Process for the preparation of a polyester-based cloth high-shrinkage electronic packaging leather

Abstract

The present application relates to the technical field of electronic packaging, and particularly relates to a preparation method of polyester base cloth high-shrinkage electronic packaging leather; the preparation method of polyester base cloth high-shrinkage electronic packaging leather is based on warp knitting machines and core-sheath composite parent yarns, the core-sheath composite parent yarns are the only knitting raw materials, through the synergistic effect of the core-sheath composite parent yarns, programmed temperature rising and selective dissolution, the integration of fiber shrinkage densification, node heat-induced self-adhesion and in-situ micro-pore generation is realized, and the polyester base cloth high-shrinkage electronic packaging leather is obtained; the present application solves the problems that the high shrinkage rate and high peel strength of the existing polyester base synthetic leather are difficult to be considered together, and the ultra-fine fiber nap and the dense skeleton need to be realized through a multi-step composite process, and provides a polyester base cloth high-shrinkage electronic packaging leather solution scheme for spontaneously completing the whole structure construction in a single base cloth in the field of electronic packaging materials.

Description

Technical Field

[0001] This invention relates to the field of electronic packaging technology, and specifically to a method for preparing a high-shrinkage electronic packaging leather based on polyester fabric. Background Technology

[0002] Polyester-based electronic packaging leather is widely used in the packaging and protection of electronic products such as laptops, tablets, and smartphones due to its excellent dimensional stability, good abrasion resistance, and recyclability. Its core structure is a composite material formed by coating a polyurethane coating onto a polyester base fabric. However, existing polyester-based electronic packaging leathers, in order to achieve a high shrinkage rate to fit the complex curved surfaces of electronic products, use high-shrinkage polyester fibers woven together and then undergo multiple heat-shrinkage treatments. However, insufficient bonding force between fibers during heat shrinkage leads to a loose base fabric skeleton and a decrease in the peel strength of the polyurethane coating. To compensate for the reduced peel strength, the coating thickness and the number of coatings need to be increased, resulting in a stiff feel and cumbersome processes. It is difficult to achieve both high shrinkage rate and high peel strength simultaneously.

[0003] Currently, the main approaches to achieving a leather-like feel in polyester-based electronic packaging leather include surface abrasion treatment and microfiber island-based fiber opening technology. Surface abrasion treatment creates a nap on the fiber surface through physical friction, but the nap is uneven and damages the fiber matrix strength, further reducing peel strength. While island-based fiber opening technology can obtain dense microfiber nap, it requires a multi-step composite process of opening and coating, which is lengthy and the transfer of the base fabric between the opening and coating processes can easily cause nap flattening and secondary contamination. Therefore, there is an urgent need to develop an integrated preparation method that can spontaneously complete shrinkage densification, node reinforcement, and surface pore creation within a single base fabric to simultaneously meet the comprehensive requirements of electronic packaging leather for high shrinkage rate, high peel strength, and a leather-like feel.

[0004] To address the above problems, the present invention provides a solution. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing a high-shrinkage electronic packaging leather based on polyester fabric, which can achieve the integration of high shrinkage, high peel strength and genuine leather-like feel, while also giving the leather antistatic function.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a method for preparing high-shrinkage electronic packaging leather based on polyester fabric, which is based on a warp knitting machine and a core-sheath composite mother yarn, with the core-sheath composite mother yarn as the only weaving material. Through the synergistic effect of the core-sheath composite mother yarn, programmed heating and selective dissolution, the integrated fiber shrinkage and densification, node thermal self-adhesion and in-situ micropore generation are achieved, thereby obtaining high-shrinkage electronic packaging leather based on polyester fabric.

[0007] Furthermore, the core-sheath composite mother yarn is composed of the following components by weight percentage: 50% high-shrinkage polyester, 32.7% low-melting-point copolyester, 12.5% ​​alkali-soluble copolyester, 4.5% maleic anhydride-grafted polyester, and 0.3% antioxidant.

[0008] Furthermore, the preparation method of the core-sheath composite mother yarn includes the following steps:

[0009] A1: Place the high-shrinkage polyester in a vacuum drying oven, set the temperature to 120-140℃, and the vacuum degree to -0.08 to -0.10MPa, and dry for 12-16 hours to obtain dried high-shrinkage polyester. Place the low-melting-point copolyester in a vacuum drying oven, set the temperature to 100-120℃, and the vacuum degree to -0.08 to -0.10MPa, and dry for 10-14 hours to obtain dried low-melting-point copolyester. Place the alkali-soluble copolyester in a vacuum drying oven, set the temperature to 120-140℃, and the vacuum degree to -0.08 to -0.10MPa, and dry for 12-16 hours to obtain dried alkali-soluble copolyester.

[0010] A2: Dry low-melting-point copolyester, dry alkali-soluble copolyester, maleic anhydride grafted polyester, and antioxidant are added to the first twin-screw extruder for melt blending and granulation. The temperature of the first twin-screw extruder is set as follows: Zone 1 temperature 240-250℃, Zone 2 temperature 255-265℃, Zone 3 temperature 265-275℃, Zone 4 temperature 270-280℃, and Die section temperature 265-275℃. The screw speed is 150-250 rpm. After blending and extrusion, the mixture is cooled in a water bath at 25℃ and drawn at a draw ratio of 1:3. After drawing, the mixture is granulated to obtain skin-layer blended masterbatch.

[0011] A3: Dry high-shrinkage polyester is added to the second twin-screw extruder for melt granulation. The temperature of the second twin-screw extruder is set as follows: Zone 1 temperature is 245-255℃, Zone 2 temperature is 260-270℃, Zone 3 temperature is 270-280℃, Zone 4 temperature is 275-285℃, and the die section temperature is 270-280℃. The screw speed is 150-250 rpm. After extrusion, the material is cooled in a water bath at a temperature of 25℃. It is then drawn at a draw ratio of 1:3. After drawing, the material is granulated to obtain the core layer masterbatch.

[0012] A4: Place the skin layer blend masterbatch and the core layer masterbatch in a vacuum drum dryer, set the drying temperature to 120-140℃, the vacuum degree to -0.08 to -0.10MPa, and the drying time to 12-16h to obtain dried skin layer blend masterbatch and dried core layer masterbatch.

[0013] A5: The dried outer layer blending masterbatch and the dried core layer masterbatch are fed into two single-screw spinning machines respectively. Composite spinning is performed using a core-sheath composite spinning assembly. For core layer spinning, the temperatures in zone one of the single-screw spinning machines are set to 260-265℃, zone two to 270-275℃, zone three to 275-280℃, and the chamber temperature to 275-280℃. For outer layer spinning, the temperatures in zone one of the single-screw spinning machines are set to 250-255℃, zone two to 260-265℃, and zone three to 270-265℃. The temperature of the extrusion zone is 265-270℃, the temperature of the chamber is 265-270℃, the spinneret orifice diameter is 0.3-0.5mm, the spinneret length-to-diameter ratio is 3-4, the core layer screw speed is 30rpm, the sheath layer screw speed is 15rpm, and after extrusion, it is cooled and shaped by side blowing. The side blowing temperature is set to 18-25℃, the relative humidity is 60-80%, the wind speed is 0.3-0.5m / s, and the winding speed is 800-1200m / min to obtain nascent fibers.

[0014] A6: The nascent fibers are fed into a hot box for stretching and heat setting. The temperature of the first-stage stretching roller is set to 80-90℃, the temperature of the second-stage stretching roller is 95-105℃, and the temperature of the third-stage stretching roller is 110-130℃. The total stretching ratio is 4-6 times. After stretching, the fibers are relaxed and heat-set at 130-150℃ for 10-30 seconds. The fineness of the single filament is controlled to be 2-4D. After processing, the core-sheath composite mother yarn is obtained.

[0015] Furthermore, the high-shrinkage polyester is polyethylene terephthalate copolymerized with isophthalic acid and neopentyl glycol, with an intrinsic viscosity of 0.75 dL / g and a boiling water shrinkage rate of 40%; the low-melting-point copolyester is polyethylene terephthalate copolymerized with isophthalic acid and diethylene glycol, with a melting point of 135℃ and a melt index of 18 g / 10 min measured under conditions of 160℃ and 2.16 kg load; the alkali-soluble copolyester is polyethylene terephthalate modified with sodium isophthalate-5-sulfonate, with a molar content of sodium isophthalate-5-sulfonate of 13% and a melting point of 235℃; the maleic anhydride-grafted polyester has a grafting rate of 1.3% and an intrinsic viscosity of 0.65 dL / g.

[0016] Furthermore, a method for preparing a polyester-based high-shrinkage electronic packaging leather includes the following steps:

[0017] S1: Place the core-sheath composite yarn on the warping machine's yarn rack. Set the warping tension to 8-15 cN / yarn, the warping linear speed to 300-500 m / min, and the number of warp yarns to 2000-3000, corresponding to a width of 100-200 cm. After warping, load the yarn onto a double-needle bed Raschel warp knitting machine. Load the pattern data file into the warp knitting machine. Align the zero-point reference of the ground guide bar traverse mechanism with the starting position. Set the knitting speed to 600-1000 rpm. The fabric is woven using a combination of chain braiding and weft insertion. The chain braiding uses closed chain braiding, and the weft insertion uses three-needle weft insertion. The warp feed rate is set to 600-900 mm / rack, the ground guide bar warp tension is 8-12 cN / thread, and the tension density is 15-25 rows / cm. During the weaving process, the workshop temperature is controlled at 20-28℃ and the relative humidity is 55-75%. The jacquard guide bar performs jacquard weaving based on the offset information of the pattern data file to obtain the polyester base fabric.

[0018] S2: After weaving, the polyester base fabric is removed from the machine and laid flat on the inspection table. Under an inspection light source with an illuminance of 1200lx, the uniformity of the stitches and surface defects of the fabric are checked. After confirming that there are no broken yarns, missing needles, or holes, the polyester base fabric is sent into the needle plate tenter heat setting machine. The preheating zone temperature is set to 100-120℃, the setting zone temperature to 150-165℃, and the cooling zone temperature to 25-30℃. There is a transition section between each temperature zone, with a length of 20-40cm. After the fabric enters the preheating zone, a pretension of 0.5-1N / cm is applied in the width direction. The fabric is gradually heated to 100-120℃, and the dwell time in the preheating zone is 45-60s.

[0019] S3: The polyester base fabric after preheating enters the setting zone. The setting zone temperature is set to 150-165℃, the main tensile tension in the width direction is 0.5-1N / cm, the overfeed rate is 1-3%, the stretching width is set to 102-105% of the target finished width, and the dwell time in the setting zone is 25-35s. The base fabric after setting enters the cooling zone. While maintaining the main tensile tension in the width direction, it is gradually cooled to below 30℃ at a cooling rate of 15-30℃ / s. After cooling, the tension in the width direction is removed to obtain the shrink-locking base fabric.

[0020] S4: Place the shrink-locking base fabric on the inspection table and check the bonding quality and shrinkage uniformity of the fabric nodes under an inspection light source with an illuminance of 1200lx. Use a handheld hot air pen to repair areas with insufficient bonding. Set the hot air pen outlet temperature to 150-165℃ and the repair time to 1-3s. After repair, immerse the shrink-locking base fabric in an alkaline treatment solution, which consists of 8g / L sodium hydroxide and 1.5g / L dodecyltrimethylammonium chloride, with pure water as the solvent. Set the treatment temperature to 75-85℃ and the treatment time to 15-25min. After treatment, remove the fabric to obtain the self-woven base fabric.

[0021] S5: The self-woven base fabric is placed in a washing tank and washed at 30-50℃ for 5-20 minutes. After removal, it is dried at 100-120℃ until the moisture content is below 1%. The dried self-woven base fabric is then fed into a vacuum coating device in its flat width. A two-component solvent-free polyurethane is used for vacuum-assisted penetration coating. The two-component solvent-free polyurethane consists of polyether polyol and isocyanate, with a mass ratio of 100:50. The coating amount is set to 40-70 g / m². 2 The vacuum degree is -0.03 to -0.06 MPa. After coating, it is cured at 80-100℃ for 10-20 min to obtain a polyester-based high-shrinkage electronic packaging leather substrate.

[0022] S6: The high-shrinkage polyester electronic packaging leather substrate is fed flat into a nitrogen atmosphere glow discharge plasma treatment device. The treatment power is set to 200-400W, the treatment speed to 3-5m / min, and the treatment spacing to 2-4mm. Online plasma etching is performed on the upper and lower surfaces of the substrate for 30-120s. After treatment, the substrate is fed flat into a padding device for padding with a blended emulsion anti-fingerprint treatment solution. The liquid content is controlled at 60-80%. The blended emulsion anti-fingerprint treatment... The liquid is composed of side-chain amino-modified polysiloxane and waterborne polyurethane, with a solid content of 15% and pure water as the solvent. The mass ratio of side-chain amino-modified polysiloxane to waterborne polyurethane is 1:4. Then, 5wt% of multi-walled carbon nanotube aqueous dispersion is impregnated and rolled. The multi-walled carbon nanotubes have a diameter of 15nm and a length of 10um. The liquid content is controlled at 50-70% by adjusting the rolling pressure. After impregnation and rolling, the product is dried and shaped at 130-140℃ for 40-60s to obtain high-shrinkage electronic packaging leather based on polyester fabric.

[0023] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are as follows:

[0024] 1. This invention utilizes the synergistic effect of the thermo-induced self-adhesion of the sheath layer of the core-sheath composite filament and the programmed shrinkage of the high-shrinkage polyester in the core layer to construct an integrated structure from shrinkage densification to node self-locking. In the preheating zone, the high-shrinkage polyester in the core layer triggers macroscopic shrinkage to densify the base fabric. In the shaping zone, the low-melting-point copolyester in the sheath layer melts and migrates to the fiber nodes under capillary action to form a spot-welded structure. After cooling, it forms a three-dimensional continuous self-adhesive skeleton, which significantly improves the peel strength and solves the problem that it is difficult to achieve both high shrinkage rate and high peel strength in existing polyester-based synthetic leather.

[0025] 2: This invention utilizes the synergistic effect of selective dissolution and pore-forming with alkali-soluble copolyester and vacuum-assisted penetration coating with solvent-free polyurethane to construct a leather-like mesh structure integrating ultra-fine fiber fluff and dense skeleton. Alkali treatment causes the fiber bundles to dissociate and form an ultra-fine fiber fluff layer. Polyurethane slurry penetrates into the fluff layer to form an interpenetrating network, giving it a leather-like feel and high peel strength. This solves the problem that ultra-fine fiber fluff and dense skeleton require a multi-step composite process to achieve.

[0026] 3: This invention encodes the three functions of shrinkage, self-locking, and pore-forming into the spatiotemporal sequence of a single fiber through the structural design of the core-sheath composite mother filament. The orderly execution of each function is triggered by programmed heating and selective dissolution, enabling the leather to spontaneously complete the full structural construction from a dense skeleton to surface nap within a single base fabric. This simplifies the process flow. At the same time, the leather is given antistatic properties through impregnation with an aqueous dispersion of carbon nanotubes, meeting the comprehensive requirements of electronic packaging for cleanliness, antistatic properties, and curved surface bonding. Detailed Implementation

[0027] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below with reference to specific embodiments.

[0028] Unless otherwise specified, the experimental methods used in the following examples are conventional methods, performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Unless otherwise specified, the materials and reagents used in the following examples are commercially available.

[0029] Example 1

[0030] 1. Place 5000g of high-shrinkage polyester in a vacuum drying oven, set the temperature to 120℃ and the vacuum degree to -0.08MPa, and dry for 12h to obtain 4997g of dried high-shrinkage polyester. Place 3270g of low-melting-point copolyester in a vacuum drying oven, set the temperature to 100℃ and the vacuum degree to -0.08MPa, and dry for 10h to obtain 3268g of dried low-melting-point copolyester. Place 1250g of alkali-soluble copolyester in a vacuum drying oven, set the temperature to 120℃ and the vacuum degree to -0.08MPa, and dry for 12h to obtain 1249g of dried alkali-soluble copolyester.

[0031] 2: 3268g of dry low-melting-point copolyester, 1249g of dry alkali-soluble copolyester, 450g of maleic anhydride-grafted polyester, and 30g of antioxidant were added to the first twin-screw extruder for melt blending and granulation. The temperatures of the first twin-screw extruder were set as follows: Zone 1: 240℃, Zone 2: 255℃, Zone 3: 265℃, Zone 4: 270℃, and Die Section: 265℃. The screw speed was 150rpm. After blending and extrusion, the mixture was cooled in a water bath at 25℃ and stretched at a stretch ratio of 1:3. After stretching, the mixture was pelletized to obtain 4985g of skin-blended masterbatch.

[0032] 3: 4997g of dried high-shrinkage polyester was added to the second twin-screw extruder for melt granulation. The temperatures of the first zone of the second twin-screw extruder were set to 245℃, the second zone to 260℃, the third zone to 270℃, the fourth zone to 275℃, and the die section to 270℃. The screw speed was 150rpm. After extrusion, the product was cooled in a water bath at 25℃ and stretched at a stretch ratio of 1:3. After stretching, the product was granulated to obtain 4985g of core layer masterbatch.

[0033] 4: Place 4985g of skin layer blending masterbatch and 4985g of core layer masterbatch into a vacuum drum dryer, set the drying temperature to 120℃, the vacuum degree to -0.08MPa, and the drying time to 12h, to obtain 4978g of dried skin layer blending masterbatch and 4978g of dried core layer masterbatch.

[0034] 5: 4978g of dried sheath blend masterbatch and 4978g of dried core masterbatch were fed into two single-screw spinning machines respectively. Composite spinning was carried out through the sheath-core composite spinning assembly. The core spinning machine was set with zone 1 temperature of 260℃, zone 2 temperature of 270℃, zone 3 temperature of 275℃, and box temperature of 275℃. The sheath spinning machine was set with zone 1 temperature of 250℃, zone 2 temperature of 260℃, zone 3 temperature of 265℃, and box temperature of 265℃. The spinneret orifice diameter was 0.3mm, the spinneret length-to-diameter ratio was 3, the core screw speed was 30rpm, and the sheath screw speed was 15rpm. After extrusion, the fibers were cooled and shaped by side blowing. The side blowing temperature was set to 18℃, the relative humidity to 60%, the wind speed to 0.3m / s, and the winding speed to 800m / min, resulting in 9941g of nascent fiber.

[0035] 6: 9941g of nascent fiber was fed into a hot box for drawing and heat setting. The temperature of the first-stage drawing roller was set to 80℃, the temperature of the second-stage drawing roller was set to 95℃, and the temperature of the third-stage drawing roller was set to 110℃. The total drawing ratio was 4 times. After drawing, the fiber was relaxed and heat-set at 130℃ for 10s. The fineness of the single filament was controlled to be 2D. After processing, 9927g of the core-sheath composite mother yarn prepared in Example 1 was obtained.

[0036] Example 2

[0037] 1. Place 5000g of high-shrinkage polyester in a vacuum drying oven, set the temperature to 140℃ and the vacuum degree to -0.10MPa, and dry for 16h to obtain 4995g of dried high-shrinkage polyester. Place 3270g of low-melting-point copolyester in a vacuum drying oven, set the temperature to 120℃ and the vacuum degree to -0.10MPa, and dry for 14h to obtain 3267g of dried low-melting-point copolyester. Place 1250g of alkali-soluble copolyester in a vacuum drying oven, set the temperature to 140℃ and the vacuum degree to -0.10MPa, and dry for 16h to obtain 1248g of dried alkali-soluble copolyester.

[0038] 2: 3267g of dry low-melting-point copolyester, 1248g of dry alkali-soluble copolyester, 450g of maleic anhydride-grafted polyester, and 30g of antioxidant were added to the first twin-screw extruder for melt blending and granulation. The temperatures of the first twin-screw extruder were set as follows: Zone 1: 250℃, Zone 2: 265℃, Zone 3: 275℃, Zone 4: 280℃, and Die Section: 275℃. The screw speed was 250rpm. After blending and extrusion, the mixture was cooled in a water bath at 25℃ and stretched at a stretch ratio of 1:3. After stretching, the mixture was pelletized to obtain 4983g of skin-blended masterbatch.

[0039] 3: 4995g of dried high-shrinkage polyester was added to the second twin-screw extruder for melt granulation. The temperatures of the first zone of the second twin-screw extruder were set to 255℃, the second zone to 270℃, the third zone to 280℃, the fourth zone to 285℃, and the die section to 280℃. The screw speed was 250rpm. After extrusion, the product was cooled in a water bath at 25℃ and stretched at a stretch ratio of 1:3. After stretching, the product was granulated to obtain 4983g of core layer masterbatch.

[0040] 4: Place 4983g of skin layer blending masterbatch and 4983g of core layer masterbatch into a vacuum drum dryer, set the drying temperature to 140℃, the vacuum degree to -0.10MPa, and the drying time to 16h, to obtain 4975g of dried skin layer blending masterbatch and 4975g of dried core layer masterbatch.

[0041] 5: 4975g of dried sheath blend masterbatch and 4975g of dried core masterbatch were fed into two single-screw spinning machines respectively. Composite spinning was carried out through the sheath-core composite spinning assembly. For core spinning, the temperature settings of the single-screw spinning machine were 265℃ in zone 1, 275℃ in zone 2, 280℃ in zone 3, and 280℃ in the chamber. For sheath spinning, the temperature settings of the single-screw spinning machine were 255℃ in zone 1, 265℃ in zone 2, 270℃ in zone 3, and 270℃ in the chamber. The spinneret orifice diameter was 0.5mm, the spinneret length-to-diameter ratio was 4, the core layer screw speed was 30rpm, and the sheath layer screw speed was 15rpm. After extrusion, the fibers were cooled and shaped by side blowing. The side blowing temperature was set to 25℃, the relative humidity to 80%, the wind speed to 0.5m / s, and the winding speed to 1200m / min, resulting in 9933g of nascent fiber.

[0042] 6: 9933g of nascent fiber was fed into a hot box for drawing and heat setting. The temperature of the first-stage drawing roller was set to 90℃, the temperature of the second-stage drawing roller was set to 105℃, and the temperature of the third-stage drawing roller was set to 130℃. The total drawing ratio was 6 times. After drawing, the fiber was relaxed and heat-set at 150℃ for 30s. The fineness of the single filament was controlled to be 4D. After processing, 9915g of the core-sheath composite mother yarn prepared in Example 2 was obtained.

[0043] Example 3

[0044] 1. The core-sheath composite yarn prepared in Example 1 is placed on the warping machine frame. The warping tension is set to 8 cN / yarn, the warping linear speed is 300 m / min, the number of warp yarns is 2000, and the corresponding width is 100 cm. After warping, the yarn is loaded onto the double-needle bed Raschel warp knitting machine. The pattern data file is loaded into the warp knitting machine. The zero point reference of the ground guide bar traverse mechanism is aligned with the starting position. The knitting speed is set to 600 rpm. A chain and weft composite structure is selected for knitting. The chain structure adopts closed chain knitting, and the weft structure adopts three-needle weft weft. The warp feed is set to 600 mm / rack, the ground guide bar warp feed tension is 8 cN / yarn, and the tension density is 15 rows / cm. During the knitting process, the workshop temperature is controlled at 20℃ and the relative humidity is 55%. The Jacquard guide bar performs jacquard knitting according to the offset information of the pattern data file to obtain the polyester base fabric.

[0045] 2: After weaving, the polyester base fabric is removed from the machine and laid flat on the inspection table. Under an inspection light source with an illuminance of 1200lx, the uniformity of the stitches and surface defects of the fabric are checked. After confirming that there are no broken yarns, missing needles, or holes, the polyester base fabric is sent into the needle plate tenter heat setting machine. The preheating zone temperature is set to 100℃, the setting zone temperature is set to 150℃, and the cooling zone temperature is set to 25℃. There is a transition section between each temperature zone, and the length of the transition section is 20cm. After the fabric enters the preheating zone, a pretension of 0.5N / cm is applied in the width direction. The fabric is gradually heated to 100℃. The dwell time in the preheating zone is 45s.

[0046] 3: The polyester base fabric after preheating enters the setting zone. The setting zone temperature is set to 150℃, the main tensile tension in the width direction is 0.5N / cm, the overfeed rate is 1%, the stretching width is set to 102% of the target finished width, and the dwell time in the setting zone is 25s. The base fabric after setting enters the cooling zone. While maintaining the main tensile tension in the width direction, it is gradually cooled to below 30℃ at a cooling rate of 15℃ / s. After cooling, the tension in the width direction is removed to obtain the shrink-locking base fabric.

[0047] 4. Place the shrink-locking base fabric on the inspection table and check the bonding quality and shrinkage uniformity of the fabric nodes under an inspection light source with an illuminance of 1200 lx. Use a handheld hot air pen to repair areas with insufficient bonding. Set the hot air pen outlet temperature to 150℃ and the repair time to 1 second. After repair, immerse the shrink-locking base fabric in an alkaline treatment solution with a treatment temperature of 75℃ and a treatment time of 15 minutes. After treatment, take it out to obtain the self-woven base fabric.

[0048] 5. Place the self-woven base fabric into a washing tank and wash at 30℃ for 5 minutes. After removal, dry it at 100℃ until the moisture content is less than 1%. Then, place the dried self-woven base fabric into a vacuum coating device and perform vacuum-assisted penetration coating using two-component solvent-free polyurethane. Set the coating amount to 40g / m². 2 The vacuum degree is -0.03MPa. After coating, it is cured at 80℃ for 10min to obtain a polyester-based high-shrinkage electronic packaging leather substrate.

[0049] 6: The polyester-based high-shrinkage electronic packaging leather substrate is fed into a nitrogen atmosphere glow discharge plasma treatment device. The treatment power is set to 200W, the treatment speed to 3m / min, and the treatment spacing to 2mm. The upper and lower surfaces of the substrate are subjected to online plasma etching treatment for 30s. After treatment, the substrate is fed into a padding device and padded with a blended emulsion anti-fingerprint treatment liquid. The liquid content is controlled at 60%. Then, 5wt% of multi-walled carbon nanotube aqueous dispersion is padded. The multi-walled carbon nanotubes have a diameter of 15nm and a length of 10um. The liquid content is controlled at 50% by adjusting the padding pressure. After padding, the substrate is dried and shaped at 130℃ for 40s to obtain the polyester-based high-shrinkage electronic packaging leather prepared in Example 3.

[0050] Example 4

[0051] 1. The core-sheath composite yarn prepared in Example 2 is placed on the warping machine frame. The warping tension is set to 15 cN / yarn, the warping linear speed is 500 m / min, the number of warp yarns is 3000, and the corresponding width is 200 cm. After warping, the yarn is loaded onto the double-needle bed Raschel warp knitting machine. The pattern data file is loaded into the warp knitting machine. The zero point reference of the ground guide bar traverse mechanism is aligned with the starting position. The knitting speed is set to 1000 rpm. A chain and weft composite structure is selected for knitting. The chain structure adopts closed chain knitting, and the weft structure adopts three-needle weft weft. The warp feed is set to 900 mm / rack, the ground guide bar warp feed tension is 12 cN / yarn, and the tension density is 25 rows / cm. During the knitting process, the workshop temperature is controlled at 28°C and the relative humidity is 75%. The Jacquard guide bar performs jacquard knitting according to the offset information of the pattern data file to obtain the polyester base fabric.

[0052] 2: After weaving, the polyester base fabric is removed from the machine and laid flat on the inspection table. Under an inspection light source with an illuminance of 1200lx, the uniformity of the stitches and surface defects of the fabric are checked. After confirming that there are no broken yarns, missing needles, or holes, the polyester base fabric is sent into the needle plate tenter heat setting machine. The preheating zone temperature is set to 100-120℃, the setting zone temperature is 165℃, and the cooling zone temperature is 30℃. There is a transition section between each temperature zone with a length of 40cm. After the fabric enters the preheating zone, a pretension of 1N / cm is applied in the width direction. The fabric is gradually heated to 120℃. The dwell time in the preheating zone is 60s.

[0053] 3: The polyester base fabric after preheating enters the setting zone. The setting zone temperature is set to 165℃, the main tensile tension in the width direction is 1N / cm, the overfeed rate is 3%, the stretching width is set to 105% of the target finished width, and the dwell time in the setting zone is 35s. The base fabric after setting enters the cooling zone. While maintaining the main tensile tension in the width direction, it is gradually cooled to below 30℃ at a cooling rate of 30℃ / s. After cooling, the tension in the width direction is removed to obtain the shrink-locking base fabric.

[0054] 4. Place the shrink-locking base fabric on the inspection table and check the bonding quality and shrinkage uniformity of the fabric nodes under an inspection light source with an illuminance of 1200lx. Use a handheld hot air pen to repair areas with insufficient bonding. Set the hot air pen outlet temperature to 165℃ and the repair time to 3s. After repair, immerse the shrink-locking base fabric in an alkaline treatment solution with a treatment temperature of 85℃ and a treatment time of 25min. After treatment, remove the fabric to obtain the self-woven base fabric.

[0055] 5. Place the self-woven base fabric into a washing tank and wash at 50℃ for 20 minutes. After removal, dry at 120℃ until the moisture content is below 1%. Then, place the dried self-woven base fabric into a vacuum coating device and perform vacuum-assisted penetration coating using two-component solvent-free polyurethane. Set the coating amount to 70g / m². 2 The vacuum degree is -0.06MPa. After coating, it is cured at 100℃ for 20 minutes to obtain a polyester-based high-shrinkage electronic packaging leather substrate.

[0056] 6: The polyester-based high-shrinkage electronic packaging leather substrate was fed into a nitrogen atmosphere glow discharge plasma treatment device. The treatment power was set to 400W, the treatment speed to 5m / min, and the treatment spacing to 4mm. The upper and lower surfaces of the substrate were subjected to online plasma etching treatment for 120s. After treatment, the substrate was fed into a padding device and padded with a blended emulsion anti-fingerprint treatment liquid. The liquid content was controlled at 80%. Then, 5wt% of a multi-walled carbon nanotube aqueous dispersion was padded. The multi-walled carbon nanotubes had a diameter of 15nm and a length of 10um. The liquid content was controlled at 70% by adjusting the padding pressure. After padding, the substrate was dried and shaped at 140℃ for 60s to obtain the polyester-based high-shrinkage electronic packaging leather prepared in Example 4.

[0057] Comparative Example 1

[0058] The difference between this comparative example and Example 3 is that the core-sheath composite mother yarn is replaced with commercially available ordinary polyethylene terephthalate (FDY), while the other components and processes remain unchanged.

[0059] The commercially available ordinary polyethylene terephthalate FDY has the specifications of 150D / 48F, a tensile strength of 4.0 cN / dtex, an elongation at break of 30%, and a boiling water shrinkage of 8%.

[0060] The specific preparation method is as follows:

[0061] 1. Place 3750g of commercially available ordinary polyethylene terephthalate (FDY) on the warping machine's yarn rack. Set the warping tension to 8cN / row, the warping linear speed to 300m / min, and the number of warp ends to 2000, corresponding to a width of 100cm. After warping, load the yarn onto a double-needle bed Raschel warp knitting machine. Load the pattern data file into the warp knitting machine. Align the zero point reference of the ground guide bar traverse mechanism with the starting position. Set the knitting speed to 600rpm. Use a chain knitting and weft weft composite structure for knitting. The chain knitting structure uses closed chain knitting, and the weft weft weft weft uses three-needle weft weft. Set the warp feed to 600mm / rack, the ground guide bar warp feed tension to 8cN / row, and the tension density to 15 rows / cm. During the knitting process, control the workshop temperature to 20℃ and the relative humidity to 55%. The jacquard guide bar performs jacquard knitting according to the offset information in the pattern data file to obtain 3747g of ordinary polyester base fabric.

[0062] 2: After weaving, the 3747g ordinary polyester base fabric is removed from the machine and laid flat on the inspection table. Under the inspection light source with an illuminance of 1200lx, the uniformity of the stitches and surface defects of the fabric are checked. After confirming that there are no broken yarns, missing needles, or holes, the ordinary polyester base fabric is sent into the needle plate tenter heat setting machine. The preheating zone temperature is set to 100℃, the setting zone temperature is set to 150℃, and the cooling zone temperature is set to 25℃. There is a transition section between each temperature zone with a length of 20cm. After the fabric enters the preheating zone, a pretension of 0.5N / cm is applied in the width direction. The fabric is gradually heated to 100℃. The dwell time in the preheating zone is 45s.

[0063] 3: The ordinary polyester base fabric after preheating enters the setting zone. The setting zone temperature is set to 150℃, the main tensile tension in the width direction is 0.5N / cm, the overfeed rate is 1%, the stretching width is set to 102% of the target finished width, and the dwell time in the setting zone is 25s. The base fabric after setting enters the cooling zone. While maintaining the main tensile tension in the width direction, it is gradually cooled to below 30℃ at a cooling rate of 15℃ / s. After cooling, the tension in the width direction is removed to obtain 3743g heat-treated ordinary polyester base fabric.

[0064] 4: Place 3743g of heat-treated ordinary polyester fabric on the inspection table and check the uniformity of the fabric surface under an inspection light source with an illuminance of 1200lx. After confirming that there are no defects, immerse the heat-treated ordinary polyester fabric in the alkali treatment solution, set the treatment temperature to 75℃ and the treatment time to 15min. After the treatment is completed, take it out to obtain 3738g of alkali-treated ordinary polyester fabric.

[0065] 5. 3738g of alkali-treated ordinary polyester base fabric was placed into a washing tank and washed at 30℃ for 5 minutes. After removal, it was dried at 100℃ until the moisture content was less than 1%. The dried alkali-treated ordinary polyester base fabric was then fed into a vacuum coating device in its flat width. Vacuum-assisted penetration coating was performed using two-component solvent-free polyurethane, with a coating amount of 40g / m². 2 The vacuum degree was -0.03MPa. After coating, it was cured at 80℃ for 10min to obtain the polyester-based electronic packaging leather substrate prepared in Comparative Example 1.

[0066] 6: The polyester-based electronic packaging leather substrate prepared in Comparative Example 1 was fed into a nitrogen atmosphere glow discharge plasma treatment device. The treatment power was set to 200W, the treatment speed to 3m / min, and the treatment spacing to 2mm. The upper and lower surfaces of the substrate were subjected to online plasma etching treatment for 30s. After the treatment, the substrate was fed into a padding device and padded with a blended emulsion anti-fingerprint treatment liquid. The liquid content was controlled at 60%. Then, 5wt% of multi-walled carbon nanotube aqueous dispersion was padded. The multi-walled carbon nanotubes had a diameter of 15nm and a length of 10um. The liquid content was controlled at 50% by adjusting the padding pressure. After padding, the substrate was dried and shaped at 130℃ for 40s to obtain the polyester-based electronic packaging leather prepared in Comparative Example 1.

[0067] Comparative Example 2

[0068] The difference between this comparative example and Example 3 is that no alkali treatment is performed, while the remaining components and processes remain unchanged.

[0069] The specific preparation method is as follows:

[0070] 1. The core-sheath composite yarn prepared in Example 1 is placed on the warping machine frame. The warping tension is set to 8 cN / yarn, the warping linear speed is 300 m / min, the number of warp yarns is 2000, and the corresponding width is 100 cm. After warping, the yarn is loaded onto the double-needle bed Raschel warp knitting machine. The pattern data file is loaded into the warp knitting machine. The zero point reference of the ground guide bar traverse mechanism is aligned with the starting position. The knitting speed is set to 600 rpm. A chain and weft composite structure is selected for knitting. The chain structure adopts closed chain knitting, and the weft structure adopts three-needle weft weft. The warp feed is set to 600 mm / rack, the ground guide bar warp feed tension is 8 cN / yarn, and the tension density is 15 rows / cm. During the knitting process, the workshop temperature is controlled at 20℃ and the relative humidity is 55%. The Jacquard guide bar performs jacquard knitting according to the offset information of the pattern data file to obtain the polyester base fabric.

[0071] 2: After weaving, the polyester base fabric is removed from the machine and laid flat on the inspection table. Under an inspection light source with an illuminance of 1200lx, the uniformity of the stitches and surface defects of the fabric are checked. After confirming that there are no broken yarns, missing needles, or holes, the polyester base fabric is sent into the needle plate tenter heat setting machine. The preheating zone temperature is set to 100℃, the setting zone temperature is set to 150℃, and the cooling zone temperature is set to 25℃. There is a transition section between each temperature zone, and the length of the transition section is 20cm. After the fabric enters the preheating zone, a pretension of 0.5N / cm is applied in the width direction. The fabric is gradually heated to 100℃. The dwell time in the preheating zone is 45s.

[0072] 3: The polyester base fabric after preheating enters the setting zone. The setting zone temperature is set to 150℃, the main tensile tension in the width direction is 0.5N / cm, the overfeed rate is 1%, the stretching width is set to 102% of the target finished width, and the dwell time in the setting zone is 25s. The base fabric after setting enters the cooling zone. While maintaining the main tensile tension in the width direction, it is gradually cooled to below 30℃ at a cooling rate of 15℃ / s. After cooling, the tension in the width direction is removed to obtain the shrink-locking base fabric.

[0073] 4. Place the shrink-locking fabric on the inspection table and check the bonding quality and shrinkage uniformity of the fabric joints under an inspection light source with an illuminance of 1200 lx. For areas with insufficient bonding, use a handheld hot air pen for spot repair. Set the hot air pen outlet temperature to 150℃ and the repair time to 1 second. After repair, send the shrink-locking fabric into a washing tank and wash at 30℃ for 5 minutes. Remove and dry at 100℃ until the moisture content is below 1%. Send the dried shrink-locking fabric flat into a vacuum coating device and perform vacuum-assisted penetration coating using two-component solvent-free polyurethane, setting the coating amount to 40 g / m². 2 The vacuum degree was -0.03MPa. After coating, it was cured at 80℃ for 10min to obtain the polyester-based electronic packaging leather substrate prepared in Comparative Example 2.

[0074] 5: The polyester-based electronic packaging leather substrate prepared in Comparative Example 2 was fed into a nitrogen atmosphere glow discharge plasma treatment device. The treatment power was set to 200W, the treatment speed to 3m / min, and the treatment spacing to 2mm. The upper and lower surfaces of the substrate were subjected to online plasma etching treatment for 30s. After the treatment, the substrate was fed into a padding device and padded with a blended emulsion anti-fingerprint treatment liquid. The liquid content was controlled at 60%. Then, 5wt% of a multi-walled carbon nanotube aqueous dispersion was padded. The multi-walled carbon nanotubes had a diameter of 15nm and a length of 10um. The liquid content was controlled at 50% by adjusting the padding pressure. After padding, the substrate was dried and shaped at 130℃ for 40s to obtain the polyester-based electronic packaging leather prepared in Comparative Example 2.

[0075] Basic physical performance testing

[0076] Samples of the high-shrinkage electronic packaging leather with polyester base fabric prepared in Examples 3, 4, Comparative Example 1, and Comparative Example 2 were cut into 300mm × 300mm specimens. After being placed under standard conditions for 24 hours, the tensile strength and elongation at break were tested according to GB / T 6344-2008 "Determination of Tensile Strength and Elongation at Break of Flexible Foam Polymer Materials", the peel strength was tested according to GB / T2791-1995 "Test Method for Peel Strength of Adhesives - Flexible Materials to Flexible Materials", the basis weight was tested according to GB / T4669-2008 "Determination of Mass per Unit Length and Mass per Unit Area of ​​Woven Textiles", and the boiling water shrinkage rate was tested according to FZ / T01004-2008 "Determination of Elongation at Constant Load and Load at Constant Elongation of Coated Fabrics". The morphology of the microfiber pile on the leather surface was observed using a scanning electron microscope. Each group of samples was tested in parallel three times, and the average value was recorded.

[0077] Table 1. Results of Basic Physical Performance Tests

[0078] Analysis of Table 1 shows that the longitudinal shrinkage rates of Examples 3 and 4 reached 22% and 25%, respectively, and the transverse shrinkage rates reached 16% and 18%, respectively. The longitudinal and transverse shrinkage rates of Comparative Example 1 were only 3% and 2%, respectively. This proves that the high-shrinkage polyester core layer of the core-sheath composite mother filament triggered significant shrinkage in the preheating zone. In contrast, the commercially available ordinary polyester FDY has a boiling water shrinkage rate of only 8%, and cannot achieve effective macroscopic densification under the same process conditions. This verifies that the high-shrinkage polyester core layer is the core source of the material's shrinkage performance.

[0079] The peel strengths of Examples 3 and 4 reached 12.5 N / 25 mm and 14.2 N / 25 mm, respectively, while the peel strength of Comparative Example 1 was only 6.8 N / 25 mm, a decrease of 45.6% compared to Example 3. The reason for this is that commercially available ordinary polyester FDY does not have a low-melting-point copolyester skin, which cannot trigger thermo-induced self-adhesion at the nodes in the 150°C setting zone. The fiber interlacing points lack spot welding structures, resulting in insufficient integrity of the base fabric skeleton and a significant decrease in interfacial bonding strength after polyurethane coating. The peel strength of Comparative Example 2 was 13.8 N / 25 mm, comparable to Example 3, proving that the main contribution to the peel strength comes from the three-dimensional continuous spot welding structure of the shrinkage self-locking skeleton. The alkali treatment pore-forming step does not affect the already formed node self-locking skeleton.

[0080] The surface fluff morphology of Examples 3 and 4 is dense and uniform. Scanning electron microscopy reveals that an ultrafine fiber fluff layer of 0.05-0.20 mm is formed on the fiber surface, exhibiting a dermal reticular layer structure. Comparative Example 1 has no fluff on its surface, and Comparative Example 2 has a smooth surface without fluff. The reason for this is that the commercially available ordinary polyester FDY in Comparative Example 1 does not contain alkali-soluble copolyester components, while Comparative Example 2, although containing alkali-soluble copolyester, has not undergone alkali treatment. As a result, the alkali-soluble copolyester was not etched and dissolved, and the fiber bundles could not be dissociated to form ultrafine fiber fluff. This verifies that sacrificial pore formation of alkali-soluble copolyester is a necessary condition for forming a dermal tactile ultrafine fiber fluff layer.

[0081] Fatigue resistance test

[0082] Samples of the high-shrinkage polyester-based electronic packaging leather prepared in Examples 3, 4, Comparative Example 1, and Comparative Example 2 were cut into 200mm × 200mm specimens. After being placed under standard conditions for 24 hours, the specimens were placed on a fatigue testing machine and subjected to repeated compression fatigue tests at a frequency of 2Hz and an amplitude of 15mm. The number of compression cycles was set to 5000. After the test, the specimens were removed and allowed to recover under standard conditions for 2 hours. The peel strength after fatigue was tested according to GB / T 2791-1995, and the tensile strength after fatigue was tested according to GB / T 6344-2008. The peel strength retention rate and tensile strength retention rate were calculated, and the surface morphology after fatigue was visually observed. Each group of samples was tested in parallel three times, and the average value was taken and the test results were recorded.

[0083] Table 2. Results of fatigue resistance test

[0084] As shown in Table 2, after 5000 cycles of repeated compression fatigue, the peel strength retention rates of Examples 3 and 4 reached 86.4% and 88.7%, respectively, and the tensile strength retention rates reached 85.4% and 88.4%, respectively. The surfaces were smooth and there was no delamination. This proves that the three-dimensional continuous spot-welded structure of the shrinkage self-locking skeleton remains stable under dynamic load, and no fatigue failure occurs at the joint bonding points. At the same time, the interpenetrating network formed by polyurethane and ultrafine fiber fluff further enhances the interface durability.

[0085] The peel strength retention rate and tensile strength retention rate of Example 4 were 2.3 and 3.0 percentage points higher than those of Example 3, respectively. The reason for this is that Example 4 used the core-sheath composite mother yarn prepared in Example 2, with a total draw ratio of 6 times. The molecular chain orientation and crystallinity of the high-shrinkage polyester core layer were higher, resulting in greater shrinkage stress and stronger node self-locking. At the same time, the higher alkali treatment temperature and time made the microfiber fluff layer denser and increased the mechanical anchor point density of the polyurethane interpenetrating network.

[0086] The peel strength retention rate of Comparative Example 1 was only 47.1%, and the tensile strength retention rate was only 58.5%. After 5000 fatigue cycles, local blistering and delamination occurred. The reason for this was that commercially available ordinary polyester FDY had neither a node self-locking skeleton nor an ultra-fine fiber fluff layer. The interface bonding between the polyurethane coating and the smooth fiber surface was mainly physical adsorption. Repeated compression led to interface debonding and gradual expansion. The base fabric skeleton itself also lacked an energy dissipation mechanism.

[0087] Comparative Example 2 exhibited a peel strength retention rate of 83.3% and a tensile strength retention rate of 82.4%. After fatigue, the surface was smooth but slightly fuzzy. The reason for this was that although Comparative Example 2 had a complete shrinkage self-locking skeleton, it did not undergo alkali treatment to create pores. The fiber surface was smooth and lacked an ultrafine fiber fluff layer. The polyurethane was only coated on the fiber surface and failed to penetrate into the fiber gaps to form an interpenetrating network. The degree of interfacial mechanical interlocking was insufficient. Under dynamic fatigue load, the polyurethane coating and the fiber surface underwent micro-slippage, resulting in slight surface fuzzing. This verified the important contribution of the ultrafine fiber fluff layer formed by alkali solution pore creation to the anchoring and fatigue resistance of the polyurethane interpenetrating network.

[0088] Antistatic performance test

[0089] Samples of high-shrinkage polyester-based electronic packaging leather prepared in Examples 3, 4, 1, and 2 were cut to a size of 150mm × 150mm. After being placed under standard conditions for 24 hours, the surface resistance and electrostatic decay time were tested according to SJ / T 10694-2006 "General Specification for Antistatic Testing of Electronic Product Manufacturing and Application Systems". Each group of samples was tested in parallel 3 times, and the average value was taken and the test results were recorded.

[0090] Table 3. Results of Antistatic Performance Tests

[0091] Analysis of Table 3 shows that the surface resistivity of Examples 3, 4, Comparative Example 1, and Comparative Example 2 is all above 10. 7 -10 8 Within the Ω / sq range, the electrostatic decay time was less than 0.2s, meeting the antistatic requirements for electronic packaging. This proves that all four samples were treated with carbon nanotube aqueous dispersion, and the antistatic function was mainly imparted by the finishing process, with no significant correlation to the type of core-sheath composite filament or the alkali treatment step.

[0092] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a high-shrinkage electronic packaging leather based on polyester fabric, characterized in that, Based on warp knitting machines and core-sheath composite yarns, with core-sheath composite yarns as the sole weaving material, the synergistic effect of core-sheath composite yarns, programmed heating, and selective dissolution is used to achieve integrated fiber shrinkage densification, node thermal self-adhesion, and in-situ micropore generation, resulting in high-shrinkage electronic packaging leather made of polyester base fabric.

2. The method for preparing a high-shrinkage electronic packaging leather based on polyester fabric according to claim 1, characterized in that, The core-sheath composite mother yarn is composed of the following components by weight percentage: 50% high-shrinkage polyester, 32.7% low-melting-point copolyester, 12.5% ​​alkali-soluble copolyester, 4.5% maleic anhydride-grafted polyester, and 0.3% antioxidant.

3. The method for preparing a high-shrinkage electronic packaging leather based on polyester fabric according to claim 1, characterized in that, The preparation method of the core-sheath composite mother yarn includes the following steps: A1: Place the high-shrinkage polyester in a vacuum drying oven, set the temperature to 120-140℃, and the vacuum degree to -0.08 to -0.10MPa, and dry for 12-16 hours to obtain dried high-shrinkage polyester. Place the low-melting-point copolyester in a vacuum drying oven, set the temperature to 100-120℃, and the vacuum degree to -0.08 to -0.10MPa, and dry for 10-14 hours to obtain dried low-melting-point copolyester. Place the alkali-soluble copolyester in a vacuum drying oven, set the temperature to 120-140℃, and the vacuum degree to -0.08 to -0.10MPa, and dry for 12-16 hours to obtain dried alkali-soluble copolyester. A2: Dry low-melting-point copolyester, dry alkali-soluble copolyester, maleic anhydride grafted polyester, and antioxidant are added to the first twin-screw extruder for melt blending and granulation. The temperature of the first twin-screw extruder is set as follows: Zone 1 temperature 240-250℃, Zone 2 temperature 255-265℃, Zone 3 temperature 265-275℃, Zone 4 temperature 270-280℃, and Die section temperature 265-275℃. The screw speed is 150-250 rpm. After blending and extrusion, the mixture is cooled in a water bath at 25℃ and drawn at a draw ratio of 1:

3. After drawing, the mixture is granulated to obtain skin-layer blended masterbatch. A3: Dry high-shrinkage polyester is added to the second twin-screw extruder for melt granulation. The temperature of the second twin-screw extruder is set as follows: Zone 1 temperature is 245-255℃, Zone 2 temperature is 260-270℃, Zone 3 temperature is 270-280℃, Zone 4 temperature is 275-285℃, and the die section temperature is 270-280℃. The screw speed is 150-250 rpm. After extrusion, the material is cooled in a water bath at a temperature of 25℃. It is then drawn at a draw ratio of 1:

3. After drawing, the material is granulated to obtain the core layer masterbatch. A4: Place the skin layer blend masterbatch and the core layer masterbatch in a vacuum drum dryer, set the drying temperature to 120-140℃, the vacuum degree to -0.08 to -0.10MPa, and the drying time to 12-16h to obtain dried skin layer blend masterbatch and dried core layer masterbatch. A5: The dried outer layer blending masterbatch and the dried core layer masterbatch are fed into two single-screw spinning machines respectively. Composite spinning is performed using a core-sheath composite spinning assembly. For core layer spinning, the temperatures in zone one of the single-screw spinning machines are set to 260-265℃, zone two to 270-275℃, zone three to 275-280℃, and the chamber temperature to 275-280℃. For outer layer spinning, the temperatures in zone one of the single-screw spinning machines are set to 250-255℃, zone two to 260-265℃, and zone three to 270-265℃. The temperature of the extrusion zone is 265-270℃, the temperature of the chamber is 265-270℃, the spinneret orifice diameter is 0.3-0.5mm, the spinneret length-to-diameter ratio is 3-4, the core layer screw speed is 30rpm, the sheath layer screw speed is 15rpm, and after extrusion, it is cooled and shaped by side blowing. The side blowing temperature is set to 18-25℃, the relative humidity is 60-80%, the wind speed is 0.3-0.5m / s, and the winding speed is 800-1200m / min to obtain nascent fibers. A6: The nascent fibers are fed into a hot box for stretching and heat setting. The temperature of the first-stage stretching roller is set to 80-90℃, the temperature of the second-stage stretching roller is 95-105℃, and the temperature of the third-stage stretching roller is 110-130℃. The total stretching ratio is 4-6 times. After stretching, the fibers are relaxed and heat-set at 130-150℃ for 10-30 seconds. The fineness of the single filament is controlled to be 2-4D. After processing, the core-sheath composite mother yarn is obtained.

4. The method for preparing a high-shrinkage electronic packaging leather based on polyester fabric according to claim 1, characterized in that, Includes the following steps: S1: Place the core-sheath composite yarn on the warping machine's yarn rack. Set the warping tension to 8-15 cN / yarn, the warping linear speed to 300-500 m / min, and the number of warp yarns to 2000-3000, corresponding to a width of 100-200 cm. After warping, load the yarn onto a double-needle bed Raschel warp knitting machine. Load the pattern data file into the warp knitting machine. Align the zero-point reference of the ground guide bar traverse mechanism with the starting position. Set the knitting speed to 600-1000 rpm. The fabric is woven using a combination of chain braiding and weft insertion. The chain braiding uses closed chain braiding, and the weft insertion uses three-needle weft insertion. The warp feed rate is set to 600-900 mm / rack, the ground guide bar warp tension is 8-12 cN / thread, and the tension density is 15-25 rows / cm. During the weaving process, the workshop temperature is controlled at 20-28℃ and the relative humidity is 55-75%. The jacquard guide bar performs jacquard weaving based on the offset information of the pattern data file to obtain the polyester base fabric. S2: After weaving, the polyester base fabric is removed from the machine and laid flat on the inspection table. Under an inspection light source with an illuminance of 1200lx, the uniformity of the stitches and surface defects of the fabric are checked. After confirming that there are no broken yarns, missing needles, or holes, the polyester base fabric is sent into the needle plate tenter heat setting machine. The preheating zone temperature is set to 100-120℃, the setting zone temperature to 150-165℃, and the cooling zone temperature to 25-30℃. There is a transition section between each temperature zone, with a length of 20-40cm. After the fabric enters the preheating zone, a pretension of 0.5-1N / cm is applied in the width direction. The fabric is gradually heated to 100-120℃, and the dwell time in the preheating zone is 45-60s. S3: The polyester base fabric after preheating enters the setting zone. The setting zone temperature is set to 150-165℃, the main tensile tension in the width direction is 0.5-1N / cm, the overfeed rate is 1-3%, the stretching width is set to 102-105% of the target finished width, and the dwell time in the setting zone is 25-35s. The base fabric after setting enters the cooling zone. While maintaining the main tensile tension in the width direction, it is gradually cooled to below 30℃ at a cooling rate of 15-30℃ / s. After cooling, the tension in the width direction is removed to obtain the shrink-locking base fabric. S4: Place the shrink-locking base fabric on the inspection table and check the bonding quality and shrinkage uniformity of the fabric nodes under an inspection light source with an illuminance of 1200lx. Use a handheld hot air pen to repair areas with insufficient bonding. Set the hot air pen outlet temperature to 150-165℃ and the repair time to 1-3s. After repair, immerse the shrink-locking base fabric in an alkaline treatment solution, which consists of 8g / L sodium hydroxide and 1.5g / L dodecyltrimethylammonium chloride, with pure water as the solvent. Set the treatment temperature to 75-85℃ and the treatment time to 15-25min. After treatment, remove the fabric to obtain the self-woven base fabric. S5: The self-woven base fabric is placed in a washing tank and washed at 30-50℃ for 5-20 minutes. After removal, it is dried at 100-120℃ until the moisture content is below 1%. The dried self-woven base fabric is then fed into a vacuum coating device in its flat width. A two-component solvent-free polyurethane is used for vacuum-assisted penetration coating. The two-component solvent-free polyurethane consists of polyether polyol and isocyanate, with a mass ratio of 100:

50. The coating amount is set to 40-70 g / m². 2 The vacuum degree is -0.03 to -0.06 MPa. After coating, it is cured at 80-100℃ for 10-20 min to obtain a polyester-based high-shrinkage electronic packaging leather substrate. S6: The high-shrinkage polyester electronic packaging leather substrate is fed flat into a nitrogen atmosphere glow discharge plasma treatment device. The treatment power is set to 200-400W, the treatment speed to 3-5m / min, and the treatment spacing to 2-4mm. Online plasma etching is performed on the upper and lower surfaces of the substrate for 30-120s. After treatment, the substrate is fed flat into a padding device for padding with a blended emulsion anti-fingerprint treatment solution. The liquid content is controlled at 60-80%. The blended emulsion anti-fingerprint treatment... The liquid is composed of side-chain amino-modified polysiloxane and waterborne polyurethane, with a solid content of 15% and pure water as the solvent. The mass ratio of side-chain amino-modified polysiloxane to waterborne polyurethane is 1:

4. Then, 5wt% of multi-walled carbon nanotube aqueous dispersion is impregnated and rolled. The multi-walled carbon nanotubes have a diameter of 15nm and a length of 10um. The liquid content is controlled at 50-70% by adjusting the rolling pressure. After impregnation and rolling, the product is dried and shaped at 130-140℃ for 40-60s to obtain high-shrinkage electronic packaging leather based on polyester fabric.

5. The method for preparing a high-shrinkage electronic packaging leather based on polyester fabric according to claim 2, characterized in that, The high-shrinkage polyester is polyethylene terephthalate copolymerized with isophthalic acid and neopentyl glycol, with an intrinsic viscosity of 0.75 dL / g and a boiling water shrinkage rate of 40%.

6. The method for preparing a high-shrinkage electronic packaging leather based on polyester fabric according to claim 2, characterized in that, The low-melting-point copolyester is polyethylene terephthalate modified by copolymerization of isophthalic acid and diethylene glycol, with a melting point of 135°C and a melt index of 18 g / 10 min measured under conditions of 160°C and 2.16 kg load.

7. The method for preparing a high-shrinkage electronic packaging leather based on polyester fabric according to claim 2, characterized in that, The alkali-soluble copolyester is a polyethylene terephthalate modified with sodium isophthalate-5-sulfonate, the molar content of sodium isophthalate-5-sulfonate is 13%, and the melting point is 235℃; the grafting rate of the maleic anhydride grafted polyester is 1.3%, and the intrinsic viscosity is 0.65 dL / g.

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