Recycling method of recyclable gloves

Abstract

The invention relates to the technical field of polyester fiber recycling, in particular to a recycling method of recyclable gloves, the recyclable gloves are made of a base layer textile material, and the base layer textile material comprises soluble polyester fibers capable of being dissolved under specific treatment conditions so that glove bodies can be deconstructed; the base layer textile material is of a single-layer structure or a double-layer structure. The recycling method of the recyclable gloves comprises the following steps: (a) pretreatment; (b) alkaline hydrolysis; (c) liquid phase treatment; (d) carrying out solid-phase separation; and (e) material regeneration. The structural design that soluble polyester fibers serve as sacrificial layers is combined with an alkaline hydrolysis deconstruction process, precise classification and recycling from waste gloves to high-purity terephthalic acid monomers, complete alkali-resistant fibers and metal reinforced filaments are achieved, solid waste which can only be buried or incinerated originally is converted into high-value regenerated raw materials, and the recycling cost is reduced. And the resource cyclic utilization rate is obviously improved.

Description

A method for recycling reusable gloves Technical Field

[0001] This invention relates to the field of polyester fiber recycling technology, specifically to a method for recycling recyclable gloves. Background Technology

[0002] To meet multiple performance requirements such as abrasion resistance, cut resistance, chemical corrosion resistance, and slip resistance, traditional industrial gloves typically employ a composite material structure. For example, common protective gloves use a base fabric woven from synthetic fibers such as polyester and nylon or cotton fibers as a support layer. To enhance protective performance, steel wire or high-performance fibers are often added as a reinforcing layer, and the surface is impregnated with polymer materials such as nitrile rubber, polyurethane, or natural latex to form an impregnation layer.

[0003] However, while this multi-material composite structure improves the performance of the gloves, it also presents significant challenges for recycling after disposal. Because the base fabric fibers, metal reinforcing filaments, and surface rubber layer have significantly different physical and chemical properties, and are tightly bonded together, discarded gloves are difficult to separate effectively using conventional physical methods.

[0004] While existing technologies have explored biodegradable glove materials, such as developing bio-based gloves made from a single material or using partially biodegradable fibers, these studies largely focus on material replacement and lack recycling solutions tailored to the complex structures of intact gloves. Particularly for high-performance gloves containing metal fiber reinforcement layers and thick rubber impregnation layers, current recycling technologies struggle to achieve efficient separation and resource utilization of polyester components, alkali-resistant polymer fibers, metal fibers, and rubber particles while ensuring the purity of the recycled products. For example, traditional acid-alkali treatments often fail to consider the characteristics of different components, leading to metal fiber corrosion, rubber layer carbonization, or a significant decrease in fiber strength, hindering high-value recycling and reuse. Summary of the Invention

[0005] The purpose of this invention is to provide a method for recycling reusable gloves to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a method for recycling recyclable gloves, wherein the recyclable gloves are composed of a base textile material, the base textile material comprising soluble polyester fibers capable of dissolving under specific processing conditions, thereby deconstructing the glove body; the base textile material is a single-layer structure or a double-layer structure; when the base textile material is a single-layer structure, it is knitted from soluble polyester fibers and insoluble fibers stable under the specific processing conditions; when the base textile material is a double-layer structure, it comprises a first layer and a second layer arranged sequentially from the inside out. The first layer is woven from core-spun yarn or soluble polyester fiber, and the second layer is woven from soluble polyester fiber. The core-spun yarn includes alkali-resistant textile fibers that are stable under the specific treatment conditions, and soluble polyester fibers covering the outer surface of the alkali-resistant textile fibers. The alkali-resistant textile fibers are twisted from ferromagnetic metal fibers and alkali-resistant high molecular weight fibers. The recycling method for the recyclable gloves includes the following steps: (a) pretreatment: washing, drying, and mechanically crushing the waste recyclable gloves into fragments with a size of 50-200 mm; (b) alkaline hydrolysis: placing the fragments in a 2 (c) Liquid phase treatment: The mixture is filtered to remove solid impurities, and 8 wt% to 10 wt% sulfuric acid is added to the filtrate for acid precipitation to obtain crude terephthalic acid, which is then purified to obtain purified terephthalic acid; (d) Solid phase separation: The solid residue obtained from filtration is washed, sieved, and magnetically separated to recover metal fibers and alkali-resistant high molecular weight fibers, respectively; (e) Material regeneration: Purified terephthalic acid is used to synthesize new polyester fibers, and the recovered alkali-resistant textile fibers are melt-re-granulated or directly reused.

[0007] Preferably, the insoluble fiber is any one of cotton fiber, polyester fiber, nylon fiber, acrylic fiber, and polypropylene fiber.

[0008] Preferably, the soluble polyester fiber is modified polyethylene terephthalate or alkali-soluble polyester fiber.

[0009] Preferably, the outer surface of the second layer is fixedly provided with an impregnation layer, which is any one of nitrile rubber, polyurethane, and natural latex.

[0010] Preferably, the thickness of the impregnation layer is 0.1 to 0.3 mm, and the impregnation layer does not penetrate into the interior of the second layer.

[0011] Preferably, step (d) is replaced by: sequentially washing and screening the filtered solid residue with water, magnetic separation, density separation and electrostatic separation to recover metal fibers, alkali-resistant high molecular weight fibers and impregnated particles respectively; step (e) is replaced by: synthesizing new polyester fibers from purified terephthalic acid, melting and regranulating the recovered alkali-resistant textile fibers or reusing them directly, and crushing the impregnated particles to 80-200 mesh for use as filler or hot-pressing regeneration.

[0012] Preferably, in step (d), the magnetic separation magnetic field strength is 0.8–1.2 T; the density separation uses a density of 1.0–1.2 g / cm³. 3 The salt solution; the electrostatic separation voltage is 20-30 kV.

[0013] Preferably, the mass ratio of NaOH solution to fragments in the alkaline hydrolysis step is 10:1 to 15:1, and the reaction process is carried out under inert gas protection.

[0014] Preferably, when the base textile material is a single-layer structure, step (d) is replaced by: sequentially washing, sieving and drying the filtered solid residue to recover the insoluble fibers.

[0015] Compared with existing technologies, this invention has the following advantages: 1. By combining the design of a sacrificial layer structure with soluble polyester fiber and an alkaline hydrolysis deconstruction process, this invention achieves precise classification and recycling of waste gloves into high-purity terephthalic acid monomers, intact alkali-resistant fibers, and metal reinforcing filaments. This transforms solid waste that could only be landfilled or incinerated into high-value recycled raw materials, significantly improving the resource recycling rate. 2. By introducing 40-60 kHz ultrasonic-assisted technology and an inert gas protection mechanism during alkaline hydrolysis, this invention utilizes the cavitation effect of ultrasound to accelerate the penetration of the reaction liquid and destroy the fiber crystallization zone, significantly shortening the hydrolysis time and reducing energy consumption. At the same time, it effectively prevents the oxidative degradation of the recycled products, solving the shortcomings of low efficiency in traditional chemical recycling methods. 3. By implementing a multi-stage solid-phase separation system including magnetic separation, density separation, and electrostatic separation, this invention achieves efficient purification of complex rubber, metal, and fiber mixed residues in rubber-containing gloves. This not only solves the problem of secondary pollution easily generated by the impregnation layer during recycling but also converts the recycled rubber particles and metal fibers into usable fillers and recycled metal resources, respectively, realizing a closed-loop recycling scheme. Detailed Implementation

[0016] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] Example 1

[0018] This embodiment provides a method for recycling recyclable gloves. The recyclable gloves consist of a first layer, a second layer, and a dipped layer arranged sequentially from the inside out. The first layer is woven from core-spun yarn, which includes alkali-resistant textile fibers and soluble polyester fibers covering the outer surface of the alkali-resistant textile fibers. The second layer is woven from soluble polyester fibers. The dipped layer is made of nitrile rubber with a thickness of 0.1 mm, and the dipped layer does not penetrate into the interior of the second layer. The alkali-resistant textile fibers are made by twisting steel wire and polyethylene fibers. The soluble polyester is modified polyethylene terephthalate.

[0019] The recycling method for recyclable gloves includes the following steps: (a) Pretreatment: The waste recyclable gloves are washed, dried, and mechanically crushed into fragments of 50 mm in size; (b) Alkaline hydrolysis: The fragments are placed in a 2 wt% NaOH solution and soaked at 120°C and normal pressure for 1 hour, while mechanical stirring and ultrasonic stimulation at a frequency of 40 kHz are applied to obtain a mixture. The mass ratio of NaOH solution to fragments is 10:1, and the reaction process is carried out under inert gas protection; (c) Liquid phase treatment: The mixture is filtered to remove solid impurities, and 8 wt% sulfuric acid is added to the filtrate for acid precipitation to obtain crude terephthalic acid, which is then purified to obtain refined terephthalic acid; (d) Solid phase separation: The filtered solid residue is subjected to water washing and sieving, magnetic separation, density separation, and electrostatic separation in sequence to recover steel wire, polyethylene fiber, and impregnated particles, respectively. The magnetic separation magnetic field strength is 0.8 T, and the density separation uses a density of 1.0 g / cm³. 3 The salt solution is electrostatically separated at a voltage of 20 kV; (e) Material regeneration: purified terephthalic acid is used to synthesize new polyester fibers, the recycled polyethylene fibers are melted and granulated or directly reused, and the impregnated particles are crushed to 80 mesh and used as fillers or hot-pressed for regeneration.

[0020] Example 2

[0021] This embodiment provides a method for recycling reusable gloves. The reusable gloves consist of a first layer, a second layer, and a dipped layer arranged sequentially from the inside out. The first layer is woven from core-spun yarn, which includes alkali-resistant textile fibers and soluble polyester fibers covering the outer surface of the alkali-resistant textile fibers. The second layer is woven from soluble polyester fibers. The dipped layer is polyurethane, with a thickness of 0.15 mm, and the dipped layer does not penetrate into the interior of the second layer. The alkali-resistant textile fibers are made by twisting steel wire and polyethylene fibers. The soluble polyester fibers are alkali-soluble polyester fibers.

[0022] The recycling method for recyclable gloves includes the following steps: (a) Pretreatment: The waste recyclable gloves are washed, dried, and mechanically crushed into fragments with a size of 80 mm; (b) Alkaline hydrolysis: The fragments are placed in a 3 wt% NaOH solution and soaked at 120°C and normal pressure for 1.2 h, while mechanical stirring and ultrasonic stimulation at a frequency of 45 kHz are applied to obtain a mixture. The mass ratio of NaOH solution to fragments is 11:1, and the reaction process is carried out under inert gas protection; (c) Liquid phase treatment: The mixture is filtered to remove solid impurities, and 8.5 wt% sulfuric acid is added to the filtrate for acid precipitation to obtain crude terephthalic acid, which is then purified to obtain refined terephthalic acid; (d) Solid phase separation: The filtered solid residue is subjected to water washing and sieving, magnetic separation, density separation, and electrostatic separation in sequence to recover steel wire, polyethylene fiber, and impregnated particles, respectively. The magnetic separation magnetic field strength is 0.9 T, and the density separation uses a density of 1.05 g / cm³. 3 The salt solution is electrostatically separated at a voltage of 24 kV; (e) Material regeneration: purified terephthalic acid is used to synthesize new polyester fibers, the recycled polyethylene fibers are melt-re-granulated or directly reused, and the impregnated particles are crushed to 100 mesh and used as fillers or hot-pressed for regeneration.

[0023] Example 3

[0024] This embodiment provides a method for recycling recyclable gloves. The recyclable gloves consist of a first layer, a second layer, and a dipped layer arranged sequentially from the inside out. The first layer is woven from core-spun yarn, which includes alkali-resistant textile fibers and soluble polyester fibers covering the outer surface of the alkali-resistant textile fibers. The second layer is woven from soluble polyester fibers. The dipped layer is made of nitrile rubber with a thickness of 0.2 mm, and the dipped layer does not penetrate into the interior of the second layer. The alkali-resistant textile fibers are made by twisting stainless steel wire and polyethylene fibers. The soluble polyester is modified polyethylene terephthalate.

[0025] The recycling method for recyclable gloves includes the following steps: (a) Pretreatment: The waste recyclable gloves are washed, dried, and mechanically crushed into fragments of 120 mm in size; (b) Alkaline hydrolysis: The fragments are placed in a 4 wt% NaOH solution and soaked at 120°C and atmospheric pressure for 1.5 h, while mechanical stirring and ultrasonic stimulation at a frequency of 50 kHz are applied to obtain a mixture. The mass ratio of NaOH solution to fragments is 13:1, and the reaction process is carried out under inert gas protection; (c) Liquid phase treatment: The mixture is filtered to remove solid impurities, and 9 wt% sulfuric acid is added to the filtrate for acid precipitation to obtain crude terephthalic acid, which is then purified to obtain refined terephthalic acid; (d) Solid phase separation: The filtered solid residue is subjected to water washing and sieving, magnetic separation, density separation, and electrostatic separation in sequence to recover stainless steel wire, polyethylene fiber, and dipped granules, respectively. The magnetic separation magnetic field strength is 1.0 T, and the density separation uses a density of 1.10 g / cm³. 3 The salt solution is electrostatically separated at a voltage of 28 kV; (e) Material regeneration: purified terephthalic acid is used to synthesize new polyester fibers, the recycled polyethylene fibers are melted and granulated or directly reused, and the impregnated granules are crushed to 150 mesh and used as fillers or hot-pressed for regeneration.

[0026] Example 4

[0027] This embodiment provides a method for recycling reusable gloves. The reusable gloves consist of a first layer, a second layer, and a dipped layer arranged sequentially from the inside out. The first layer is woven from core-spun yarn, which includes alkali-resistant textile fibers and soluble polyester fibers covering the outer surface of the alkali-resistant textile fibers. The second layer is woven from soluble polyester fibers. The dipped layer is made of natural latex with a thickness of 0.3 mm, and the dipped layer does not penetrate into the interior of the second layer. The alkali-resistant textile fibers are made by twisting steel wire and ultra-high molecular weight polyethylene fibers. The soluble polyester fibers are alkali-soluble polyester fibers.

[0028] The recycling method for recyclable gloves includes the following steps: (a) Pretreatment: The waste recyclable gloves are washed, dried, and mechanically crushed into fragments of 200 mm in size; (b) Alkaline hydrolysis: The fragments are placed in a 5 wt% NaOH solution and soaked at 120°C and normal pressure for 2 h, while mechanical stirring and ultrasonic waves at a frequency of 60 kHz are applied simultaneously to obtain a mixture. The mass ratio of NaOH solution to fragments is 15:1, and the reaction process is carried out under inert gas protection; (c) Liquid phase treatment: The mixture is filtered to remove solid impurities, and 10 wt% sulfuric acid is added to the filtrate for acid precipitation to obtain crude terephthalic acid, which is then purified to obtain refined terephthalic acid; (d) Solid phase separation: The filtered solid residue is subjected to water washing and sieving, magnetic separation, density separation, and electrostatic separation in sequence to recover steel wire, ultra-high molecular weight polyethylene fiber, and impregnated particles, respectively. The magnetic separation magnetic field strength is 1.2 T, and the density separation uses a density of 1.20 g / cm³. 3 The salt solution is electrostatically separated at a voltage of 30 kV; (e) Material regeneration: purified terephthalic acid is used to synthesize new polyester fibers, the recycled ultra-high molecular weight polyethylene fibers are melt-re-granulated or directly reused, and the impregnated particles are crushed to 200 mesh and used as fillers or hot-pressed for regeneration.

[0029] Example 5

[0030] This embodiment provides a method for recycling recyclable gloves. The recyclable glove includes a glove body made of a base textile material, which comprises a first layer and a second layer arranged sequentially from the inside out. The first layer is woven from core-spun yarn, which includes alkali-resistant textile fibers and soluble polyester fibers covering the outer surface of the alkali-resistant textile fibers. The second layer is woven from soluble polyester fibers. The alkali-resistant textile fibers are made by twisting steel wire and high-strength polypropylene fibers. The soluble polyester is modified polyethylene terephthalate.

[0031] The recycling method for recyclable gloves includes the following steps: (a) Pretreatment: The waste recyclable gloves are washed, dried, and mechanically crushed into fragments of 200 mm in size; (b) Alkaline hydrolysis: The fragments are placed in a 5 wt% NaOH solution and soaked at 120°C and normal pressure for 2 h, while mechanical stirring and ultrasonic stimulation at a frequency of 60 kHz are applied simultaneously to obtain a mixture. The mass ratio of NaOH solution to fragments is 15:1, and the reaction process is carried out under inert gas protection; (c) Liquid phase treatment: The mixture is filtered to remove solid impurities, and 10 wt% sulfuric acid is added to the filtrate for acid precipitation to obtain crude terephthalic acid, which is then purified to obtain refined terephthalic acid; (d) Solid phase separation: The filtered solid residue is sequentially washed, sieved, and magnetically separated to recover steel wire and high-strength polypropylene fiber, respectively. The magnetic separation magnetic field strength is 1.2. T; (e) Material recycling: synthesize new polyester fibers from purified terephthalic acid, and melt-re-granulate or directly reuse the recycled high-strength polypropylene fibers.

[0032] Example 6

[0033] This embodiment provides a recyclable glove, which is made of a base textile material. The base textile material is knitted from soluble polyester fiber and cotton fiber, and the soluble polyester fiber is modified polyethylene terephthalate.

[0034] The recycling method for recyclable gloves includes the following steps: (a) Pretreatment: The waste recyclable gloves are washed, dried, and mechanically crushed into fragments of 200 mm in size; (b) Alkaline hydrolysis: The fragments are placed in a 5 wt% NaOH solution and soaked at 120°C and normal pressure for 2 h, while mechanical stirring and ultrasonic waves at a frequency of 60 kHz are applied to obtain a mixture, wherein the mass ratio of NaOH solution to fragments is 15:1, and the reaction process is carried out under inert gas protection; (c) Liquid phase treatment: The mixture is filtered to remove solid impurities, and 10 wt% sulfuric acid is added to the filtrate for acid precipitation to obtain crude terephthalic acid, which is then purified to obtain purified terephthalic acid; (d) Solid phase separation: The solid residue obtained from filtration is washed, sieved, and dried sequentially to recover cotton fibers; (e) Material regeneration: Purified terephthalic acid is used to synthesize new polyester fibers; the recovered cotton fibers are used for respinning or as environmentally friendly fillers.

[0035] Example 7

[0036] It is basically the same as Example 6, except that the non-soluble fiber is polyester fiber.

[0037] Example 8

[0038] It is basically the same as Example 6, except that the non-soluble fiber is nylon fiber.

[0039] Example 9

[0040] It is basically the same as Example 6, except that the insoluble fiber is acrylic fiber.

[0041] Example 10

[0042] It is basically the same as Example 6, except that the non-soluble fiber is polypropylene fiber.

[0043] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for recycling reusable gloves, characterized in that, The recyclable gloves are made of a base textile material, which includes soluble polyester fibers that can dissolve under specific treatment conditions to deconstruct the glove body. The base textile material is a single-layer or double-layer structure. When the base textile material is a single-layer structure, it is knitted from soluble polyester fibers and insoluble fibers that are stable under the specific treatment conditions. When the base textile material is a double-layer structure, it includes a first layer and a second layer arranged sequentially from the inside out. The first layer is woven from core-spun yarn or soluble polyester fibers, and the second layer is woven from soluble polyester fibers. The core-spun yarn includes alkali-resistant textile fibers that are stable under the specific treatment conditions, and soluble polyester fibers covering the outer surface of the alkali-resistant textile fibers. The alkali-resistant textile fibers are twisted from ferromagnetic metal fibers and alkali-resistant high molecular weight fibers. The recycling method of the recyclable gloves includes the following steps: (a) Pretreatment: washing, drying, and mechanically crushing the waste recyclable gloves into fragments with a size of 50-200 mm; (b) Alkaline hydrolysis: placing the fragments in a 2 (c) Liquid phase treatment: The mixture is filtered to remove solid impurities, and 8 wt% to 10 wt% sulfuric acid is added to the filtrate for acid precipitation to obtain crude terephthalic acid, which is then purified to obtain purified terephthalic acid; (d) Solid phase separation: The solid residue obtained from filtration is washed, sieved, and magnetically separated to recover metal fibers and alkali-resistant high molecular weight fibers, respectively; (e) Material regeneration: Purified terephthalic acid is used to synthesize new polyester fibers, and the recovered alkali-resistant textile fibers are melt-re-granulated or directly reused.

2. The recycling method for recyclable gloves according to claim 1, characterized in that, The insoluble fiber is any one of cotton fiber, polyester fiber, nylon fiber, acrylic fiber, and polypropylene fiber.

3. The recycling method for recyclable gloves according to claim 1, characterized in that, The soluble polyester fiber is modified polyethylene terephthalate or alkali-soluble polyester fiber.

4. The recycling method for recyclable gloves according to claim 1, characterized in that, The outer surface of the second layer is fixedly provided with an impregnation layer, which is any one of nitrile rubber, polyurethane, and natural latex.

5. The recycling method for recyclable gloves according to claim 4, characterized in that, The thickness of the impregnation layer is 0.1 to 0.3 mm, and the impregnation layer does not penetrate into the interior of the second layer.

6. The recycling method for recyclable gloves according to claim 4, characterized in that, Step (d) is replaced by: sequentially washing and screening the filtered solid residue, magnetic separation, density separation and electrostatic separation to recover metal fibers, alkali-resistant high molecular weight fibers and impregnated particles respectively; Step (e) is replaced by: synthesizing new polyester fibers from purified terephthalic acid, melting and regranulating the recovered alkali-resistant textile fibers or reusing them directly, and crushing the impregnated particles to 80-200 mesh for use as filler or hot-pressing regeneration.

7. The recycling method for recyclable gloves according to claim 6, characterized in that, In step (d), the magnetic separation magnetic field strength is 0.8–1.2 T; the density separation uses a density of 1.0–1.2 g / cm³. 3 The salt solution; the electrostatic separation voltage is 20-30 kV.

8. The recycling method for recyclable gloves according to claim 1, characterized in that, In the alkaline hydrolysis step, the mass ratio of NaOH solution to fragments is 10:1 to 15:1, and the reaction process is carried out under inert gas protection.

9. The recycling method for recyclable gloves according to claim 1, characterized in that, When the base textile material is a single-layer structure, step (d) is replaced by: washing, sieving and drying the filtered solid residue in sequence to recover the insoluble fibers.