High-modulus low-creep bio-based fabric integral belt core and preparation method thereof

Abstract

The invention discloses a high-modulus and low-creep bio-based fabric integral belt core and a preparation method thereof, and belongs to the technical field of conveyor belts, the high-modulus and low-creep bio-based fabric integral belt core has high initial modulus, low running creep and excellent anti-deviation performance, and the high-modulus and low-creep bio-based fabric integral belt core is prepared through an anti-conventional material configuration scheme. The antistatic polyester has good hydrolysis resistance and heat resistance, and is endowed with antistatic property when being prepared into a conveyor belt for use; according to the invention, the graphene polylactic acid fiber filaments are'wrapped 'in a multi-layer structure and are supported and fixed by the tough bio-based nylon 56 wefts in the transverse direction, so that a microscopic'reinforced concrete' structure is formed, and the brittle fracture tendency of the graphene polylactic acid fiber filaments under dynamic load is greatly restrained and buffered; and the special structure of the graphene polylactic acid fiber filament can be embedded into a micro reinforced concrete structure, so that the high modulus advantage of the graphene polylactic acid fiber filament can be fully played, and the weakness can be effectively inhibited.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of conveying belts, and particularly relates to a high-modulus low-creep bio-based fabric integrated belt core and a preparation method thereof. BACKGROUND

[0002] In the field of conveying belts, the warp (longitudinal) performance of the belt core directly determines the tensile strength, impact resistance and grooving property of the conveying belt, while the weft (transverse) performance is crucial for the rigidity, anti-deviation and dimensional stability of the conveying belt. Traditional high-strength conveying belts mostly adopt nylon / polyester / cotton structures, in which nylon is widely used due to its excellent toughness and fatigue resistance. However, nylon material, especially when used as warp, has the disadvantages of low initial modulus, large change in dry and wet strength, and large creep. This leads to a large elongation of the conveying belt under long-term high-load operation, which requires frequent tensioning, increasing energy consumption and maintenance costs. Although polyester (EP) has a higher modulus, its adhesion to rubber and resistance to repeated impact are not as good as nylon.

[0003] With the development of bio-based materials, materials such as polylactic acid (PLA) and bio-based nylon 56 have been tried for use in conveying belts. PLA has the advantages of high modulus and low creep, but its brittleness, poor hydrolysis resistance and poor heat resistance limit its application in high-performance conveying belts, especially in the warp position that needs to bear the main tension and repeated bending. The prior art generally avoids using PLA as the main load-bearing thread, especially the warp load-bearing thread, because its inherent brittleness can cause the belt core to break prematurely during dynamic use. Therefore, it has become a technical problem to be solved in the field to provide a belt core structure that can take advantage of the high modulus and low creep of PLA while overcoming its brittleness, while maintaining high strength and good durability. SUMMARY

[0004] The purpose of the present application is to provide a high-modulus low-creep bio-based fabric integrated belt core and a preparation method thereof, which has a bio-based fabric integrated belt core with high initial modulus, low running creep and excellent anti-deviation performance. Through an unconventional material configuration scheme, the application effectively solves the application bottleneck of PLA as a warp material, while having good hydrolysis resistance and heat resistance, and can impart antistatic properties when used as a conveying belt.

[0005] The purpose of the present application can be achieved by the following technical solutions:

[0006] A preparation method of a high-modulus low-creep bio-based fabric integrated belt core, comprising the following steps:

[0007] Step one: form porous polylactic acid fiber by pore-forming treatment of modified polylactic acid sheet with polyvinylpyrrolidone, then coat polyaniline and graphene by in-situ polymerization, and then obtain graphene polylactic acid fiber filament through oiling, stretching, heat setting and high-speed winding.

[0008] Step two: use 1000-1050 dtex / 180 f graphene polylactic acid fiber filament as warp, use 1110-1120 dtex / 192 f bio-based nylon 56 filament as weft, use 32 cotton yarns as buffer, use three-layer stitching organization on a heavy-duty rapier loom, and use three-layer weaving to form a high-modulus low-creep bio-based fabric whole core.

[0009] Further, the strength of the graphene polylactic acid fiber filament is 5.2-5.4 cN / dtex, and the initial modulus is 110-114 cN / dtex.

[0010] Further, the graphene polylactic acid fiber filament is prepared according to the following steps:

[0011] The graphene powder with a particle size of 10-15 μm and the hydrochloric acid solution with a mass fraction of 50-60% are added to the reaction kettle, stirred at 20-25℃ and 500-600 r / min for 30-40 min, then aniline and porous polylactic acid fiber are added, and the stirring is continued for 30-40 min, the temperature is lowered to 5-7℃, then ammonium persulfate is added, and the stirring is continued for 30-40 min, then the fiber is taken out, washed with ionized water and anhydrous ethanol until the last washing liquid is neutral, vacuum dried at 60-80℃ for 8-9 h, then oiled with oiling agent, stretched, heat set at 120-125℃, and high-speed wound at 4000-4200 m / min to obtain graphene polylactic acid fiber filament with a size of 1000-1050 dtex / 180 f;

[0012] Further, the mass ratio of graphene powder, hydrochloric acid solution, aniline, porous polylactic acid fiber and ammonium persulfate is 20-30:100-120:2-3:40-42:2-3.

[0013] Further, the porous polylactic acid fiber is prepared according to the following steps:

[0014] The spinning solution is transferred into a plastic syringe, matched with an 18G needle, fixed on a syringe pump, the receiving distance is adjusted to 15-16cm, the advancing rate is 1-1.2mL / h, a metal needle is applied with a voltage of 14-16kV, the collecting device is applied with a voltage of-0.9kV, and the spinning is performed for 20-30min, so that the porous polylactic acid fiber with an average diameter of 2um and an average length of 30mm is obtained.

[0015] Further, the specific preparation steps of the spinning solution are as follows:

[0016] The modified polylactic acid sheet and N,N-dimethylformamide are added into a reaction kettle, stirred at 60-65℃ and 500-600r / min for 4-5h, then polyvinylpyrrolidone is added, and the stirring is continued for 4-5h, so that the spinning solution is obtained.

[0017] Further, the usage ratio of the modified polylactic acid sheet, N,N-dimethylformamide and polyvinylpyrrolidone is 50-60g:500-520mL:10-12g; the viscosity of the spinning solution is 589-592cP, the conductivity is 72.6-73.1us / cm, and the surface tension is 34.56-35.14mN / m.

[0018] Further, the specific preparation steps of the modified polylactic acid sheet are as follows:

[0019] The acetyl citric acid tri-n-butyl ester, polycarbodiimide, basf chain extender and polylactic acid are stirred and mixed, melt blended at 180-185℃ and 60-70r / min for 5-7min, transferred onto a flat plate vulcanizing machine, hot pressed at 180-182℃ and 10-12MPa for 5-8min, and then cold pressed for 5-8min, so that the modified polylactic acid sheet is obtained.

[0020] Further, the usage ratio of the acetyl citric acid tri-n-butyl ester, polycarbodiimide, basf chain extender and polylactic acid is 5-6mL:4-5g:1-2g:50-60g.

[0021] The beneficial effects of the present application are as follows:

[0022] 1. The application breaks the traditional technical prejudice of "high toughness material is placed in the warp direction", and creatively places graphene polylactic acid fiber filaments in the warp direction as the main stress line, and places high toughness bio-based nylon 56 in the weft direction. This "reverse structure" design brings unexpected technical effects. The graphene polylactic acid fiber filaments directly bear tension in the warp direction, so that the elongation of the conveyor belt during startup and operation is extremely small, significantly reducing the running creep, reducing the need for frequent tensioning, and the energy saving effect is obvious. The use of high-toughness bio-based nylon 56 in the weft direction provides the necessary transverse flexibility and elastic recovery force for the belt core, making the conveyor belt more smooth and natural when forming a trough shape, and together giving the belt core excellent anti-deviation ability and overall dynamic durability.

[0023] 2. The application uses polycarbodiimide and basf chain extender as a synergistic anti-hydrolysis agent for polylactic acid, and prepares modified polylactic acid sheet through melt blending process, and then uses polyvinylpyrrolidone for pore forming treatment to obtain porous polylactic acid fiber. The porous structure can act as a stress dispersion unit. When the fiber bears tensile, bending or impact load, the porous structure will elastically deform, thereby dispersing the concentrated stress, solving the problem of large brittleness of traditional polylactic acid fiber.

[0024] 3. The application uses porous polylactic acid fiber as a carrier. The porous structure can provide physical adsorption sites for graphene, and polyaniline is in-situ polymerized on the surface of the porous polylactic acid fiber through an in-situ polymerization method to obtain graphene polylactic acid fiber filaments. The sheet structure of graphene can further improve the mechanical properties of the fiber, and the surface-polymerized polyaniline can give the high-modulus and low-creep bio-based fabric overall belt core antistatic property, avoiding the generation of static electricity by friction between coal dust and the conveyor belt during operation in the coal mine, which can ignite the flammable gas in the mine and cause safety accidents.

[0025] 4. The application forms a micro "reinforced concrete" structure by "wrapping" the graphene polylactic acid fiber filaments inside a multi-layer structure and supporting and fixing them in the transverse direction by the tough bio-based nylon 56 weft, greatly constraining and buffering the brittle fracture tendency of the graphene polylactic acid fiber filaments under dynamic load, and the special structure of the graphene polylactic acid fiber filaments can be embedded in the micro "reinforced concrete" structure, so that the high modulus advantage can be fully utilized and the weakness can be effectively inhibited. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the application will be clearly and completely described below in combination with the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, not all embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the application.

[0027] Embodiment 1: A method for preparing a high modulus and low creep bio-based fabric integrated core, comprising the following steps:

[0028] S1: 5 g of acetyl citric acid tri-n-butyl ester, 4 g of polycarbodiimide, 1 g of BASF chain extender and 50 g of polylactic acid are stirred and mixed, and then melt blended at 180°C and 60 r / min for 5 min, and then transferred to a flat vulcanizing machine, and then hot pressed at 180°C and 10 MPa for 5 min, and then cold pressed for 5 min to obtain a modified polylactic acid sheet.

[0029] S2: 50 g of the modified polylactic acid sheet and 500 mL of N,N-dimethylformamide are added to a reaction kettle, stirred at 60°C and 500 r / min for 4 h, and then 10 g of polyvinylpyrrolidone is added, and stirring is continued for 4 h to obtain a spinning solution with a viscosity of 589 cP, a conductivity of 72.6 μS / cm and a surface tension of 34.56 mN / m; the spinning solution is transferred to a plastic syringe, and an 18G needle (with an inner diameter of 0.86 mm) is fixed on the syringe, and the receiving distance is adjusted to 15 cm, the push rate is 1 mL / h, the metal needle is applied with a voltage of 14 kV, and the collecting device is applied with a voltage of -0.9 kV, and the spinning is carried out for 20 min to obtain porous polylactic acid fibers with an average diameter of 2 μm and an average length of 30 mm.

[0030] S3: 20 g of graphene powder with a particle size of 10 μm and 100 g of a 50% by mass hydrochloric acid solution are added to a reaction kettle, stirred at 20°C and 500 r / min for 30 min, and then 2 g of aniline and 40 g of the porous polylactic acid fibers are added, and stirring is continued for 30 min, and then the temperature is lowered to 5°C, and then 2 g of ammonium persulfate is added, and stirring is continued for 30 min, and then the fibers are taken out, and the fibers are washed with ionized water and anhydrous ethanol until the last washing liquid is neutral, and then vacuum dried at 60°C for 8 h, and then oiled with an oiling agent, stretched, heat set at 120°C and high-speed wound at 4000 m / min to obtain graphene polylactic acid fiber filaments with a strength of 5.2 cN / dtex, an initial modulus of 110 cN / dtex and a size of 1000 dtex / 180 f.

[0031] S4: The 1000 dtex / 180 f graphene polylactic acid fiber filaments are used as warp threads, 1110 dtex / 192 f bio-based nylon 56 filaments are used as weft threads, and 32 cotton yarns are used as buffers, and then three-layer interlocking weave is used to integrally weave the high modulus and low creep bio-based fabric integrated core on a heavy-duty rapier loom, and then multi-layer weaving is carried out for 3 layers, and then the warp density is 55 threads / cm and the weft density is 38 threads / cm, and then heat setting is carried out at 135°C for 2 min to obtain the high modulus and low creep bio-based fabric integrated core.

[0032] Embodiment 2: A method for preparing a high-modulus low-creep bio-based fabric integrated core, comprising the following steps:

[0033] S1: 5.5 g of acetyl citric acid tri-n-butyl ester, 4.5 g of polycarbodiimide, 1.5 g of BASF chain extender, and 55 g of polylactic acid are stirred and mixed, and then melt blended at 182.5°C and 65 r / min for 6 min, and then transferred to a flat vulcanizing machine, and then hot pressed at 181°C and 11 MPa for 6.5 min, and then cold pressed for 6.5 min, to obtain a modified polylactic acid sheet.

[0034] S2: 55 g of the modified polylactic acid sheet and 510 mL of N,N-dimethylformamide are added to a reaction kettle, stirred at 62.5°C and 550 r / min for 4.5 h, and then 11 g of polyvinylpyrrolidone is added, and stirring is continued for 4.5 h to obtain a spinning solution with a viscosity of 590.5 cP, a conductivity of 72.85 μS / cm, and a surface tension of 34.85 mN / m; the spinning solution is transferred to a plastic syringe, and an 18G needle (with an inner diameter of 0.86 mm) is fixed to the syringe, and the syringe is fixed to a syringe pump, and the receiving distance is adjusted to 15.5 cm, the pushing rate is 1.1 mL / h, a 15 kV voltage is applied to the metal needle, and a -0.9 kV voltage is applied to the collection device, and spinning is performed for 25 min to obtain porous polylactic acid fibers with an average diameter of 2 μm and an average length of 30 mm.

[0035] S3: 25 g of graphene powder with a particle size of 12.5 μm and 110 g of a 55% by mass hydrochloric acid solution are added to a reaction kettle, stirred at 22.5°C and 550 r / min for 35 min, and then 2.5 g of aniline and 41 g of the porous polylactic acid fibers are added, and stirring is continued for 35 min, and then the temperature is lowered to 6°C, and then 2.5 g of ammonium persulfate is added, and stirring is continued for 35 min, and then the fibers are removed, and the fibers are washed with ionized water and anhydrous ethanol until the last washing liquid is neutral, and then the fibers are vacuum dried at 70°C for 8.5 h, and then the fibers are oiled with an oiling agent, stretched, heat set at 122.5°C, and high-speed wound at 4100 m / min to obtain graphene polylactic acid fiber filaments with a strength of 5.3 cN / dtex, an initial modulus of 112 cN / dtex, and a size of 1025 dtex / 180 f.

[0036] S4: The 1025 dtex / 180 f graphene polylactic acid fiber filaments are used as warp threads, 1115 dtex / 192 f bio-based nylon 56 filaments are used as weft threads, and 32 cotton yarns are used as a buffer, and then three-layer interlocking weave is used to integrally weave the bio-based fabric integrated core on a heavy-duty rapier loom, and then four-layer multi-layer weaving is performed with a warp density of 55 threads / cm and a weft density of 38 threads / cm, and then heat setting is performed on a heat setting machine at 137.5°C for 3 min to obtain the high-modulus low-creep bio-based fabric integrated core.

[0037] Embodiment 3: A method for preparing a high-modulus low-creep bio-based fabric integrated core, comprising the following steps:

[0038] S1: 6 g of acetyl citric acid tri-n-butyl ester, 5 g of polycarbodiimide, 2 g of BASF chain extender, and 60 g of polylactic acid are stirred and mixed, melt blended at 185°C and 70 r / min for 7 min, transferred to a flat vulcanizing machine, hot pressed at 182°C and 12 MPa for 8 min, and then cold pressed for 8 min to obtain a modified polylactic acid sheet.

[0039] S2: 60 g of the modified polylactic acid sheet and 520 mL of N,N-dimethylformamide are added to a reaction kettle, stirred at 65°C and 600 r / min for 5 h, then 12 g of polyvinylpyrrolidone is added, and stirring is continued for 5 h to obtain a spinning solution with a viscosity of 592 cP, an electrical conductivity of 73.1 μS / cm, and a surface tension of 35.14 mN / m; the spinning solution is transferred to a plastic syringe, matched with an 18G needle (inner diameter of 0.86 mm), fixed on a syringe pump, the receiving distance is adjusted to 16 cm, the push rate is 1.2 mL / h, a 16 kV voltage is applied to the metal needle, and a -0.9 kV voltage is applied to the collection device, and spinning is performed for 30 min to obtain porous polylactic acid fibers with an average diameter of 2 μm and an average length of 30 mm.

[0040] S3: 30 g of graphene powder with a particle size of 15 μm and 120 g of a 60% mass fraction hydrochloric acid solution are added to a reaction kettle, stirred at 25°C and 600 r / min for 40 min, then 3 g of aniline and 42 g of porous polylactic acid fibers are added, and stirring is continued for 40 min, the temperature is lowered to 7°C, then 3 g of ammonium persulfate is added, and stirring is continued for 40 min, the fibers are removed, the fibers are washed with ionized water and anhydrous ethanol until the last washing liquid is neutral, vacuum dried at 80°C for 9 h, then oiled with an oiling agent, stretched, heat set at 125°C, and high-speed wound at 4200 m / min to obtain graphene polylactic acid fiber filaments with a strength of 5.4 cN / dtex, an initial modulus of 114 cN / dtex, and a size of 1050 dtex / 180 f.

[0041] S4: 1050 dtex / 180 f graphene polylactic acid fiber filaments are used as warp threads, 1120 dtex / 192 f bio-based nylon 56 filaments are used as weft threads, and 32 cotton yarns are used as buffers, a three-layer interlocking weave is integrated and woven on a heavy-duty rapier loom, five layers of multi-layer weaving are performed, the warp density is 55 roots / cm, the weft density is 38 roots / cm, then heat setting is performed on a heat setting machine at 140°C for 4 min to obtain a high-modulus low-creep bio-based fabric integrated core.

[0042] Comparative Example 1: On the basis of Example 3, the modified polylactic acid sheet in step S2 is replaced by the raw material polylactic acid in step S1, and the remaining steps are unchanged, to prepare a high modulus low creep bio-based fabric whole belt core.

[0043] Comparative Example 2: On the basis of Example 3, the polyvinylpyrrolidone in step S2 is removed, and the remaining steps are unchanged, to prepare a high modulus low creep bio-based fabric whole belt core.

[0044] Comparative Example 3: On the basis of Example 3, the graphene polylactic acid fiber in step S3 is replaced by the porous polylactic acid fiber prepared in step S2, and the remaining steps are unchanged, to prepare a high modulus low creep bio-based fabric whole belt core.

[0045] In the examples and comparative examples:

[0046] The oiling agent is selected from the oiling agent described in the specification paragraph 53 of a high-strength polyester filament fiber and a preparation method thereof disclosed in Chinese patent publication No. CN105019244A.

[0047] The polycarbodiimide is purchased from Shanghai Aldrich Biochemical Technology Co., Ltd., with the item number A298745-250g and the molecular weight 4000.

[0048] Acetyl tri-n-butyl citrate is purchased from Shanghai Aldrich Biochemical Technology Co., Ltd., with the CAS number 77-90-7 and the molecular weight 402.48.

[0049] The basf chain extender is purchased from Dongguan Weicai Plastic Raw Material Co., Ltd., with the CAS number 852966.

[0050] The polylactic acid is purchased from Shanghai Drum Bio-Technology Co., Ltd., with the CAS number 26100-51-6 and the item number GC22696-1g.

[0051] The polyvinylpyrrolidone is purchased from Sigma-Aldrich, with the CAS number 9003-39-8.

[0052] The bio-based nylon 56 is purchased from Shanghai Likas Industry Co., Ltd., with the CAS number 41724-56-5.

[0053] The high modulus low creep bio-based fabric whole belt core obtained in Example 1-Example 3 and Comparative Example 1-Comparative Example 3 is prepared into a conveyor belt for testing, and the specific preparation method is as follows:

[0054] The high modulus and low creep bio-based fabric whole belt core is driven by a traction machine to pass through an impregnation tank filled with impregnation sizing and a vacuum box impregnation at a speed of 1.2 m / min, and the vacuum degree is -0.085 MPa. The impregnated high modulus and low creep bio-based fabric whole belt core enters a plasticizing tank at 175°C for plasticizing at a plasticizing speed of 1.2 m / min, to obtain a plasticized belt core. The cover layer granular material is dynamically vulcanized by two extruders and a mold, the rotating speed of the extruder is 50 rpm, the temperature of the extruder and the mold is 175°C, the surface temperature of the plasticized belt core is 165°C for direct bonding with the plasticized belt core in a hot state, and the thickness of the cover layer is 8 mm, to obtain a conveyor belt. According to the standard of MT / T914-2019, the tensile strength, elongation at break and surface resistance are tested, and the DMA testing instrument model Q800 of American TA company is used to analyze the hydrolysis resistance. The temperature test range is 40-150°C, the test frequency and amplitude are set to 1 Hz and 25 μm respectively, and the retention of tensile strength and elongation at break after hydrolysis for 1 h is tested.

[0055] The belt core impregnation sizing is selected from the belt core impregnation sizing described in paragraph 82 of the specification of the energy-saving and environment-friendly polyarylate fabric whole core flame-retardant conveyor belt and its manufacturing method disclosed in Chinese patent publication No. CN119795702A.

[0056] The cover layer granular material is selected from the cover layer granular material described in paragraph 81 of the specification of the energy-saving and environment-friendly polyarylate fabric whole core flame-retardant conveyor belt and its manufacturing method disclosed in Chinese patent publication No. CN119795702A.

[0057] The results are shown in Table 1:

[0058] Table 1

[0059]

[0060] As can be seen from Table 1, the high modulus and low creep bio-based fabric whole belt core obtained in Examples 1-3 has a bio-based fabric whole belt core with high initial modulus, low running creep and excellent anti-deviation performance, and also has good hydrolysis resistance and heat resistance, which can impart antistatic property when used in the preparation of a conveyor belt.

[0061] In Comparative Example 1, the modified polylactic acid sheet is replaced by raw polylactic acid, and no polycarbodiimide and BASF chain extender is added. The ester bond of the raw polylactic acid is easy to hydrolyze and break, and the longitudinal tensile strength decreases after hydrolysis, which cannot be used in the humid coal mine for a long time. The raw polylactic acid is brittle, the longitudinal elongation at break decreases before hydrolysis, and brittle fracture easily occurs. Static electricity generated by friction is easy to accumulate and discharge, which ignites underground gas and coal dust, and there is a serious safety hazard.

[0062] The comparative example 2 removes the polyvinylpyrrolidone without a porous structure as a stress dispersion unit, and when the fiber is stressed, the stress is concentrated at the weak site of the molecular chain, the longitudinal tensile elongation before hydrolysis decreases, and the conveyor belt is prone to transverse cracking when grooving. Although the anti-hydrolysis modification is retained, the stress concentration of the dense fiber exacerbates the performance loss after hydrolysis, and the longitudinal strength decreases after hydrolysis; lacking the buffering effect of the porous structure, the belt core is prone to breakage, and it cannot adapt to the operation scene of high-frequency start and stop of coal mines.

[0063] The comparative example 3 replaces the graphene polylactic acid fiber with a porous polylactic acid fiber, without the reinforcing effect of the graphene sheet, the longitudinal full-thickness tensile strength before hydrolysis decreases, and it cannot withstand the traction force of long-distance conveying in coal mines; without the conductive modification of polyaniline, the risk of static electricity accumulation is high, which does not meet the safety specifications underground.

[0064] Although the embodiments of the present application have been shown and described, it can be understood by those of ordinary skill in the art that various changes, modifications, replacements and variations can be made to these embodiments without departing from the principles and spirits of the present application.

Claims

1. A method of making a high modulus low creep bio-based fabric unitized belt core, characterized by, Comprising the following steps: Step one: the porous polylactic acid fiber is formed after the polylactic acid sheet is treated by polyvinylpyrrolidone, then polyaniline and graphene are coated by in-situ polymerization, and then the graphene polylactic acid fiber filament is obtained after oiling, stretching, heat setting and high-speed winding; Step two: 1000-1050dtex / 180f graphene polylactic acid fiber filament is used as the warp, 1110-1120dtex / 192f bio-based nylon 56 filament is used as the weft, and 32 cotton yarns are used as the buffer, and a three-layer interlocking structure is used to weave the bio-based fabric on a heavy-duty rapier loom, and the fabric is formed by 3-5 layers of multi-layer weaving, the warp density is 55 roots / cm, and the weft density is 38 roots / cm, then the fabric is heat set in a heat setting machine at 135-140℃ for 2-4min, and a high modulus and low creep bio-based fabric whole core is obtained.

2. A process for preparing a high modulus low creep bio-based unitary textile braid core according to claim 1, characterized in that, The strength of the graphene polylactic acid fiber filament is 5.2-5.4cN / dtex, and the initial modulus is 110-114cN / dtex.

3. The method for preparing a high-modulus, low-creep bio-based fabric integral core according to claim 1, characterized in that, The specific preparation steps of the graphene polylactic acid fiber filament are as follows: The graphene powder with a particle size of 10-15μm and a hydrochloric acid solution with a mass fraction of 50-60% are added to the reaction kettle, stirred at 20-25℃ and 500-600r / min for 30-40min, then aniline and porous polylactic acid fiber are added, and continue to stir for 30-40min, then cool to 5-7℃, then add ammonium persulfate, continue to stir for 30-40min, take out the fiber, wash the fiber with ion water and anhydrous ethanol until the last washing liquid is neutral, vacuum dry at 60-80℃ for 8-9h, then oil with oiling agent, stretch, heat set at 120-125℃, and high-speed winding at 4000-4200m / min, to obtain a graphene polylactic acid fiber filament with a size of 1000-1050dtex / 180f.

4. The method for preparing a high-modulus, low-creep bio-based fabric integral core according to claim 3, characterized in that, The mass ratio of the graphene powder, the hydrochloric acid solution, the aniline, the porous polylactic acid fiber and the ammonium persulfate is 20-30:100-120:2-3:40-42:2-3.

5. The method of claim 1, wherein the bio-based fabric is a woven fabric. 5 The specific preparation steps of the porous polylactic acid fiber are as follows: The spinning solution is transferred to a plastic syringe, matched with an 18G needle, fixed on a syringe pump, the receiving distance is adjusted to 15-16cm, the pushing rate is 1-1.2mL / h, the metal needle applies a voltage of 14-16kV, the collection device applies a voltage of-0.9kV, and the spinning is performed for 20-30min to obtain a porous polylactic acid fiber with an average diameter of 2μm and an average length of 30mm.

6. A process for preparing a high modulus low creep bio-based fabric unitized belt core according to claim 5, characterized in that, The spinning solution is prepared by the following steps: The modified polylactic acid sheet and N,N-dimethylformamide are added to the reaction kettle, stirred at 60-65℃ and 500-600r / min for 4-5h, then polyvinylpyrrolidone is added, and continue to stir for 4-5h to obtain the spinning solution.

7. The method for preparing a high-modulus, low-creep bio-based fabric integral core according to claim 6, characterized in that, The modified polylactic acid sheet, N,N-dimethylformamide and polyvinylpyrrolidone are used in a ratio of 50-60 g: 500-520 mL: 10-12 g; the viscosity of the spinning solution is 589-592 cP, the conductivity is 72.6-73.1 muS / cm, and the surface tension is 34.56-35.14 mN / m.

8. The method of claim 1, wherein the bio-based fabric unitary belt core has a modulus of elasticity of at least 1000 psi. The modified polylactic acid sheet is prepared according to the following specific steps: The acetyl tri-n-butyl citrate, polycarbodiimide, basf chain extender and polylactic acid are stirred and mixed, melt blended at 180-185 DEG C and 60-70 r / min for 5-7 min, transferred to a flat vulcanizing machine, hot pressed at 180-182 DEG C and 10-12 MPa for 5-8 min, and then cold pressed for 5-8 min to obtain the modified polylactic acid sheet.

9. The method for preparing a high-modulus, low-creep bio-based fabric integral core according to claim 8, characterized in that, The acetyl tri-n-butyl citrate, polycarbodiimide, basf chain extender and polylactic acid are used in a ratio of 5-6 mL: 4-5 g: 1-2 g: 50-60 g.

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