ECS13-4.5-534A, chopped length 4.5mm, purchased from China Jushi Co., Ltd.; Nucleating agent: Organic nucleating agent 1: Sodium lignite, LICOMONT NAV101 PWD, purchased from Clariant; Organic nucleating agent 2: calcium lignite, LICOMONT CAV102 PWD, purchased from Clariant; Organic nucleating agent 3: Ethylene-zinc acrylate ionomer, 295A, purchased from Honeywell; Organic nucleating agent 4: Ethylene-sodium methacrylate ionomer, Surlyn 8320, purchased from DuPont; Inorganic nucleating agent 1: Talc, HTPULTRA 5L, purchased from Imfabi; Inorganic nucleating agent 2: mica powder, 300HC, purchased from Lingshou County Huajing Mica Co., Ltd.; Toughening agent: Ethylene-methyl acrylate-glycidyl methacrylate block copolymer, ELVALOY RESINSPTW, purchased from DuPont; Processing aids: Antioxidant: A compound of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and tris(2,4-di-tert-butylphenyl) phosphite in a mass ratio of 1:1; Lubricant: Pentaerythritol stearate; all processing aids are commercially available. It should be noted that the same raw materials were used in the parallel experiments in the examples and comparative examples.

[0054] 2. The PBT compositions in each embodiment and comparative example were prepared according to the formulations in Tables 1-2 and the following preparation methods: S1. Treat all components except glass fiber at 700-900 rpm for 2-4 minutes in proportion, and mix evenly to obtain a premix; S2. The premixed material and glass fiber described in step S1 are melt-blended and extruded and granulated using a twin-screw extruder to obtain a PBT composition; the temperature of the twin-screw extruder is 200-230℃ in zone 1, 240-260℃ in zone 2, 235-255℃ in zone 3, 235-255℃ in zone 4, 235-255℃ in zone 5, 240-260℃ in zone 6, 240-260℃ in zone 7, 220-240℃ in zone 8, 220-240℃ in zone 9, and 240-260℃ in zone 10; the screw speed of the twin-screw extruder is 300-1000 rpm.

[0055] 3. Performance Testing: (1) Shrinkage rate after high-temperature baking: A long strip-shaped cross-shaped shrinkage rate mold was prepared, with a fixed spacing of 200.0072 mm between two points in the flow direction of the mold. The PBT compositions prepared in each example and comparative example were injection molded using this mold. After cooling, the fixed spacing of the two points in the flow direction was measured and recorded as X1. The square plate was placed in an oven for treatment (150°C, 3h). After cooling, the fixed spacing of the two points in the flow direction was measured and recorded as X2. After high-temperature treatment, the shrinkage rate of the material was recorded as ΔX, ΔX=[(X1-X2) / 200.0072]×1000‰; (2) Flame retardant performance: The PBT compositions prepared in each example and comparative example were injection molded into 125mm×13mm×0.75mm specimens and tested according to the UL94-2023 vertical burning standard; (3) Tensile strength test: The PBT compositions prepared in each example and comparative example were injection molded into type IA specimens and tested according to standard ISO 527-2024; (4) Crystallinity test: The PBT compositions prepared in each example and comparative example were placed in a DSC device for testing. The program was set as follows: 30~300℃, 20℃ / min, 1.5 cycles. The enthalpy of melting of the material (H) of the second heating curve was calculated and recorded. The crystallinity was recorded as Xc, Xc=H / 142×100%, where 142 is the theoretical enthalpy of PBT resin.

[0056] Examples 1-18 and Comparative Examples 1-4 Table 1. Amounts (parts by weight) and properties of each component in the PBT compositions of Examples 1-9

[0057] Table 2. Amounts (parts by weight) and properties of each component in the PBT compositions of Examples 10-18

[0058] Table 3. Amounts (parts by weight) and properties of each component in the PBT compositions of Comparative Examples 1-4

[0059] As can be seen from Tables 1 and 2, the PBT prepared by the present invention has good high-temperature dimensional stability, and also has good flame retardant and mechanical properties. Specifically, the shrinkage rate after high-temperature baking is not higher than 0.25‰, the tensile strength is not lower than 110MPa, and it can achieve V-0 flame retardancy; preferably, the shrinkage rate after high-temperature baking is not higher than 0.2‰, and the tensile strength is not lower than 125MPa.

[0060] As can be seen from Examples 1-4, the number of glass fiber dots per unit area of ​​the extruded strip cross-section in the PBT composition is 3600-4000 dots / mm. 2 The preferred retention length of glass fibers in the PBT composition is 300-350 μm, more preferably 320-340 μm, resulting in a PBT composition with better overall performance.

[0061] As can be seen from Examples 4 and 10-12, when the mass ratio of organic nucleating agent to inorganic nucleating agent is 1:(0.5-3), more preferably 1:(0.6-2, the prepared PBT composition has better overall performance.

[0062] As can be seen from Examples 4 and 13-15, when the brominated flame retardant is brominated polystyrene and / or pentabromobenzyl polyacrylate, the PBT composition prepared has better high-temperature dimensional stability.

[0063] As can be seen from Comparative Examples 1 and 2, if the number of glass fiber dots per unit area of ​​the extruder cross-section in the PBT composition is too high or too low, the high-temperature dimensional stability of the PBT composition will be significantly worse. If the number of glass fiber dots per unit area of ​​the extruder cross-section is too low, the composition will have poor ability to resist softening and deformation at high temperatures. If the number of glass fiber dots per unit area of ​​the extruder cross-section is too high, the uneven dispersion will easily form agglomerates, which will introduce a large number of micro-defect interfaces. Under thermal stress, interface debonding is likely to occur, resulting in poor high-temperature dimensional stability.

[0064] As can be seen from Comparative Examples 3 and 4, the high-temperature dimensional stability of PBT compositions prepared using a single nucleating agent is significantly worse.

[0065] 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 composition, characterized in that, Includes the following components, calculated in parts by weight: 42-55 parts of PBT resin; 8-18 parts of brominated flame retardant; Synergistic flame retardant 1-7 parts; 22-38 parts glass fiber; Nucleating agent 0.3~2.7 parts; The nucleating agent includes organic and inorganic nucleating agents; the number of glass fiber dots per unit area of ​​the cross-section of the PBT composition extrusion strip is 3300~4300 / mm. 2 The preferred density is 3600~4000 pieces / mm. 2 .

2. The PBT composition according to claim 1, characterized in that, The mass ratio of organic nucleating agent to inorganic nucleating agent in the nucleating agent is 1:(0.13~7); preferably, the mass ratio of organic nucleating agent to inorganic nucleating agent in the nucleating agent is 1:(0.5~3); more preferably, the mass ratio of organic nucleating agent to inorganic nucleating agent in the nucleating agent is 1:(0.6~2).

3. The PBT composition according to claim 1, characterized in that, The retained length of the glass fiber in the PBT composition is 180~420μm; preferably, the retained length of the glass fiber is 300~350μm; more preferably, the retained length of the glass fiber is 320~340μm.

4. The PBT composition according to claim 1, characterized in that, The brominated flame retardant includes one or more of brominated polystyrene, brominated polycarbonate, brominated epoxy resin, or pentabromobenzyl polyacrylate; preferably, the brominated flame retardant is brominated polystyrene and / or pentabromobenzyl polyacrylate.

5. The PBT composition according to claim 1, characterized in that, The organic nucleating agent includes fatty acid salts and / or ethylene-zinc acrylate ionomers.

6. The PBT composition according to claim 1, characterized in that, The inorganic nucleating agent includes one or more of talc, calcium oxide, calcium carbonate, mica, or kaolin.

7. The PBT composition according to claim 1, characterized in that, At least one of the following three conditions must be met: (a) The intrinsic viscosity of the PBT resin is 0.5~1.5 dL / g; (b) It also includes 0.1 to 5 parts toughening agent; (c) It also includes 0.1 to 5 parts of processing aids.

8. A method for preparing the PBT composition according to any one of claims 1 to 7, characterized in that, Includes the following steps: S1. Mix all components except glass fiber in proportion to obtain a premix; S2. The premixed material described in step S1 and glass fiber are melt-blended and extruded to obtain a PBT composition.

9. The application of the PBT composition according to any one of claims 1 to 7 in robot components, low-altitude economic devices, new energy materials or 5G communication materials.

10. An electronic circuit component, characterized in that, It is prepared using the PBT composition according to any one of claims 1 to 7.

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