Preparation method of PPS (polyphenylene sulfide) polymer material for multi-strand stranded cable

Abstract

The invention discloses a preparation method of a multi-strand stranded cable PPS polymer material, and belongs to the field of cable insulation protection.The method comprises the steps that polyphenylene sulfide and ferrite magnetic powder are weighed and mixed to obtain a first mixed material, and the proportion of the polyphenylene sulfide and the ferrite magnetic powder meets the magnetic powder volume ratio # imgabs0 # = 65%-70%; adding branched polyethylene into the first mixed material, and synchronously adding a polar graft and a composite lubricant to prepare a second mixed material; placing the second mixed material in a high-speed mixer, setting the rotating speed to be 800-1200 rpm, and mixing for 10-15 min to obtain a first mixed material; and putting the first mixture into a double-screw extruder, and finally melting and shearing to obtain the polyphenylene sulfide. The polyphenylene sulfide disclosed by the invention has excellent chemical stability, oxidation resistance and heat resistance.

Description

Technical Field

[0001] The present invention relates to the field of cable insulation protection, and particularly to a preparation method of a PPS polymer material for multi-strand stranded cables. Background Art

[0002] Polyphenylene sulfide (PPS) is a thermoplastic special engineering plastic with excellent comprehensive properties, having excellent heat resistance, chemical stability, mechanical strength and electrical insulation properties, and is very suitable as a cable insulation protection material. However, pure PPS has defects such as poor impact toughness and poor fluidity, and problems such as non-compliance of products or uneven injection molding are likely to occur during the injection molding process, affecting product quality.

[0003] A multi-strand stranded cable is a structure in which several or several groups of wires are twisted into a rope-like structure, and then a rubber sleeve is wrapped around its outer layer to form a cable. In order to improve the insulation performance and heat resistance of the cable, an insulating protective layer is usually wrapped around the outer layer of the cable. Traditional insulating protective materials such as rubber and polyvinyl chloride have problems such as poor heat resistance, fast aging, and environmental pollution, and it is difficult to meet the long-term use requirements of the cable. Summary of the Invention

[0004] One of the purposes of the present invention is to provide a preparation method of a PPS polymer material for multi-strand stranded cables to solve the problems of incomplete injection molding and uneven injection molding of products caused by poor fluidity of PPS in the prior art.

[0005] The present invention is realized through the following technical solutions. A preparation method of a PPS polymer material for multi-strand stranded cables includes the following steps: S100, weighing polyphenylene sulfide and ferrite magnetic powder, and mixing to obtain a first mixed material, and the ratio of the polyphenylene sulfide and the ferrite magnetic powder satisfies that the volume ratio of the magnetic powder = 65 - 70%; S200, adding branched polyethylene to the first mixed material, and synchronously adding a polar graft and a composite lubricant to prepare a second mixed material; S300, placing the second mixed material in a high-speed mixer with a set rotation speed of 800 - 1200 rpm and a mixing time of 10 - 15 min to prepare a first mixed material; S400, placing the first mixed material in a twin-screw extruder, and the parameters of the twin-screw extruder are set as follows: segmented temperature zone setting (unit: °C): feeding section 275 ± 5 °C; melting section 305 ± 5 °C; mixing section 310 ± 5 °C; die head section 295 ± 5 °C; screw rotation speed is: 280 - 350 rpm, the length-diameter ratio is 40:1, and the vacuum degree ≤ -0.08 MPa; finally, melt shearing is performed to obtain the PPS polymer material.

[0006] Furthermore, the volume fraction of the magnetic powder is calculated by the following formula: Volume fraction of magnetic powder, mass of magnetic powder, magnetic powder, mass of magnetic powder, mass of magnetic powder resin, where the magnetic powder is the density of magnetic powder and the magnetic powder is the density of polyphenylene sulfide.

[0007] Further, the addition amount of branched polyethylene is 11.5% of the mass of polyphenylene sulfide, and the degree of branching of the branched polyethylene is 18%.

[0008] Further, the polar grafted substance is polyethylene or polypropylene with a grafting rate of 10 wt% and an epoxy group content of 3.5 mmol / g.

[0009] Further, the polar grafted substance also includes maleic anhydride with a grafting rate of 10 wt% and a maleic anhydride group content of 3.5 mmol / g.

[0010] Further, the composite lubricant is a mixture of calcium stearate and silicone oil with a ratio of 3:1.

[0011] Further, the D50 of the first mixture is ≤ 80 μm and the water content is ≤ 0.03%.

[0012] Further, the control parameters of melt shearing are: the melt residence time is ≤ 3 minutes to avoid thermal degradation; the extruded product is granulated by water-cooled strand cutting to obtain PPS polymer pellets, and the particle size of the PPS polymer pellets is 2 - 3 mm × 3 - 4 mm.

[0013] On the other hand, the present invention provides a multi-strand cable PPS polymer material. The PPS polymer material prepared according to the method described above is used for insert injection molding of short multi-strand cable segments or continuous production of multi-strand cables.

[0014] Further, the insert injection molding of the short multi-strand cable segment is carried out by injecting the pellets of the PPS polymer material into a mold pre-set with a multi-strand conductor to form an insulating sheath assembly covering a partial area of the conductor, and then connecting with other cable segments through assembly.

[0015] Further, the continuous production of the multi-strand cable is carried out by forming a continuous protective layer on the surface of the stranded conductor through an extrusion coating process using the pellets of the PPS polymer material.

[0016] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0017] 1. By adding modifiers such as branched polyethylene, polar graft copolymers, and lubricants to PPS, the present invention significantly improves the impact toughness, polar compatibility, and flowability of modified PPS, solves the defects of incomplete injection molding and uneven injection molding caused by poor fluidity of PPS, and improves the product quality.

[0018] 2. The modified PPS of the present invention has excellent mechanical properties and magnetic properties, high strength and good toughness, is suitable for making various ferrite / PPS plastic magnetic material products, and is easy to injection mold, and is applicable to fields such as cable insulation protection.

[0019] 3. The modified PPS of the present invention has excellent chemical stability, antioxidant properties and heat resistance, can provide additional protection for multi-strand stranded cables, maintain the integrity of insulation and heat insulation under thermal runaway conditions, extend the service life of the cables, and is environmentally friendly, safe and reliable to use, meeting the concept of green environmental protection. Detailed implementation manners

[0021] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention.

[0022] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. Although the present invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein can also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In case of conflict with any incorporated document, the content of this specification shall prevail. Regarding the terms "comprising", "including", "having", "containing", etc. used herein, they are all open-ended terms, that is, they are intended to include but not limited to. Unless otherwise clearly specified in the context, the expressions "a" and "an" used herein include plural references. It should be noted that "first", "second", etc. are only for convenience of description and easy distinction, and cannot be understood as indicating or implying relative importance. The term "about" used herein represents a range of ±20% of the value thereafter. In some embodiments, the term "about" represents a range of ±10% of the value thereafter. In some embodiments, the term "about" represents a range of ±5% of the value thereafter.

[0023] Example 1

[0024] In the prior art, there are problems such as insufficient impact toughness, flow performance, mechanical properties, magnetic properties, insulation properties and heat resistance of the modified PPS material, as well as poor environmental friendliness and recyclability. Therefore, in this embodiment, to solve the above problems, a preparation method of modified PPS is provided.

[0025] The materials used in this embodiment include:

[0026] Using the base PPS resin as the main binder to provide high temperature resistance, high rigidity and chemical stability; using ferrite magnetic powder as the main raw material to endow the material with magnetism; using branched polyethylene as the toughening agent to improve the impact toughness of PPS and reduce brittleness; using a polar graft copolymer as the compatibilizer to enhance the interfacial bonding force between PPS and the polar / non-polar system (such as the cable insulation layer). At the same time, lubricants can be added to improve the melt fluidity and avoid injection molding defects. It should be noted that in this embodiment, the concentration of the raw material ratio is in parts by mass.

[0027] The modification method in this embodiment is to disperse branched polyethylene into the PPS resin matrix by melt blending. Branched polyethylene has a long-chain branched structure, can absorb impact energy, and can form a heterogeneous structure with PPS, and improve toughness through the crack deflection mechanism. By introducing a graft copolymer with polar functional groups (such as carboxyl group, epoxy group), hydrogen bonds or chemical bonds are formed with PPS to improve the interfacial bonding. Finally, internal / external lubricants (such as calcium stearate, silicone oil) can also be added to reduce the melt viscosity and reduce the frictional resistance during processing. The specific steps are as follows:

[0028] Step 1: Weigh 52 parts of PPS resin (MFI = 80 g / 10min, melting point 285 °C) and 40 parts of ferrite magnetic powder (particle size D50 = 4 μm, Hc = 2.5 kOe).

[0029] The ratio of the two needs to satisfy the volume fraction of the magnetic powder ; The volume fraction of the magnetic powder can be calculated by the following formula:

[0030] ,

[0031] where, , .

[0032] Step 2: Add 6 parts of branched polyethylene (branching degree is 18%, Tg = -60 °C), and its dosage is 11.5% of the mass of PPS (6 / 52);

[0033] Synchronously add 3 parts of a polar graft (grafting rate 10 wt%, epoxy group content 3.5 mmol / g) and 1.2 parts of a composite lubricant (calcium stearate: silicone oil = 3:1). The total amount of the lubricant is 1.1 wt% of the system (1.2 / (52 + 40 + 6 + 3 + 1.2)).

[0034] In this embodiment, the polar graft is a polymer grafted with epoxy groups, specifically it can be polyethylene (PE).

[0035] Step 3: Place each component in a high-speed mixer, set the rotation speed to 800 rpm, and the mixing time to 10 minutes; prepare a mixed material, and the mixed material should meet the requirements of D50≤80μm and water content≤0.03%.

[0036] Step 4: After mixing is completed, place the mixed material in a twin-screw extruder,

[0037] Set the parameters of the twin-screw extruder as follows:

[0038] Set the segmented temperature zones (unit: °C): feeding section 275±5°C; melting section 305±5°C; mixing section 310±5°C; die head section 295±5°C.

[0039] It should be noted that the purpose of setting the segmented temperature zones is:

[0040] The temperature of the feeding section should match the melting point of PPS in the premixed material (285°C) to prevent feeding blockage caused by premature melting; the temperature of the melting section should be higher than the Tg of branched polyethylene (-60°C) but lower than its decomposition temperature (380°C) to ensure stable dispersion of the toughening agent; the temperature of the die head section should be based on the melt rheological properties (1.2 parts of lubricant added to the premixed material) to avoid melt fracture.

[0041] The screw rotation speed is: 280 - 350 rpm, the length-diameter ratio is (L / D) 40:1, and the vacuum degree ≤ -0.08 MPa.

[0042] Melting shear control:

[0043] The melt residence time ≤ 3 minutes to avoid thermal degradation; the extruded product is cut into pellets by water-cooled strand cutting, and the particle size requirements are 2 - 3mm×3 - 4mm;

[0044] The melt flow index MFI of the final pellets = 90 - 110 g / 10min (test conditions 316°C / 5kg).

[0045] Vacuum devolatilization control: The vacuum degree is -0.085 MPa.

[0046] Prepare pellets of modified PPS.

[0047] Step 5: The prepared pellets of modified PPS can be used for insert injection molding of short multi-strand cable segments and continuous production of multi-strand cables.

[0048] Among them, insert injection molding of short multi-strand cable segments is carried out by injecting modified PPS pellets into a mold pre-set with a multi-strand cable conductor to form an insulating sheath assembly (such as a cable terminal sealing head) covering a local area of the conductor, and then connecting with other cable segments through assembly.

[0049] The continuous production of multi-strand stranded wires is achieved by passing modified PPS pellets through an extrusion coating process to form a continuous protective layer on the surface of the stranded conductor, supplemented by shaping in a cooling water tank and on-line defect detection, thereby preparing a multi-strand stranded wire cable insulated with modified PPS.

[0050] Example 2

[0051] The main steps of this example are basically the same as those of Example 1. The difference is that in this example, the polar graft in Step 2 is a polymer grafted with epoxy groups, specifically it can be polypropylene (PP).

[0052] The set rotation speed of the high-speed mixer in Step 3 is 1000 rpm, and the mixing time is 12 minutes.

[0053] Example 3

[0054] The main steps of this example are basically the same as those of Example 1. The difference is that in this example, the polar graft in Step 2 is maleic anhydride with a grafting rate of 10 wt% and a maleic anhydride group content of 3.5 mmol / g.

[0055] The set rotation speed of the high-speed mixer in Step 3 is 1200 rpm, and the mixing time is 15 minutes.

[0056] The specific embodiments described above further elaborate on the purpose, technical solutions, and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not used to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for preparing a PPS polymer material for a multi-strand twisted cable, characterized in that: The preparation method comprises: S100, weighing polyphenylene sulfide and ferrite magnetic powder, and mixing them to obtain a first mixed material, The ratio of polyphenylene sulfide and ferrite magnetic powder meets the volume ratio of magnetic powder. =65-70%; S200, adding branched polyethylene to the first mixed material, and simultaneously adding a polar graft and a composite lubricant to prepare a second mixed material; S300, placing the second mixed material in a high-speed mixer and setting the speed to 800-1200 rpm for a mixing time of 10-15 min to prepare a first mixed material; S400, putting the first mixed material into a twin-screw extruder, and setting the parameters of the twin-screw extruder as follows: Segmented temperature zone settings (unit: °C): feeding section 275±5°C; melting section 305±5°C; mixing section 310±5°C; die section 295±5°C; The screw speed is: 280-350rpm, the aspect ratio is 40:1, and the vacuum degree is ≤-0.08 MPa; Finally, the PPS polymer material is obtained by melt shearing.

2. The method for preparing the PPS polymer material of a multi-stranded cable according to claim 1, characterized in that: The volume fraction of the magnetic powder is calculated by the following formula: ， in, is the density of magnetic powder, ; is the density of polyphenylene sulfide, .

3. The method for preparing the PPS polymer material of a multi-strand twisted wire cable according to claim 1, characterized in that: The added amount of the branched polyethylene is 11.5% of the mass of polyphenylene sulfide, and the branching degree of the branched polyethylene is 18%.

4. The method for preparing the PPS polymer material of a multi-stranded cable according to claim 1, characterized in that: The polar grafted material is polyethylene or polypropylene with a grafting rate of 10 wt % and an epoxy content of 3.5 mmol / g; The polar grafted material further includes maleic anhydride with a grafting rate of 10 wt % and a maleic anhydride group content of 3.5 mmol / g.

5. The method for preparing the PPS polymer material of a multi-strand twisted wire cable according to claim 1, characterized in that: The composite lubricant is a mixture of calcium stearate and silicone oil in a ratio of 3:

1.

6. The method for preparing the PPS polymer material of a multi-strand twisted wire cable according to claim 1, characterized in that: The D50 of the first mixture is ≤80 μm and the water content is ≤0.03%.

7. The method for preparing the PPS polymer material of a multi-strand twisted wire cable according to claim 1, characterized in that: The control parameters of the melt shearing are: Melt residence time ≤ 3 minutes to avoid thermal degradation; The extruded product is pelletized by water-cooling strand drawing to obtain PPS polymer material pellets. The particle size of the PPS polymer pellets is 2-3 mm x 3-4 mm.

8. A PPS polymer material for a multi-stranded cable, characterized in that: The PPS polymer material prepared by the method according to any one of claims 1 to 7 is used for insert injection molding of short multi-strand cable segments or continuous production of multi-strand cable.

9. The PPS polymer material of the stranded cable according to claim 8, characterized in that: The short stranded cable segment insert molding is performed by injecting the pellets of the PPS polymer material into a mold pre-set with a stranded conductor to form an insulating sheath component covering a local area of ​​the conductor, and then connected with other cable segments by assembly.

10. The PPS polymer material of the stranded cable according to claim 8, characterized in that: The multi-strand twisted cable is continuously produced by subjecting the pellets of the PPS polymer to an extrusion coating process to form a continuous protective layer on the surface of the twisted conductor.

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