Polyphenylene sulfide composition, and preparation method therefor and use thereof

Abstract

The present application belongs to the field of polymer materials, and discloses a polyphenylene sulfide composition, and a preparation method therefor and the use thereof. Under the synergistic action of specific types of a PPS resin and glass fibers with specific contents, the polyphenylene sulfide composition of the present application exhibits a high laser transmittance, thereby providing a relatively good laser welding effect, and is suitable for laser welding, for example, is suitable for related parts and components in automotive, electrical and electronic applications requiring laser welding.

Description

A polyphenylene sulfide composition, its preparation method and application Technical Field

[0001] This application relates to the field of polymer materials, specifically to a polyphenylene sulfide composition and its preparation method and application. Background Technology

[0002] Polyphenylene sulfide (PPS) is a specialty engineering plastic with excellent comprehensive properties. While possessing intrinsic flame retardant characteristics, it also exhibits a series of features such as high strength, high rigidity, high insulation, and ultra-high heat resistance. It is widely used in the automotive, environmental protection, electronics, petrochemical, and military industries. In recent years, with the rapid development of the new energy vehicle market, the application of PPS materials in the three-electric systems of new energy vehicles has increased significantly.

[0003] However, in the production of precision manufacturing and complex structural components, traditional welding techniques often fail to meet the application requirements of PPS materials due to limitations in precision and weld strength. High-precision, high-speed, and non-contact laser welding technology offers a new approach to solving this problem. As a crystalline polymer material, the anisotropic crystal structure of PPS affects its laser transmittance, limiting the effectiveness of laser welding. Therefore, there is an urgent need to develop a technology to improve the laser transmittance of PPS. Summary of the Invention

[0004] Based on the deficiencies of the existing technology, the purpose of this application is to provide a polyphenylene sulfide composition, its preparation method and application, so as to improve the laser transmittance of PPS and improve its laser welding effect.

[0005] To achieve the above objectives, in a first aspect, this application provides a polyphenylene sulfide composition comprising the following components in parts by weight:

[0006] 60-85 parts of PPS resin

[0007] 15-40 parts of flat glass fiber;

[0008] The PPS resin satisfies the following condition: 10A+10B+C≤6050.

[0009] Wherein, Ag / 10min is the melt index of the PPS resin at 316℃ and 5kg.

[0010] B℃ is the crystallization temperature of the PPS resin.

[0011] C ppm represents the end-group chlorine content of the PPS resin.

[0012] As a crystalline polymer, the anisotropic crystal structure of PPS significantly affects its laser transmittance. The crystallization temperature of PPS resin influences the crystallinity of the composition, thus affecting its laser transmittance. The melt index of PPS resin affects the movement of its molecular chains during processing, influencing the formation of a regular crystal structure and consequently the crystallinity and laser transmittance of the composition. The end-chlorine content of PPS resin affects the proportion of reactive groups, thus influencing the reactivity of PPS molecules and consequently the interactions between PPS molecules, further affecting the movement of PPS molecular chains. By controlling the crystallization temperature, melt index, and end-chlorine content of PPS resin to satisfy the above specific relationships, the crystallinity of the polyphenylene sulfide composition can be effectively reduced, improving laser transmittance. Simultaneously, compared to round glass fibers, flat glass fibers have a higher packing density in the composition, reducing interfacial inhomogeneities and porosity, which is beneficial for improving the composition's laser transmittance.

[0013] The polyphenylene sulfide composition, under the synergistic effect of specific amounts and types of PPS resin and glass fiber, has high laser transmittance, thus exhibiting good laser welding effect. It is suitable for laser welding, such as for automotive, electronic and electrical components that require laser welding applications.

[0014] In this application, the PPS resin satisfies 10A+10B+C≤6050. For example, 10A+10B+C can be a range formed by any two of the following values: 6000, 5900, 5800, 5700, 5600, 5500, 5400, 5300, 5200, 5100, 5000, or more. In some embodiments, 10A+10B+C is 5000 to 6010.

[0015] Preferably, the melt index A of the PPS resin at 316°C and 5kg is ≤200g / 10min. For example, the melt index A can be 200g / 10min, 190g / 10min, 180g / 10min, 170g / 10min, 160g / 10min, 150g / 10min, or any range formed by any two of the above values.

[0016] Controlling the melt flow index A to ≤200g / 10min helps to limit the movement of PPS resin molecular chains during processing, reduces the possibility of them arranging to form a regular crystal structure, and improves the laser transmittance of the composition.

[0017] More preferably, the melt flow index A is 160 g / 10 min to 190 g / 10 min, which ensures that a low crystallinity product is obtained while also taking into account the processing performance of the material.

[0018] The melt flow index A can be obtained by testing at 316°C and 5kg load according to ISO 1133:2011.

[0019] Preferably, the crystallization temperature B of the PPS resin is less than 220°C. For example, the crystallization temperature B can be 219°C, 217°C, 215°C, 212°C, 210°C, 207°C, 205°C, 203°C, 200°C, 197°C, 195°C, 192°C, 190°C, or any range formed by any two of the above values.

[0020] Controlling the crystallization temperature B to < 220°C can reduce the crystallinity of the composition and improve its laser transmittance.

[0021] More preferably, the crystallization temperature B is 195℃~215℃, which can ensure that the mechanical properties of the material meet the application requirements of the product.

[0022] The crystallization temperature B can be obtained by testing according to GB / T 13464:2008. Under a nitrogen atmosphere, the temperature is increased from 30℃ to 320℃, held for 5 minutes, and then decreased from 320℃ to 30℃. The crystallization temperature during the cooling stage is tested, and the heating and cooling rates are both 20℃ / min.

[0023] Preferably, the end-chlorine content C of the PPS resin is ≤2500ppm. For example, the end-chlorine content C can be any range formed by any two of the following values: 2500ppm, 2200ppm, 2000ppm, 1800ppm, 1600ppm, 1400ppm, 1200ppm, 1000ppm, 800ppm, 600ppm, or more.

[0024] Controlling the end-chlorine content C to ≤2500ppm is beneficial to increasing the proportion of reactive groups in PPS resin, increasing the reactivity of PPS molecules, increasing the interaction between components, restricting the movement of PPS molecular chains, and improving the laser transmittance of the composition.

[0025] More preferably, the terminal chlorine content C is 1500ppm to 2200ppm.

[0026] The terminal chloride content C can be obtained by ion chromatography according to BS EN14582:2016.

[0027] In some embodiments, the method for preparing the PPS resin includes the following steps:

[0028] Sodium sulfide nonahydrate, NMP (N-methylpyrrolidone), lithium chloride and sodium hydroxide were added to a reaction vessel in a molar ratio of 1:(4-6):(0.5-0.7):(0.04-0.06). The mixture was continuously stirred at a rate of 75-100 r / min under continuous nitrogen protection and heated to 200-220℃ under a vacuum of -0.05--0.09 MPa to obtain dehydrated sodium sulfide.

[0029] Dehydrated sodium sulfide and p-dichlorobenzene were added to a reactor for polymerization, wherein the molar ratio of dehydrated sodium sulfide to p-dichlorobenzene was 1:(1~1.01). The reaction was carried out at 210~230℃ for 1~3h and at 240~260℃ for 3~5h. After cooling, PPS resin semi-finished product was obtained.

[0030] Using p-hydroxythiophenol as an end-group regulator, it is added to a reaction vessel along with the obtained PPS resin semi-finished product, NMP, and sodium hydroxide solution. The molar ratio of the PPS resin semi-finished product, p-hydroxythiophenol, NMP, and sodium hydroxide solution is 1:(0.05~0.15):(4~6):(1.5~2.5), and the mass percentage of sodium hydroxide in the sodium hydroxide solution is 40%~45%. The obtained PPS resin semi-finished product, NMP, and sodium hydroxide solution are then reacted at a temperature of 230-260℃ for 3~5 hours, followed by high-temperature acid washing to obtain PPS resin.

[0031] Preferably, the aspect ratio of the flat glass fiber is 2.4 to 4.2. For example, the aspect ratio of the flat glass fiber can be within the range formed by any two of the following values: 2.5, 2.8, 3, 3.2, 3.4, 3.6, 3.8, 4, or more.

[0032] Limiting the aspect ratio of the flat glass fiber to the range of 2.4 to 4.2 helps to reduce defects such as inhomogeneity and porosity at the phase interface between the glass fiber and PPS resin, thereby improving the laser transmittance of the composition.

[0033] Preferably, the average short side length of the cross-section of the flat glass fiber is 5-7 μm, and the average long side length is 18-28 μm. For example, the average short side length of the cross-section of the flat glass fiber can be within the range formed by any two of the following values: 5 μm, 5.2 μm, 5.5 μm, 5.7 μm, 6 μm, 6.2 μm, 6.5 μm, 6.7 μm, 7 μm, or more; and the average long side length can be within the range formed by any two of the following values: 18 μm, 20 μm, 22 μm, 24 μm, 26 μm, 28 μm, or more.

[0034] When the average short side length of the cross-section of the flat glass fiber is 5-7 μm and the average long side length is 18-28 μm, the mechanical properties of the composition can be better enhanced.

[0035] The aspect ratio of a flat glass fiber refers to the ratio of the length of its long side to the length of its short side in its cross-section. The average aspect ratio, average short side length, and average long side length of the cross-section of the flat glass fiber can be obtained by testing as follows: Observe the glass fiber sample using a scanning electron microscope, measure the short and long side lengths of the cross-sections of 300 glass fibers, and take the average value to obtain the average short and long side lengths of the cross-section of the flat glass fiber; calculate the aspect ratio of each of the 300 glass fibers, and take the average value to obtain the average aspect ratio of the flat glass fiber.

[0036] Preferably, the average length of the flat glass fiber is 2-5 mm. For example, the average length of the flat glass fiber can be within the range formed by any two of the following values: 2 mm, 3 mm, 4 mm, 5 mm, or more.

[0037] The average length of the flat glass fiber can be obtained by the following method: observe the glass fiber sample using a two-dimensional optical microscope, measure the length of 300 glass fibers, and take the average value.

[0038] Preferably, the crystallization temperature of the polyphenylene sulfide composition is less than 210°C. For example, the crystallization temperature of the polyphenylene sulfide composition can be 205°C, 203°C, 200°C, 197°C, 195°C, 193°C, 190°C, 187°C, 185°C, 182°C, 180°C, or any range formed by any two of the above values.

[0039] More preferably, the crystallization temperature of the polyphenylene sulfide composition can be 180–200°C.

[0040] The crystallization temperature of the polyphenylene sulfide composition can be determined by the following method: Differential scanning calorimetry (DSC) is used for testing. Under a nitrogen atmosphere, the temperature is increased from 30°C to 320°C, held for 5 minutes, and then decreased from 320°C to 30°C. The crystallization temperature during the cooling stage is tested, and the heating and cooling rates are both 20°C / min.

[0041] Preferably, the polyphenylene sulfide composition further includes 0 to 1 part of a colorant.

[0042] For example, the colorant includes at least one of aniline black, oil black, or carbon black.

[0043] Preferably, the polyphenylene sulfide composition further includes 0.1 to 1 part of a processing aid.

[0044] For example, the processing aids include, but are not limited to, at least one of antioxidants, lubricants, etc.

[0045] For example, the antioxidant includes at least one of antioxidant 1010, RINOX 1098, REVONOX 608, and PEP-36.

[0046] For example, the lubricant includes at least one of polyethylene wax, zinc stearate, and lithium stearate.

[0047] Without significantly impairing the technology of this application, the polyphenylene sulfide composition of this application may further contain a UV stabilizer, wherein the amount of the UV stabilizer is 0 to 0.5 parts by weight. For example, the amount of the UV stabilizer may be 0 parts by weight, 0.1 parts by weight, 0.2 parts by weight, 0.3 parts by weight, 0.4 parts by weight, 0.5 parts by weight, or any two of the above values ​​within a range. Exemplarily, the UV stabilizer includes at least one of cinnamic acid ester UV stabilizers, hydroxybenzophenone UV stabilizers, and hydroxyphenylbenzotriazole UV stabilizers.

[0048] In some embodiments, the PPS resin comprises 50% or more by weight in the polyphenylene sulfide composition. For example, the weight percentage of the PPS resin in the polyphenylene sulfide composition can be within a range formed by any two of the following values: 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, or more.

[0049] Secondly, this application provides a method for preparing the polyphenylene sulfide composition, comprising the following steps: mixing all raw materials, melt extruding, granulating, and obtaining the polyphenylene sulfide composition.

[0050] Preferably, the melt extrusion is carried out in a twin-screw extruder, with a melt extrusion temperature of 220–300°C, a screw speed of 300–450 rpm, and a screw length-to-diameter ratio of (38–42):1.

[0051] Thirdly, this application provides the application of the polyphenylene sulfide composition in the field of laser welding.

[0052] Compared with the prior art, the beneficial effects of this application are as follows: the polyphenylene sulfide composition of this application has a high laser transmittance under the synergistic effect of PPS resin and glass fiber with specific content and type, and thus has a better laser welding effect, making it suitable for laser welding, such as for automotive, electronic and electrical parts that have laser welding application requirements. Detailed Implementation

[0053] To better illustrate the purpose, technical solutions, and advantages of this application, the following description, in conjunction with specific embodiments and comparative examples, will further explain this application. These embodiments are intended to provide a detailed understanding of the content of this application, and not to limit it. All other embodiments obtained by those skilled in the art without inventive effort are within the protection scope of this application. Unless otherwise specified, the experimental reagents and instruments involved in the implementation of this application are commonly used reagents and instruments. In this application, the technical features described in an open-ended manner include both closed-ended technical solutions composed of the listed features and open-ended technical solutions that include the listed features.

[0054] Unless otherwise specified, all raw materials used in the following examples and comparative examples are commercially available, and the raw materials used in each parallel experiment are the same.

[0055] Examples 1-7 and Comparative Examples 1-4

[0056] These examples and comparative examples each provide a polyphenylene sulfide composition. The preparation method of these polyphenylene sulfide compositions includes the following steps: mixing and dispersing 78 parts by weight of PPS resin, 20 parts by weight of glass fiber, 1 part by weight of colorant and 1 part by weight of processing aid, feeding them into a twin-screw extruder, granulating them, and obtaining the polyphenylene sulfide composition.

[0057] The twin-screw extruder has a screw length-to-diameter ratio of 48:1, a screw speed of 450 r / min, and a melt extrusion temperature of 300℃.

[0058] Table 1 shows the relevant information or parameters of the PPS resin used in these examples and comparative examples. The PPS resin was prepared in-house, and the preparation method is as follows:

[0059] (1) Sodium hydrate sulfide, NMP, lithium chloride, and sodium hydroxide were added to a reactor in a molar ratio of 1:5:0.6:0.05. The mixture was continuously stirred at 80 r / min under nitrogen protection and heated to 210 °C under a vacuum of -0.05 to -0.09 MPa for dehydration. Depending on the vacuum level, sodium sulfide with different water of crystallization contents was obtained after dehydration. The dehydrated sodium sulfide and p-dichlorobenzene were added to the reactor for polymerization. The reaction was carried out at 220 °C for 2 h and at 250 °C for 4 h. After cooling, PPS resin semi-finished product was obtained, wherein the molar ratio of dehydrated sodium sulfide to p-dichlorobenzene was 1:1.005. By controlling the degree of dehydration of sodium sulfide after dehydration, the melt index of PPS resin semi-finished product is controlled within the range of 160-220 g / 10 min under the conditions of 316℃ and 5 kg. This allows the melt index of PPS resin (finished product) obtained in subsequent steps to be within a specific range under the conditions of 316℃ and 5 kg.

[0060] (2) Using p-hydroxythiophenol as an end-group regulator, it was added to a reaction vessel along with the PPS resin semi-finished product obtained in the previous step, NMP, and sodium hydroxide solution. The molar ratio of the PPS resin semi-finished product, p-hydroxythiophenol, NMP, and sodium hydroxide solution was 1:0.1:5:2, and the sodium hydroxide solution contained 45% sodium hydroxide by mass. The reaction was then carried out at 230-260℃ for 4 hours. Different reaction temperatures could control the end-group activity of the PPS resin, resulting in a PPS resin with a crystallization temperature of 195-225℃. Further, the PPS resin was subjected to high-temperature acid washing treatment, which could control its end-group chlorine content to 1500ppm-2500ppm. The test results of the melt index A, crystallization temperature B, and end-group chlorine content C of the obtained PPS resin at 316℃ and 5kg are shown in Table 1. The glass fiber used is designated as Glass Fiber 1, purchased from Jushi Co., Ltd., model ECS3F-03-568H. It is a flat glass fiber with an average flatness ratio of 3.8, an average short side length of 5μm, an average long side length of 19μm, and an average length of 3mm. The colorant used is aniline black. The processing aids used are antioxidant RINOX 1098, antioxidant REVONOX 608, and lubricant polyethylene wax, with a mass ratio of 1:2:2.

[0061] Table 1

[0062] Examples 8-13 and Comparative Examples 4-5

[0063] These examples and comparative examples all provide a polyphenylene sulfide composition. The preparation methods of these polyphenylene sulfide compositions are the same as in Example 1, except that the glass fibers used are different, or the weight ratios of PPS resin, glass fibers, colorants, and processing aids differ from those in Example 1. The specific glass fibers used, and the weight ratios of PPS resin, glass fibers, colorants, and processing aids, are shown in Table 2. Information regarding glass fibers 2 to 7 used is as follows:

[0064] Glass fiber 2: Flat glass fiber, with an average flatness ratio of 2.6, an average short side length of 7μm, an average long side length of 18μm, and an average length of 3mm. Model: TFG-3.0-T436. Manufacturer: Taishan Glass Fiber Co., Ltd.

[0065] Glass fiber 3: Flat glass fiber, with an average flatness ratio of 4, an average short side length of 7μm, an average long side length of 28μm, and an average length of 3mm. Model: TFG-3.0-T4355. Manufacturer: Taishan Glass Fiber Co., Ltd.

[0066] Glass fiber 4: Flat glass fiber, with an average flatness ratio of 3.8, an average short side length of 6μm, an average long side length of 23μm, and an average length of 3mm. Model: ESC4F-03-584. Manufacturer: Jushi Co., Ltd.

[0067] Glass fiber 5: Flat glass fiber, with an average flatness ratio of 3, an average short side length of 6.8μm, an average long side length of 20μm, an average length of 3mm, model ECS3F-03-508A, and manufactured by Jushi Co., Ltd.

[0068] Glass fiber 6: Round glass fiber, with an average cross-sectional diameter of 7μm and an average length of 3mm, model ECS301CL-3-H, manufactured by Chongqing Yuntianhua Group Co., Ltd.

[0069] Glass fiber 7: Round glass fiber with an average cross-sectional diameter of 17μm and an average length of 3mm, model ECS17-3.0-T635H, manufactured by Taishan Glass Fiber Co., Ltd.

[0070] Table 2

[0071] The polyphenylene sulfide compositions of the above embodiments and comparative examples were subjected to the following performance tests:

[0072] (1) Crystallization temperature: Differential scanning calorimetry (DSC) was used to test the crystallization temperature. Under nitrogen atmosphere, the temperature was increased from 30℃ to 320℃, held for 5 min, and then decreased from 320℃ to 30℃. The crystallization temperature during the cooling stage was then tested. The heating and cooling rates were both 20℃ / min.

[0073] (2) Crystallinity: The crystallinity was tested using X-ray diffraction (XRD) on a color sample with an injection molding thickness of 2 mm.

[0074] (3) Laser transmittance: Using a color plate with an injection molding thickness of 2mm, the infrared transmittance of the material at a wavelength of 980nm was tested using an infrared spectrophotometer.

[0075] The test results are shown in Table 3.

[0076] Table 3

[0077] As can be seen from the above data, the polyphenylene sulfide compositions obtained in the various embodiments of this application have a crystallization temperature of less than 210°C, a crystallinity of less than 20%, and a laser transmittance of greater than 30%.

[0078] As can be seen from the comparison between Examples 1-13 and Comparative Examples 1-3, when the PPS resin satisfies 10A+10B+C≤6000, the laser transmittance of the composition is significantly higher.

[0079] As can be seen from the comparison between Example 1 and Comparative Examples 4-5, flat glass fibers can significantly improve the laser transmittance of the composition compared to round glass fibers.

[0080] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit the scope of protection of this application. Although this application 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 this application without departing from the substance and scope of the technical solutions of this application.

Claims

1. A polyphenylene sulfide composition, characterized in that, The product comprises the following components in parts by weight: 60-85 parts PPS resin and 15-40 parts flat glass fiber; wherein the PPS resin satisfies: 10A+10B+C≤6050. Wherein, Ag / 10min is the melt index of the PPS resin at 316℃ and 5kg. B℃ is the crystallization temperature of the PPS resin. C ppm represents the end-group chlorine content of the PPS resin.

2. The polyphenylene sulfide composition according to claim 1, characterized in that, The value of 10A+10B+C is 5000 to 6010.

3. The polyphenylene sulfide composition according to claim 1 or 2, characterized in that, The PPS resin has a melt flow index A of ≤200 g / 10 min at 316°C and 5 kg, preferably 160 g / 10 min to 190 g / 10 min; and / or The crystallization temperature B of the PPS resin is <220℃, preferably 195℃~215℃; and / or The terminal chlorine content of the PPS resin is C≤2500ppm, preferably 1500ppm~2200ppm.

4. The polyphenylene sulfide composition according to any one of claims 1-3, characterized in that, The average aspect ratio of the flat glass fiber is 2.4 to 4.

2.

5. The polyphenylene sulfide composition according to any one of claims 1-4, characterized in that, The average short side length of the flat glass fiber cross-section is 5-7 μm, and the average long side length is 18-28 μm.

6. The polyphenylene sulfide composition according to any one of claims 1-5, characterized in that, The average length of the flat glass fiber is 2-5 mm.

7. The polyphenylene sulfide composition according to any one of claims 1-6, characterized in that, The crystallization temperature of the polyphenylene sulfide composition is less than 210°C, preferably 180–200°C.

8. The polyphenylene sulfide composition according to any one of claims 1-7, characterized in that, The polyphenylene sulfide composition further includes the following components in parts by weight: 0.1 to 1 part of colorant and 0.1 to 1 part of processing aid; preferably, the colorant includes at least one of aniline black, oil black or carbon black.

9. The method for preparing the polyphenylene sulfide composition according to any one of claims 1 to 8, characterized in that, The process includes the following steps: mixing all raw materials, melt extruding, granulating, and obtaining the polyphenylene sulfide composition.

10. The application of the polyphenylene sulfide composition according to any one of claims 1 to 8 in the field of laser welding.

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