High-flexibility shielding type drag chain cable and preparation method thereof

Abstract

The invention relates to the field of drag chain cables, in particular to a high-flexibility shielding type drag chain cable and a preparation method thereof. The drag chain cable sequentially comprises a conductor layer, a shielding layer and a sheath layer from inside to outside. The conductor layer is formed by compositely twisting silver-plated copper wires and carbon fibers; the shielding layer comprises an inner shielding layer and an outer shielding layer, the inner shielding layer is wrapped by an aluminum-plastic composite belt, and the outer shielding layer is a tinned copper wire woven mesh. The sheath layer comprises the following components: a modified polyurethane elastomer, an ethylene-vinyl acetate copolymer, nitrile rubber, a composite flame retardant, a plasticizer, an antioxidant, a light stabilizer and a lubricant. Through the structural design of the conductor layer, the shielding layer and the sheath layer and the optimization of the material formula of the sheath layer, the problems that an existing drag chain cable is insufficient in strength and flexibility, limited in shielding effectiveness, poor in wear resistance and weather resistance and difficult to consider both flame retardance and mechanical property are solved.

Description

Technical Field

[0001] This invention relates to the field of drag chain cables, and specifically to a highly flexible shielded drag chain cable and its manufacturing method. Background Technology

[0002] In modern industrial automation, robotics, CNC machine tools, high-end logistics systems, and semiconductor manufacturing equipment, drag chain cables serve as a crucial energy source and data transmission carrier, and their performance directly impacts the stability, reliability, and service life of the entire system. Drag chain cables undergo frequent, high-speed reciprocating bending movements within enclosed drag chain systems, placing extremely stringent requirements on the cable's mechanical flexibility, fatigue resistance, and signal transmission stability.

[0003] Currently, the shielded control cables commonly used in drag chain systems have gradually revealed the following technical defects during long-term use: (1) Traditional drag chain cables mostly use simple stranded conductor structures. When subjected to repeated bending and torsional stress, the internal single wires are prone to relative displacement and friction, leading to hardening and fatigue fracture of the conductor material; (2) Existing technologies generally use braided or wound metal wire shielding layers. However, under long-term dynamic bending conditions, the metal shielding wires will undergo plastic deformation and fatigue fracture, resulting in a decrease in shielding coverage; (3) Some cables have improperly selected sheath materials, and their wear resistance, oil resistance, and tear resistance are insufficient to cope with harsh industrial environments. At the same time, the hardness of the insulation and sheath materials is not coordinated with the internal components, and they cannot provide effective support and buffer for the internal core wires when bending, further aggravating the damage to the internal structure.

[0004] Therefore, a new type of highly flexible shielded drag chain cable is needed, which has excellent bending fatigue resistance, stable and reliable high shielding efficiency, and longer service life to meet the increasingly high-end and demanding industrial application requirements. Summary of the Invention

[0005] To address the problems existing in the prior art, the purpose of this invention is to provide a highly flexible shielded drag chain cable and its preparation method.

[0006] The objective of this invention is achieved through the following technical solution: In a first aspect, the present invention provides a highly flexible shielded drag chain cable, which includes, from the inside out, a conductor layer, a shielding layer and a sheath layer; Preferably, the conductor layer is composed of silver-plated copper wire and carbon fiber wire stranded together, wherein the mass ratio of silver-plated copper wire to carbon fiber wire is 90-95:5-10.

[0007] Preferably, the diameter of the silver-plated copper wire is 0.12-0.18 mm and the silver layer thickness is 0.8-1.2 μm; the carbon fiber wire is carbon fiber T700 with a diameter of 0.06-0.10 mm.

[0008] Preferably, the shielding layer includes an inner shielding layer and an outer shielding layer; wherein, the inner shielding layer is an aluminum-plastic composite tape wrapped with a thickness of 0.02-0.1mm; the outer shielding layer is a tin-plated copper wire braided mesh with a single wire diameter of 0.10-0.15mm and a tin layer thickness of 0.5-0.8μm.

[0009] Preferably, the sheath layer, calculated by weight, comprises: 40-60 parts modified polyurethane elastomer, 15-25 parts ethylene-vinyl acetate copolymer, 10-20 parts nitrile rubber, 20-30 parts composite flame retardant, 5-8 parts plasticizer, 0.5-1.5 parts antioxidant, 0.3-0.8 parts light stabilizer and 0.8-1.2 parts lubricant.

[0010] Preferably, the modified polyurethane elastomer is prepared using polypropylene glycol as the diol, 4,4'-diphenylmethane diisocyanate as the diisocyanate, and a modified chain extender as the chain extender.

[0011] Preferably, the ethylene-vinyl acetate copolymer (EVA) has a VA content of 20-30 wt%, a melt index (190℃, 2.16 kg) of 2-5 g / 10 min, and a density of 0.93-0.95 g / cm³. 3 .

[0012] Preferably, the nitrile rubber is one or a mixture of NBR3365, NBR3606, and NBR2907.

[0013] Preferably, the composite flame retardant has a particle size of 2-5 μm, and is specifically a mixture of aluminum hydroxide, magnesium hydroxide, polyphosphoric acid and montmorillonite in a mass ratio of 4-8:2-4:0.1-1:0.1-1.

[0014] Preferably, the plasticizer is a mixture of trioctyl trimellitate and epoxidized soybean oil in a mass ratio of 1-3:1.

[0015] Preferably, the antioxidant is one or more of antioxidant 1010, antioxidant 1076, antioxidant 168, antioxidant DSTP, and antioxidant TH-1135. More preferably, antioxidant 1010 and antioxidant 168 are mixed in a mass ratio of 2:1.

[0016] Preferably, the light stabilizer is one or a mixture of UV328, UV329, UV770, and UV1164. More preferably, UV329 and UV770 are mixed in a mass ratio of 2:1.

[0017] Preferably, the lubricant is a mixture of polyethylene wax and calcium stearate in a mass ratio of 2-4:1.

[0018] Preferably, the preparation method of the modified chain extender includes: S1. Weigh out bis(4-carboxyphenyl)phenylphosphine oxide, thionyl chloride, catalyst and anhydrous solvent and mix them. Under the protection of nitrogen, heat to 55-65℃ and reflux for 4-6 hours. After the reaction is completed, distill under reduced pressure to obtain a light yellow solid intermediate product. S2. Under ice-water bath conditions, weigh isopropanolamine and acid-binding agent and dissolve them in tetrahydrofuran. Gradually add the solid intermediate product. After the addition is complete, heat to room temperature and stir the reaction for 3-4 hours. After the reaction is complete, filter and collect the filtrate. Distill under reduced pressure, wash and dry to obtain the modified chain extender.

[0019] Preferably, in S1, the ratio of bis(4-carboxyphenyl)phenylphosphine oxide, sulfoxide, and anhydrous solvent is 3.86 g:(2.86-4.76) g:(10-20) mL.

[0020] Preferably, in S1, the anhydrous solvent is anhydrous dichloromethane or anhydrous chloroform.

[0021] Preferably, in S1, the catalyst is N,N-dimethylamide, and the amount added is 1%-2% of the mass of bis(4-carboxyphenyl)phenylphosphine oxide.

[0022] Preferably, in S2, the ratio of solid intermediate product, isopropanolamine, acid-binding agent and tetrahydrofuran is 4.03g:(1.5-1.65)g:(2-2.5)g:(25-45)mL.

[0023] Preferably, the method for preparing the modified polyurethane elastomer includes: S3. Weigh out polypropylene glycol and dry it in a vacuum. Then put it into a flask and heat it to 55-75°C under nitrogen protection. Add 4,4'-diphenylmethane diisocyanate and continuously heat it to 75-95°C while stirring. Add the catalyst dibutyltin dilaurate (DBTDL), keep it heated and stirred for 2-3 hours, and then cool it down to 55-65°C to obtain the prepolymer. S4. Add the modified chain extender to the prepolymer and stir at 55-65℃ for half an hour. Then quickly pour the reaction solution into the mold, degas it, and place it in an oven at 75-85℃ for 1.5-2.5 hours. Then raise the oven temperature to 100℃ and keep it at that temperature for 3-4 hours. After cooling to room temperature, remove the mold to obtain the modified polyurethane elastomer.

[0024] Preferably, in S3, the ratio of polyoxypropylene glycol to 4,4'-diphenylmethane diisocyanate is (3.8-4.2)g:1g.

[0025] Preferably, in step S3, the catalyst is dibutyltin dilaurate (DBTDL), and the amount added is 0.02%-0.06% of the mass of polypropylene glycol.

[0026] Preferably, in step S4, the ratio of modified chain extender to prepolymer is (0.34-0.41)g:1g.

[0027] Secondly, the present invention provides a method for preparing a highly flexible shielded drag chain cable, comprising the following steps: Step 1, stranding conductor layer: Weigh silver-plated copper wire and carbon fiber wire and add them to the stranding machine for stranding; add the stranded conductor to the re-stranding machine for re-stranding to obtain the conductor layer; Step 2, Wrapping the inner shielding layer: The twisted conductor layer is introduced into the wrapping machine and wrapped with aluminum-plastic composite tape to obtain the inner shielding layer; Step 3, braiding the outer shielding layer: The cable wrapped with the inner shielding layer is introduced into the braiding machine and braided using tinned copper wire to obtain the outer shielding layer; Step 4, preparing sheath material granules: Weigh the raw materials of the sheath layer according to the formula and put them into a high-speed mixer to mix and obtain a uniform mixed powder; add the mixed powder to a twin-screw extruder, extrude and granulate to obtain sheath material granules; Step 5, Sheathing: The shielded cable and sheathing material particles are introduced into the sheathing extruder, so that the sheathing material covers the surface of the shielded cable. After shaping, it is wound up to obtain a highly flexible shielded drag chain cable.

[0028] The beneficial effects of this invention are as follows: 1. This invention solves the problems of insufficient strength and flexibility, limited shielding effectiveness, poor wear and weather resistance, and difficulty in balancing flame retardancy and mechanical properties in existing drag chain cables by structural design of conductor layer, shielding layer and sheath layer and optimization of sheath layer material formula.

[0029] 2. The conductor layer of this invention adopts a composite stranded structure of silver-plated copper wire and carbon fiber wire. The silver-plated copper wire ensures high conductivity, while the carbon fiber wire enhances tensile strength and bending toughness, preventing core breakage under high-frequency bending and increasing the cable's bending life by more than 2 times compared to pure copper wire conductors. The shielding layer adopts a double-layer structure of aluminum-plastic composite tape wrapping and tin-plated copper wire braiding. The high-overlap wrapping of the inner shielding layer blocks low-frequency electromagnetic interference, while the high-density braiding of the outer shielding layer resists high-frequency interference. The synergy of these two elements significantly increases shielding effectiveness, ensuring distortion-free signal transmission. The sheath layer uses modified polyurethane elastomer as the base material, compounded with EVA and nitrile rubber, balancing high elasticity and oil resistance. Composite flame retardants and various functional additives optimize performance, giving the sheath layer high flame retardancy, high strength, high flexibility, and long life.

[0030] 3. The modified polyurethane elastomer of the sheath layer of this invention is prepared using polypropylene glycol as the diol and 4,4'-diphenylmethane diisocyanate as the diisocyanate, supplemented with a modified chain extender. The modified chain extender is obtained by amide bonding of acyl-chlorinated bis(4-carboxyphenyl)phenylphosphine oxide with isopropanolamine. The introduction of phosphorus and amide groups into the molecular structure of the modified chain extender achieves both flame-retardant modification of the polyurethane elastomer and enhances the mechanical properties of the elastomer by optimizing the crosslinking density through chain extension. This allows the sheath layer to maintain high flexibility while possessing excellent flame retardancy and flexural fatigue resistance. Detailed Implementation

[0031] To better understand the above technical solutions, exemplary embodiments of the present invention are described in more detail below. While exemplary embodiments of the present invention are shown, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present invention and to fully convey the scope of the invention to those skilled in the art.

[0032] The present invention will be further described below with reference to the following embodiments.

[0033] Example 1 A highly flexible shielded drag chain cable comprises, from the inside out, a conductor layer, a shielding layer, and a sheath layer; the conductor layer is composed of silver-plated copper wire and carbon fiber wire stranded together; the shielding layer comprises an inner shielding layer and an outer shielding layer; wherein the inner shielding layer is wrapped with aluminum-plastic composite tape, and the outer shielding layer is tin-plated copper wire braided mesh.

[0034] The sheath layer, calculated by weight, comprises: 50 parts modified polyurethane elastomer, 20 parts ethylene-vinyl acetate copolymer, 16 parts nitrile rubber, 24 parts composite flame retardant, 7 parts plasticizer, 1 part antioxidant, 0.5 parts light stabilizer and 1 part lubricant.

[0035] The ethylene-vinyl acetate copolymer (EVA) has an VA content of 25 wt%, a melt index (190℃, 2.16 kg) of 3 g / 10 min, and a density of 0.94 g / cm³. 3 The grade of the nitrile rubber is NBR3365; the particle size of the composite flame retardant is 2-5 μm, specifically a mixture of aluminum hydroxide, magnesium hydroxide, polyphosphoric acid, and montmorillonite in a mass ratio of 6:3:0.5:0.5; the plasticizer is a mixture of trioctyl trimellitate and epoxidized soybean oil in a mass ratio of 2:1; the antioxidant is a mixture of antioxidant 1010 and antioxidant 168 in a mass ratio of 2:1; the light stabilizer is a mixture of UV329 and UV770 in a mass ratio of 2:1; and the lubricant is a mixture of polyethylene wax and calcium stearate in a mass ratio of 3:1.

[0036] The method for preparing the modified polyurethane elastomer includes: S1, Acyl chloride of bis(4-carboxyphenyl)phenylphosphine oxide: Weigh 3.86 g of bis(4-carboxyphenyl)phenylphosphine oxide, 3.92 g of thionyl chloride and 15 mL of anhydrous dichloromethane and mix them. Add 1.5% N,N-dimethylamide by mass of bis(4-carboxyphenyl)phenylphosphine oxide as a catalyst. Under a nitrogen atmosphere, heat to 60 °C and reflux for 5 h. After the reaction is completed, remove excess thionyl chloride and solvent by vacuum distillation to obtain a light yellow solid intermediate product. S2. Preparation of modified chain extenders: Under ice-water bath conditions, 1.58 g of isopropanolamine and 2.2 g of triethylamine, an acid-binding agent, were weighed and dissolved in 40 mL of tetrahydrofuran to form a mixture. 4.03 g of solid intermediate product was gradually added to the mixture over a period of 1 hour. After the addition was complete, the ice bath was removed, the temperature was raised to room temperature, and the reaction was continued for 3 hours. After the reaction was completed, the white solid generated was removed by filtration, the filtrate was collected, the solvent was removed by vacuum distillation, the product was washed three times with deionized water, and then dried under vacuum to obtain a white solid product, which is the modified chain extender.

[0037] S3. Preparation of polyurethane prepolymer: Weigh 40g of polypropylene glycol (PPG-2000), dry it in a vacuum, and then put it into a flask. Under nitrogen protection, heat it to 65°C, add 10g of 4,4'-diphenylmethane diisocyanate (MDI-100), and continuously heat it to 85°C while stirring. Add 0.04% by weight of dibutyltin dilaurate (DBTDL) as a catalyst, keep it heated and stirred for 2 hours, and then cool it down to 60°C to obtain the prepolymer. S4. Preparation of modified polyurethane elastomer: Weigh the modified chain extender and prepolymer at a mass ratio of 0.37:1, add it to the prepolymer, stir at 60°C for half an hour, then quickly pour the reaction solution into a mold, vent the air, place it in an 80°C oven for 2 hours, then raise the oven temperature to 100°C and keep it at that temperature for 3 hours. After cooling to room temperature, remove the mold to obtain the modified polyurethane elastomer.

[0038] Example 2 A highly flexible shielded drag chain cable differs from Example 1 in that the composition and ratio of the sheath layer are slightly different.

[0039] The sheath layer, calculated by weight, comprises: 40 parts modified polyurethane elastomer, 15 parts ethylene-vinyl acetate copolymer, 10 parts nitrile rubber, 20 parts composite flame retardant, 5 parts plasticizer, 0.5 parts antioxidant, 0.3 parts light stabilizer and 0.8 parts lubricant.

[0040] The ethylene-vinyl acetate copolymer (EVA) has an VA content of 25 wt%, a melt index (190℃, 2.16 kg) of 3 g / 10 min, and a density of 0.94 g / cm³. 3 The grade of the nitrile rubber is NBR3606; the particle size of the composite flame retardant is 2-5 μm, specifically a mixture of aluminum hydroxide, magnesium hydroxide, polyphosphoric acid, and montmorillonite in a mass ratio of 4:2:0.3:0.3; the plasticizer is a mixture of trioctyl trimellitate and epoxidized soybean oil in a mass ratio of 1:1; the antioxidant is a mixture of antioxidant 1010 and antioxidant 168 in a mass ratio of 2:1; the light stabilizer is a mixture of UV329 and UV770 in a mass ratio of 2:1; and the lubricant is a mixture of polyethylene wax and calcium stearate in a mass ratio of 2:1.

[0041] The method for preparing the modified polyurethane elastomer includes: S1, Acyl chloride of bis(4-carboxyphenyl)phenylphosphine oxide: Weigh 3.86 g of bis(4-carboxyphenyl)phenylphosphine oxide, 2.86 g of thionyl chloride and 10 mL of anhydrous dichloromethane and mix them. Add 1% by mass of N,N-dimethylamide of bis(4-carboxyphenyl)phenylphosphine oxide as a catalyst. Under a nitrogen atmosphere, heat to 55 °C and reflux for 4 h. After the reaction is completed, remove excess thionyl chloride and solvent by vacuum distillation to obtain a light yellow solid intermediate product. S2. Preparation of modified chain extenders: Under ice-water bath conditions, 1.5 g of isopropanolamine and 2 g of triethylamine, an acid-binding agent, were dissolved in 25 mL of tetrahydrofuran to form a mixture. 4.03 g of solid intermediate product was gradually added to the mixture over a period of 1 hour. After the addition was complete, the ice bath was removed, the temperature was raised to room temperature, and the reaction was continued for 3 hours. After the reaction was completed, the white solid generated was removed by filtration, the filtrate was collected, the solvent was removed by vacuum distillation, the product was washed three times with deionized water, and then dried under vacuum to obtain a white solid product, which is the modified chain extender.

[0042] S3. Preparation of polyurethane prepolymer: Weigh 38g of polypropylene glycol (PPG-2000), dry it in a vacuum, and then put it into a flask. Under nitrogen protection, heat it to 55°C, add 10g of 4,4'-diphenylmethane diisocyanate (MDI-100), and continuously heat it to 75°C while stirring. Add 0.02% by weight of dibutyltin dilaurate (DBTDL) as a catalyst, keep it heated and stirred for 2 hours, and then cool it down to 55°C to obtain the prepolymer. S4. Preparation of modified polyurethane elastomer: Weigh the modified chain extender according to the mass ratio of modified chain extender to prepolymer of 0.34:1, add it to the prepolymer, stir at 55℃ for half an hour, then quickly pour the reaction solution into the mold, vent the air, place it in a 75℃ oven for 1.5 hours, then raise the oven temperature to 100℃ and keep it at that temperature for 3 hours. After cooling to room temperature, remove the mold to obtain the modified polyurethane elastomer.

[0043] Example 3 A highly flexible shielded drag chain cable differs from Example 1 in that the composition and ratio of the sheath layer are slightly different.

[0044] The sheath layer, calculated by weight, comprises: 60 parts modified polyurethane elastomer, 25 parts ethylene-vinyl acetate copolymer, 20 parts nitrile rubber, 30 parts composite flame retardant, 8 parts plasticizer, 1.5 parts antioxidant, 0.8 parts light stabilizer and 1.2 parts lubricant.

[0045] The ethylene-vinyl acetate copolymer (EVA) has an VA content of 25 wt%, a melt index (190℃, 2.16 kg) of 3 g / 10 min, and a density of 0.94 g / cm³. 3The grade of the nitrile rubber is NBR2907; the particle size of the composite flame retardant is 2-5 μm, specifically a mixture of aluminum hydroxide, magnesium hydroxide, polyphosphoric acid, and montmorillonite in a mass ratio of 8:4:1:1; the plasticizer is a mixture of trioctyl trimellitate and epoxidized soybean oil in a mass ratio of 3:1; the antioxidant is a mixture of antioxidant 1010 and antioxidant 168 in a mass ratio of 2:1; the light stabilizer is a mixture of UV329 and UV770 in a mass ratio of 2:1; and the lubricant is a mixture of polyethylene wax and calcium stearate in a mass ratio of 4:1.

[0046] The method for preparing the modified polyurethane elastomer includes: S1, Acyl chloride of bis(4-carboxyphenyl)phenylphosphine oxide: Weigh 3.86 g of bis(4-carboxyphenyl)phenylphosphine oxide, 4.76 g of thionyl chloride and 20 mL of anhydrous dichloromethane and mix them. Add 2% by mass of N,N-dimethylamide of bis(4-carboxyphenyl)phenylphosphine oxide as a catalyst. Under a nitrogen atmosphere, heat to 65 °C and reflux for 6 h. After the reaction is completed, remove excess thionyl chloride and solvent by vacuum distillation to obtain a light yellow solid intermediate product. S2. Preparation of modified chain extenders: Under ice-water bath conditions, 1.65 g of isopropanolamine and 2.5 g of triethylamine (an acid-binding agent) were weighed and dissolved in 45 mL of tetrahydrofuran to form a mixture. 4.03 g of solid intermediate product was gradually added to the mixture over a period of 1 hour. After the addition was complete, the ice bath was removed, the temperature was raised to room temperature, and the reaction was continued for 4 hours. After the reaction was completed, the white solid was removed by filtration, the filtrate was collected, the solvent was removed by vacuum distillation, the product was washed three times with deionized water, and then dried under vacuum to obtain a white solid product, which is the modified chain extender.

[0047] S3. Preparation of polyurethane prepolymer: Weigh 42g of polypropylene glycol (PPG-2000), dry it in a vacuum, and then put it into a flask. Under nitrogen protection, heat it to 75°C, add 10g of 4,4'-diphenylmethane diisocyanate (MDI-100), and continuously heat it to 95°C while stirring. Add 0.06% by weight of dibutyltin dilaurate (DBTDL) as a catalyst, keep it heated and stirred for 3 hours, and then cool it down to 65°C to obtain the prepolymer. S4. Preparation of modified polyurethane elastomer: Weigh the modified chain extender and prepolymer at a mass ratio of 0.41:1, add it to the prepolymer, stir at 65°C for half an hour, then quickly pour the reaction solution into a mold, vent the air, and place it in an 85°C oven for 2.5 hours. Then raise the oven temperature to 100°C and keep it at that temperature for 4 hours. After cooling to room temperature, remove the mold to obtain the modified polyurethane elastomer.

[0048] Example 4 The preparation method of any one of Examples 1-3 of the highly flexible shielded drag chain cable includes the following steps: Step 1, stranding conductor layer: Weigh silver-plated copper wire and carbon fiber wire at a mass ratio of 92:8 and add them to the stranding machine. After stranding, the diameter of a single conductor is controlled at 1.0±0.02mm. Add the stranded conductor to the re-stranding machine, set the re-stranding pitch to 25mm, and the stranding direction to the right. After re-stranding, the diameter of the conductor layer is 2.8±0.05mm. Step 2, wrapping the inner shielding layer: The twisted conductor layer is introduced into the wrapping machine, the aluminum-plastic composite tape is installed on the tape feeding frame, the wrapping direction is set to the right, the overlap rate is 45%, the outer diameter of the inner shielding layer after wrapping is 3.0±0.05mm, and the surface is wrinkle-free; Step 3, braiding the outer shielding layer: introduce the cable wrapped with the inner shielding layer into the braiding machine, place tinned copper wire, set the braiding density to 90%, and after braiding, the outer diameter of the outer shielding layer is 3.3±0.05mm, the mesh surface is flat, and there are no missing braids; Step 4, Preparation of sheath material granules: Weigh the raw materials for the sheath layer according to the formula and put them into a high-speed mixer. Set the speed to 1200 r / min and the temperature to 80℃, and mix for 10 min to obtain a uniform powder. Add the powder to a twin-screw extruder and set the screw speed to 220 r / min. Control the temperature in stages: 135℃ for the feeding section, 165℃ for the compression section, and 175℃ for the homogenization section. Set the die head pressure to 15 MPa and the pellet length to 3 mm to obtain sheath material granules. Step 5, Apply the sheath layer: The shielded cable is introduced into the sheath extruder, and the sheath material particles are added to the hopper. The single screw speed is set to 50 r / min, and the temperature is controlled in stages: 140℃ for the feeding stage, 170℃ for the compression stage, and 180℃ for the homogenization stage, with a die temperature of 185℃. An extrusion die is used, the sizing sleeve cooling water temperature is 25℃, the sheath thickness is 1.2mm, and the eccentricity is ≤0.05mm. After cooling and shaping in three cooling water tanks, the cable is wound up by a take-up machine to obtain a highly flexible shielded drag chain cable.

[0049] Comparative Example 1 A drag chain cable differs from Example 1 in that the preparation process of the modified polyurethane elastomer in the sheath layer is different. In the preparation process of the modified polyurethane elastomer, the chain extender is replaced with isopropanolamine, specifically: S1. Preparation of polyurethane prepolymer: Weigh 40g of polypropylene glycol (PPG-2000), dry it in a vacuum, and then put it into a flask. Under nitrogen protection, heat it to 65°C, add 10g of 4,4'-diphenylmethane diisocyanate, and continuously heat it to 85°C while stirring. Add 0.04% of the mass of polypropylene glycol as a catalyst, dibutyltin dilaurate, keep it heated and stirred for 2 hours, and then cool it down to 60°C to obtain the prepolymer. S2. Preparation of modified polyurethane elastomer: Isopropanolamine was weighed according to the chain extender isopropanolamine and the prepolymer mass ratio of 0.37:1 and added to the prepolymer. The mixture was stirred at 60°C for half an hour. The reaction solution was then quickly poured into a mold. After degassing, the mixture was placed in an 80°C oven for 2 hours. The oven temperature was then raised to 100°C and kept at that temperature for 3 hours. After cooling to room temperature, the mold was removed to obtain the modified polyurethane elastomer.

[0050] Comparative Example 2 A drag chain cable differs from Example 1 in that the preparation process of the modified polyurethane elastomer in the sheath layer is different. In the preparation process of the modified polyurethane elastomer, the chain extender is replaced with bis(4-carboxyphenyl)phenylphosphine oxide, specifically: S1. Preparation of polyurethane prepolymer: Weigh 40g of polypropylene glycol (PPG-2000), dry it in a vacuum, and then put it into a flask. Under nitrogen protection, heat it to 65°C, add 10g of 4,4'-diphenylmethane diisocyanate, and continuously heat it to 85°C while stirring. Add 0.04% of the mass of polypropylene glycol as a catalyst, dibutyltin dilaurate, keep it heated and stirred for 2 hours, and then cool it down to 60°C to obtain the prepolymer. S2. Preparation of modified polyurethane elastomer: Bis(4-carboxyphenyl)phenylphosphine oxide was weighed according to a mass ratio of 0.37:1 to the prepolymer and added to the prepolymer. The mixture was stirred at 60°C for half an hour. The reaction solution was then quickly poured into a mold, and after degassing, it was placed in an 80°C oven for 2 hours. The oven temperature was then raised to 100°C and kept at that temperature for 3 hours. After cooling to room temperature, the mold was removed to obtain the modified polyurethane elastomer.

[0051] Experimental testing In order to clearly illustrate the content of the present invention, the performance of the sheath layer material and drag chain cable prepared in Example 1, Comparative Example 1 and Comparative Example 2 were tested respectively.

[0052] (1) The properties of the sheath layer materials prepared in Example 1, Comparative Example 1 and Comparative Example 2 were tested. The tests included tensile strength (GB / T 1040.2-2006), elongation at break (GB / T 1040.2-2006), Shore A hardness (GB / T531.1-2008), oil immersion volume change rate (GB / T 1690-2010, IRM 903 oil immersion (100℃, 72h)) and smoke density rating (GB / T 8627-2007, burning time 4min).

[0053] The results are shown in Table 1: Table 1 Performance of sheath materials for different drag chain cables (2) For the sheath layers prepared in Example 1, Comparative Example 1 and Comparative Example 2, drag chain cables were prepared using the method in Example 4, and then the performance was tested and compared. The tests included bending fatigue resistance (GB / T 5023.2-2008, bending frequency 20Hz, bending radius 5× cable outer diameter), shielding effectiveness (GB / T 12772-2021, coaxial method test), flame retardant rating (UL94-2013, vertical burning test), operating temperature range (IEC 60228-2004, performance test after aging in high and low temperature chamber) and service life (accelerated aging test calculation, 120℃ heat aging for 1000h is equivalent to 2 years at room temperature).

[0054] The test results are shown in Table 2: Table 2 Overall performance of different drag chain cables As can be seen from Tables 1 and 2, the sheath material prepared in Example 1 has high strength and high toughness, as well as excellent oil resistance and flame retardancy. Cables prepared using the sheath material from Example 1 exhibit excellent bending fatigue resistance, a flame retardancy rating of UL94 V0, and a somewhat enhanced temperature range, with a service life of ≥7 years. The isopropanolamine used in Comparative Example 1 is a traditional chain extender, possessing only chain-extending function, resulting in lower flame retardancy of the polyurethane elastomer compared to Example 1; furthermore, the lack of rigid aromatic ring groups in the molecular structure leads to a loose cross-linking structure, decreased mechanical properties and bending fatigue resistance, and a worsened temperature range and oil resistance. The bis(4-carboxyphenyl)phenylphosphine oxide used in Comparative Example 2 may not have effectively extended the chain with the -NCO groups of the polyurethane prepolymer, and was used more as a filler-type flame retardant, resulting in insufficient cross-linking density of the polyurethane elastomer, a significant decrease in mechanical properties, poor compatibility with the elastomer, and a substantial reduction in bending fatigue resistance and abrasion resistance.

[0055] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A highly flexible shielded drag chain cable, characterized in that, The drag chain cable comprises, from the inside out, a conductor layer, a shielding layer, and a sheath layer; the conductor layer is composed of silver-plated copper wire and carbon fiber wire stranded together; the shielding layer comprises an inner shielding layer and an outer shielding layer, the inner shielding layer being wrapped with aluminum-plastic composite tape, and the outer shielding layer being tin-plated copper wire braided mesh. The sheath layer, calculated by weight, comprises: 40-60 parts modified polyurethane elastomer, 15-25 parts ethylene-vinyl acetate copolymer, 10-20 parts nitrile rubber, 20-30 parts composite flame retardant, 5-8 parts plasticizer, 0.5-1.5 parts antioxidant, 0.3-0.8 parts light stabilizer and 0.8-1.2 parts lubricant; The modified polyurethane elastomer is prepared using polypropylene glycol as the diol, 4,4'-diphenylmethane diisocyanate as the diisocyanate, and a modified chain extender as the chain extender. The modified chain extender is obtained by first treating bis(4-carboxyphenyl)phenyl oxyphosphonochlorination and then reacting it with isopropanolamine via an amide bonding reaction.

2. The highly flexible shielded drag chain cable according to claim 1, characterized in that, In the conductor layer, the mass ratio of silver-plated copper wire to carbon fiber wire is 90-95:5-10; the diameter of the silver-plated copper wire is 0.12-0.18 mm, and the silver layer thickness is 0.8-1.2 μm; the carbon fiber wire is carbon fiber T700, with a diameter of 0.06-0.10 mm.

3. The highly flexible shielded drag chain cable according to claim 1, characterized in that, The thickness of the inner shielding layer is 0.02-0.1mm; the diameter of the single tin-plated copper wire in the outer shielding layer is 0.10-0.15mm, and the tin layer thickness is 0.5-0.8μm.

4. The highly flexible shielded drag chain cable according to claim 1, characterized in that, The ethylene-vinyl acetate copolymer has a VA content of 20-30 wt%, a melt index of 2-5 g / 10 min at 190℃ and 2.16 kg, and a density of 0.93-0.95 g / cm³. 3 .

5. The highly flexible shielded drag chain cable according to claim 1, characterized in that, The nitrile rubber is one or a mixture of NBR3365, NBR3606, and NBR2907.

6. The highly flexible shielded drag chain cable according to claim 1, characterized in that, The composite flame retardant has a particle size of 2-5 μm and is specifically a mixture of aluminum hydroxide, magnesium hydroxide, polyphosphoric acid, and montmorillonite in a mass ratio of 4-8:2-4:0.1-1:0.1-1.

7. The highly flexible shielded drag chain cable according to claim 1, characterized in that, The plasticizer is a mixture of trioctyl trimellitate and epoxidized soybean oil in a mass ratio of 1-3:1; the antioxidant is one or more of antioxidant 1010, antioxidant 1076, antioxidant 168, antioxidant DSTP, and antioxidant TH-1135; the light stabilizer is one or more of UV328, UV329, UV770, and UV1164; and the lubricant is a mixture of polyethylene wax and calcium stearate in a mass ratio of 2-4:

1.

8. The highly flexible shielded drag chain cable according to claim 1, characterized in that, The preparation method of the modified chain extender includes: S1. Weigh out bis(4-carboxyphenyl)phenylphosphine oxide, thionyl chloride, catalyst and anhydrous solvent and mix them. Under the protection of nitrogen, heat to 55-65℃ and reflux for 4-6 hours. After the reaction is completed, distill under reduced pressure to obtain a light yellow solid intermediate product. S2. Under ice-water bath conditions, weigh isopropanolamine and acid-binding agent and dissolve them in tetrahydrofuran. Gradually add the solid intermediate product. After the addition is complete, heat to room temperature and stir the reaction for 3-4 hours. After the reaction is complete, filter and collect the filtrate. Distill under reduced pressure, wash and dry to obtain the modified chain extender.

9. A highly flexible shielded drag chain cable according to claim 8, characterized in that, In S1, the ratio of bis(4-carboxyphenyl)phenylphosphine oxide, sulfoxide, and anhydrous solvent is 3.86 g:(2.86-4.76) g:(10-20) mL; in S2, the ratio of solid intermediate, isopropanolamine, acid-binding agent, and tetrahydrofuran is 4.03 g:(1.5-1.65) g:(2-2.5) g:(25-45) mL.

10. A method for preparing the highly flexible shielded drag chain cable according to claim 1, characterized in that, Includes the following steps: Step 1: Weigh out silver-plated copper wire and carbon fiber wire and add them to the bundling machine for bundling; add the bundled conductor to the re-stranding machine for re-stranding to obtain the conductor layer; Step 2: The twisted conductor layer is introduced into the wrapping machine and wrapped with aluminum-plastic composite tape to obtain the inner shielding layer; Step 3: The cable with the inner shielding layer wrapped around it is introduced into the braiding machine and braided with tinned copper wire to obtain the outer shielding layer; Step 4: Weigh the raw materials for the sheath layer according to the formula and put them into a high-speed mixer to mix and obtain a uniform mixed powder; add the mixed powder to a twin-screw extruder, extrude and granulate to obtain sheath material granules; Step 5: Introduce the shielded cable and sheath material granules into the sheath extruder, so that the sheath material covers the surface of the shielded cable. After shaping, it is wound up to obtain a highly flexible shielded drag chain cable.

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