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 belongs to the field of high polymer materials. The polyphenylene sulfide composite material is prepared from the following components in parts by weight: 49 to 91 parts of polyphenylene sulfide resin, 10 to 50 parts of glass fiber and 1 to 5 parts of silane compound, wherein the polyphenylene sulfide resin meets the conditions that the sodium ion content is greater than 1100 ppm, and the weight-average molecular weight is 43000-62000. The glass fiber and the silane compound with specific contents are added into the PPS, and the sodium ion content and the weight-average molecular weight of the PPS are controlled to be within a specific range, so that the obtained polyphenylene sulfide composite material has relatively high laser welding capability and is suitable for being used as a material needing to be welded in products such as automobiles, aerospace and mobile electronic equipment.

Description

Technical Field

[0001] This application relates to the field of polymer materials, and particularly relates to a polyphenylene sulfide composite material, a preparation method thereof, and an application thereof. Background Art

[0002] Polyphenylene sulfide resin (PPS) is a semi-crystalline polymer with symmetry and regularity in which the main molecular chain is alternately arranged by benzene rings and sulfur atoms. Due to the crystallinity of PPS itself, the laser transmittance of PPS material is low and the laser welding ability is poor, so it is difficult to fabricate molded products by laser welding in practical applications. Moreover, the toughness and strength of pure PPS resin are poor and it cannot be directly used. Therefore, when using PPS material, physical modification is carried out by adding glass fiber, etc. However, the glass fiber acts as a nucleating agent, which will further promote the crystallization of PPS and reduce the laser transmittance.

[0003] Therefore, it is necessary to develop a glass fiber-reinforced PPS composite material with good laser welding ability. Summary of the Invention

[0004] Based on the defects existing in the prior art, the purpose of this application is to provide a polyphenylene sulfide composite material, a preparation method thereof, and an application thereof. The obtained polyphenylene sulfide composite material has high laser transmittance, high laser welding strength, and strong laser welding ability.

[0005] To achieve the above purpose, in the first aspect, this application provides a polyphenylene sulfide composite material, which comprises the following components in parts by weight:

[0006] Polyphenylene sulfide resin: 49 - 91 parts,

[0007] Glass fiber: 10 - 50 parts,

[0008] Silane compound: 1 - 5 parts;

[0009] The polyphenylene sulfide resin satisfies: sodium ion content > 1100 ppm, and the weight average molecular weight is 43000 - 62000.

[0010] The inventors have found through research that the sodium ion content of PPS will affect its crystallization rate, thereby affecting the laser transmittance and welding effect of the material. When the sodium ion content of PPS is too low, the crystallization rate is too fast, resulting in low laser transmittance, inability to weld or low welding strength; moreover, the weight average molecular weight of PPS itself will affect the laser transmittance; adding a silane compound can improve the compatibility between glass fiber and PPS and improve the laser welding effect. The polyphenylene sulfide composite material of this application has strong laser welding ability, such as high laser transmittance and high laser welding strength, by controlling the sodium ion content and weight average molecular weight of PPS within a specific range, and adding a specific content of glass fiber and silane compound.

[0011] The polyphenylene sulfide resin is 49 to 91 parts by weight, such as 49 parts by weight, 55 parts by weight, 60 parts by weight, 65 parts by weight, 70 parts by weight, 75 parts by weight, 80 parts by weight, 85 parts by weight, 91 parts by weight or the range formed by any two of the above values. Preferably, the weight percentage content of the polyphenylene sulfide resin in the polyphenylene sulfide composite material is above 40%, such as 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 89.2% or the range formed by any two of the above values.

[0012] The glass fiber is 10 to 50 parts by weight, such as 10 parts by weight, 15 parts by weight, 20 parts by weight, 25 parts by weight, 30 parts by weight, 35 parts by weight, 40 parts by weight, 45 parts by weight, 50 parts by weight or the range formed by any two of the above values.

[0013] Preferably, the sum of the mass ratios of the polyphenylene sulfide resin and the glass fiber in the polyphenylene sulfide composite material is above 90%, such as 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or the range formed by any two of the above values.

[0014] The silane compound is 1 to 5 parts by weight, such as 1 part by weight, 2 parts by weight, 3 parts by weight, 4 parts by weight, 5 parts by weight or the range formed by any two of the above values.

[0015] The sodium ion content of the polyphenylene sulfide resin is > 1100 ppm, such as 1110 ppm, 1120 ppm, 1130 ppm, 1140 ppm, 1150 ppm, 1160 ppm, 1170 ppm, 1180 ppm, 1190 ppm, 1200 ppm, 1300 ppm, 1400 ppm, 1500 ppm, 1600 ppm, 1700 ppm, 1800 ppm, 1900 ppm, 2000 ppm or the range formed by any two of the above values. Preferably, the sodium ion content in the polyphenylene sulfide resin is 1110 to 2000 ppm, so that the laser transmittance of the composite material is higher and the laser welding performance is better.

[0016] The sodium ion content of the polyphenylene sulfide resin is measured with reference to the test method in GB / T23942-2009, specifically as follows: 0.1 g of PPS is calcined at 700° C. for 1 h to obtain a calcined sample, which is dissolved in a dilute hydrochloric acid solution (HCl mass percentage is 6%), and the volume is fixed to 50 mL with the same hydrochloric acid solution. The sodium ion content in the solution is tested using an inductively coupled plasma spectrometer (Agilent 710), and the plasma power is set to 1300 W, the cooling gas flow rate is 12 L / min, the auxiliary gas flow rate is 0.8 L / min, the atomizing gas flow rate is 0.8 L / min, and the additional gas flow rate is 0 L / min, and then the sodium ion content of the PPS is calculated.

[0017] The weight average molecular weight of the polyphenylene sulfide resin is 43000-62000, such as 43000, 44000, 45000, 46000, 47000, 48000, 49000, 50000, 51000, 52000, 53000, 54000, 55000, 56000, 57000, 58000, 59000, 60000, 61000, 62000 or an interval formed by any two of the above values.

[0018] The weight average molecular weight of the polyphenylene sulfide resin was measured using a gel permeation chromatograph (manufacturer: Waters, model: ACQUITYAPC), with polystyrene as the standard sample, 1-chloronaphthalene as the mobile phase, a column temperature of 220° C., a flow rate of 1 mL / min, and a refractive index detector.

[0019] The polyphenylene sulfide resin can be purchased or made by yourself. In some embodiments, the preparation method of the polyphenylene sulfide resin comprises the following steps:

[0020] Sodium sulfide and p-dichlorobenzene are added to NMP solvent in a mass ratio of (1.05-1.2):1, and then a catalyst is added. The first reaction is carried out at 180-220°C for 2-4 hours, and then the temperature is increased to 240-270°C for a second reaction for 40-60 hours. After washing with a NMP-ethylene glycol mixed solution, the mixture is washed with water and dried to obtain a polyphenylene sulfide resin.

[0021] In one embodiment, the second reaction is performed after the second reaction is completed.

[0022] In one embodiment, the catalyst is selected from at least one of sodium phosphate and lithium carbonate.

[0023] The weight-average molecular weight of the polyphenylene sulfide resin is affected by factors such as the temperature and time of the two reactions, whether sieving is performed after the second reaction, and the pore size of the sieve used; the sodium ion content is affected by factors such as the number of water washing times, water washing time, water consumption for water washing, and type of catalyst.

[0024] Preferably, the glass fiber is at least one of circular glass fiber and flat glass fiber. More preferably, the glass fiber is circular glass fiber. Compared with adding flat glass fiber, adding circular glass fiber can enable the composite material to have better mechanical properties (such as higher tensile strength) and lower cost, and higher cost performance while obtaining similar laser welding performance.

[0025] Preferably, the average diameter of the circular glass fiber is 9 - 14 μm, and the average length is 2 - 5 mm. For example, the average diameter of the circular glass fiber is 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm or the range formed by any two of the above values; the average length is 2 mm, 3 mm, 4 mm, 5 mm or the range formed by any two of the above values.

[0026] The average diameter and average length of the circular glass fiber are obtained by testing according to the following method: observing the glass fiber sample using a scanning electron microscope, measuring the sizes of 300 glass fibers, and taking the average value.

[0027] Preferably, the average flat ratio of the flat glass fiber is 3 - 4, the average length of the long side of the cross-section is 15 - 30 μm, the average length of the short side of the cross-section is 4 - 8 μm, and the average length is 2 - 4 mm. Among them, the flat ratio refers to the ratio of the length of the long side to the length of the short side of the cross-section of the flat glass fiber.

[0028] For example, the average flat ratio of the flat glass fiber is 3, 3.2, 3.4, 3.6, 3.8, 4 or the range formed by any two of the above values; the average length of the long side of the cross-section is 15 μm, 17 μm, 20 μm, 22 μm, 25 μm, 28 μm, 30 μm or the range formed by any two of the above values; the average length of the short side of the cross-section is 4 μm, 5 μm, 6 μm, 7 μm, 8 μm or the range formed by any two of the above values; the average length is 2 mm, 3 mm, 4 mm or the range formed by any two of the above values.

[0029] The average flat ratio, the average length of the long side and the average length of the short side of the cross-section, and the average length of the flat glass fiber are obtained by testing according to the following method: observing the glass fiber sample using a scanning electron microscope, measuring the sizes of 300 glass fibers, and taking the average value.

[0030] Preferably, the silane compound includes at least one of an amino silane compound, an epoxy silane compound, and a vinyl silane compound. Exemplarily, the amino silane compound includes at least one of 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropylmethyldiethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, and N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane; the epoxy silane compound includes at least one of 3-(2,3-epoxypropoxy)propyltrimethoxysilane, 3-(2,3-epoxypropoxy)propyltriethoxysilane, 3-[(2,3)-epoxypropoxy]propylmethyldimethoxysilane, 3-(2,3-epoxypropoxy)propylmethyldiethoxysilane, and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane; and the vinyl silane compound includes at least one of vinyltrimethoxysilane, vinyltris(β-methoxyethoxy)silane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, vinyltrimethoxysilane, and vinyltriethoxysilane.

[0031] The polyphenylene sulfide composite material may further include the following components in parts by weight: 0 to 6 parts of an auxiliary agent. The auxiliary agent may optionally include at least one of an antioxidant, a lubricant, and a toughening agent.

[0032] Exemplarily, the antioxidant includes at least one of p-phenylenediamine, diaryl secondary amine, hindered phenol, phosphite, and organic sulfide.

[0033] Exemplarily, the lubricant includes at least one of silicone powder, stearate, amide, and fatty ester.

[0034] Exemplarily, the toughening agent includes at least one of ethylene-butyl acrylate-glycidyl methacrylate terpolymer, ethylene-propylene rubber, ethylene-vinyl acetate copolymer, styrene-ethylene / butene-styrene block copolymer, and glycidyl methacrylate graft.

[0035] In a second aspect, the present application provides a method for preparing the polyphenylene sulfide composite material, including the following steps:

[0036] Mix and disperse the raw materials other than glass fiber to obtain a premix;

[0037] Feed the premix into the main feed port of a screw extruder, and feed glass fiber into the side feed port of the screw extruder, and perform melt extrusion and pelletization to obtain the polyphenylene sulfide composite material.

[0038] In some embodiments, the screw extruder is a single-screw extruder or a twin-screw extruder.

[0039] Preferably, the screw extruder is a twin-screw extruder with a length-diameter ratio of 40-48:1, a barrel temperature of 240-350 °C, a screw rotation speed of 200-550 rpm, and a die temperature of 230-280 °C.

[0040] In a third aspect, the present application also provides the use of the polyphenylene sulfide composite material in the field of laser welding.

[0041] In a fourth aspect, the present application also provides the use of the polyphenylene sulfide composite material in automobiles, aerospace or mobile electronic devices. The polyphenylene sulfide composite material can be used as a material for components in automobiles, aerospace, mobile electronic devices, etc., especially for components that are difficult to connect by conventional connection methods due to shape and / or size limitations, such as the battery housing and transmission gears of automobiles, the fuel tanks and fuel pipelines of aerospace equipment, precision sensors, microelectronic components and internal brackets in mobile electronic devices, etc.

[0042] Compared with the prior art, the beneficial effects of the present application are as follows: By adding a specific content of glass fiber and silane compound to PPS and controlling the sodium ion content and weight average molecular weight of PPS within a specific range, the obtained polyphenylene sulfide composite material has strong laser welding ability and is suitable for products such as automobiles, aerospace, and mobile electronic devices. Detailed Embodiments

[0043] To better illustrate the purpose, technical solutions and advantages of the present application, the present application will be further described below in conjunction with specific examples and comparative examples. The purpose is to understand the content of the present application in detail, rather than to limit the present application. All other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present application. The experimental reagents and instruments involved in the implementation of the present application are all common ordinary reagents and instruments unless otherwise specified. In the present application, among the technically characterized descriptions in an open-ended manner, a closed technical solution composed of the listed features is included, and an open technical solution including the listed features is also included.

[0044] The following examples and comparative examples all provide a polyphenylene sulfide composite material. The information of the raw materials used is shown in Table 1, and unless otherwise specified, they are all commercially available raw materials. In addition, the component raw materials used in each parallel experiment are the same. The formulations of these polyphenylene sulfide composite materials are shown in Tables 2 and 3, and their preparation methods include the following steps:

[0045] Mix and disperse the raw materials except for the glass fiber to obtain a premix;

[0046] Feed the obtained premix into the main feeding port of the twin-screw extruder, and feed the glass fiber into the side feeding port of the twin-screw extruder, and melt and extrude and pelletize to obtain the polyphenylene sulfide composite material;

[0047] Among them, the length-diameter ratio of the screw of the twin-screw extruder is 48:1, the screw rotation speed is 300 r / min, the melting and extrusion temperature is 270 °C, and the die temperature is 250 °C.

[0048] Table 1

[0049]

[0050]

[0051] Among them, PPS1-7 are prepared by the following preparation method:

[0052] Industrial-grade sodium sulfide and p-dichlorobenzene are added to the NMP solvent according to a mass ratio of (1.05-1.2):1, and then sodium phosphate or lithium carbonate is added as a catalyst. First, a first reaction is carried out at 180-220 °C for 2-4 h, and then the temperature is raised to 240-270 °C for a second reaction. The time of the second reaction is 40-60 h. After sieving, it is washed once with a NMP-ethylene glycol mixture and then washed with water 2-3 times, 5 min each time. Then it is dried in vacuum at 100 °C to obtain the corresponding PPS;

[0053] The weight-average molecular weight and sodium ion content of PPS are regulated by adjusting the temperature and time of the second reaction, whether to sieve after the second reaction and the size of the sieve pore diameter, the type of catalyst used, and the number of water washings to obtain PPS1-7.

[0054] Table 2

[0055]

[0056]

[0057] The following performance tests are carried out on the above-mentioned examples and comparative examples of polyphenylene sulfide composites:

[0058] Crystallization rate: It is tested by DSC. The instrument used is a differential scanning calorimeter (type 200F3, NETZCH, Germany). The melting temperature is 350 °C, the cooling rate is 10 °C / min, and the crystallization temperature is measured. Calculate ΔT = melting point (286 °C) - crystallization temperature according to the following formula. ΔT is used to reflect the crystallization rate. The larger ΔT is, the slower the crystallization rate is;

[0059] Laser transmittance: The polyphenylene sulfide composite is injection-molded into a spline of 50 mm × 50 mm × 2 mm, and the laser transmittance at 940 nm is measured by a spectrophotometer (SPM-28160, Hangzhou Yuanfang Optoelectronics);

[0060] Laser welding strength: The polyphenylene sulfide composite material was injection molded into a spline with dimensions of 125 mm × 13 mm × 2 mm (i.e., the laser-transmitting spline). At the same time, the polyphenylene sulfide composite material and carbon black were mixed and injection molded into a spline with dimensions of 125 mm × 13 mm × 2 mm according to a mass ratio of 99.5:0.5 (i.e., the laser-absorbing spline). The laser-transmitting spline and the laser-absorbing spline were overlapped and placed in a plastic material laser welding system (Han's Laser, model WFD120 W-PCTS333SP) for laser welding. The welding conditions were as follows: diode laser (wavelength 940 nm), laser radius 200 μm, welding power 80 W, welding speed 1000 mm / s, welding length 125 mm × 3 (to reduce errors, 3 independent non-overlapping welds were performed, and each weld bead was parallel and spaced 6 mm apart), and the pressure of the pneumatic clamping device was 0.5 MPa. After placing the laser-welded spline in an environment with 50% relative humidity and a temperature of 23 ± 2 °C for 4 hours, a tensile test was carried out using a tensile testing machine (zwick / roell z010). The two ends were clamped along the long axis direction of the welded spline, the span was 120 mm, and the tensile speed was 10 mm / min. The welding strength was the maximum load of the tensile testing machine at the time of fracture.

[0061] The test results are shown in Table 3.

[0062] Table 3

[0063]

[0064]

[0065] From the above data, it can be seen that the polyphenylene sulfide composite materials of the embodiments of the present application have excellent laser welding performance, such as a laser transmittance of more than 25% at 940 nm, a laser welding strength of more than 625 N, and a △T of more than 70 °C.

[0066] Compared with Examples 1, 4 - 6, in Comparative Example 1, due to the low sodium ion content of PPS, the △T was low and the laser transmittance at 940 nm was low, resulting in inability to perform laser welding; in Comparative Example 2, due to the low weight-average molecular weight of PPS, the △T was low and the laser transmittance at 940 nm was low, resulting in inability to perform laser welding; in Comparative Example 3, the weight-average molecular weight of PPS was relatively large, resulting in a low end group content and a low sodium ion content, thus causing a low △T, a low laser transmittance at 940 nm, and a low laser welding strength.

[0067] Comparing Examples 1 and 7 - 8, it can be seen that compared with flat glass fibers, using round glass fibers can obtain similar laser welding performance while having lower costs and better mechanical properties such as the tensile strength of the material.

[0068] Comparing Examples 1, 7-8 with Comparative Examples 4-5, it can be seen that, compared with not adding a silane compound or replacing the silane compound with other compatibilizers, adding a silane compound can make the material have a higher laser transmittance and stronger laser welding strength.

[0069] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application rather than to limit the protection scope of the present application. Although the present application has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present application can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present application.

Claims

1. A polyphenylene sulfide composite material, characterized in that: Contains the following components by weight: 49 to 91 parts of polyphenylene sulfide resin, 10-50 parts of glass fiber, 1 to 5 parts of silane compound; The polyphenylene sulfide resin meets the following requirements: sodium ion content>1100ppm, and weight average molecular weight of 43000-62000.

2. The polyphenylene sulfide composite material according to claim 1, characterized in that: The sodium ion content in the polyphenylene sulfide resin is 1110-2000ppm.

3. The polyphenylene sulfide composite material according to claim 1, characterized in that: The glass fiber is at least one of round glass fiber and flat glass fiber.

4. The polyphenylene sulfide composite material according to claim 3, characterized in that: The glass fibers are round glass fibers.

5. The polyphenylene sulfide composite material according to claim 3, characterized in that: At least one of the following conditions is met: (1) The average diameter of the round glass fibers is 9 to 14 μm, and the average length is 2 to 5 mm; (2) The flat glass fibers have an average flatness ratio of 3 to 4, an average cross-sectional long side length of 15 to 30 μm, an average cross-sectional short side length of 4 to 8 μm, and an average length of 2 to 4 mm.

6. The polyphenylene sulfide composite material according to claim 1, characterized in that: The silane compound includes at least one of an aminosilane compound, an epoxysilane compound, and a vinylsilane compound.

7. The method for preparing the polyphenylene sulfide composite material according to claim 1, characterized in that: The following steps are involved: Mixing and dispersing raw materials except glass fiber to obtain a premix; The premix is ​​fed from the main feeding port of the screw extruder, and the glass fiber is fed from the side feeding port of the screw extruder, and the mixture is melt-extruded and granulated to obtain a polyphenylene sulfide composite material.

8. The method for preparing the polyphenylene sulfide composite material according to claim 7, characterized in that: The screw extruder is a twin-screw extruder with a length-to-diameter ratio of 40 to 48:1, a barrel temperature of 240 to 350° C., a screw speed of 200 to 550 rpm, and a die temperature of 230 to 280° C.

9. Use of the polyphenylene sulfide composite material according to any one of claims 1 to 7 in the field of laser welding.

10. Use of the polyphenylene sulfide composite material according to any one of claims 1 to 7 in automobiles, aerospace or mobile electronic devices.

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