Manufacturing process of medical-grade antibacterial body fluid corrosion-resistant polyester-nylon composite yarn

Abstract

The invention belongs to the technical field of textile materials, and particularly relates to a medical-grade antibacterial body fluid corrosion-resistant polyester-nylon composite yarn manufacturing process which comprises the following steps: proportioning raw materials (74 parts of PET slices, 14 parts of PA6 slices, 6 parts of PET-based colored master batches and 6 parts of nano-silver antibacterial master batches), deeply drying (the moisture content is less than or equal to 30ppm after PET nitrogen drying), and carrying out melt spinning, so as to obtain the medical-grade antibacterial body fluid corrosion-resistant polyester-nylon composite yarn. The vacuum drying moisture content of PA6 is smaller than or equal to 80 ppm), double-system independent melt blending, double-melt precise metering (the flow error is + / -0.1%), conjugate composite spinning (the orange section type section is adopted, and the PET / PA6 area ratio is 74: 14), tow cooling and oiling, winding balancing and elasticizing splitting (the NaOH concentration is 8% and alkali decrement is conducted) are conducted; double melting systems are used for isolated processing, ester-amide exchange reaction is avoided, the molecular weight retention rate is larger than 98%, nano-silver is directionally dispersed (the viscosity difference of a carrier is smaller than 18%, and the particle size of silver ions is smaller than or equal to 100 nm), and the antibacterial durability is improved to 120 days.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of textile materials, and particularly relates to a manufacturing process of medical-grade antibacterial and body fluid corrosion-resistant polyester-polyamide composite yarn. BACKGROUND

[0002] The polyester-polyamide composite yarn is an ultra-fine fiber material made of polyester (polyester fiber) and polyamide (nylon) through composite spinning technology, and the fineness of the single yarn can reach 1 / 20 of ordinary fiber. The material has a special cross-section structure, realizes double-component parallel composite through the FDY process, forms a fiber network with large specific surface area and significant capillary effect, and the water absorption capacity reaches 20 times that of ordinary cotton fabric.

[0003] The medical-grade polyester-polyamide composite yarn is a polyester-polyamide composite fiber specially designed for the medical field, which is made through a special process. Since the human body fluid is weakly alkaline and contains various enzymes, ordinary polyester is prone to hydrolysis and chain breaking, resulting in a sharp decrease in strength. Silver ion antibacterial agents are prone to agglomeration and inactivation, and high content can degrade the mechanical properties of the fiber. Therefore, in the field of medical textiles, the fiber needs to meet the requirements of body fluid corrosion resistance, long-acting broad-spectrum antibacterial primary fine denier, and skin friendliness.

[0004] The existing technology has the following defects: the single antibacterial master batch carrier is not matched, the PA6 carrier antibacterial master batch has poor compatibility with PET, leading to uneven dispersion of silver ions, insufficient drying, strong moisture absorption of PA6, water content >100ppm after conventional drying, and contamination of melt blending. When melting, the direct blending of hydrolysis-degraded PET / PA6 triggers ester-amide exchange reaction, resulting in a decrease in molecular weight. SUMMARY

[0005] To solve the problems of single antibacterial master batch carrier mismatch, poor compatibility of PA6 carrier antibacterial master batch with PET, uneven dispersion of silver ions, insufficient drying, strong moisture absorption of PA6, water content >100ppm after conventional drying, and contamination of melt blending, the application provides a medical-grade antibacterial and body fluid corrosion-resistant polyester-polyamide composite yarn manufacturing process.

[0006] To achieve the above purpose, the application provides the following technical scheme: a medical-grade antibacterial and body fluid corrosion-resistant polyester-polyamide composite yarn manufacturing process, comprising the following steps:

[0007] Step one, raw material ratio: take 74 parts of polyester chip with intrinsic viscosity IV = 0.642 dl / g, 14 parts of nylon 6 chip with relative viscosity 2.7, 6 parts of colored masterbatch with PET-based carrier and intrinsic viscosity IV = 0.520 dl / g, 6 parts of nano-silver ion antibacterial masterbatch with silver loading of 800 ± 50 ppm and intrinsic viscosity IV = 0.540 dl / g, all raw material particle size is controlled in Φ2-3mm, screen out >5mm agglomerates;

[0008] Step two, deep drying: PET chip is dried at 130 ± 2 ℃ for 5 hours under nitrogen protection, water content ≤30 ppm, nylon 6 chip is dried at 85 ± 1 ℃ under vacuum degree-0.08 MPa for 8 hours, water content ≤80 ppm, colored masterbatch and antibacterial masterbatch are dried by 100 ± 3 ℃ hot air circulation for 4 hours, water content ≤80 ppm, after drying, the raw materials are temporarily stored in airtight tank with dew point ≤-40 ℃;

[0009] Step three, double system melt blending:

[0010] PET system: put the dried 74 parts of PET chip into the co-rotating twin screw extruder (L / D = 40), the main feeding section is fed at 180 ± 5 ℃, 5 parts of colored masterbatch and 5 parts of antibacterial masterbatch are injected laterally in the fifth zone compression section, 0.3wt% of epoxy-based chain extender ADR-4468 is injected in the melting zone at 265 ± 2 ℃, the homogenizing section pressure is 12 ± 0.5 MPa and the temperature is 280 ± 1 ℃, filtered through a 10 μm filter screen;

[0011] PA6 system: put the dried 14 parts of PA6 chip into an independent twin screw extruder (L / D = 36), the main feeding section is fed at 160 ± 3 ℃, 1 part of colored masterbatch and 1 part of antibacterial masterbatch are injected in the melting section at 240 ± 2 ℃, 0.5wt% of carbodiimide hydrolysis resistant agent Stabaxol P200 is added synchronously, the homogenizing section temperature is 255 ± 1 ℃ and the pressure is 10 ± 0.3 MPa;

[0012] Step four, double melt precise metering: gear metering pump is used to control the PET mixed melt flow rate of 74 L / h and the PA6 mixed melt flow rate of 14 L / h, metering error ±0.1%, 20 μm coarse filter + 10 μm fine filter double-stage filter screen is set before the pump;

[0013] Step five, conjugate composite spinning: through parallel spinning assembly, spinneret 72 × 16 holes, hole diameter 0.25 mm, box temperature 290 ± 1 ℃, die head 280 ± 1 ℃, assembly inlet pressure 15 ± 0.2 MPa, ET / PA6 bi-component is conjugate compounded in "orange segment type" cross section with area ratio 74:14;

[0014] Step six, the tow processing: using the side blowing cooling, keep the temperature 22±0.5℃, humidity 80±2%, wind speed 0.4m / s, cooling length 1.8m, through the ceramic microporous roller oil, keep the oil agent concentration 12%, oiling rate 1.0±0.05%;

[0015] Step seven, winding and balancing: winding speed 3200m / min, winding hardness 82±2 Shore A, constant temperature room 25±1℃ / 65±3%RH balancing 48 hours, tension attenuation to ≤0.5cN / dtex;

[0016] Step eight, elasticizing, opening and setting: keep the elasticizing speed 650m / min, draw ratio 1.6, deformation temperature 180±2℃, setting temperature 160±1℃, through the alkali reduction opening, keep the NaOH concentration 8%, 95℃ treatment 60min, filament fineness 0.086dpf.

[0017] As a preferred medical-grade antibacterial and body fluid corrosion-resistant polyester-polyamide composite yarn manufacturing process of the application, the viscosity difference between the PET carrier of the nano-silver ion antibacterial master batch in step one and the main PET chip is less than 18%, and the silver ion dispersion particle size is less than or equal to 100nm.

[0018] As a preferred medical-grade antibacterial and body fluid corrosion-resistant polyester-polyamide composite yarn manufacturing process of the application, the PET drying in step two uses a Karl Fischer moisture meter to monitor the water content online, and the nylon 6 needs to be transferred to the melting system within 30 minutes after drying.

[0019] As a preferred medical-grade antibacterial and body fluid corrosion-resistant polyester-polyamide composite yarn manufacturing process of the application, the PET system in step three uses a Coperion ZSK series co-rotating twin-screw extruder with a compression section length-diameter ratio greater than or equal to 1:5 and a melting zone residence time less than or equal to 90 seconds.

[0020] As a preferred medical-grade antibacterial and body fluid corrosion-resistant polyester-polyamide composite yarn manufacturing process of the application, the spinneret hole type in step five is a 16-leaf orange petal structure, and the PET / PA6 interface bonding angle is 115±5°.

[0021] As a preferred medical-grade antibacterial and body fluid corrosion-resistant polyester-polyamide composite yarn manufacturing process of the application, the single fiber opening rate after alkali reduction in step eight is greater than or equal to 98%, and the silver ion residual amount on the fiber surface is greater than or equal to 750ppm.

[0022] Compared with the prior art, the application has the beneficial effects that: in the application, the carrier is accurately matched, the antibacterial master batch adopts a PET-based carrier (IV = 0.540 dl / g) with a viscosity difference of less than 18% from the main PET, the silver ions (800 ± 50 ppm) are uniformly dispersed in the melt, the PA6 system independently adds a hydrolysis-resistant agent (carbodiimide) to block the erosion path of body fluid, the strength retention rate is greater than 90% after being soaked in a pH = 8.5 buffer for 30 days, and the problem of mismatching of a single antibacterial master batch carrier is prevented.

[0023] In the application, a step-by-step drying process is adopted, PET chips are dried under nitrogen protection (130 DEG C / 5h) -> water content is less than or equal to 30 ppm (verified by Karl Fischer method), PA6 is dried at low temperature under vacuum (85 DEG C / 8h) -> water content is less than or equal to 80 ppm, the melt hydrolysis bubbles are inhibited from the source, and the problem of insufficient drying is prevented.

[0024] In the application, a double-screw isolation blending process is adopted, PET and PA6 are melted at optimized temperatures of 265 DEG C / 240 DEG C respectively, the high-temperature-induced thermal oxidation of PA6 is avoided, an epoxy chain extender (ADR-4468) is added to the PET system to repair hydrolysis chain scission, the characteristic viscosity is increased by greater than or equal to 15%, and the problem of contamination in melt blending is prevented. BRIEF DESCRIPTION OF DRAWINGS

[0025] The accompanying drawings are included to provide a further understanding of the application, and constitute a part of the specification, illustrate the application, and are used to explain the application, and do not constitute a limitation on the application. In the drawings:

[0026] Figure 1 It is a schematic diagram of the overall process flow of the application. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only a part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the application.

[0028] Embodiment 1

[0029] As Figure 1 ;

[0030] A medical-grade antibacterial body fluid corrosion-resistant polyester-polyamide composite yarn manufacturing process, comprising the following steps:

[0031] Step one, raw material ratio: take 74 parts of polyester chip with intrinsic viscosity IV = 0.642 dl / g, 14 parts of nylon 6 chip with relative viscosity 2.7, 6 parts of colored masterbatch with PET-based carrier and intrinsic viscosity IV = 0.520 dl / g, 6 parts of nano-silver ion antibacterial masterbatch with silver loading of 800 ± 50 ppm and intrinsic viscosity IV = 0.540 dl / g, all raw material particle size is controlled in Φ2-3mm, screen out >5mm agglomerates;

[0032] Step two, deep drying: PET chip is dried at 130 ± 2 ℃ for 5 hours under nitrogen protection, water content ≤30 ppm, nylon 6 chip is dried at 85 ± 1 ℃ under vacuum degree-0.08 MPa for 8 hours, water content ≤80 ppm, colored masterbatch and antibacterial masterbatch are dried by 100 ± 3 ℃ hot air circulation for 4 hours, water content ≤80 ppm, after drying, the raw materials are temporarily stored in airtight tank with dew point ≤-40 ℃;

[0033] Step three, double system melt blending:

[0034] PET system: put the dried 74 parts of PET chip into the co-rotating twin screw extruder (L / D = 40), the main feeding section is fed at 180 ± 5 ℃, 5 parts of colored masterbatch and 5 parts of antibacterial masterbatch are injected laterally in the fifth zone compression section, 0.3wt% of epoxy-based chain extender ADR-4468 is injected in the melting zone at 265 ± 2 ℃, the homogenizing section pressure is 12 ± 0.5 MPa and the temperature is 280 ± 1 ℃, and it is filtered through a 10 μm filter screen;

[0035] PA6 system: put the dried 14 parts of PA6 chip into an independent twin screw extruder (L / D = 36), the main feeding section is fed at 160 ± 3 ℃, 1 part of colored masterbatch and 1 part of antibacterial masterbatch are injected in the melting section at 240 ± 2 ℃, 0.5wt% of carbodiimide hydrolysis resistant agent Stabaxol P200 is added synchronously, the homogenizing section temperature is 255 ± 1 ℃ and the pressure is 10 ± 0.3 MPa;

[0036] Step four, double melt precise metering: gear metering pump is used to control the PET mixed melt flow rate of 74 L / h and the PA6 mixed melt flow rate of 14 L / h, the metering error is ±0.1%, 20 μm coarse filter + 10 μm fine filter double-stage filter screen is set before the pump;

[0037] Step five, conjugate composite spinning: through parallel spinning assembly, the spinneret plate is 72 × 16 holes with a pore size of 0.25 mm, the box temperature is 290 ± 1 ℃, the die temperature is 280 ± 1 ℃, the assembly inlet pressure is 15 ± 0.2 MPa, and the ET / PA6 bi-component is conjugate compounded in "orange segment type" cross section with area ratio of 74:14;

[0038] Step six, tow treatment: using side blowing cooling, keeping temperature 22±0.5℃, humidity 80±2%, wind speed 0.4m / s, cooling length 1.8m, oiling through ceramic microporous roller, keeping oil agent concentration 12%, oiling rate 1.0±0.05%;

[0039] Step seven, winding and balancing: winding speed 3200m / min, package hardness 82±2 Shore A, constant temperature room 25±1℃ / 65±3%RH balancing 48 hours, tension decay to≤0.5cN / dtex;

[0040] Step eight, elasticizing, opening and setting: keeping elasticizing speed 650m / min, draw ratio 1.6, deformation temperature 180±2℃, setting temperature 160±1℃, opening through alkali reduction, keeping NaOH concentration 8%, 95℃ treatment 60min, filament fineness 0.086dpf.

[0041] In the embodiment: the application precisely matches the carrier, the antibacterial master batch uses PET-based carrier (IV=0.540dl / g) with a viscosity difference of less than 18% from the main PET, ensuring uniform dispersion of silver ions (800±50ppm) in the melt, PA6 system independently adds a hydrolysis-resistant agent (carbodiimide) to block the erosion path of body fluids, and after testing in a pH=8.5 buffer for 30 days, the strength retention rate is greater than 90%, preventing the problem of mismatching of a single antibacterial master batch carrier, through a step-by-step drying process, PET chips are dried under nitrogen protection (130℃ / 5h)→moisture content≤30ppm (verified by Karl Fischer method), PA6 is vacuum low-temperature dried (85℃ / 8h)→moisture content≤80ppm, inhibiting melt hydrolysis bubbles from the source and preventing the problem of insufficient drying, through double-screw isolation blending, PET and PA6 are melted at optimized temperatures of 265℃ / 240℃, avoiding high-temperature-induced PA6 thermal oxidation, the PET system adds an epoxy chain extender (ADR-4468) to repair hydrolysis chain scission, the intrinsic viscosity improvement rate is greater than or equal to 15%, and the problem of contamination during melt blending is prevented.

[0042] In an alternative embodiment, the PET carrier of the nano-silver ion antibacterial master batch in step one has a viscosity difference of less than 18% from the main PET chip, and the silver ion particle size is less than or equal to 100nm.

[0043] In the embodiment: the viscosity difference is less than 18%, ensuring that the antibacterial master batch PET carrier is consistent with the main PET melt rheological behavior, avoiding local enrichment of silver ions due to viscosity mismatch, the silver ion particle size is less than or equal to 100nm, the specific surface area is increased to 2.3 times that of traditional master batches through nanodispersion technology, the bacteriostatic ingredient covers 100% of the fiber surface, the effect is quantified, and the silver ion release amount is still greater than or equal to 750ppm (atomic absorption spectrometry) after 100 washes, breaking through the bottleneck of 50 wash life of medical textiles.

[0044] In an alternative embodiment, the PET drying in step two is monitored online for moisture content using a Karl Fischer moisture meter, and the nylon 6 is transferred to the melt system within 30 minutes after drying.

[0045] In this embodiment: the source of hydrolytic degradation is blocked, online monitoring using a Karl Fischer moisture meter is used to achieve dynamic control of the moisture content of the PET to ≤30 ppm (accuracy ±2 ppm), the risk of ester bond hydrolysis during high-temperature melting is eliminated (molecular weight drop rate from 12% down to <3%), and the nylon 6 is transferred within 30 minutes after drying: preventing moisture absorption and re-moistening of the nylon 6 during the temporary storage period (experiments have confirmed that exposure for 60 minutes causes the moisture content to rebound to 120 ppm), and eliminating melt bubbles and spinning breaks from the root cause (breakage rate down by 87.5%).

[0046] In an alternative embodiment, the co-rotating twin-screw extruder of the PET system in step three is a Coperion ZSK series, with a compression section length-diameter ratio ≥1:5 and a melt zone residence time ≤90 seconds.

[0047] In this embodiment: the Coperion ZSK series compression section length-diameter ratio ≥1:5, the shear dispersion effect is enhanced, the dispersion uniformity CV value of the antibacterial agent in the PA6 melt ≤5% (traditional equipment CV >15%), the melt zone residence time ≤90 seconds, the PA6 heat exposure time is shortened by 40%, the molecular weight retention rate is increased to 98% (GPC test), and the fiber brittleness caused by amide bond breakage is avoided (elongation at break remains >45%).

[0048] In an alternative embodiment, the spinneret hole type in step five is a 16-leaf orange petal structure, and the PET / PA6 interface bonding angle is 115±5°.

[0049] In this embodiment: the 16-leaf orange petal structure increases the PET / PA6 phase interface contact line length by 3.8 times, the alkali reduction opening efficiency is increased from 82% to ≥98% (electron microscope statistics), the interface bonding angle is 115±5°, the bicomponent stress distribution is optimized, the bending stiffness is reduced to 0.78 cN / cm (40% lower than traditional parallel type), and the flexibility requirement of the surgical suture is met. 2

[0050] In an alternative embodiment, the single fiber opening rate after alkali reduction in step eight is ≥98%, and the silver ion residual amount on the fiber surface is ≥750 ppm.

[0051] In this embodiment: the opening rate is ≥98%, the single fiber fineness is stabilized at 0.086 dpf (diameter about 5.2 μm), and the specific surface area of the fiber reaches 2100 cm 2 ​ / g (BET method), 3 times of the adsorption rate of body fluid, the residual amount of silver ions ≥750 ppm, through the interface anchoring technology (orange segment structure groove retention), the silver ion slow-release period is extended to 120 days (simulated body fluid immersion experiment), far exceeding the 30-day antibacterial standard of medical dressings.

[0052] The process breaks through the strength retention rate (body fluid corrosion for 30 days > 90%) and antibacterial durability bottleneck of medical fibers, and is suitable for high-end medical textiles such as surgical sutures and antibacterial dressings.

[0053] Working principle:

[0054] Raw material ratio and property control, prepare 74 parts of polyester chip with intrinsic viscosity IV = 0.642 dl / g, 14 parts of nylon 6 chip with relative viscosity 2.7, 6 parts of colored master batch with intrinsic viscosity IV = 0.520 dl / g, carrier is PET-based, 6 parts of nano-silver ion antibacterial master batch with silver loading of 800 ± 50 ppm, intrinsic viscosity IV = 0.540 dl / g, and all raw material particle sizes are controlled in Φ2-3mm, and the >5mm agglomerates are removed by screening;

[0055] Deep drying treatment of raw materials, use double-tower crystallization dryer (model XT-300D) to treat PET polyester chip, nylon 6 chip, and colored master batch and antibacterial master batch, respectively, PET chip is dried at 130±2℃ for 5 hours under nitrogen protection, so that the water content is ≤30ppm, and Karl Fischer moisture meter is used for online monitoring, nylon 6 chip is dried at 85±1℃ for 8 hours under vacuum degree-0.08MPa, so that the water content is ≤80ppm, colored master batch and antibacterial master batch are dried by hot air circulation drying oven at 100±3℃ / 4 hours, the water content is ≤80ppm, and the dried raw materials need to be temporarily stored in airtight tanks with dew point ≤-40℃;

[0056] PET system melt blending, put the dried 74 parts of PET chip into a co-rotating twin screw extruder with L / D = 40, the twin screw extruder is a Kobe Long ZSK series, the main feeding section is kept at 180±5℃ for continuous feeding of PET chip, the side injection port in the fifth zone compression section is injected with 5 parts of colored master batch through a precision color injection machine, 5 parts of nano-silver antibacterial master batch is injected synchronously, 0.3wt% epoxy-based chain extender (ADR-4468) is injected at 265±2℃ in the melt zone, the homogenization section pressure is kept at 12±0.5MPa, the melt temperature is 280±1℃, and the impurities are filtered through a 10μm sintered metal filter;

[0057] PA6 system melt blending, dry 14 parts of PA6 chip, that is, nylon 6 chip, is put into a separate twin-screw extruder (L / D=36), the main feeding section temperature is 160±3°C, PA6 chip is fed, the injection temperature of the melting section is 240±2°C, 1 part of colored master batch and 1 part of nano-silver antibacterial master batch are injected, 0.5wt% of carbonized diimine hydrolysis resistant agent (Stabaxol P200) is synchronously added, the homogenizing section temperature is 255±1°C, and the melt pressure is 10±0.3MPa;

[0058] Double-melt precision metering, a Bosch Rexroth G series high-precision gear metering pump is used, the PET mixed melt flow is 74L / h corresponding to 74 parts of raw materials, the metering error is ±0.1%, the PA6 mixed melt flow is 14L / h corresponding to 14 parts of raw materials, and the metering error is ±0.1%, a double-stage filter screen is installed before the pump, 20μm coarse filtering + 10μm fine filtering;

[0059] Conjugate composite spinning, through a parallel type spinning assembly, a spinneret 72×16 holes, a hole diameter of 0.25mm, the box temperature is controlled to be 290±1°C, the die head is 280±1°C, the assembly inlet pressure is 15±0.2MPa, and real-time feedback is achieved through a piezoelectric sensor, the PET / PA6 bicomponent is parallelly compounded in an “orange segment type” cross section with an area ratio of 74:14;

[0060] Yarn cooling and oiling, side blowing condition, temperature 22±0.5°C, humidity 80±2%, wind speed 0.4m / s, laminar turbulence degree ≤3%, cooling length 1.8m, yarn solidification time 3.2±0.2 seconds;

[0061] A ceramic microporous roller oiling machine is used, the oil concentration is 12%, the oiling rate is 1.0±0.05%, and the online calibration is achieved by using the weight method;

[0062] Winding and stress balancing, a Murata automatic winding machine No.861 type is used for high-speed winding, the winding speed is 3200m / min, and the package hardness is 82±2 Shore A;

[0063] Balancing treatment, constant temperature room 25±1°C / 65±3%RH, stress attenuation to ≤0.5cN / dtex within 48 hours, detected by a tension meter;

[0064] Elasticity adding, fiber opening and setting, a Oerlikon FTF12 type elasticizer is used, the elasticizing speed is set to 650m / min, the stretching multiple is controlled by the speed ratio of the feeding roller / output roller to be 1.6, the hot box deformation temperature is 180±2°C, and the hot plate setting temperature is 160±1°C;

[0065] Fiber opening treatment, alkali reduction process, NaOH concentration 8%, temperature 95°C, time 60min, single yarn fineness 0.086dpf, verified by a scanning electron microscope.

[0066]

[0067] The 0.086 dpf superfine fiber produced by the process has a strength retention rate of ≥ 88% after being soaked in artificial sweat (pH 4.3) for 30 days, meeting the YY / T0506 medical dressing standard.

[0068] Finally, it should be noted that the above only for the preferred embodiments of the present application, and is not intended to limit the present application, although the foregoing embodiments of the present application have been described in detail, for those skilled in the art, it still can be modified, or part of the technical features of the equivalent replacement of the technical solutions described in the foregoing embodiments. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application shall be included within the scope of the present application.

Claims

1. A process for manufacturing a medical grade, antibacterial, body fluid resistant, polyester-polyamide composite yarn, characterized in that, Comprising the following steps: Step one, raw material ratio: take 74 parts of polyester chip with intrinsic viscosity IV = 0.642 dl / g, 14 parts of nylon 6 chip with relative viscosity 2.7, 6 parts of colored masterbatch with PET-based carrier and intrinsic viscosity IV = 0.520 dl / g, 6 parts of nano-silver ion antibacterial masterbatch with silver loading of 800 ± 50 ppm and intrinsic viscosity IV = 0.540 dl / g, all raw material particle size is controlled in Φ2-3mm, screen out >5mm lump; Step two, deep drying: PET chip is dried at 130±2℃ for 5 hours under nitrogen protection, water content ≤30ppm, nylon 6 chip is dried at 85±1℃ under vacuum degree-0.08MPa for 8 hours, water content ≤80ppm, colored masterbatch and antibacterial masterbatch are dried by 100±3℃ hot air circulation for 4 hours, water content ≤80ppm, after drying, the raw materials are temporarily stored in airtight storage tank with dew point ≤-40℃; Step three, double system melt blending: PET system: put the dried 74 parts of PET chip into the co-rotating twin screw extruder (L / D = 40), the main feeding section is fed at 180±5℃, 5 parts of colored masterbatch and 5 parts of antibacterial masterbatch are injected laterally in the fifth zone compression section, 0.3wt% of epoxy-based chain extender ADR-4468 is injected in the melting zone at 265±2℃, the homogenizing section pressure is 12±0.5MPa and the temperature is 280±1℃, filtered through a 10μm filter screen; PA6 system: put the dried 14 parts of PA6 chip into an independent twin screw extruder (L / D = 36), the main feeding section is fed at 160±3℃, 1 part of colored masterbatch and 1 part of antibacterial masterbatch are injected in the melting section at 240±2℃, 0.5wt% of carbodiimide hydrolysis resistant agent Stabaxol P200 is added synchronously, the homogenizing section temperature is 255±1℃ and the pressure is 10±0.3MPa; Step four, double melt precise metering: gear metering pump is used to control the PET mixed melt flow rate of 74L / h and the PA6 mixed melt flow rate of 14L / h, metering error ±0.1%, 20μm coarse filter +10μm fine filter double-stage filter screen is set before the pump; Step five, conjugate composite spinning: through parallel spinning assembly, spinneret 72×16 holes, hole diameter 0.25mm, box temperature 290±1℃, die head 280±1℃, assembly inlet pressure 15±0.2MPa, ET / PA6 double components are conjugate compounded in "orange segment type” cross section with area ratio 74:14; Step six, filament treatment: side blowing cooling is used, temperature is maintained at 22±0.5℃, humidity is maintained at 80±2%, wind speed is maintained at 0.4m / s, cooling length is 1.8m, oiling is carried out through ceramic microporous roller, oil agent concentration is maintained at 12%, oiling rate is 1.0±0.05%; Step seven, winding and balancing: winding speed is 3200m / min, winding hardness is 82±2 Shore A, constant temperature room 25±1℃ / 65±3%RH balancing for 48 hours, tension attenuation is ≤0.5cN / dtex; Step eight, elasticizing, fiberizing and setting: keeping the elasticizing speed 650 m / min, the draw ratio 1.6, the deformation temperature 180±2℃, the setting temperature 160±1℃, the fiberizing by alkali reduction, keeping the NaOH concentration 8%, the treatment temperature 95℃, the treatment time 60 min, the single fiber fineness 0.086 dpf.

2. The medical grade antimicrobial body fluid resistant polyester-polyamide composite yarn manufacturing process as claimed in claim 1 wherein: The PET carrier of the nano-silver ion antibacterial master batch in the step one has a viscosity difference of less than 18% with the main PET chip, and the silver ion dispersion particle size is less than or equal to 100 nm.

3. The medical grade antimicrobial body fluid resistant polyester-polyamide composite yarn manufacturing process as claimed in claim 1 wherein: The PET drying in the step two adopts a Karl Fischer moisture meter for online monitoring of the water content, and the nylon 6 needs to be transferred to the melting system within 30 minutes after drying.

4. The medical grade antimicrobial body fluid resistant polyester-polyamide composite yarn manufacturing process as claimed in claim 1 wherein: The co-rotating twin-screw extruder of the PET system in the step three is a Kobe Long ZSK series, the compression section length-diameter ratio is greater than or equal to 1:5, and the melting zone residence time is less than or equal to 90 seconds.

5. The medical grade antimicrobial body fluid resistant polyester-polyamide composite yarn manufacturing process as claimed in claim 1 wherein: The spinneret hole type in the step five is a 16-leaf orange segment structure, and the PET / PA6 interface bonding angle is 115±5°.

6. The medical grade antimicrobial body fluid resistant polyester-polyamide composite yarn manufacturing process as claimed in claim 1 wherein: The single fiber fiberizing rate after alkali reduction in the step eight is greater than or equal to 98%, and the silver ion residual amount on the fiber surface is greater than or equal to 750 ppm.

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