UHMWPE (Ultra High Molecular Weight Polyethylene) stab-resistant insole for safety protection shoes and preparation method thereof

Abstract

The invention relates to the technical field of shoe material preparation, in particular to a UHMWPE puncture-proof insole for safety protection shoes and a preparation method of the UHMWPE puncture-proof insole. The preparation method comprises the following steps: processing UHMWPE (Ultra High Molecular Weight Polyethylene) into chopped fibers, opening and mixing by an opener, carding the fibers, feeding the fibers to a lapping machine, uniformly lapping to obtain a fiber web, needling the fiber web on a pre-needling machine to obtain sheets, stacking the sheets, performing main needling, and performing secondary needling to obtain the UHMWPE composite fiber. And finally, the non-woven fabric is cut into the shape of the shoe insole through laser cutting. The prepared UHMWPE puncture-proof insole is light, comfortable and good in air permeability, meanwhile, good overall strength and puncture resistance are guaranteed, and layering is not prone to occurring.

Description

Technical Field

[0001] The invention relates to the technical field of shoe material preparation, and in particular to a UHMWPE stab-proof midsole for safety shoes and a preparation method thereof. Background Art

[0002] The stab-proof midsole is a key component of safety shoes. It is mainly used to prevent sharp objects such as nails and glass fragments from piercing the soles of shoes, protecting the human foot from injury. The stab-proof midsole is widely used in work shoes in high-risk industries such as construction, manufacturing, and logistics. Due to its light weight and high efficiency in stab-proof performance, workers in these industries can get effective foot protection in complex working environments. In addition, it can also be used in outdoor safety shoes. In mountaineering and outdoor adventures, the stab-proof midsole can prevent outdoor sharp objects (such as rocks and branches) from piercing, providing effective safety protection.

[0003] The traditional stab-proof midsole material is steel plate, which has good stab-proof performance and durability. The thickness of the steel plate is usually between 1.5-2.0mm, and the stab-proof effect is significant, but the weight is large, which affects comfort and flexibility. In recent years, single-layer graphene oxide, aramid, ultra-high molecular weight polyethylene (UHMWPE) and other polymer fibers have been widely used in the preparation of stab-proof midsoles for safety shoes due to their light weight, high strength and high modulus. It has the advantages of being lighter and softer than steel plates, and greatly improves the comfort of stab-proof midsoles. However, in the preparation process, in order to improve the stab-proof performance, most of them use thermosetting resin impregnated woven fabrics or thermoplastic resins through hot pressing processes. Due to the addition of glue, there are still problems such as poor air permeability and easy delamination. Therefore, with the improvement of people's safety awareness and the demand for comfort, there is an urgent need for a stab-proof midsole that can provide excellent stab-proof performance and has the characteristics of being light, thin, flexible and comfortable. Summary of the invention

[0004] In order to overcome the shortcomings and deficiencies in the prior art, the object of the present invention is to provide a method for preparing a UHMWPE stab-proof midsole for safety shoes.

[0005] The purpose of the present invention is achieved by the following technical solution: A method for preparing a UHMWPE stab-proof midsole for safety shoes, comprising the following steps:

[0006] (S1) Raw material preparation: selecting ultra-high molecular weight polyethylene filaments with super-drawn lengths and cutting them into short fibers;

[0007] (S2) fiber opening and mixing: spraying an antistatic agent on the surface of the chopped fibers obtained in step S1, then placing the chopped fibers in an opening machine for opening, and mixing the opened fibers uniformly;

[0008] (S3) Fiber combing and laying: combing the fibers opened in step S2 into a single fiber state, combing the curled fibers into a straight state with the ends overlapping, and then conveying the combed fibers to a web laying machine through a conveyor belt, and the web laying machine evenly lays the fibers into a web to obtain a fiber web;

[0009] (S4) pre-needling: the fluffy web is needle-punched on a pre-needling machine to obtain a sheet;

[0010] (S5) Main needling: stacking 2-3 sheets prepared by pre-needling in the same direction for main needling to obtain a UHMWPE nonwoven fabric;

[0011] (S6) Cutting the stab-resistant midsole: using design software to pre-draw the shape of the midsole of a certain shoe size, importing the design file into a laser cutting machine, fixing the UHMWPE non-woven fabric prepared in step S5 on a cutting platform, adjusting the laser cutting machine parameters for cutting, and finally trimming the cut edge of the UHMWPE non-woven fabric to obtain the UHMWPE stab-resistant midsole.

[0012] Furthermore, in step S1, the fineness of the ultra-high molecular weight polyethylene filaments is 300-400 dtex, and the length of the chopped fibers is 38-56 mm.

[0013] Furthermore, in the present invention, the method for preparing the ultra-high molecular weight polyethylene filament comprises the following steps:

[0014] (A) placing ultra-high molecular weight polyethylene powder, an antioxidant and liquid paraffin in a reactor, heating and stirring them uniformly to prepare a solution A with a mass concentration of 8-10%;

[0015] (B) taking carbon material powder and placing it in anhydrous ethanol for ultrasonic dispersion, then adding octadecylamine thereto, heating and stirring at 60-80° C. for 5-6 hours, then washing and filtering with anhydrous ethanol for multiple times, and uniformly dispersing the obtained modified graphite oxide in dichloromethane to prepare solution B, and adding solution B to solution A and heating and stirring to obtain a mixed spinning solution;

[0016] (C) adding the spinning mixture obtained in step (B) to a twin-screw extruder through a peristaltic pump to extrude ultra-high molecular weight polyethylene precursor, cooling and shaping in a water bath, and then winding it with a winder;

[0017] (D) extracting the obtained ultra-high molecular weight polyethylene precursor with dichloromethane after phase separation equilibrium for 20-24 hours, and drying the extracted fiber at room temperature;

[0018] (E) The dried fiber is heat-stretched at 120-130° C. with a heat-stretching ratio of 5-10 times to obtain ultra-high molecular weight polyethylene filaments.

[0019] Furthermore, in step (A), the molecular weight of the ultra-high molecular weight polyethylene powder is 3 million to 4 million. The antioxidant is at least one of antioxidant B215, antioxidant 168, and antioxidant 1076, and the amount of the antioxidant is 0.5-1% of the mass of the ultra-high molecular weight polyethylene powder.

[0020] Furthermore, in step (B), the carbon material is one or more of graphite oxide, single-walled carbon nanotubes, and single-layer graphene oxide. The mass ratio of the carbon material to octadecylamine is 1:2. The volume ratio of solution A to solution B is 1:5, the heating temperature is 42-45°C, and the time is 6-12h.

[0021] In the present invention, the ultra-high molecular weight polyethylene fiber prepared by the above preparation method has excellent mechanical properties, wear resistance and aging resistance. Among them, by adding carbon materials such as graphite oxide, single-walled carbon nanotubes and single-layer graphene oxide into ultra-high molecular weight polyethylene, the toughness and strength of the fiber can be significantly improved, and its heat resistance can be improved.

[0022] Furthermore, the preparation of the ultra-high molecular weight polyethylene filament also includes step (F), placing the ultra-high molecular weight polyethylene fiber obtained in step (E) in anhydrous ethanol for ultrasonic treatment for 15-30 minutes, then repeatedly ultrasonically cleaning it with deionized water for multiple times, and transferring it to an oven for drying; then placing the cleaned ultra-high molecular weight polyethylene fiber in the chamber of a cold plasma modification treatment instrument, reducing the chamber pressure to 15-30Pa, and then introducing oxygen therein, controlling the plasma treatment power to 50-80W, and the time to 2-4 minutes, after which the plasma-treated ultra-high molecular weight polyethylene filament is obtained.

[0023] In the present invention, by plasma treating ultra-high molecular weight polyethylene fibers, the roughness of the fiber surface can be increased and the number of surface active functional groups can be increased, thereby making the fiber easier to open, significantly improving spinnability, and improving the density uniformity of the midsole.

[0024] Furthermore, in step S2, the antistatic agent is any one of ethoxylated alkylamine, polyether ester amide antistatic agent, and glycerol-stearate. The present invention can reduce the generation of static electricity and effectively avoid fiber entanglement by using the antistatic agent.

[0025] Furthermore, in step S3, the web laying machine uses a cross-lapping or parallel-lapping method. In the present invention, the cross-lapping method is preferred to improve the uniformity and puncture-proof performance of the product.

[0026] Furthermore, in step S4, the pre-needling density is 200-300 needles / cm 2The needle punching depth is 3-8mm, and the surface density of the sheet is 500-800g / m 2 In the present invention, the pre-needling generally uses a needle with barbs, which can better entangle and fix the fibers.

[0027] Furthermore, in step S5, the main acupuncture needs to go through at least the first acupuncture, and the density of the first acupuncture is 350-450 needles / cm 2 The acupuncture depth is 8-12mm.

[0028] Furthermore, in step S5, the main needling process also requires a second needling process, and the density of the second needling process is 300-400 needles / cm 2 The acupuncture depth is 6-10mm.

[0029] Furthermore, in step S5, the main acupuncture needs to go through a third acupuncture, and the density of the third acupuncture is 250-350 needles / cm 2 The acupuncture depth is 4-8mm.

[0030] Furthermore, in step S5, the surface density of the UHMWPE nonwoven fabric is 1.5-2.2 kg / m 2 , thickness is 2.5-3mm.

[0031] In the present invention, in order to optimize the puncture resistance and structural stability of the product and improve the fiber uniformity, the main needling step preferably undergoes three needling passes, the first needling pass is mainly used to fix the sheet to form a relatively stable structure; the second needling pass is mainly used to further combine and compact the fibers to improve the structural density and strength; the third needling pass is mainly used to fine-tune and improve the uniformity of the product. The UHMWPE nonwoven fabric obtained by this step has good overall strength and puncture resistance.

[0032] Further, in step S6, the power of the laser cutting machine is 100-300W, the cutting speed is 10-20mm / s, and the laser wavelength is 900-1100nm. In the present invention, the power of the laser cutting machine is controlled within an appropriate range to ensure good cutting efficiency. At the same time, attention should be paid to the hot melting phenomenon of the cutting edge of the UHMWPE non-woven fabric, and the burrs and uneven parts generated by the hot melting of the non-woven fabric are removed by trimming, thereby ensuring the smoothness of the midsole edge. The laser wavelength of the present invention is preferably 1064nm, and the efficient cutting of the non-woven fabric is achieved by selecting this wavelength.

[0033] The UHMWPE puncture-resistant midsole for safety shoes prepared by the preparation method of the present invention adopts a unique needle-punching process to tightly combine the ultra-high molecular weight polyethylene fibers to form a solid integrated structure, which significantly improves the overall strength and puncture resistance of the midsole; at the same time, the needle-punching process gives the midsole a certain gap, which has better air permeability than the traditional gluing process, is conducive to keeping the feet dry and improving the comfort of the wearer.

[0034] The beneficial effects of the present invention are as follows: (1) the present invention uses a unique needle punching process to tightly combine ultra-high molecular weight polyethylene fibers to form a strong integrated structure, which significantly improves the overall strength and puncture resistance of the midsole;

[0035] (2) Due to the low density of ultra-high molecular weight polyethylene fibers, the UHMWPE stab-resistant midsole made by the needle punching process is light and comfortable, while retaining the flexibility of the material, so that the midsole does not affect its overall softness and flexibility while ensuring protective performance;

[0036] (3) The preparation process of the UHMWPE stab-proof midsole of the present invention does not contain any glue, and the UHMWPE is recyclable, realizing the concept of green environmental protection. The UHMWPE stab-proof midsole prepared by the needle punching process will not delaminate in a wet or hot environment, which is conducive to continuously maintaining good stab-proof performance;

[0037] (4) The UHMWPE puncture-resistant midsole prepared by the needle-punching process of the present invention has certain gaps. Compared with the traditional gluing process, the midsole has better air permeability, which is beneficial to keeping the feet dry and improving the comfort of the wearer. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a flow chart of the method for preparing the UHMWPE stab-proof midsole for safety shoes according to the present invention;

[0039] Figure 2 Schematic diagram of the operation of UHMWPE nonwoven fabric before the main needling step;

[0040] Figure 3 This is a front view of the UHMWPE puncture-resistant midsole.

[0041] The reference numerals are: 1, 2, 3 are all thin sheets, and 4 is a UHMWPE stab-proof midsole. DETAILED DESCRIPTION

[0042] In order to facilitate the understanding of those skilled in the art, the present invention is further described below in conjunction with embodiments, and the contents mentioned in the implementation modes are not intended to limit the present invention.

[0043] In an embodiment of the present invention, a method for preparing a UHMWPE stab-proof midsole for safety shoes comprises the following steps:

[0044] (S1) Raw material preparation: selecting ultra-high molecular weight polyethylene filaments with super-drawn lengths and cutting them into short fibers;

[0045] (S2) fiber opening and mixing: spraying an antistatic agent on the surface of the chopped fibers obtained in step S1, then placing the chopped fibers in an opening machine for opening, and mixing the opened fibers uniformly;

[0046] (S3) Fiber combing and laying: combing the fibers opened in step S2 into a single fiber state, combing the curled fibers into a straight state with the ends overlapping, and then conveying the combed fibers to a web laying machine through a conveyor belt, and the web laying machine evenly lays the fibers into a web to obtain a fiber web;

[0047] (S4) pre-needling: the fluffy web is needle-punched on a pre-needling machine to obtain a sheet;

[0048] (S5) Main needling: stacking 2-3 sheets prepared by pre-needling in the same direction for main needling to obtain a UHMWPE nonwoven fabric;

[0049] (S6) Cutting the stab-resistant midsole: using design software to pre-draw the shape of the midsole of a certain shoe size, importing the design file into a laser cutting machine, fixing the UHMWPE non-woven fabric prepared in step S5 on a cutting platform, adjusting the laser cutting machine parameters for cutting, and finally trimming the cut edge of the UHMWPE non-woven fabric to obtain the UHMWPE stab-resistant midsole.

[0050] In some embodiments of the present invention, in step S1, the fineness of the ultra-high molecular weight polyethylene filament is 300-400 dtex, and the length of the chopped fibers is 38-56 mm.

[0051] In some embodiments of the present invention, the method for preparing the ultra-high molecular weight polyethylene filament comprises the following steps:

[0052] (A) placing ultra-high molecular weight polyethylene powder, an antioxidant and liquid paraffin in a reactor, heating and stirring them uniformly to prepare a solution A with a mass concentration of 8-10%;

[0053] (B) taking carbon material powder and placing it in anhydrous ethanol for ultrasonic dispersion, then adding octadecylamine thereto, heating and stirring at 60-80° C. for 5-6 hours, then washing and filtering with anhydrous ethanol for multiple times, and uniformly dispersing the obtained modified graphite oxide in dichloromethane to prepare solution B, and adding solution B to solution A and heating and stirring to obtain a mixed spinning solution;

[0054] (C) adding the spinning mixture obtained in step (B) to a twin-screw extruder through a peristaltic pump to extrude ultra-high molecular weight polyethylene precursor, cooling and shaping in a water bath, and then winding it with a winder;

[0055] (D) extracting the obtained ultra-high molecular weight polyethylene precursor with dichloromethane after phase separation equilibrium for 20-24 hours, and drying the extracted fiber at room temperature;

[0056] (E) The dried fiber is heat-stretched at 120-130° C. with a heat-stretching ratio of 5-10 times to obtain ultra-high molecular weight polyethylene filaments.

[0057] Furthermore, in step (A), the molecular weight of the ultra-high molecular weight polyethylene powder is 3 million to 4 million. The antioxidant is at least one of antioxidant B215, antioxidant 168, and antioxidant 1076, and the amount of the antioxidant is 0.5-1% of the mass of the ultra-high molecular weight polyethylene powder.

[0058] Furthermore, in step (B), the carbon material is one or more of graphite oxide, single-walled carbon nanotubes, and single-layer graphene oxide. The mass ratio of the carbon material to octadecylamine is 1:2. The volume ratio of solution A to solution B is 1:5, the heating temperature is 42-45°C, and the time is 6-12h.

[0059] In some embodiments of the present invention, the preparation of the ultra-high molecular weight polyethylene filament also includes step (F), placing the ultra-high molecular weight polyethylene fiber obtained in step (E) in anhydrous ethanol for ultrasonic treatment for 15-30 minutes, then repeatedly ultrasonically cleaning it with deionized water for multiple times, and transferring it to an oven for drying; then placing the cleaned ultra-high molecular weight polyethylene fiber in the chamber of a cold plasma modification treatment instrument, reducing the chamber pressure to 15-30Pa, and then introducing oxygen therein, controlling the plasma treatment power to 50-80W, and the time to 2-4 minutes, and after the end, obtaining the plasma-treated ultra-high molecular weight polyethylene filament.

[0060] In some embodiments of the present invention, in step S2, the antistatic agent is any one of ethoxylated alkylamine, polyetheresteramide antistatic agent, and glycerol stearate.

[0061] In some embodiments of the present invention, in step S3, the web laying method of the web laying machine is cross-laying or parallel-laying.

[0062] In some embodiments of the present invention, in step S4, the pre-needling density is 200-300 needles / cm 2 The needle punching depth is 3-8mm, and the surface density of the sheet is 500-800g / m 2 .

[0063] In some embodiments of the present invention, in step S5, the main acupuncture needs to go through at least the first acupuncture, and the density of the first acupuncture is 350-450 needles / cm 2 The acupuncture depth is 8-12mm.

[0064] In some embodiments of the present invention, in step S5, the main needling also needs to go through a second needling, and the second needling density is 300-400 needles / cm 2 The acupuncture depth is 6-10mm.

[0065] In some embodiments of the present invention, in step S5, the main needling also needs to go through a third needling, and the density of the third needling is 250-350 needles / cm 2 The acupuncture depth is 4-8mm.

[0066] In some embodiments of the present invention, in step S6, the power of the laser cutting machine is 100-300 W, the cutting speed is 10-20 mm / s, and the laser wavelength is 900-1100 nm.

[0067] Example 1

[0068] This embodiment provides a method for preparing a UHMWPE stab-proof midsole for safety shoes, comprising the following steps:

[0069] (S1) Raw material preparation: selecting ultra-high molecular weight polyethylene filaments with super-drawn lengths and cutting them into short fibers;

[0070] (S2) fiber opening and mixing: spraying an antistatic agent on the surface of the chopped fibers obtained in step S1, then placing the chopped fibers in an opening machine for opening, and mixing the opened fibers uniformly;

[0071] (S3) Fiber combing and laying: combing the fibers opened in step S2 into a single fiber state, combing the curled fibers into a straight state with the ends overlapping, and then conveying the combed fibers to a web laying machine through a conveyor belt, and the web laying machine evenly lays the fibers into a web to obtain a fiber web;

[0072] (S4) pre-needling: the fluffy web is needle-punched on a pre-needling machine to obtain a sheet;

[0073] (S5) Main needling: stacking two sheets prepared by pre-needling in the same direction for main needling to obtain a UHMWPE nonwoven fabric;

[0074] (S6) Cutting the stab-resistant midsole: using design software to pre-draw the shape of the midsole of a certain shoe size, importing the design file into a laser cutting machine, fixing the UHMWPE non-woven fabric prepared in step S5 on a cutting platform, adjusting the laser cutting machine parameters for cutting, and finally trimming the cut edge of the UHMWPE non-woven fabric to obtain the UHMWPE stab-resistant midsole.

[0075] Furthermore, in step S1, the fineness of the ultra-high molecular weight polyethylene filament is 300 dtex, and the length of the chopped fibers is 40 mm.

[0076] Furthermore, in the present invention, the method for preparing the ultra-high molecular weight polyethylene filament comprises the following steps:

[0077] (A) ultra-high molecular weight polyethylene powder, antioxidant and liquid paraffin are placed in a reactor and heated and stirred to prepare a solution A with a mass concentration of 8%;

[0078] (B) taking carbon material powder and placing it in anhydrous ethanol for ultrasonic dispersion, then adding octadecylamine thereto, heating and stirring at 65° C. for 5 h, then washing and filtering with anhydrous ethanol for multiple times, the obtained modified graphite oxide is uniformly dispersed in dichloromethane to prepare solution B, and solution B is added to solution A and heated and stirred to obtain a mixed spinning solution;

[0079] (C) adding the spinning mixture obtained in step (B) to a twin-screw extruder through a peristaltic pump to extrude ultra-high molecular weight polyethylene precursor, cooling and shaping in a water bath, and then winding it with a winder;

[0080] (D) extracting the obtained ultra-high molecular weight polyethylene precursor with dichloromethane after 20 hours of phase separation equilibrium, and drying the extracted fiber at room temperature;

[0081] (E) The dried fiber is subjected to heat drawing, wherein the temperatures of the three heat drawing stages are 120° C., 125° C., and 130° C., respectively, and the heat drawing multiple is 10 times, thereby obtaining ultra-high molecular weight polyethylene filaments.

[0082] Furthermore, in step (A), the molecular weight of the ultra-high molecular weight polyethylene powder is 3.5 million. The antioxidant is antioxidant 1076, and the amount of the antioxidant is 0.7% of the mass of the ultra-high molecular weight polyethylene powder.

[0083] Furthermore, in step (B), the carbon material is a single-layer graphene oxide. The mass ratio of the carbon material to octadecylamine is 1:2. The volume ratio of solution A to solution B is 1:5, the heating temperature is 42° C., and the heating time is 8 hours.

[0084] Furthermore, in step S2, the antistatic agent is a polyetheresteramide antistatic agent PEBAX.

[0085] Furthermore, in step S3, the web laying machine uses parallel web laying.

[0086] Furthermore, in step S4, the pre-acupuncture density is 200 punctures / cm 2 The needle penetration depth is 5 mm and the surface density of the sheet is 600 g / m 2 .

[0087] Further, in step S5, the main acupuncture needs to go through the first acupuncture, and the density of the first acupuncture is 380 needles / cm 2 The acupuncture depth is 10 mm.

[0088] Further, in step S5, the main needling process also requires a second needling process, and the second needling process density is 350 needles / cm 2 The acupuncture depth is 8 mm.

[0089] Further, in step S5, the main acupuncture needs to go through a third acupuncture, and the density of the third acupuncture is 300 needles / cm 2 The acupuncture depth is 6 mm.

[0090] Furthermore, in step S6, the power of the laser cutting machine is 200 W, the cutting speed is 12 mm / s, and the laser wavelength is 1064 nm.

[0091] In this embodiment, the strength of the ultra-high molecular weight polyethylene filament is 32 cN / dtex, and the elongation at break is 3.2%. The surface density of the UHMWPE non-woven fabric obtained in step S5 is 1.5 kg / m 2 The thickness is 2.5 mm. The UHMWPE stab-proof midsole prepared in this embodiment is tested and its puncture force is greater than 1300N.

[0092] Example 2

[0093] This embodiment provides a method for preparing a UHMWPE stab-proof midsole for safety shoes, comprising the following steps:

[0094] (S1) Raw material preparation: selecting ultra-high molecular weight polyethylene filaments with super-drawn lengths and cutting them into short fibers;

[0095] (S2) fiber opening and mixing: spraying an antistatic agent on the surface of the chopped fibers obtained in step S1, then placing the chopped fibers in an opening machine for opening, and mixing the opened fibers uniformly;

[0096] (S3) Fiber combing and laying: combing the fibers opened in step S2 into a single fiber state, combing the curled fibers into a straight state with the ends overlapping, and then conveying the combed fibers to a web laying machine through a conveyor belt, and the web laying machine evenly lays the fibers into a web to obtain a fiber web;

[0097] (S4) pre-needling: the fluffy web is needle-punched on a pre-needling machine to obtain a sheet;

[0098] (S5) Main needling: stacking two sheets prepared by pre-needling in the same direction for main needling to obtain a UHMWPE nonwoven fabric;

[0099] (S6) Cutting the stab-resistant midsole: using design software to pre-draw the shape of the midsole of a certain shoe size, importing the design file into a laser cutting machine, fixing the UHMWPE non-woven fabric prepared in step S5 on a cutting platform, adjusting the laser cutting machine parameters for cutting, and finally trimming the cut edge of the UHMWPE non-woven fabric to obtain the UHMWPE stab-resistant midsole.

[0100] Furthermore, in step S1, the fineness of the ultra-high molecular weight polyethylene filament is 350 dtex, and the length of the chopped fibers is 45 mm.

[0101] Furthermore, in the present invention, the method for preparing the ultra-high molecular weight polyethylene filament comprises the following steps:

[0102] (A) ultra-high molecular weight polyethylene powder, antioxidant and liquid paraffin are placed in a reactor and heated and stirred to prepare a solution A with a mass concentration of 10%;

[0103] (B) taking carbon material powder and placing it in anhydrous ethanol for ultrasonic dispersion, then adding octadecylamine thereto, heating and stirring at 70° C. for 6 h, then washing and filtering with anhydrous ethanol for multiple times, and uniformly dispersing the obtained modified graphite oxide in dichloromethane to prepare solution B, and adding solution B to solution A and heating and stirring to obtain a mixed spinning solution;

[0104] (C) adding the spinning mixture obtained in step (B) to a twin-screw extruder through a peristaltic pump to extrude ultra-high molecular weight polyethylene precursor, cooling and shaping in a water bath, and then winding it with a winder;

[0105] (D) extracting the obtained ultra-high molecular weight polyethylene precursor with dichloromethane after 24 hours of phase separation equilibrium, and drying the extracted fiber at room temperature;

[0106] (E) The dried fiber is subjected to heat drawing, wherein the temperatures of the three heat drawing stages are 120° C., 125° C., and 130° C., respectively, and the heat drawing multiple is 10 times, thereby obtaining ultra-high molecular weight polyethylene filaments.

[0107] Furthermore, in step (A), the molecular weight of the ultra-high molecular weight polyethylene powder is 3.5 million. The antioxidant is antioxidant B215, and the amount of the antioxidant is 0.8% of the mass of the ultra-high molecular weight polyethylene powder.

[0108] Furthermore, in step (B), the carbon material is graphite oxide. The mass ratio of the carbon material to octadecylamine is 1:2. The volume ratio of solution A to solution B is 1:5, the heating temperature is 45° C., and the heating time is 10 h.

[0109] Furthermore, the preparation of the ultra-high molecular weight polyethylene filament also includes step (F), placing the ultra-high molecular weight polyethylene fiber obtained in step (E) in anhydrous ethanol for ultrasonic treatment for 20 minutes, then repeatedly ultrasonically cleaning it with deionized water for multiple times, and transferring it to an oven for drying; then placing the cleaned ultra-high molecular weight polyethylene fiber in the chamber of a cold plasma modification treatment instrument, reducing the chamber pressure to 20Pa, and then introducing oxygen therein, controlling the plasma treatment power to 70W, and the time to 3 minutes, after which the plasma-treated ultra-high molecular weight polyethylene filament is obtained.

[0110] Furthermore, in step S2, the antistatic agent is ethoxylated alkylamine.

[0111] Furthermore, in step S3, the web laying method of the web laying machine is cross-lapping.

[0112] Furthermore, in step S4, the pre-acupuncture density is 250 needles / cm 2 The needle penetration depth is 5 mm and the surface density of the sheet is 600 g / m 2 .

[0113] Further, in step S5, the main acupuncture needs to go through the first acupuncture, and the density of the first acupuncture is 400 needles / cm 2 The acupuncture depth is 10 mm.

[0114] Further, in step S5, the main needling process also requires a second needling process, and the second needling process density is 350 needles / cm 2 The acupuncture depth is 8 mm.

[0115] Further, in step S5, the main acupuncture needs to go through a third acupuncture, and the density of the third acupuncture is 300 needles / cm 2 The acupuncture depth is 6 mm.

[0116] Furthermore, in step S6, the power of the laser cutting machine is 250 W, the cutting speed is 15 mm / s, and the laser wavelength is 1060 nm.

[0117] In this embodiment, the strength of the ultra-high molecular weight polyethylene filament is 40 cN / dtex and the elongation at break is 5%. The surface density of the UHMWPE non-woven fabric obtained in step S5 is 1.8 kg / m 2 The thickness is 2.8 mm. The UHMWPE puncture-resistant midsole prepared in this embodiment is tested and its zero puncture force is greater than 1100N.

[0118] Comparative Example 1

[0119] The difference between this comparative example and Example 2 is that the ultra-high molecular weight polyethylene fiber (fineness of 350 dtex, strength of 35 cN / dtex, elongation at break of 2.58%) customized by Guangdong Tewilong New Materials Application Co., Ltd. is used to replace the ultra-high molecular weight polyethylene filament in Example 2.

[0120] The rest of the contents are the same as those in Example 2 and will not be described again here.

[0121] The surface density of the UHMWPE nonwoven fabric obtained in this comparative example is 1.5 kg / m 2 The thickness is 2.5 mm. The UHMWPE puncture-resistant midsole prepared in this comparative example is tested and its puncture force is less than 1300N.

[0122] The present invention uses a unique needle punching process to tightly combine ultra-high molecular weight polyethylene fibers to form a solid integrated structure, which significantly improves the overall strength and puncture resistance of the midsole. Among them, by adding carbon materials in the preparation of ultra-high molecular weight polyethylene filaments, its mechanical properties and toughness can be significantly improved. Furthermore, by plasma treating the ultra-high molecular weight polyethylene filaments, the fibers can be easily opened and the density uniformity of the midsole can be improved.

[0123] The above embodiments are preferred implementation schemes of the present invention. In addition, the present invention may also be implemented in other ways. Any obvious replacement without departing from the concept of the present invention is within the protection scope of the present invention.

Claims

1. A method for preparing a UHMWPE stab-proof midsole for safety shoes, characterized in that: The steps include: (S1) Raw material preparation: selecting ultra-high molecular weight polyethylene filaments with super-drawn lengths and cutting them into short fibers; (S2) fiber opening and mixing: spraying an antistatic agent on the surface of the chopped fibers obtained in step S1, then placing the chopped fibers in an opening machine for opening, and mixing the opened fibers uniformly; (S3) Fiber combing and laying: combing the fibers opened in step S2 into a single fiber state, combing the curled fibers into a straight state with the ends overlapping, and then conveying the combed fibers to a web laying machine through a conveyor belt, and the web laying machine evenly lays the fibers into a web to obtain a fiber web; (S4) pre-needling: the fluffy web is needle-punched on a pre-needling machine to obtain a sheet; (S5) Main needling: stacking 2-3 sheets prepared by pre-needling in the same direction for main needling to obtain a UHMWPE nonwoven fabric; (S6) Cutting the stab-resistant midsole: using design software to pre-draw the shape of the midsole of a certain shoe size, importing the design file into a laser cutting machine, fixing the UHMWPE non-woven fabric prepared in step S5 on a cutting platform, adjusting the laser cutting machine parameters for cutting, and finally trimming the cut edge of the UHMWPE non-woven fabric to obtain the UHMWPE stab-resistant midsole.

2. The method for preparing a UHMWPE stab-proof midsole for safety shoes according to claim 1, characterized in that: In step S1, the fineness of the ultra-high molecular weight polyethylene filaments is 300-400 dtex, and the length of the chopped fibers is 38-56 mm.

3. The method for preparing a UHMWPE stab-proof midsole for safety shoes according to claim 1, characterized in that: In step S3, the web laying machine lays the web in a cross-laying or parallel-laying manner.

4. The method for preparing a UHMWPE stab-proof midsole for safety shoes according to claim 1, characterized in that: In step S4, the pre-needling density is 200-300 needles / cm 2 The needle punching depth is 3-8mm, and the surface density of the sheet is 500-800g / m 2 .

5. The method for preparing a UHMWPE stab-proof midsole for safety shoes according to claim 1, characterized in that: In step S5, the main acupuncture needs to go through at least the first acupuncture pass, and the density of the first acupuncture pass is 350-450 needles / cm 2 The acupuncture depth is 8-12mm.

6. The method for preparing a UHMWPE stab-proof midsole for safety shoes according to claim 5, characterized in that: In step S5, the main needling process also needs to go through a second needling process, and the density of the second needling process is 300-400 needles / cm 2 The acupuncture depth is 6-10mm.

7. The method for preparing a UHMWPE stab-proof midsole for safety shoes according to claim 6, characterized in that: In step S5, the main acupuncture needs to go through a third acupuncture pass, and the density of the third acupuncture pass is 250-350 needles / cm 2 The acupuncture depth is 4-8mm.

8. The method for preparing a UHMWPE stab-proof midsole for safety shoes according to claim 1, characterized in that: In step S5, the surface density of the UHMWPE nonwoven fabric is 1.5-2.2 kg / m 2 , thickness is 2.5-3mm.

9. The method for preparing a UHMWPE stab-resistant midsole for safety shoes according to claim 1, characterized in that: In step S6, the power of the laser cutting machine is 100-300 W, the cutting speed is 10-20 mm / s, and the laser wavelength is 900-1100 nm.

10. A UHMWPE stab-proof midsole for safety shoes, characterized by: The invention discloses a UHMWPE stab-proof midsole for safety shoes according to any one of claims 1 to 9.

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