A modified polyphenylene sulfide resin and a method for preparing the same

Abstract

The application relates to a modified polyphenylene sulfide resin and a preparation method thereof, and relates to the field of high polymer materials. The modified polyphenylene sulfide resin comprises the following raw materials in parts by weight: 37.4-67.8 parts of polyphenylene sulfide resin; 30-50 parts of glass fiber; 2-10 parts of a toughening agent; 0.1-0.6 parts of an antioxidant; and 0.1-2 parts of a processing aid. The toughening agent is an ethylene-glycidyl methacrylate copolymer. The impact toughness of the polyphenylene sulfide resin is improved by compounding the glass fiber with the polyphenylene sulfide, the brittleness of the polyphenylene sulfide resin composite material is reduced, the flowability of the polyphenylene sulfide resin in the injection molding process is improved by adding the glass fiber, and the polyphenylene sulfide resin is easy to process and mold; the ethylene-glycidyl methacrylate copolymer is selected as the toughening agent, the compatibility of the glass fiber and the polyphenylene sulfide resin is enhanced, and the rigidity and toughness of the polyphenylene sulfide resin product are enhanced.

Description

Technical Field

[0001] This application relates to the field of polymer composite materials, and in particular to a modified polyphenylene sulfide resin and a method for preparing the same. Background Technology

[0002] Polyphenylene sulfide (PPS) is a special engineering plastic with excellent comprehensive performance. Also known as polyphenylene sulfide or polyphenylene sulfide, it is a type of polymer whose molecular chain contains only phenylene and sulfide groups. It is a semi-crystalline high-performance resin. Polyphenylene sulfide (PPS) resin possesses many excellent properties, including: excellent chemical stability (PPS resin is insoluble in any known solvent below 200°C, making it considered a material with excellent chemical resistance, second only to polytetrafluoroethylene); excellent flame retardancy (the flame retardancy of PPS resin is determined by its chemical structure, with a vertical flame retardancy rating reaching UL-94V-0 and an oxygen index of 44–53); good mechanical properties (PPS resin has high strength and rigidity, with minimal reduction in rigidity under high temperatures, exhibiting excellent fatigue resistance and creep resistance); outstanding heat resistance (modified PPS resin has a short-term heat distortion temperature as high as 260°C, and a long-term continuous use temperature of 200–240°C, making it one of the most thermally stable thermoplastic resins); and dimensional stability (PPS resin retains almost no dimensional change after absorbing moisture at high temperatures, exceeding that of thermosetting materials).

[0003] Polyphenylene sulfide resin has many excellent properties and is widely used in electronics, electrical appliances, automobiles, precision machinery, aerospace, nuclear power, petrochemicals and food processing. However, it also has some disadvantages, such as poor impact strength leading to brittle products, poor weld strength, rough surface and poor gloss after glass fiber reinforcement, easy flow, and difficulty in injection molding of pure resin. These disadvantages limit the application of polyphenylene sulfide materials to a certain extent. Summary of the Invention

[0004] To address the problems existing in the prior art, this application provides a modified polyphenylene sulfide resin and its preparation method, which further improves the impact toughness and processing performance of polyphenylene sulfide resin without reducing its temperature resistance and rigidity.

[0005] In a first aspect, this application provides a modified polyphenylene sulfide resin, employing the following technical solution:

[0006] A modified polyphenylene sulfide resin, comprising the following raw materials in parts by weight:

[0007] 37.4–67.8 parts of polyphenylene sulfide resin;

[0008] 30-50 parts glass fiber;

[0009] Toughening agent 2-10 parts;

[0010] Antioxidant 0.1–0.6 parts;

[0011] Processing aids: 0.1–2 parts;

[0012] The toughening agent is an ethylene-glycidyl methacrylate copolymer.

[0013] By adopting the above technical solutions, glass fiber exhibits excellent heat resistance and corrosion resistance, as well as high mechanical strength. The composite of glass fiber and polyphenylene sulfide (PPS) resin effectively enhances the impact toughness of PPS and reduces the brittleness of PPS resin products. Since pure PPS resin melt is highly fluid, it is difficult to injection mold. The addition of glass fiber can reduce the fluidity of PPS resin during injection molding to a certain extent, making it easier to process and mold. Ethylene-glycidyl methacrylate copolymer is selected as a toughening agent. The addition of ethylene-glycidyl methacrylate copolymer can enhance the compatibility between glass fiber and PPS resin, improve the impact strength of the copolymer, and enhance the rigidity and toughness of PPS resin products. Furthermore, the addition of ethylene-glycidyl methacrylate copolymer can improve the extrusion moldability of PPS resin, reduce the surface roughness of products caused by composite glass fiber, improve the surface gloss of PPS resin products, and improve surface wetting effects, thereby enhancing its surface coatability and colorability. The addition of antioxidants can enhance the antioxidant properties of polyphenylene sulfide resin, effectively delaying the degradation or thermo-oxidative aging of polyphenylene sulfide resin products. The addition of processing aids can improve the melt flowability of polyphenylene sulfide resin, which is beneficial for its injection molding.

[0014] Optionally, the molecular weight of the polyphenylene sulfide resin is not less than 50,000.

[0015] By adopting the above technical solution, the molecular weight of polyphenylene sulfide resin is limited to a higher range, which can appropriately improve the melt flowability of polyphenylene sulfide resin, which is beneficial to the injection molding of polyphenylene sulfide resin and enhances its processability. In addition, limiting the molecular weight of polyphenylene sulfide resin to the above range results in products with better mechanical strength and impact toughness after being compounded with glass fiber.

[0016] Optionally, the glass fiber is an alkali-free glass fiber roving.

[0017] Further preferably, the monofilament diameter of the alkali-free glass fiber roving is 10-14 μm, and the linear density is 1800-2400 tex.

[0018] By adopting the above technical solution, alkali-free glass fiber rovings can be used to reinforce polyphenylene sulfide (PPS) resin, effectively enhancing the rigidity and toughness of PPS resin products. Alkali-free glass fiber rovings possess better strength and weather resistance, along with good modulus and excellent alkali resistance. When combined with PPS resin, they provide good mechanical properties while effectively improving the weather resistance of the products. Limiting the specifications of alkali-free long glass fiber rovings within the aforementioned range allows for better integration with PPS resin, resulting in better modification and reinforcement effects.

[0019] Optionally, the antioxidant is one or a combination of two of phenolic antioxidants and phosphite antioxidants.

[0020] Optionally, the phenolic antioxidant is pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]; the phosphite antioxidant is tris(2,4-di-tert-butylphenyl) phosphite.

[0021] By adopting the above technical solutions, both phenolic antioxidants and phosphite antioxidants have good antioxidant effects, which can effectively enhance the antioxidant properties of polyphenylene sulfide resin and reduce the degradation or thermo-oxidative aging of polyphenylene sulfide resin composites.

[0022] Optionally, the processing aid includes one or more of fatty acids, calcium stearate, zinc stearate, and silicone powder.

[0023] By adopting the above technical solutions, the addition of calcium stearate, zinc stearate or silicone powder can provide good lubrication for polyphenylene sulfide resin during melt extrusion, improve the processing and molding performance of polyphenylene sulfide resin, reduce the friction during the extrusion molding process of polyphenylene sulfide resin, and improve the surface properties of polyphenylene sulfide resin after extrusion molding, thereby improving its surface smoothness and giving polyphenylene sulfide resin products a better gloss.

[0024] Secondly, this application provides a method for preparing modified polyphenylene sulfide resin, using the following technical solution:

[0025] A method for preparing modified polyphenylene sulfide resin includes the following steps:

[0026] S1. Dry the polyphenylene sulfide resin at 140-160℃ for 3-5 hours;

[0027] S2. Mix the dried polyphenylene sulfide resin, toughening agent, antioxidant, and processing aid to obtain a premix;

[0028] S3. The premixed material and glass fiber are melt-blended, extruded, and granulated to obtain modified polyphenylene sulfide resin.

[0029] Optionally, in step S3, the premix and glass fiber are melt-blended using a twin-screw extruder. The temperatures of the twin-screw extruder are as follows: Zone 1: 270–280°C; Zone 2: 270–280°C; Zone 3: 285–295°C; Zone 4: 285–295°C; Zone 5: 285–295°C; Zone 6: 300–310°C; Zone 7: 300–310°C; Zone 8: 300–310°C; Zone 9: 300–310°C; and the die head temperature is 290–300°C. The screw speed of the twin-screw extruder is 250–350 r / min.

[0030] Optionally, in step S3, the premix is ​​added from the main feed port of the twin-screw extruder, and the glass fiber is added from the side feed port of the twin-screw extruder.

[0031] By adopting the above technical solution, the polyphenylene sulfide resin is dried at high temperature before being mixed with other additives to fully remove the moisture present in the polyphenylene sulfide resin, reduce the degradation of the polyphenylene sulfide resin base after molding, and improve the stability and impact strength of the polyphenylene sulfide resin material. During the melt extrusion process of the mixture, glass fiber and premix are added through different feed ports, which can make the glass fiber more evenly dispersed in the polyphenylene sulfide resin and reduce the occurrence of fiber floating phenomenon after the polyphenylene sulfide resin base is molded.

[0032] In summary, this application includes at least one of the following beneficial technical effects:

[0033] 1. In this application's technical solution, the impact toughness of polyphenylene sulfide (PPS) resin is improved by combining glass fiber with PPS, the brittleness of the PPS resin composite material is reduced, and the overall strength of the PPS resin product is enhanced. Ethylene-glycidyl methacrylate copolymer is selected as a toughening agent. The addition of ethylene-glycidyl methacrylate copolymer can enhance the compatibility between glass fiber and PPS resin, further improving the impact strength of the product and enhancing the rigidity and toughness of the PPS resin product.

[0034] 2. The addition of ethylene-glycidyl methacrylate copolymer can improve the extrusion molding properties of polyphenylene sulfide resin, reduce the surface roughness of products caused by composite glass fiber, improve the gloss of polyphenylene sulfide resin products, improve the surface wetting effect, and enhance its surface coating and colorability.

[0035] 3. Adding calcium stearate, zinc stearate, or silicone powder as processing aids can provide good lubrication for polyphenylene sulfide resin during melt extrusion, improve the processing and molding performance of polyphenylene sulfide resin, reduce the friction during the extrusion molding process, and improve the surface properties of polyphenylene sulfide resin after extrusion molding, thereby improving its surface smoothness and giving polyphenylene sulfide resin products a better gloss. Detailed Implementation

[0036] The present application will be further described in detail below with reference to specific embodiments. It should be noted that, unless otherwise specified, all embodiments below are performed under conventional conditions or conditions recommended by the manufacturer; and all raw materials used in the embodiments below, unless otherwise specified, are commercially available.

[0037] In the following embodiments, unless otherwise specified, the models of some raw materials are as follows:

[0038] Pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]: Irganox1010;

[0039] Tris(2,4-di-tert-butylphenyl) phosphite: Irganox168;

[0040] Ethylene-glycidyl methacrylate copolymer: GMAAX8840.

[0041] Example 1

[0042] A modified polyphenylene sulfide resin, with the component proportions shown in Table 1, was prepared according to the following method:

[0043] S1. Dry the polyphenylene sulfide resin with a molecular weight of 50,000 at 140°C for 5 hours.

[0044] S2. According to the formula, dry polyphenylene sulfide resin, ethylene-glycidyl methacrylate copolymer, antioxidant (pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and tris(2,4-di-tert-butylphenyl phosphite) are mixed at high speed for 5 minutes to obtain the premix.

[0045] S3. The premixed material is added from the main feed port of the twin-screw extruder, and the glass fiber (alkali-free glass fiber untwisted roving, with a single filament diameter of 10μm and a linear density of 1800tex) is added from the side feed port. After melt blending, extrusion, and granulation, modified polyphenylene sulfide resin is obtained. The temperatures of the twin-screw extruder are as follows: Zone 1: 270℃, Zone 2: 270℃, Zone 3: 285℃, Zone 4: 285℃, Zone 5: 285~295℃, Zone 6: 300℃, Zone 7: 300℃, Zone 8: 300℃, Zone 9: 300℃, and the die head temperature is 290℃. The screw speed of the twin-screw extruder is 250r / min.

[0046] Examples 2-5

[0047] The difference between Examples 2-5 and Example 1 is that the composition ratio of the raw materials is different. The specific composition ratio is shown in Table 1.

[0048] Comparative Example 1

[0049] The difference between this comparative example and Example 1 is that an equal amount of polyphenylene sulfide resin is used instead of the toughening agent, while all other aspects remain the same as in Example 1.

[0050] Comparative Example 2

[0051] The difference between this comparative example and Example 1 is that an equal amount of polyphenylene sulfide resin is used instead of glass fiber, while all other aspects remain the same as in Example 1.

[0052] Comparative Examples 3-6

[0053] The difference between Comparative Examples 3-6 and Example 1 is that the raw material composition ratios are different. The specific composition ratios are shown in Table 1. All other aspects are consistent with Example 1.

[0054] Table 1: Raw material composition ratios for Examples 1-5 (unit: kg)

[0055]

[0056] Performance testing

[0057] The modified polyphenylene sulfide resins prepared in each embodiment were injection molded using an injection molding machine to obtain test samples, which were then subjected to performance testing. The test items are as follows:

[0058] Notched impact strength: tested according to GB / T 1843 standard;

[0059] Tensile strength: Tested according to GB / T 1040 standard, tensile speed 5 mm / min;

[0060] Elongation at break: Tested according to GB / T 1040 standard, tensile speed 5 mm / min;

[0061] Bending strength: Tested according to GB / T 9341 standard, bending speed 1.25 mm / min;

[0062] Flexural modulus: Tested according to GB / T 9341 standard, bending speed 1.25 mm / min;

[0063] Heat distortion temperature: tested according to GB / T 1634 standard, with a load of 1.8 MPa.

[0064] The performance test results of Examples 1-5 and Comparative Examples 1-6 are shown in Table 2 below.

[0065] Table 2: Performance test results of Examples 1-5 and Comparative Examples 1-6

[0066]

[0067]

[0068] The data in Table 2 show that the addition of glass fiber and toughening agent significantly improves the impact toughness and strength of polyphenylene sulfide (PPS) resin composite products. Performance test data from Examples 1-5 and Comparative Examples 3 and 4 show that the impact toughness of PPS resin products is effectively improved with increasing toughening agent content. However, when the amount exceeds the limits specified in this application, the impact toughness of the PPS resin products decreases significantly, and the bending performance of the products also weakens to some extent. This may be because excessive addition of toughening agent affects the compatibility of PPS resin with other composite materials, especially the uniformity of glass fiber dispersion in the PPS resin, resulting in a certain decrease in the mechanical strength of the products. Comparative Examples 5 and 6 show adjustments to the amount of glass fiber added. It can be seen that when the amount of glass fiber added exceeds the limits specified in this application, the performance of the PPS resin products decreases to some extent, and the toughness of the products is significantly reduced.

[0069] Example 6

[0070] The difference between this embodiment and Embodiment 1 is that the molecular weight of the polyphenylene sulfide resin is 40,000, while all other aspects remain the same as in Embodiment 1.

[0071] Example 7

[0072] The difference between this embodiment and Embodiment 1 is that the linear density of the alkali-free glass fiber untwisted roving is 2400 tex, while the rest are the same as in Embodiment 1.

[0073] Example 8

[0074] The difference between this embodiment and Embodiment 1 is that the linear density of the alkali-free glass fiber untwisted roving is 2200 tex, while the rest are the same as in Embodiment 1.

[0075] Example 9

[0076] The difference between this embodiment and Embodiment 1 is that the linear density of the alkali-free glass fiber untwisted roving is 2600 tex, while the rest are the same as in Embodiment 1.

[0077] Example 10

[0078] The difference between this embodiment and Embodiment 1 is that the diameter of the monofilament of the alkali-free glass fiber untwisted roving is 14μm, while the rest are the same as in Embodiment 1.

[0079] Example 11

[0080] The difference between this embodiment and Embodiment 1 is that an equal amount of silicone powder is used instead of zinc stearate as a processing aid, while the rest remains the same as in Embodiment 1.

[0081] Example 12

[0082] The difference between this embodiment and Embodiment 1 is that the processing aid is a mixture of equal amounts of silicone powder and calcium stearate instead of zinc stearate, and the mass ratio of calcium stearate to silicone powder is 1:1. All other aspects are the same as in Embodiment 1.

[0083] Example 13

[0084] The difference between this embodiment and Example 1 is that the polyphenylene sulfide is not dried during the preparation process. The specific preparation method is as follows:

[0085] S1. Weigh out the polyphenylene sulfide resin, toughening agent, antioxidant, and processing aid according to the formula and mix them to obtain a premix;

[0086] S2. The premixed material and glass fiber are added to a twin-screw extruder, melt-blended, extruded, and granulated to obtain modified polyphenylene sulfide resin. The temperatures of the twin-screw extruder are as follows: Zone 1: 270℃, Zone 2: 270℃, Zone 3: 285℃, Zone 4: 285℃, Zone 5: 285-295℃, Zone 6: 300℃, Zone 7: 300℃, Zone 8: 300℃, Zone 9: 300℃, and the die head temperature is 290℃. The screw speed of the twin-screw extruder is 250 r / min.

[0087] Everything else is consistent with Example 1.

[0088] Example 14

[0089] The difference between this embodiment and Embodiment 1 lies in the preparation method, which is as follows:

[0090] S1. Dry the polyphenylene sulfide resin at 140℃ for 5 hours;

[0091] S2. According to the formula, dry the dried polyphenylene sulfide resin, ethylene-glycidyl methacrylate copolymer, antioxidant, and zinc stearate at high speed for 5 minutes to obtain the premix.

[0092] S3. The premixed material and glass fiber are added together from the main feed port of the twin-screw extruder, melt-blended, extruded, and granulated to obtain modified polyphenylene sulfide resin; wherein, the temperature of the twin-screw extruder is: zone 1 270℃, zone 2 270℃, zone 3 285℃, zone 4 285℃, zone 5 285~295℃, zone 6 300℃, zone 7 300℃, zone 8 300℃, zone 9 300℃, and die head temperature 290℃; the screw speed of the twin-screw extruder is 250r / min.

[0093] Everything else is consistent with Example 1.

[0094] The performance test results of Examples 6-14 are shown in Table 3 below.

[0095] Table 3: Performance test results of Examples 6-14

[0096]

[0097] Examples 6-14 further adjusted the performance parameters and specifications of the raw materials based on Example 1. As can be seen from the data in Table 3, when the specifications of the glass fiber are outside the range defined in this application, the properties of the polyphenylene sulfide resin products are weakened to a certain extent. The reason may be that when the specifications are outside the preferred range of this application, the modification effect of the glass fiber on the polyphenylene sulfide resin is weakened, and the compatibility between the glass fiber, polyphenylene sulfide resin and other raw materials deteriorates, resulting in a certain decrease in the stability and strength of the product.

[0098] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A modified polyphenylene sulfide resin characterized in that, The raw materials include the following weight parts: polyphenylene sulfide resin 37.4~63.4 parts; glass fiber 30~50 parts; toughening agent 2~10 parts; antioxidant 0.1~0.6 parts; processing aid 0.1~2 parts; the toughening agent is ethylene-glycidyl methacrylate copolymer; The molecular weight of the polyphenylene sulfide resin is not less than 50000; The glass fiber is alkali-free glass fiber untwisted roving, the single filament diameter is 10μm, and the linear density is 1800tex; The processing aid includes a combination of one or more of fatty acid, calcium stearate, zinc stearate, and silicone powder.

2. The modified polyphenylene sulfide resin according to claim 1, characterized by, The antioxidant is a combination of one or more of phenolic antioxidant and phosphite antioxidant.

3. The modified polyphenylene sulfide resin of claim 2, wherein The phenolic antioxidant is tetrakis [3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid] pentaerythritol ester; the phosphite antioxidant is tris(2,4-di-tert-butylphenyl) phosphite.

4. A process for the preparation of a modified polyphenyIene sulfide resin according to any one of claims 1 to 3, characterized in that, The method includes the following steps: S1, drying the polyphenylene sulfide resin at 140~160℃ for 3~5h; S2, mixing the dried polyphenylene sulfide resin, toughening agent, antioxidant, and processing aid to obtain a premix; S3, melt blending, extruding, and granulating the premix and glass fiber to prepare a modified polyphenylene sulfide resin.

5. The method of claim 4, wherein the polyphenylene sulfide resin is prepared by the steps of: (a) polymerizing a monomer mixture comprising a polyphenylene sulfide and a modifier; and (b) recovering the polyphenylene sulfide resin. The method includes the following steps: In step S3, the premix and glass fiber are melt blended by a double screw extruder, the temperature of the double screw extruder is: zone 1 temperature 270~280℃, zone 2 temperature 270~280℃, zone 3 temperature 285~295℃, zone 4 temperature 285~295℃, zone 5 temperature 285~295℃, zone 6 temperature 300~310℃, zone 7 temperature 300~310℃, zone 8 temperature 300~310℃, zone 9 temperature 300~310℃, and the die temperature is 290~300℃; the screw rotation speed of the double screw extruder is 250~350r / min.

6. The method of claim 4, wherein the modified polyphenylene sulfide resin is prepared by the steps of: (a) dissolving the polyphenylene sulfide resin in a solvent; (b) adding the compound to the solution; and (c) precipitating the modified polyphenylene sulfide resin. In step S3, the premix is added from the main feeding port of the double screw extruder, and the glass fiber is added from the side feeding port of the double screw extruder.

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