Corrosion-resistant and fracture-resistant plastic woven bag and preparation method thereof

Abstract

The invention belongs to the technical field of plastic woven bags, and particularly relates to a corrosion-resistant and fracture-resistant plastic woven bag which is prepared from the following raw materials: modified polypropylene particles, a silane coupling agent, modified lignin fiber powder, a corrosion-resistant agent, an antioxidant, a corrosion-resistant synergist, a lubricant and a flexibilizer. The preparation method comprises the following steps: S1, stirring the modified polypropylene particles, the silane coupling agent, the modified lignin fiber powder, the corrosion-resistant agent, the antioxidant, the corrosion-resistant synergist, the lubricant and the flexibilizer, then extruding, cutting into blank filaments, and drawing into flat filaments; s2, fixing the flat filament on a plasma processing device, and starting the plasma processing device to obtain a modified flat filament; and S3, the modified flat filaments are woven, and the corrosion-resistant and fracture-resistant plastic woven bag is obtained. The problems that in the prior art, woven bags are poor in interface compatibility, corrosive media are prone to permeating, and the fracture resistance is insufficient can be solved, and the mechanical property and the corrosion resistance of the polypropylene woven bag are remarkably improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of plastic woven bags, and particularly relates to a corrosion-resistant and anti-breaking plastic woven bag and a preparation method thereof. BACKGROUND

[0002] When traditional polypropylene woven bags are used to contain acid and alkali chemical raw materials or are exposed to a humid environment, the bags are often damaged due to insufficient corrosion resistance of the matrix and weak interfacial bonding between the additives and the matrix. Although the existing technology improves the performance by adding antioxidants, weather-resistant agents and the like, the following bottlenecks exist: 1. poor interfacial compatibility: the non-polar characteristics of polypropylene and the polar group-containing additives, such as antioxidants and organic silicon corrosion-resistant agents, produce significant surface polarity difference, resulting in micro-phase separation in the mixing process, weakening the efficacy of the additives and introducing internal defects; 2. easy penetration of corrosive medium: the traditional woven bags lack an effective corrosion barrier layer, and the acid and alkali environment easily corrodes the matrix, accelerating the decay of mechanical properties; 3. insufficient anti-breaking performance: especially in the seam bottom area, the bags are prone to breaking due to stress concentration, and the existing toughener system is difficult to balance multi-stage energy dissipation and interfacial bonding strengthening. SUMMARY

[0003] The application aims to provide a corrosion-resistant and anti-breaking plastic woven bag and a preparation method thereof to solve the technical problems in the background.

[0004] In order to achieve the above-mentioned purpose, the application adopts the following technical solutions: A corrosion-resistant and anti-breaking plastic woven bag is prepared from the following raw materials by weight: 70-80 parts of modified polypropylene particles, 3-5 parts of silane coupling agent, 10-22 parts of modified lignin fiber powder, 1-3 parts of corrosion-resistant agent, 1-2 parts of antioxidant, 0-5 parts of corrosion-resistant synergist, 2-4 parts of lubricant and 6-7.5 parts of toughener.

[0005] Further, the modified polypropylene particles are prepared from initial polypropylene particles through pretreatment, ultraviolet grafting and gradient grafting; the initial polypropylene particles are one of homopolymer polypropylene, block copolymer polypropylene or random copolymer polypropylene.

[0006] Further, the corrosion-resistant agent is organic silicon corrosion-resistant agent perfluorooctyl triethoxysilane; the corrosion-resistant synergist is magnesium stearate; and the antioxidant is phosphorus-containing antioxidant phosphite compound.

[0007] Further, the method for the pre-treatment is as follows: the initial polypropylene particles are put into deionized water, soaked for 20-30 min at a temperature of 20-25℃ to remove surface impurities; then the cleaned initial polypropylene particles are transferred to an ultrasonic cleaning tank, cleaned for 5-10 min at an ultrasonic frequency of 40-60 kHz, and finally the initial polypropylene particles are placed in a vacuum drying oven and dried for 2-3 h at a temperature of 50-70℃.

[0008] Further, the method for the ultraviolet grafting is as follows: the pre-treated initial polypropylene particles are put into a low-power ultraviolet light irradiation device, irradiated for 15-30 min at a power density of 2-3 mW / cm 2 at a temperature of 22-27℃.

[0009] Further, the method for the gradient grafting is as follows: the ultraviolet grafted polypropylene particles are immersed in a polar monomer solution containing 1.5wt% acrylic acid, heated at a certain heating rate from an initial temperature of 40℃ to 60℃, so as to form grafted polypropylene particles; finally, the grafted polypropylene particles are exposed to a humidity environment with a humidity of 50%-70%RH for 10-30 min to obtain modified polypropylene particles.

[0010] Further, the method for preparing the modified lignin fiber powder is as follows: the dried lignin fiber is immersed in an aqueous solution containing sodium persulfate, ethylene glycol and stearic acid for 1-3 h, the mass ratio of the sodium persulfate, ethylene glycol, stearic acid and water is (2-3):(3-6):(40-55):(40-50), and then the polymerization reaction is carried out at 80-100℃ to obtain the modified lignin fiber powder.

[0011] Further, the toughening agent is a maleic anhydride grafted polyolefin elastomer-polyester thermoplastic elastomer system, which is prepared from the following raw materials by weight: maleic anhydride grafted polyolefin elastomer 4-5 parts, polyester thermoplastic elastomer 2-2.8 parts, and erucic amide 0.4-0.5 parts; the preparation method of the toughening agent is as follows: the maleic anhydride grafted polyolefin elastomer, the polyester thermoplastic elastomer and the erucic amide are added to an internal mixer, mixed at 190-200℃ for 5-8 min, discharged and cooled.

[0012] Further, the maleic anhydride grafted polyolefin elastomer is prepared from the following raw materials by weight: polyolefin elastomer 80-120 parts, maleic anhydride 1-2 parts, and dicumyl peroxide 0.1-0.2 parts; the preparation method of the maleic anhydride grafted polyolefin elastomer is as follows: the polyolefin elastomer, the maleic anhydride and the dicumyl peroxide are pre-mixed in a high-speed mixer, then melt grafted in a twin-screw extruder, and water-cooled and granulated.

[0013] A preparation method of a corrosion-resistant and break-resistant plastic woven bag, comprising the following steps: S1: Put modified polypropylene particles, silane coupling agent, modified lignin fiber powder, antioxidant, lubricant and toughening agent into a high-speed stirrer, stir at 100-120 DEG C and 500-1000 rpm for 10-20 min, then send to a flat wire drawing machine, extrude at a plasticizing temperature of 230-250 DEG C, cool to room temperature after extrusion, cut into embryonic wires by a blade, heat and soften the embryonic wires, then draw and stretch 6-6.3 times into flat wires; S2: Fix the flat wires on a sample table of a plasma treatment device, input gas, adjust the gas flow to 50-100 sccm, start the plasma treatment device, set the discharge power to 100-200 W, and treat for 15-30 min to obtain modified flat wires; S3: Connect the modified flat wires to a circular weaving machine, weave according to the warp density of 55-65 roots / 10 cm and the weft density of 65-75 roots / 10 cm, and finally weave to obtain the corrosion-resistant and break-resistant plastic woven bag.

[0014] Further, in S2, the gas is oxygen or a mixed gas of oxygen and argon; in the mixed gas of oxygen and argon, the ratio of oxygen to argon is 7:3.

[0015] In the present application, the principles and roles of each raw material are as follows: Modified polypropylene particles: as the main material of the woven bag, after pretreatment and impurity removal, ultraviolet light activation generates a surface free radical structure, then reacts with a polar monomer to graft -COOH and other polar groups on the polypropylene particles, and at the same time, the surface of the polypropylene particles is uniformly distributed with polar groups to avoid agglomeration and further enhance the chemical activity, so that the surface energy difference of the polypropylene particles is reduced, the interfacial compatibility is improved, and the phase separation with additives is reduced.

[0016] Silane coupling agent: one end of the silane coupling agent is combined with the -OH of the lignin fiber after hydrolysis of the siloxane group, and the other end of the alkyl group is entangled with the PP chain, which plays a bridging role and enhances the adhesion between polypropylene and other additives.

[0017] Modified lignin fiber: as a filler, it can reduce the use amount of petroleum-based resin polypropylene, reduce the cost and improve the rigidity; after modification, the stearic acid reacts with the hydroxyl groups on the surface of the lignin fiber to form an ester bond cross-linked hydrophobic layer, which blocks the penetration of water and acid-base medium, greatly reduces the erosion of the matrix in the acid-base environment, and at the same time, the modified oxygen-containing functional groups form hydrogen bonds with the silane coupling agent and the polar groups of polypropylene, eliminating agglomeration and stress points and enhancing the break resistance of the woven bag.

[0018] Corrosion-resistant agent: it plays a chemical corrosion-resistant function and cooperates with the plasma treatment to strengthen the surface barrier, block the penetration of acid and alkali, and further improve the corrosion resistance of the product.

[0019] Antioxidant: prevent oxidation of raw material components during processing to ensure processing stability.

[0020] Corrosion-resistant synergist: used to avoid acid medium erosion of PP molecular chain, protect the integrity of the matrix, and also can synergistically block the oxidation reaction with antioxidant to improve stability.

[0021] Lubricant: reduce melt viscosity, reduce friction heat and shear stress, and improve processing fluidity during processing.

[0022] Toughening agent: maleic anhydride grafted polyolefin elastomer-polyester thermoplastic elastomer system is used, the anhydride groups of maleic anhydride grafted polyolefin elastomer form hydrogen bonds with the -COOH of modified polypropylene and the -OH of modified lignin fiber, strengthen the interface bonding and improve the interface compatibility agent; the ester groups of polyester thermoplastic elastomer construct a polar network, and the aromatic ring structure absorbs impact energy through molecular chain slipping, serving as the main body of energy dissipation; erucic acid amide reduces the melt viscosity to avoid degradation caused by shear heat during mixing of the compounded system; when the three are used together, impact energy can be absorbed in the seam bottom area, stress is dissipated through the anhydride-ester group network, and the anhydride groups form ionic bonds with modified lignin fiber and polypropylene, improving the overall toughness.

[0023] The principle of the preparation process of the application is: By plasma treatment of the flat wire, oxygen or mixed gas plasma bombards the surface of the flat wire, causing the surface polyolefin chain to break and oxidize, generating a dense oxidation layer with a void diameter much smaller than the size of acid-base ions, blocking the penetration of corrosive media.

[0024] The beneficial effects of the application compared to the prior art are: 1. The application modifies the surface of the polypropylene particles by UV gradient grafting technology to construct a gradient distribution of polar groups, enabling the polypropylene particles to form strong hydrogen bonds with the oxygen-containing functional groups of lignin fiber, and solving the problem of phase separation between non-polar polypropylene and polar additives through the bridging action of silane coupling agent, significantly improving the interfacial compatibility.

[0025] 2. The toughening system of the application uses a maleic anhydride grafted polyolefin elastomer-polyester thermoplastic elastomer system, which constructs a strong electronic attraction force of a multi-level polar network through the anhydride groups of maleic anhydride grafted polyolefin elastomer and the ester groups of polyester thermoplastic elastomer, and the aromatic ring structure of polyester thermoplastic elastomer enhances energy dissipation and synergistically absorbs impact energy, effectively solving the problem of easy breakage at the seam bottom.

[0026] 3.The application adopts plasma surface oxidation treatment to generate a dense oxide layer on the surface of the flat yarn, which blocks the penetration of corrosive medium; at the same time, the modified lignin fiber also forms a hydrophobic network, which greatly reduces the corrosion of the substrate in acid and alkali environment, and the two synergistically enhance the corrosion resistance and mechanical properties of the woven bag.

[0027] 4.The application uses modified lignin fiber as raw material, which significantly reduces the amount of petroleum-based resin; and the activation process uses sodium persulfate / ethylene glycol system aqueous reaction to avoid organic solvent pollution, which meets the green manufacturing requirements. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is a process flow chart of the application; Figure 2 is the FT-IR spectrum of the modified polypropylene particles of Example 1 of the application. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical scheme and advantages of the application clearer and more apparent, the application will be further described in detail below with reference to the drawings and preferred embodiments. However, it should be noted that many details in the description are only to make the reader have a thorough understanding of one or more aspects of the application, and the aspects of the application can be realized even without these specific details.

[0030] As shown in Figure 1 A corrosion-resistant and break-resistant plastic woven bag, which is made of the following raw materials in parts by weight: modified polypropylene particles 70-80 parts, silane coupling agent 3-5 parts, modified lignin fiber powder 10-22 parts, corrosion-resistant agent perfluorooctyltriethoxysilane 1-3 parts, antioxidant phosphite compound 1-2 parts, corrosion-resistant synergist magnesium stearate 0-5 parts, lubricant 2-4 parts, toughening agent 6-7.5 parts; the lubricant is a compound of calcium stearate and Fischer-Tropsch wax in a mass ratio of 5:1.

[0031] The modified polypropylene particles are prepared by pretreatment, ultraviolet grafting and gradient grafting of the initial polypropylene particles; the initial polypropylene particles are one of homopolymer polypropylene, block copolymer polypropylene or random copolymer polypropylene.

[0032] The pre-treatment method is: placing the initial polypropylene particles in deionized water with an electrical conductivity of less than 1 μS / cm, soaking for 20-30 min at a temperature of 20-25℃ to remove surface impurities; then transferring the cleaned initial polypropylene particles to an ultrasonic cleaning tank, cleaning for 5-10 min at an ultrasonic frequency of 40-60 kHz, the oscillation of the ultrasonic waves can effectively remove the small impurities on the surface of the particles, and finally placing the initial polypropylene particles in a vacuum drying oven, drying at a temperature of 50-70℃ for 2-3 h to ensure that there is no residual moisture on the surface of the particles.

[0033] The ultraviolet light grafting method is: placing the pre-treated initial polypropylene particles in a low-power ultraviolet light irradiation device, irradiating for 15-30 min at a power density of 2-3 mW / cm 2 , a temperature of 22-27℃, so that the polypropylene particles form a free radical structure.

[0034] The gradient grafting method is: immersing the ultraviolet light grafted polypropylene particles in a polar monomer solution containing 1.5wt% acrylic acid for grafting reaction, at an initial temperature of 40℃, with a heating rate of 5℃ / 10 min, heating to 60℃, achieving gradient distribution of polar groups on different regions of the surface of the polypropylene particles, thereby forming grafted polypropylene particles; finally exposing the grafted polypropylene particles to a humidity environment with a humidity of 50%-70% RH for 10-30 min, so that uniform distribution of polar groups is formed on the surface of the polypropylene particles, further enhancing the chemical activity, and obtaining modified polypropylene particles.

[0035] After the modification of the polypropylene particles is completed, Fourier transform infrared spectroscopy is used for detection to obtain the distribution of active groups on the surface of the modified polypropylene particles, forming an analysis spectrum; based on the intensity of the characteristic absorption peak in the analysis spectrum, the distribution of the active groups on the modified polypropylene particles is verified, and according to the verification result, it is decided whether to perform secondary modification.

[0036] The preparation method of the modified lignin fiber powder is: placing the dried lignin fiber into an aqueous solution containing sodium persulfate, ethylene glycol and stearic acid for 1-3 h, the mass ratio of sodium persulfate, ethylene glycol, stearic acid and water is (2-3):(3-6):(40-55):(40-50), and then placing it in a glass-lined reaction kettle for polymerization reaction at 80-100℃, 100-200 rpm and normal pressure for 1-2 h to obtain the modified lignin fiber powder.

[0037] The toughening agent is a maleic anhydride grafted polyolefin elastomer-polyester thermoplastic elastomer system, which is prepared from the following raw materials by weight: maleic anhydride grafted polyolefin elastomer 4-5 parts, polyester thermoplastic elastomer 2-2.8 parts, erucic acid amide 0.4-0.5 parts; the preparation method of the toughening agent is: adding maleic anhydride grafted polyolefin elastomer, polyester thermoplastic elastomer and erucic acid amide into an internal mixer, mixing at 190-200℃ for 5-8min, discharging and cooling, and then obtaining.

[0038] The maleic anhydride grafted polyolefin elastomer is prepared from the following raw materials by weight: polyolefin elastomer 80-120 parts, maleic anhydride 1-2 parts, dicumyl peroxide 0.1-0.2 parts; the preparation method of the maleic anhydride grafted polyolefin elastomer is: adding polyolefin elastomer, maleic anhydride and dicumyl peroxide into a high-speed mixer for premixing, and then melt grafting through a twin-screw extruder, water cooling and granulating, and then obtaining.

[0039] A preparation method of a corrosion-resistant and break-resistant plastic woven bag, comprising the following steps: S1: putting modified polypropylene particles, silane coupling agent, modified lignin fiber powder, corrosion-resistant agent, antioxidant, corrosion-resistant synergist, lubricant and toughening agent into a high-speed stirrer, stirring at 100-120℃ and 500-1000rpm for 10-20min, then feeding into a flat wire drawing machine, extruding at a plasticizing temperature of 230-250℃, cooling to room temperature after extrusion, cutting into embryonic wires by a blade, heating and softening the embryonic wires, and then drawing and stretching 6-6.3 times to form flat wires; S2: fixing the flat wires on a sample table of a plasma treatment device, introducing a gas, adjusting the gas flow to 50-100sccm, starting the plasma treatment device, setting the discharge power to 100-200W, and treating for 15-30min to form an oxidation layer on the surface of the formed woven bag flat wires, and obtaining modified flat wires; the gas is oxygen or a mixture of oxygen and argon; the ratio of oxygen to argon in the mixture of oxygen and argon is 7:3.

[0040] S3: connecting the modified flat wires to a circular weaving machine, weaving according to the warp density of 55-65 roots / 10cm and the weft density of 65-75 roots / 10cm, and finally weaving a corrosion-resistant and break-resistant plastic woven bag.

[0041] The following is illustrated by more specific examples.

[0042] Example 1 The application discloses a kind of corrosion-resistant and fracture-resistant plastic woven bags, including the following weight parts of raw materials: modified polypropylene particles 75 parts, silane coupling agent 4 parts, modified lignin fiber powder 15 parts, corrosion-resistant agent perfluorooctyl triethoxysilane 3 parts, antioxidant phosphite compound 1.5 parts, corrosion-resistant synergist magnesium stearate 0 parts, lubricant 3 parts, toughening agent 6 parts;The lubricant is calcium stearate and fischer-tropsch wax are compounded into 5:1 by mass ratio.

[0043] The modified polypropylene particles are prepared by pretreatment, ultraviolet grafting and gradient grafting of initial polypropylene particles.

[0044] The pretreatment method is as follows: the initial polypropylene particles are soaked in deionized water at a temperature of 20°C for 30 min to remove surface impurities; then the cleaned initial polypropylene particles are transferred to an ultrasonic cleaning tank and cleaned at an ultrasonic frequency of 50 kHz for 12 min; finally, the initial polypropylene particles are placed in a vacuum drying oven and dried at a temperature of 65°C for 2.5 h.

[0045] The ultraviolet grafting method is as follows: the pretreated initial polypropylene particles are placed in a low-power ultraviolet irradiation device and irradiated at a power density of 2.5 mW / cm 2 at a temperature of 27°C for 20 min.

[0046] The gradient grafting method is as follows: the ultraviolet grafted polypropylene particles are immersed in a polar monomer solution containing 1.5 wt% acrylic acid, and heated at an initial temperature of 40°C to 60°C at a heating rate of 5°C / 10 min, so as to form grafted polypropylene particles; finally, the grafted polypropylene particles are exposed to a humidity environment with a humidity of 65% RH for 30 min to obtain modified polypropylene particles.

[0047] The preparation method of the modified lignin fiber powder is as follows: dry lignin fibers are immersed in an aqueous solution containing sodium persulfate, ethylene glycol and stearic acid for 2 h, the mass ratio of sodium persulfate, ethylene glycol, stearic acid and water is 4:6:40:50, and then the lignin fibers are placed in a glass-lined reaction kettle and subjected to a polymerization reaction at 90°C, 100 rpm and normal pressure for 1.5 h to obtain modified lignin fiber powder.

[0048] The toughening agent is a maleic anhydride grafted polyolefin elastomer-polyester thermoplastic elastomer system, which is prepared from the following raw materials by weight: maleic anhydride grafted polyolefin elastomer 4 parts, polyester thermoplastic elastomer 2 parts, and erucic acid amide 0.4 parts; the preparation method of the toughening agent is as follows: the maleic anhydride grafted polyolefin elastomer, the polyester thermoplastic elastomer and the erucic acid amide are added to a banbury mixer and mixed at 192°C for 6 min, and then discharged and cooled to obtain the toughening agent.

[0049] The maleic anhydride grafted polyolefin elastomer is prepared from the following raw materials by weight: 100 parts of polyolefin elastomer, 1.8 parts of maleic anhydride, and 0.15 parts of dicumyl peroxide; the preparation method of the maleic anhydride grafted polyolefin elastomer comprises the following steps: pre-mixing the polyolefin elastomer, maleic anhydride, and dicumyl peroxide in a high-speed mixer, then melt grafting through a double-screw extruder, and water-cooling and granulating.

[0050] A preparation method of a corrosion-resistant and break-resistant plastic woven bag, comprising the following steps: S1: Put modified polypropylene particles, silane coupling agent, modified lignin fiber powder, corrosion-resistant agent, antioxidant, lubricant, and toughening agent into a high-speed stirrer, stir at 100℃ and 950rpm for 15min, then send to a flat wire drawing machine, extrude at a plasticizing temperature of 240℃, cool to room temperature after extrusion, cut into embryonic wires by a blade, heat and soften the embryonic wires, then draw and stretch the embryonic wires by 6.0 times at a speed of 205m / min to form flat wires; S2: Fix the flat wires on a sample table of a plasma treatment device, input oxygen, adjust the gas flow to 100sccm, start the plasma treatment device, set the discharge power to 180W, and treat for 20min to obtain modified flat wires; S3: Connect the modified flat wires to a circular weaving machine, weave according to the warp density of 60 roots / 10cm and the weft density of 70 roots / 10cm, and finally weave to obtain the corrosion-resistant and break-resistant plastic woven bag.

[0051] Example 2 A corrosion-resistant and break-resistant plastic woven bag is prepared from the following raw materials by weight: 75 parts of modified polypropylene particles, 4 parts of silane coupling agent, 15 parts of modified lignin fiber powder, 3 parts of corrosion-resistant agent, 1.5 parts of antioxidant, 0 parts of corrosion-resistant synergist, 3 parts of lubricant, and 6.8 parts of toughening agent; the lubricant is a compound of calcium stearate and Fischer-Tropsch wax with a mass ratio of 5:1.

[0052] The modified polypropylene particles are prepared from initial polypropylene particles through pretreatment, ultraviolet grafting, and gradient grafting; the initial polypropylene particles are block copolymerized polypropylene.

[0053] The pretreatment method comprises the following steps: soaking the initial polypropylene particles in deionized water at a temperature of 25℃ for 20min to remove surface impurities; then transferring the cleaned initial polypropylene particles to an ultrasonic cleaning tank, cleaning for 10min at an ultrasonic frequency of 60kHz; and finally placing the initial polypropylene particles in a vacuum drying oven and drying at a temperature of 70℃ for 2.2h.

[0054] The method of the ultraviolet grafting is: placing the pretreated initial polypropylene particles in a low-power ultraviolet light irradiation device, and irradiating for 15 min at a power density of 2.5 mW / cm 2 at a temperature of 22℃.

[0055] The method of the gradient grafting is: immersing the polypropylene particles after the ultraviolet grafting in a polar monomer solution containing 1.5 wt% acrylic acid, and heating from an initial temperature of 40℃ to 60℃ at a heating rate of 5℃ / 10 min, so as to form grafted polypropylene particles; finally, exposing the grafted polypropylene particles to a humidity environment with a humidity of 50% RH for 20 min, to obtain modified polypropylene particles.

[0056] The preparation method of the modified lignin fiber powder is: placing dry lignin fibers into an aqueous solution containing sodium persulfate, ethylene glycol and stearic acid, and immersing for 1.5 h, the mass ratio of the sodium persulfate, ethylene glycol, stearic acid and water being 3:5:50:50; taking out and placing in a glass-lined reaction kettle, and performing a polymerization reaction at 85℃, 200 rpm and normal pressure for 2 h, to obtain modified lignin fiber powder.

[0057] The toughening agent is a maleic anhydride grafted polyolefin elastomer-polyester thermoplastic elastomer system, which is prepared from the following raw materials in parts by weight: 5 parts of maleic anhydride grafted polyolefin elastomer, 2.5 parts of polyester thermoplastic elastomer, and 0.5 parts of erucic amide; and the preparation method of the toughening agent is: adding the maleic anhydride grafted polyolefin elastomer, the polyester thermoplastic elastomer and the erucic amide into a banbury mixer, and mixing at 190℃ for 8 min, and discharging and cooling, to obtain the toughening agent.

[0058] The maleic anhydride grafted polyolefin elastomer is prepared from the following raw materials in parts by weight: 100 parts of polyolefin elastomer, 1.8 parts of maleic anhydride, and 0.15 parts of dicumyl peroxide; and the preparation method of the maleic anhydride grafted polyolefin elastomer is: pre-mixing the polyolefin elastomer, the maleic anhydride and the dicumyl peroxide in a high-speed mixer, and then melt grafting through a twin-screw extruder, and water-cooling and granulating, to obtain the maleic anhydride grafted polyolefin elastomer.

[0059] A preparation method of a corrosion-resistant and anti-breaking plastic woven bag, comprising the following steps: S1: placing modified polypropylene particles, a silane coupling agent, modified lignin fiber powder, a corrosion-resistant agent, an antioxidant, a lubricant and a toughening agent into a high-speed stirrer, and stirring at 105℃ and 800 rpm for 20 min, and then feeding into a flat wire drawing machine, and extruding at a plasticizing temperature of 250℃, and cooling to room temperature after extrusion, and cutting into embryonic wires through a blade, and heating and softening the embryonic wires, and then drawing and stretching at a speed of 220 m / min by 6.3 times into flat wires; S2: The flat filaments are fixed on the sample table of the plasma treatment device, oxygen is introduced, the gas flow is adjusted to 50 sccm, after the plasma treatment device is started, the discharge power is set to 200 W, and the treatment is performed for 25 min to obtain modified flat filaments; S3: The modified flat filaments are connected to a circular weaving machine, and are woven according to the warp density of 65 roots / 10 cm and the weft density of 70 roots / 10 cm, and finally an anti-corrosion and anti-breaking plastic woven bag is obtained.

[0060] Example 3 An anti-corrosion and anti-breaking plastic woven bag is made of the following raw materials by weight: 75 parts of modified polypropylene particles, 4 parts of silane coupling agent, 15 parts of modified lignin fiber powder, 3 parts of corrosion-resistant agent perfluoro-octyl triethoxy silane, 1.5 parts of antioxidant phosphite compound, 5 parts of corrosion-resistant synergist magnesium stearate, 3 parts of lubricant, and 6 parts of toughening agent. The lubricant is a compound of calcium stearate and Fischer-Tropsch wax with a mass ratio of 5:1.

[0061] The modified polypropylene particles are prepared by pretreatment, ultraviolet grafting and gradient grafting of initial polypropylene particles. The initial polypropylene particles are random copolymerized polypropylene.

[0062] The pretreatment method is as follows: the initial polypropylene particles are soaked in deionized water at a temperature of 22℃ for 25 min to remove surface impurities; then the cleaned initial polypropylene particles are transferred to an ultrasonic cleaning tank and cleaned for 5 min at an ultrasonic frequency of 55 kHz; finally, the initial polypropylene particles are placed in a vacuum drying oven and dried at a temperature of 60℃ for 3 h.

[0063] The ultraviolet grafting method is as follows: the pretreated initial polypropylene particles are placed in a low-power ultraviolet light irradiation device and irradiated at a power density of 2.5 mW / cm 2 at a temperature of 25℃ for 15 min.

[0064] The gradient grafting method is as follows: the ultraviolet grafted polypropylene particles are immersed in a polar monomer solution containing 1.5wt% acrylic acid, heated to 60℃ at an initial temperature of 40℃ and a heating rate of 5℃ / 10 min, to form grafted polypropylene particles; finally, the grafted polypropylene particles are exposed to a humidity environment with a humidity of 55%RH for 30 min to obtain modified polypropylene particles.

[0065] The preparation method of the modified lignin fiber powder is as follows: dry lignin fibers are soaked in an aqueous solution containing sodium persulfate, ethylene glycol, and stearic acid for 3 hours, the mass ratio of the sodium persulfate, ethylene glycol, stearic acid, and water being 2.5:4.5:55:45; the soaked lignin fibers are taken out and put into a glass-lined reaction kettle for polymerization at 90 DEG C, 180 rpm, and normal pressure for 1.5 hours to obtain the modified lignin fiber powder.

[0066] The toughening agent is a maleic anhydride grafted polyolefin elastomer-polyester thermoplastic elastomer system, which is prepared from the following raw materials in parts by weight: 4 parts of maleic anhydride grafted polyolefin elastomer, 2 parts of polyester thermoplastic elastomer, and 0.4 parts of erucic amide; the preparation method of the toughening agent is as follows: the maleic anhydride grafted polyolefin elastomer, the polyester thermoplastic elastomer, and the erucic amide are added into an internal mixer, and mixed at 192 DEG C for 6 minutes, and then discharged and cooled.

[0067] The maleic anhydride grafted polyolefin elastomer is prepared from the following raw materials in parts by weight: 100 parts of polyolefin elastomer, 1.8 parts of maleic anhydride, and 0.15 parts of dicumyl peroxide; the preparation method of the maleic anhydride grafted polyolefin elastomer is as follows: the polyolefin elastomer, the maleic anhydride, and the dicumyl peroxide are pre-mixed in a high-speed mixer, and then melt grafted in a twin-screw extruder, and then water-cooled and granulated.

[0068] A preparation method of a corrosion-resistant and break-resistant plastic woven bag, comprising the following steps: S1: modified polypropylene particles, silane coupling agent, modified lignin fiber powder, corrosion-resistant agent, antioxidant, corrosion-resistant synergist, lubricant, and toughening agent are put into a high-speed stirrer, stirred at 100 DEG C and 1000 rpm for 10 minutes, then sent to a flat wire drawing machine, extruded at a plasticizing temperature of 230 DEG C, cooled to room temperature after extrusion, cut into embryonic wires by a blade, heated and softened, and then drawn at a speed of 205 m / min to 6.0 times to form flat wires; S2: the flat wires are fixed on a sample table of a plasma treatment device, oxygen-argon mixed gas is introduced, the ratio of oxygen to argon being 7:3, the gas flow is adjusted to 80 sccm, the plasma treatment device is started, the discharge power is set to 200 W, and the treatment is performed for 30 minutes to obtain modified flat wires; S3: the modified flat wires are connected to a circular weaving machine, and woven according to the warp density of 60 wires / 10 cm and the weft density of 65 wires / 10 cm, and finally a corrosion-resistant and break-resistant plastic woven bag is obtained.

[0069] Example 4 The application discloses a kind of corrosion-resistant and fracture-resistant plastic woven bags, including the following weight parts of raw materials: modified polypropylene particles 70 parts, silane coupling agent 5 parts, modified lignin fiber powder 10 parts, corrosion-resistant agent perfluorooctyl triethoxysilane 2 parts, antioxidant phosphite compound 2 parts, corrosion-resistant synergist magnesium stearate 3 parts, lubricant 4 parts, toughening agent 6.5 parts;The lubricant is calcium stearate and fischer-tropsch wax are compounded into 5:1 by mass ratio.

[0070] The modified polypropylene particles are prepared by pretreatment, ultraviolet grafting and gradient grafting of initial polypropylene particles.

[0071] The pretreatment method is as follows: the initial polypropylene particles are soaked in deionized water at a temperature of 20 DEG C for 22 min to remove surface impurities; then the cleaned initial polypropylene particles are transferred to an ultrasonic cleaning tank and cleaned at an ultrasonic frequency of 45 kHz for 8 min; finally, the initial polypropylene particles are placed in a vacuum drying oven and dried at a temperature of 55 DEG C for 2 h.

[0072] The ultraviolet grafting method is as follows: the pretreated initial polypropylene particles are placed in a low-power ultraviolet irradiation device and irradiated at a power density of 2 mW / cm 2 at a temperature of 24 DEG C for 30 min.

[0073] The gradient grafting method is as follows: the ultraviolet grafted polypropylene particles are immersed in a polar monomer solution containing 1.5 wt% acrylic acid, and heated at an initial temperature of 40 DEG C to 60 DEG C at a heating rate of 5 DEG C / 10 min, so as to form grafted polypropylene particles; finally, the grafted polypropylene particles are exposed to a humidity environment with a humidity of 70% RH for 10 min to obtain modified polypropylene particles.

[0074] The preparation method of the modified lignin fiber powder is as follows: dry lignin fibers are immersed in an aqueous solution containing sodium persulfate, ethylene glycol and stearic acid for 2.5 h, the mass ratio of sodium persulfate, ethylene glycol, stearic acid and water is 2:4:45:40; after taking out, the lignin fibers are placed in a glass-lined reaction kettle and subjected to polymerization reaction at 100 DEG C, 150 rpm and normal pressure for 1 h to obtain modified lignin fiber powder.

[0075] The toughening agent is a maleic anhydride grafted polyolefin elastomer-polyester thermoplastic elastomer system, which is prepared from the following raw materials by weight: maleic anhydride grafted polyolefin elastomer 5 parts, polyester thermoplastic elastomer 2.2 parts, and erucic acid amide 0.4 part; the preparation method of the toughening agent is as follows: the maleic anhydride grafted polyolefin elastomer, polyester thermoplastic elastomer and erucic acid amide are added to a banbury mixer and mixed at 195 DEG C for 5 min, and then discharged and cooled.

[0076] The maleic anhydride grafted polyolefin elastomer is prepared from the following raw materials by weight: 90 parts of polyolefin elastomer, 1 part of maleic anhydride, and 0.1 part of dicumyl peroxide; the preparation method of the maleic anhydride grafted polyolefin elastomer comprises the following steps: pre-mixing the polyolefin elastomer, maleic anhydride, and dicumyl peroxide in a high-speed mixer, then melt grafting through a twin-screw extruder, and water-cooling and granulating.

[0077] A preparation method of a corrosion-resistant and break-resistant plastic woven bag, comprising the following steps: S1: Put modified polypropylene particles, silane coupling agent, modified lignin fiber powder, corrosion-resistant agent, antioxidant, corrosion-resistant synergist, lubricant, and toughening agent into a high-speed stirrer, stir at 120℃ and 600rpm for 18min, then send to a flat wire drawing machine, extrude at a plasticizing temperature of 230℃, cool to room temperature after extrusion, cut into embryonic wires by a blade, heat and soften the embryonic wires, then draw and stretch the embryonic wires at a speed of 210m / min by 6.1 times to form flat wires; S2: Fix the flat wires on a sample table of a plasma treatment device, input oxygen, adjust the gas flow to 60sccm, start the plasma treatment device, set the discharge power to 120W, and treat for 20min to obtain modified flat wires; S3: Connect the modified flat wires to a circular weaving machine, weave according to the warp density of 55 roots / 10cm and the weft density of 75 roots / 10cm, and finally weave to obtain the corrosion-resistant and break-resistant plastic woven bag.

[0078] Example 5 A corrosion-resistant and break-resistant plastic woven bag is prepared from the following raw materials by weight: 85 parts of modified polypropylene particles, 3 parts of silane coupling agent, 20 parts of modified lignin fiber powder, 1 part of corrosion-resistant agent, 1 part of antioxidant, 1 part of corrosion-resistant synergist, 2 parts of lubricant, and 7 parts of toughening agent; the lubricant is a compound of calcium stearate and Fischer-Tropsch wax with a mass ratio of 5:1.

[0079] The modified polypropylene particles are prepared from initial polypropylene particles through pretreatment, ultraviolet grafting, and gradient grafting; the initial polypropylene particles are block copolymerized polypropylene.

[0080] The pretreatment method comprises the following steps: soaking the initial polypropylene particles in deionized water at a temperature of 25℃ for 28min to remove surface impurities; then transferring the cleaned initial polypropylene particles to an ultrasonic cleaning tank, cleaning for 10min under an ultrasonic frequency of 40kHz, and finally placing the initial polypropylene particles in a vacuum drying oven and drying at a temperature of 50℃ for 3h.

[0081] The method of the ultraviolet grafting is: placing the pretreated initial polypropylene particles in a low-power ultraviolet light irradiation device, and irradiating for 25 min at a power density of 3 mW / cm 2 at a temperature of 25℃.

[0082] The method of the gradient grafting is: immersing the polypropylene particles after ultraviolet grafting in a polar monomer solution containing 1.5wt% acrylic acid, and heating from an initial temperature of 40℃ to 60℃ at a rate of 5℃ / 10min, so as to form grafted polypropylene particles; finally, exposing the grafted polypropylene particles to a humidity environment with a humidity of 60%RH for 20 min, to obtain modified polypropylene particles.

[0083] The preparation method of the modified lignin fiber powder is: placing dry lignin fibers into an aqueous solution containing sodium persulfate, ethylene glycol and stearic acid, and immersing for 1h, the mass ratio of the sodium persulfate, ethylene glycol, stearic acid and water being 5:3:40:45; taking out and placing in a glass-lined reaction kettle, and performing a polymerization reaction at 80℃, 120rpm and normal pressure for 2h, to obtain modified lignin fiber powder.

[0084] The toughening agent is a maleic anhydride grafted polyolefin elastomer-polyester thermoplastic elastomer system, which is prepared from the following raw materials by weight: 4 parts of maleic anhydride grafted polyolefin elastomer, 2.5 parts of polyester thermoplastic elastomer, and 0.4 parts of erucic amide; the preparation method of the toughening agent is: adding the maleic anhydride grafted polyolefin elastomer, the polyester thermoplastic elastomer and the erucic amide into an internal mixer, and mixing at 200℃ for 7min, and discharging and cooling, to obtain the toughening agent.

[0085] The maleic anhydride grafted polyolefin elastomer is prepared from the following raw materials by weight: 80 parts of polyolefin elastomer, 2 parts of maleic anhydride, and 0.2 parts of dicumyl peroxide; the preparation method of the maleic anhydride grafted polyolefin elastomer is: pre-mixing the polyolefin elastomer, the maleic anhydride and the dicumyl peroxide in a high-speed mixer, and then melt grafting through a twin-screw extruder, and water-cooling and granulating, to obtain the maleic anhydride grafted polyolefin elastomer.

[0086] A preparation method of a corrosion-resistant and anti-breaking plastic woven bag, comprising the following steps: S1: placing modified polypropylene particles, a silane coupling agent, modified lignin fiber powder, a corrosion-resistant agent, an antioxidant, a corrosion-resistant synergist, a lubricant and a toughening agent into a high-speed stirrer, and stirring at 100℃ and 500rpm for 12min, and then feeding into a flat wire drawing machine, and extruding at a plasticizing temperature of 240℃, and cooling to room temperature after extrusion, and cutting into embryonic wires through a blade, and heating and softening the embryonic wires, and then drawing and stretching at a speed of 215m / min by 6.2 times into flat wires; S2: The flat filaments are fixed on the sample table of the plasma treatment device, oxygen is introduced, the gas flow is adjusted to 50 sccm, after the plasma treatment device is started, the discharge power is set to 150 W, and the treatment is performed for 15 min to obtain modified flat filaments; S3: The modified flat filaments are connected to a circular weaving machine, and are woven according to the warp density of 60 roots / 10 cm and the weft density of 65 roots / 10 cm, and finally an anti-corrosion and anti-breaking plastic woven bag is obtained.

[0087] Comparative Example 1 The preparation method is basically the same as that of Example 1, except that the raw material polypropylene is not modified; the modified lignin fiber is replaced by ordinary wood powder; only the polyester thermoplastic elastomer system is used in the toughening agent, and the plasma treatment is not used during preparation.

[0088] The modified polypropylene particles obtained in Example 1 are subjected to FT-IR (Fourier transform infrared spectroscopy) test together with unmodified polypropylene, and the results are shown in Figure 2 .

[0089] As can be seen from Figure 2 , the FT-IR spectrum shows that the modified polypropylene has a carboxyl (-COOH) characteristic peak at 1650 cm -1 , which proves that the acrylic acid grafting is successful.

[0090] The woven bags prepared in Examples 1-5 are tested for mechanical properties and corrosion resistance according to the method in GB / T8946, and the results are shown in Table 1.

[0091] Table 1: Performance of woven bags As can be seen from Table 1, the seam breaking force of Examples 1-5 is 375 N / 50 mm, 390 N / 50 mm, 402 N / 50 mm, 368 N / 50 mm, and 386 N / 50 mm, respectively, and the acid resistance retention rate is 92%, 90%, 96%, 95%, and 93%, respectively, while the seam breaking force of Comparative Example 1 is only 313 N / 50 mm, and the acid resistance retention rate is only 61%, which shows that the woven bag prepared by modifying the polypropylene, adding modified lignin, and using the toughening agent and plasma treatment of the application has the advantages of good mechanical properties, high toughness, high acid resistance, and strong corrosion resistance.

[0092] As can be seen from Examples 1-5, the seaming pull force of Example 2 is greater than that of Example 1, indicating that the application can effectively improve the mechanical properties of the woven bag when the high filler ratio, i.e. the high amount of modified lignin fiber, and the high amount of toughening agent are used. The acid resistance strength retention rates of Examples 3-5 are all greater than that of Example 1, indicating that by adding the corrosion-resistant synergist, the corrosion resistance of the woven bag can be significantly improved, and at the same time, by increasing the amount of polyester thermoplastic elastomer in the toughening agent, the mechanical properties of the woven bag can be further improved, thereby obtaining a woven bag product with excellent mechanical properties and corrosion resistance. In addition, the gas used for plasma treatment in Example 3 is a mixed gas, and compared with Example 1 which only uses oxygen, the mechanical properties are also improved.

[0093] The above only describes the preferred embodiments of the present application, and it should be noted that for those skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, and these improvements and refinements should also be considered within the scope of protection of the present application.

Claims

1. A corrosion-resistant and fracture-resistant plastic woven bag, characterized in that: The invention is prepared from the following raw materials in parts by weight: 70-80 parts of modified polypropylene particles, 3-5 parts of silane coupling agent, 10-22 parts of modified lignin fiber powder, 1-3 parts of corrosion resistance agent, 1-2 parts of antioxidant, 0-5 parts of corrosion resistance synergist, 2-4 parts of lubricant and 6-7.5 parts of toughening agent.

2. The corrosion-resistant and fracture-resistant plastic woven bag according to claim 1, characterized in that: The modified polypropylene particles are prepared from initial polypropylene particles through pretreatment, ultraviolet grafting, and gradient grafting; the initial polypropylene particles are one of homopolymer polypropylene, block copolymer polypropylene, and random copolymer polypropylene.

3. The corrosion-resistant and fracture-resistant plastic woven bag according to claim 2, characterized in that: The pretreatment method comprises: placing initial polypropylene particles in deionized water, soaking them at a temperature of 20-25° C. for 20-30 minutes to remove surface impurities; then transferring the cleaned initial polypropylene particles to an ultrasonic cleaning tank, cleaning them at an ultrasonic frequency of 40-60 kHz for 5-10 minutes, and finally placing the initial polypropylene particles in a vacuum drying oven, and drying them at a temperature of 50-70° C. for 2-3 hours.

4. The corrosion-resistant and fracture-resistant plastic woven bag according to claim 3, characterized in that: The UV grafting method is as follows: placing the pretreated initial polypropylene particles in a low-power UV irradiation device at a power density of 2-3 mW / cm 2 , irradiate at a temperature of 22-27°C for 15-30 minutes.

5. The corrosion-resistant and fracture-resistant plastic woven bag according to claim 4, characterized in that: The gradient grafting method comprises the following steps: immersing polypropylene particles grafted by ultraviolet light into a polar monomer solution containing 1.5 wt% acrylic acid, heating the solution from an initial temperature of 40°C to 60°C at a certain heating rate, thereby forming grafted polypropylene particles; and finally exposing the grafted polypropylene particles to a humid environment with a humidity of 50%-70% RH for 10-30 minutes to obtain modified polypropylene particles.

6. The corrosion-resistant and fracture-resistant plastic woven bag according to claim 1, characterized in that: The modified lignin fiber powder is prepared by immersing dried lignin fiber in an aqueous solution containing sodium persulfate, ethylene glycol, and stearic acid for 1-3 hours, wherein the mass ratio of the sodium persulfate, ethylene glycol, stearic acid, and water is (2-3):(3-6):(40-55):(40-50). After the fiber is taken out, a polymerization reaction is carried out at 80-100°C to obtain the modified lignin fiber powder.

7. The corrosion-resistant and fracture-resistant plastic woven bag according to claim 1, characterized in that: The toughening agent is a maleic anhydride grafted polyolefin elastomer-polyester thermoplastic elastomer system, which is made of the following raw materials in parts by weight: 4-5 parts of maleic anhydride grafted polyolefin elastomer, 2-2.8 parts of polyester thermoplastic elastomer, and 0.4-0.5 parts of erucamide. The preparation method of the toughening agent is: adding the maleic anhydride grafted polyolefin elastomer, polyester thermoplastic elastomer, and erucamide into an internal mixer, mixing at 190-200°C for 5-8 minutes, and cooling the discharged material to obtain the toughening agent.

8. The corrosion-resistant and fracture-resistant plastic woven bag according to claim 7, characterized in that: The maleic anhydride grafted polyolefin elastomer is made from the following raw materials in parts by weight: 80-120 parts of polyolefin elastomer, 1-2 parts of maleic anhydride, and 0.1-0.2 parts of dicumyl peroxide. The preparation method of the maleic anhydride grafted polyolefin elastomer is as follows: the polyolefin elastomer, maleic anhydride, and dicumyl peroxide are added to a high-speed mixer for premixing, followed by melt grafting through a twin-screw extruder, and water-cooling and granulation to obtain the elastomer.

9. The method for preparing a corrosion-resistant and fracture-resistant plastic woven bag according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1: Place modified polypropylene particles, silane coupling agent, modified lignin fiber powder, corrosion inhibitor, antioxidant, corrosion synergist, lubricant, and toughening agent into a high-speed mixer, stir at 100-120°C and 500-1000 rpm for 10-20 minutes, then feed into a flat yarn drawing machine, extrude at a plasticizing temperature of 230-250°C, cool to room temperature after extrusion, cut into embryonic yarns with a blade, heat and soften the embryonic yarns, and then stretch them by 6-6.3 times to form flat yarns; S2: Fix the flat yarn on the sample stage of the plasma treatment device, introduce gas, adjust the gas flow rate to 50-100 sccm, start the plasma treatment device, set the discharge power to 100-200 W, and treat for 15-30 minutes to obtain the modified flat yarn; S3: The modified flat yarn is connected to a circular loom and woven according to the warp density of 55-65 yarns / 10cm and the weft density of 65-75 yarns / 10cm, and finally a corrosion-resistant and fracture-resistant plastic woven bag is obtained.

10. The method for preparing a corrosion-resistant and fracture-resistant plastic woven bag according to claim 9, characterized in that: In S2, the gas is oxygen or a mixed gas of oxygen and argon; in the mixed gas of oxygen and argon, the ratio of oxygen to argon is 7:3.

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