Polyphenylene sulfide composite material as well as preparation method and application thereof

Abstract

The invention discloses a polyphenylene sulfide composite material as well as a preparation method and application thereof, and relates to the technical field of high polymer materials. The invention provides a polyphenylene sulfide composite material. The polyphenylene sulfide composite material comprises the following components in parts by weight: 50-90 parts of PPS resin, 0.3-1.5 parts of a nucleating agent, 0.3-1.5 parts of a silane coupling agent and 10-45 parts of glass fibers, the nucleating agent is a mixture of an organic phosphate nucleating agent and a sorbitol nucleating agent; the melt mass flow rate of the PPS resin is greater than or equal to 200g / 10min under the conditions that the test temperature is 316 DEG C and the load is 5kg according to ISO 1133-2022. According to the invention, through selection of components such as the specific nucleating agent, the PPS composite material with high laser transmittance and high welding strength under high crystallinity is prepared.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high polymer materials, in particular to a polyphenylene sulfide composite material and a preparation method and application thereof. BACKGROUND

[0002] As a typical special engineering plastic, polyphenylene sulfide (PPS) has become a key basic material in the fields of automobiles, electronics and electrical appliances, and industrial equipment due to its intrinsic flame-retardant properties and comprehensive performance advantages such as high strength, high rigidity, high insulation, and ultra-high heat resistance. In particular, under the trend of rapid expansion of the new energy vehicle market in recent years, PPS materials can meet the stringent requirements of the three-electric system (battery, motor, and electronic control), and their application solutions in this field continue to increase. However, in the production process of PPS precision components and complex structural parts, traditional welding technologies (such as hot melt welding and ultrasonic welding) are limited by low welding precision, insufficient joint strength, and easy damage to the surface of the components, which cannot meet the requirements of high-end application scenarios for connection reliability. Under this background, high-precision, high-speed, and non-contact laser welding technology has become the core direction to solve this problem. However, as a crystalline high polymer material, the anisotropic crystal structure of PPS significantly affects the transmission efficiency of laser on the material, which limits the welding strength and forming effect, and becomes a key bottleneck restricting the industrial application of PPS laser welding technology. In view of the above bottleneck, the prior art has made preliminary improvement attempts, for example, patent CN118450982A discloses a polyarylene sulfide resin composition and a manufacturing method thereof, which selects a resin substrate with a low crystallization rate (i.e. the idea of inhibiting resin crystallization) to improve the laser transmission rate of PPS to a certain extent and provide a basic condition for laser welding. However, this technical solution only relies on the crystallization characteristics of the resin itself for regulation and control, which has the defects of single regulation and control dimension, limited transmission rate improvement, and difficulty in balancing the welding strength, and cannot meet the high-performance requirements of PPS laser welding components in high-end fields.

[0003] Therefore, it is urgent to develop a PPS composite material scheme that can achieve high laser transmission rate and high welding strength under high crystallinity through multi-component synergistic regulation and control. SUMMARY

[0004] Based on this, the purpose of the present application is to overcome the deficiencies of the prior art and provide a polyphenylene sulfide composite material and a preparation method and application thereof.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a polyphenylene sulfide composite material, comprising the following components in parts by weight: 50-90 parts of PPS resin, 0.3-1.5 parts of nucleating agent, 0.3-1.5 parts of silane coupling agent, and 10-45 parts of glass fiber; wherein the nucleating agent is a mixture of organophosphate nucleating agents and sorbitol nucleating agents; and wherein the PPS resin, according to ISO1133-2022, has a melt flow rate ≥200g / 10min under test conditions of 316℃ and 5kg load.

[0006] Preferably, the weight percentage of PPS resin in the PPS composite material is not less than 50%.

[0007] This invention selects PPS resin with a melt flow rate ≥200g / 10min. On one hand, its molecular chain mobility is extremely high, allowing for rapid response to nucleating agent induction upon cooling, laying the foundation for high crystallinity. On the other hand, its excellent melt flowability ensures uniform dispersion of the nucleating agent and glass fiber in the matrix, avoiding interfacial defects caused by insufficient flowability in traditional low melt flow rate PPS. This invention employs a synergistic combination of organophosphate and sorbitol nucleating agents. Organophosphates provide high-density crystallization nuclei, significantly increasing nucleation density; sorbitol nucleating agents limit spherulite growth rate through intermolecular interactions. The synergistic effect of both allows for control of spherulite size within a small range. The fine spherulite structure significantly reduces laser scattering and improves laser transmittance. A silane coupling agent improves the interfacial compatibility between the glass fiber and the PPS matrix, enhancing interfacial bonding and eliminating interfacial phase separation caused by poor dispersion, thus better ensuring laser transmission and improving laser transmittance. This invention refines the crystal size by selecting specific nucleating agents and other components and using induced crystallization. When the crystal size in the final composite material is smaller than the laser wavelength, laser transmission can still be guaranteed under high crystallinity. At the same time, high crystallinity is also beneficial to the stability of material performance. Finally, a PPS composite material with both high laser transmittance and high welding strength under high crystallinity is prepared.

[0008] Preferably, the polyphenylene sulfide composite material comprises the following components in parts by weight: 65-85 parts of PPS resin, 0.5-1.2 parts of nucleating agent, 0.5-1.2 parts of silane coupling agent, and 20-30 parts of glass fiber.

[0009] Optionally, the PPS resin is in the range of 50 parts, 60 parts, 61 parts, 65 parts, 68 parts, 70 parts, 80 parts, and 90 parts by weight, or any two of these values; the nucleating agent is in the range of 0.3 parts, 0.5 parts, 0.8 parts, 1.2 parts, and 1.5 parts by weight, or any two of these values; the silane coupling agent is in the range of 0.3 parts, 0.5 parts, 0.8 parts, 1.2 parts, and 1.5 parts by weight, or any two of these values; and the glass fiber is in the range of 10 parts, 15 parts, 20 parts, 25 parts, 35 parts, and 45 parts by weight, or any two of these values.

[0010] Optionally, the PPS resin, according to ISO 1133-2022, under test conditions of 316°C and 5kg load, has melt flow rates of 200 g / 10min, 300 g / 10min, 500 g / 10min, 550 g / 10min, 600 g / 10min, 650 g / 10min, 700 g / 10min, 800 g / 10min, 900 g / 10min, 1000 g / 10min, 1100 g / 10min, 1200 g / 10min, 1250 g / 10min, 1300 g / 10min, 1350 g / 10min, 1400 g / 10min, 1450 g / 10min, 1500 g / 10min, 1600 g / 10min, 1700 g / 10min, 1800 g / 10min, and 1900 g / 10min. The value is within the range of one or both of g / 10min and 2000 g / 10min. Optionally, the PPS resin has a melt mass flow rate of 200-2000 g / 10min under test conditions of 316°C and 5 kg load, according to ISO 1133-2022.

[0011] Preferably, the PPS resin has a melt flow rate of 400-1600 g / 10 min under test conditions of 316°C and 5 kg load, according to ISO 1133-2022.

[0012] Optionally, the weight ratio of the organophosphate nucleating agent and the sorbitol nucleating agent is one or any two of the following: 0.5:1, 0.8:1, 1:1, 1.5:1, 2:1, 2.5:1, 3:1.

[0013] Preferably, the weight ratio of the organophosphate nucleating agent to the sorbitol nucleating agent is (0.5-3):1; more preferably, the weight ratio of the organophosphate nucleating agent to the sorbitol nucleating agent is (1-1.7):1.

[0014] Preferably, the organophosphate nucleating agent is selected from at least one of sodium 2,2'-methylene bis(4,6-di-tert-butylphenyl) phosphate, sodium bis(4-tert-butylphenyl) phosphate, and basic aluminum 2,2-methylene-bis(4,6-di-tert-butylphenyl phosphate); and / or, the sorbitol nucleating agent is selected from at least one of 1,3:2,4-bis(3,4-dimethylbenzyl)-D-sorbitol, 1,3:2,4-bis(4'-propylbenzyl)-D-sorbitol, 1,3:2,4-bis(4'-ethylbenzyl)-D-sorbitol, and 1,3:2,4-bis(p-methylbenzyl)-D-sorbitol.

[0015] Preferably, the silane coupling agent is selected from at least one of γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-methacryloyloxypropyltrimethoxysilane; and / or, the glass fiber is alkali-free glass fiber.

[0016] Optionally, the glass fiber has an average retention length of 50-600 μm and an average diameter of 8-15 μm; Optionally, the average retained length of the glass fiber is a value within the range of one or any two of 50μm, 100μm, 150μm, 200μm, 300μm, 400μm, 450μm, 500μm, 550μm, and 600μm, and the diameter of the glass fiber is a value within the range of one or any two of 8μm, 10μm, 11μm, 12μm, 13μm, and 15μm.

[0017] Optionally, the glass fiber is tested as follows: the sample is calcined in a muffle furnace at 650°C for 1 h to obtain ash, which is then dispersed in water and observed and tested with an optical microscope to measure the length and diameter of the glass fibers in the ash. A total of 200 fibers are counted and the average value is taken.

[0018] The length of the glass fibers changes during extrusion, but the diameter remains constant. The average retention length refers to the length of the glass fibers in the final polyphenylene sulfide composite material, and the average diameter refers to the diameter of the glass fibers in the final polyphenylene sulfide composite material.

[0019] Optionally, the polyphenylene sulfide composite material further includes 0-1 parts of processing aid, wherein the processing aid is at least one of lubricant and antioxidant.

[0020] Optionally, the antioxidant is 0.1-0.5 parts by weight, and the antioxidant is at least one of hindered phenolic antioxidants and phosphite antioxidants, such as antioxidant 168 (tris[2,4-di-tert-butylphenyl] phosphite), antioxidant 1010 (pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]), etc.

[0021] Optionally, the lubricant is 0.1-0.5 parts by weight, and the lubricant is at least one of stearates, stearates, and ethylene bis-stearamides, such as pentaerythritol stearate, zinc stearate, etc.

[0022] Furthermore, the present invention provides a method for preparing the aforementioned polyphenylene sulfide composite material, comprising the following steps: (1) Weigh each component according to its weight parts; (2) Mix all components except glass fiber and add them to an extruder for melt mixing. Add glass fiber to the extruder through the side feed port and extrude and granulate to obtain the polyphenylene sulfide composite material.

[0023] Preferably, the melt extrusion is carried out in a twin-screw extruder; the temperature of the twin-screw extruder is 170-300℃; the length-to-diameter ratio of the twin-screw extruder is 45-50:1, and the screw speed is 250-350 rpm.

[0024] Furthermore, the present invention provides the application of the aforementioned polyphenylene sulfide composite material in automobiles, industrial equipment, and household appliances; specifically, the polyphenylene sulfide composite material of the present invention is used to prepare the three-electric system of new energy vehicles.

[0025] Compared to existing technologies, the beneficial effects of this invention are as follows: This invention selects PPS resin with a melt flow rate ≥200g / 10min. On the one hand, the molecular chain mobility is extremely strong, allowing for rapid response to nucleating agent induction upon cooling, laying the foundation for high crystallinity. On the other hand, the excellent melt flowability ensures uniform dispersion of the nucleating agent and glass fiber in the matrix, avoiding interface defects caused by insufficient flowability in traditional low melt flow rate PPS. This invention selects organophosphate nucleating agents and sorbitol nucleating agents in synergy. Organophosphates provide high-density crystallization nuclei, significantly increasing the nucleation density; sorbitol nucleating agents limit the spherulite growth rate through intermolecular interactions. The synergy of the two can control the spherulite size within a small range. The fine spherulite structure can significantly reduce laser scattering and improve laser transmittance. Silane coupling agents improve the interfacial compatibility between glass fiber and the PPS matrix, enhancing interfacial bonding ability, thereby eliminating interfacial phase separation caused by poor dispersion, better ensuring laser transmission effect, and improving laser transmittance. This invention prepares a PPS composite material that achieves both high laser transmittance and high welding strength under high crystallinity by selecting specific nucleating agents and other components. Detailed Implementation

[0026] To better illustrate the purpose, technical solution, and advantages of this invention, the invention will be further described below with reference to specific embodiments. The purpose is to provide a detailed understanding of the invention, not to limit it. All other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this invention. Unless otherwise specified, the experimental reagents and instruments designed in the embodiments and comparative examples of this invention are commonly used reagents and instruments, all of which are commercially available. Unless otherwise specified, the experimental methods used in the embodiments and comparative examples are conventional methods; and unless otherwise specified, the raw materials used in parallel experiments are from the same batch.

[0027] The raw materials used in the embodiments and comparative examples are described below, but are not limited to these materials: PPS Resin-1: Melt flow rate 300 g / 10min (316℃ / 5kg), grade PPS 20230C, manufacturer: Zhejiang Xinhecheng Special Materials Co., Ltd. PPS Resin-2: Melt flow rate 500 g / 10min (316℃ / 5kg), grade PPS 3450, manufacturer: Zhejiang Xinhecheng Special Materials Co., Ltd. PPS Resin-3: Melt flow rate 750 g / 10min (316℃ / 5kg), grade PPS 3470, manufacturer: Zhejiang Xinhecheng Special Materials Co., Ltd. PPS Resin-4: Melt flow rate 1400g / 10min (316℃ / 5kg), grade PPS 3490, manufacturer: Zhejiang Xinhecheng Special Materials Co., Ltd. PPS Resin-5: Melt flow rate 1700 g / 10min (316℃ / 5kg), grade PPS 34100, manufacturer: Zhejiang Xinhecheng Special Materials Co., Ltd. PPS Resin-6: Melt flow rate 80 g / 10min (316℃ / 5kg), grade PPS 3508, manufacturer: Zhejiang Xinhecheng Special Materials Co., Ltd. Nucleating agent-1: Organophosphate nucleating agent, 2,2-methylene-bis(4,6-di-tert-butylphenylphosphine) basic aluminum, CAS151841-65-5; Nucleating agent-2: Organophosphate nucleating agent, sodium 2,2'-methylene bis(4,6-di-tert-butylphenyl) phosphate, CAS 85209-91-2; Nucleating agent-3: Sorbitol nucleating agent, 1,3:2,4-bis(3,4-dimethylbenzyl)-D-sorbitol, CAS135861-56-2; Nucleating agent-4: Sorbitol nucleating agent, 1,3:2,4-bis(4'-ethylbenzyl)-D-sorbitol, CAS79072-96-1; Nucleating agent-5: Carboxylate nucleating agent, sodium benzoate, CAS 532-32-1; Nucleating agent-6: Inorganic nucleating agent, boron nitride (D50 2.82μm, specific surface area 12.7m²). 2 / g), grade PN02, manufacturer: Zibo Jingyi Ceramics Technology Co., Ltd.; Silane Coupling Agent-1: γ-aminopropyltriethoxysilane, CAS 919-30-2; Silane Coupling Agent-2: γ-Methacryloxypropyltrimethoxysilane, CAS 2530-85-0; Fiberglass: ECS10-03-568H, average diameter 10μm, manufacturer: China Jushi Co., Ltd. The antioxidant is a compound of commercially available hindered phenolic antioxidant 1010 and commercially available phosphite antioxidant 168 in a mass ratio of 1:1.

[0028] The lubricant is pentaerythritol stearate, which is commercially available.

[0029] Examples and Comparative Examples The composition of the PPS composite material of the present invention is shown in Tables 1-2. The preparation method of the PPS composite material includes the following steps: (1) Weigh each component according to the proportions; (2) All components except glass fiber are mixed and added to an extruder for melt mixing. Glass fiber is added to the extruder through a side feed port and extruded and granulated to obtain the polyphenylene sulfide composite material. The melt extrusion is carried out in a twin-screw extruder; the temperature of the twin-screw extruder is: Zone 1: 170℃, Zone 2: 270℃, Zone 3: 280℃, Zone 4: 300℃, Zone 5: 280℃, Zone 6: 280℃, Zone 7: 280℃, Zone 8: 280℃; the length-to-diameter ratio of the twin-screw extruder is 48:1, and the screw speed is 300 rpm.

[0030] Performance testing (1) Welding strength: The material is placed in an injection molding machine at an injection temperature of 270℃ and injection molded into a 125mm×13mm×2mm sample (i.e., laser-transmitting sample). At the same time, the polyphenylene sulfide composite material and carbon black are mixed at a mass ratio of 99.5:0.5 and injection molded into a 125mm×13mm×2mm sample (i.e., laser-absorbing sample). The laser-transmitting sample and the laser-absorbing sample are stacked and placed in a plastic material laser welding system (Han's Laser, model WFD120 W-PCTS333SP) for laser welding. The stacking is a partial stacking along the length direction.

[0031] The welding conditions are as follows: diode laser (wavelength 940nm), laser radius 200μm, welding power 80W, welding speed 1000mm / s, welding length 13mm×3 (in order to reduce error, three independent non-overlapping welds were performed, each weld pass was parallel and spaced 6mm apart), and pneumatic clamping device pressure 0.5MPa.

[0032] After the laser-welded specimen was placed in an environment with 50% relative humidity and 23±2℃ for 4 hours, a tensile test was performed using a tensile testing machine (Zwick / Roell Z010). The two unoverlapped parts were clamped along the long axis of the welded specimen with a span of 120mm and a tensile speed of 10mm / min. The weld strength was the maximum load of the tensile testing machine at the time of fracture.

[0033] (2) Laser transmittance: The material was placed in an injection molding machine at an injection temperature of 270°C. A 2mm thick color plate was injected. The infrared transmittance of the material at a wavelength of 980nm was tested using an infrared spectrophotometer. (3) Crystallinity: The color plate with a thickness of 2mm was tested using an X-ray diffraction analyzer (XRD). The X-ray source was Cu-Kα (λ=0.154nm), the current and voltage were 40kV and 40mA respectively, and the scanning rate was 4° / min.

[0034] Table 1 Table 2 As shown in the table above, the polyphenylene sulfide composite material prepared in the embodiments of the present invention has a crystallinity between 40-60%, a laser transmittance of >20%, and a welding strength of >650N.

[0035] As can be seen from the comparison of Examples 1-5 and Comparative Example 1, when the melt flow rate is ≥200g / 10min, the laser welding strength is higher, and when the melt mass flow rate is 400-1600g / 10min, the laser transmittance and welding strength are even better.

[0036] When the melt flow rate of the PPS resin is too low, the crystallinity of the composite material is too low, the spherulite size is too large, and the laser transmittance and welding strength are both very poor.

[0037] As can be seen from the comparison of Examples 3, 6, and Comparative Examples 2-5, when the nucleating agent is a mixture of organophosphate nucleating agents and sorbitol nucleating agents, high laser transmittance and welding strength can be achieved. Comparative Examples 2-3, using only organophosphate nucleating agents or sorbitol nucleating agents, failed to induce crystallization effectively, resulting in low crystallinity, excessively large spherulite size, and poor laser transmittance and welding strength. Comparative Examples 4-5, using other types of nucleating agents instead of the specific type described in this application, also failed to induce crystallization effectively, resulting in low crystallinity, excessively large spherulite size, and poor laser transmittance and welding strength.

[0038] As can be seen from the comparison of Examples 3 and 7-9, when the weight ratio of the organophosphate nucleating agent to the sorbitol nucleating agent is (0.5-3):1, both can achieve high laser transmittance and welding strength.

[0039] As can be seen from the comparison of Examples 3 and Examples 10-12, when the amount of PPS resin is 65-85 parts, nucleating agent is 0.5-1.2 parts, silane coupling agent is 0.5-1.2 parts, and glass fiber is 20-30 parts, the laser transmittance and welding strength are better.

[0040] As can be seen from the comparison of Example 3 and Comparative Example 6, the lack of silane coupling agent cannot improve the interfacial compatibility between glass fiber and PPS matrix, resulting in poor interfacial bonding and interfacial phase separation. Although the crystallinity is high and the spherulite size is low, the laser transmittance and welding strength are still very poor.

[0041] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A polyphenylene sulfide composite material, characterized in that, The product comprises the following components in parts by weight: 50-90 parts PPS resin, 0.3-1.5 parts nucleating agent, 0.3-1.5 parts silane coupling agent, and 10-45 parts glass fiber; the nucleating agent is a mixture of organophosphate nucleating agents and sorbitol nucleating agents; the PPS resin has a melt flow rate ≥200g / 10min under test conditions of 316℃ and 5kg load according to ISO 1133-2022.

2. The polyphenylene sulfide composite material as described in claim 1, characterized in that, It includes the following components in parts by weight: 65-85 parts PPS resin, 0.5-1.2 parts nucleating agent, 0.5-1.2 parts silane coupling agent, and 20-30 parts glass fiber.

3. The polyphenylene sulfide composite material as described in claim 1, characterized in that, The PPS resin, according to ISO 1133-2022, has a melt flow rate of 400-1600 g / 10 min under test conditions of 316°C and 5 kg load.

4. The polyphenylene sulfide composite material as described in claim 1, characterized in that, The weight ratio of the organophosphate nucleating agent to the sorbitol nucleating agent is (0.5-3):

1.

5. The polyphenylene sulfide composite material as described in claim 1, characterized in that, The organophosphate nucleating agent is selected from at least one of sodium 2,2'-methylene bis(4,6-di-tert-butylphenyl) phosphate, sodium bis(4-tert-butylphenyl) phosphate, and basic aluminum 2,2-methylene-bis(4,6-di-tert-butylphenyl) phosphate. And / or, the sorbitol nucleating agent is selected from at least one of 1,3:2,4-bis(3,4-dimethylbenzyl)-D-sorbitol, 1,3:2,4-bis(4'-propylbenzyl)-D-sorbitol, 1,3:2,4-bis(4'-ethylbenzyl)-D-sorbitol, and 1,3:2,4-bis(p-methylbenzyl)-D-sorbitol.

6. The polyphenylene sulfide composite material as described in claim 1, characterized in that, The silane coupling agent is selected from at least one of γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-methacryloyloxypropyltrimethoxysilane; and / or, the glass fiber is alkali-free glass fiber.

7. The polyphenylene sulfide composite material as described in claim 1, characterized in that, The polyphenylene sulfide composite material also includes 0-1 parts of processing aids, wherein the processing aids are at least one of lubricant and antioxidant.

8. A method for preparing a polyphenylene sulfide composite material as described in any one of claims 1-7, characterized in that, Includes the following steps: (1) Weigh each component according to its weight parts; (2) Mix all components except glass fiber and add them to an extruder for melt mixing. Add glass fiber to the extruder through the side feed port and extrude and granulate to obtain the polyphenylene sulfide composite material.

9. The application of a polyphenylene sulfide composite material as described in any one of claims 1-7 in the fields of automobiles, industrial equipment, and household appliances.

10. The application as described in claim 9, characterized in that, The polyphenylene sulfide composite material is used to prepare the three-electric system of new energy vehicles.

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