A method for preparing chopsticks by using a pure physical carbonization process

Abstract

This invention belongs to the field of bamboo and wood tableware processing technology, specifically a method for preparing chopsticks using a purely physical carbonization process. This method includes steps such as raw material selection, bamboo splitting and skeining, high-temperature carbonization, moisture rebalancing, re-carbonization and conditioning, segmentation and sharpening / beveling, polishing, sorting, and sterilization. Through a composite treatment of primary carbonization, moisture rebalancing, secondary carbonization, and conditioning, this invention thoroughly decomposes and denatures the sugars, proteins, and other nutrients within the bamboo and wood, destroying conditions for mold growth. Simultaneously, the natural coloring occurs during carbonization, eliminating the need for sulfur fumigation and hydrogen peroxide bleaching. Combined with multiple physical polishing processes, this results in healthy chopsticks with a smooth surface, free of paint and wax, and with zero chemical residue. This invention's process is green and environmentally friendly, producing safe, non-toxic chopsticks with excellent mold resistance, dimensional stability, and resistance to deformation, meeting food contact material safety standards and possessing promising market application prospects.

Description

Technical Field

[0001] This invention belongs to the field of bamboo and wood tableware processing technology, specifically a method for preparing chopsticks using a purely physical carbonization process. Background Technology

[0002] Bamboo and wooden chopsticks are widely used as everyday tableware due to their lightweight, smooth texture, and biodegradability. Traditionally, bamboo and wooden chopsticks undergo the following chemical treatments during processing to prevent mold, insects, and whitening: 1. Sulfur fumigation: Using sulfur dioxide produced by burning sulfur for bleaching and insect control can easily lead to excessive sulfur dioxide residue. Long-term use may irritate the respiratory tract and harm human health. 2. Hydrogen peroxide bleaching: This method uses hydrogen peroxide for oxidation and bleaching, which can improve the whiteness of the appearance. However, industrial-grade hydrogen peroxide may contain heavy metal impurities, and the residue can easily irritate the oral mucosa. 3. Surface coating: Some products are coated with chemical paints or waxes to increase gloss, which poses a risk of migration of harmful substances such as formaldehyde and heavy metals.

[0003] The aforementioned traditional processes suffer from problems such as chemical residues, reliance on chemical agents for mold prevention, and the generation of sulfur- and chlorine-containing wastewater during production, which do not meet the current high standards for green manufacturing and food safety. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention aims to provide a method for producing healthy chopsticks using a carbonization process that eliminates the need for sulfur fumigation and hydrogen peroxide bleaching. Through purely physical modification, it completely abandons chemical bleaching and fumigation processes, achieving natural mold resistance, uniform color, no chemical residue, and a safe and environmentally friendly product. The technical solution adopted by this invention to solve its technical problems is: a method for preparing chopsticks using a purely physical carbonization process, comprising the following steps: Step 1: Raw material screening. Select bamboo or hardwood. Choose high-quality moso bamboo or high-density hardwood (such as red sandalwood, chicken wing wood, ironwood) that is 3-5 years old as raw material. Remove raw materials with insect holes, mold and cracks to ensure the quality of raw materials. Step 2: Bamboo splitting and drawing. The raw bamboo is split into strips and then drawn into blanks. The screened raw bamboo is split into bamboo strips and then processed into bamboo strips or bamboo filaments of specified sizes by a drawing machine. The moisture content is controlled to be around 35% before carbonization. Step 3: High-temperature carbonization. The raw material is treated in an oxygen-free or oxygen-deficient environment at 160℃-220℃ for 2-6 hours. The raw material is placed in a high-temperature carbonization furnace and saturated steam is introduced at 160℃-220℃ for 2-4 hours. During the carbonization process, the hemicellulose, sugars, and proteins inside the bamboo and wood undergo pyrolysis and denaturation. The high temperature destroys the hydrophilic hydroxyl structure inside the bamboo and wood, decomposes the sugars, starches, and proteins on which mold depends for survival, and fundamentally solves the problem of mold growth. Finally, the bamboo or wood undergoes Maillard reaction and caramelization reaction at high temperature, and the color changes from the original light yellow to a natural "coffee color" or "dark reddish-brown", showing the natural color of wood. No further bleaching is required. Then, it is dried to 0 moisture. Step 4: Moisture absorption and balance. The moisture content of the carbonized blank is restored to 8%-12%. The carbonized blank is placed in a constant temperature and humidity environment and left to stand for 7 days. The moisture content of the carbonized wood is extremely low (about 2%-4%), and the texture becomes brittle. Physical moisture absorption is used to restore the moisture content to the optimal balance point of 8%-12%, which ensures toughness without cracking and is below the critical point of 14% required for mold growth. Step 5: Re-carbonization and conditioning. After a second carbonization process, the raw material is heated at a constant temperature. The material is then placed in the carbonization furnace for a second carbonization process to further stabilize the material. Afterward, it is placed in a constant temperature environment for 15 days to fully release the internal stress, eliminate the risk of deformation, and make the chopsticks less prone to bending and deformation. Step Six: Segmentation and Tipping / Beveling. Segment the chopsticks according to specifications and process the tips. Cut the chopsticks into segments according to the length specifications and process them into the shape of the tips using a tipping machine to ensure that the tips are round and burr-free. Step 7: Polishing and grinding. After multiple physical polishing processes, the chopsticks are shaped. More than six fine physical polishing processes are used, with the sander grit increasing from 150 grit to 600 grit to gradually refine and polish the surface, making the chopsticks smooth and delicate. Step 8: Sorting and sterilization. After color sorting, the products are physically sterilized and packaged. The carbonized color difference is manually removed to ensure uniform color. Ultraviolet light or ozone is used for physical sterilization before leaving the factory to prevent secondary pollution.

[0005] Furthermore, in step three, saturated steam is used as the heat transfer medium for the high-temperature carbonization.

[0006] Furthermore, in step five, the re-carbonization treatment temperature is 160℃-200℃, and the treatment time is 1-3 hours.

[0007] Furthermore, the multi-stage physical polishing described in step seven is performed by gradually grinding with a sander ranging from 150 grit to 600 grit.

[0008] Furthermore, in step eight, the sterilization method is physical sterilization using ultraviolet light or ozone.

[0009] Furthermore, the raw material is 3-5 year old moso bamboo with a moisture content of 35% before carbonization.

[0010] The beneficial effects of this invention are as follows: 1. Zero chemical residue: No sulfur, hydrogen peroxide, or chemical coatings are used throughout the process. The migration of harmful substances such as sulfur dioxide, formaldehyde, and heavy metals all comply with the GB 4806.12-2022 standard, and the sulfur dioxide and hydrogen peroxide levels reach the "not detected" level. 2. Double carbonization, stable and reliable: Through a composite treatment of "one-time carbonization + re-moistening + re-carbonization + health preservation", the sugar decomposition is more thorough, the material stability is significantly improved, and the chopsticks are not easy to bend or deform. 3. Natural Mold Resistance: Ordinary chopsticks have micropores on their surface, making them prone to absorbing moisture and developing mold. High-temperature carbonization completely decomposes the sugars and proteins inside the bamboo and wood, destroying the environment for mold growth. Combined with a balanced moisture content of 8%-12%, their mold resistance is significantly superior to traditional processes. The high temperature reshapes the wood structure of carbonized chopsticks, blocking the water absorption ducts, reducing the moisture absorption rate by more than 60% compared to ordinary bamboo chopsticks. In an environment with a relative humidity of 80%, the mold rate is far below the national standard requirements. 4. Physical coloring: The dark color is naturally formed through the carbonization process, resulting in a uniform and beautiful color that does not require bleaching and preserves the natural texture of bamboo and wood. 5. Environmentally friendly: No sulfur-containing or chlorine-containing wastewater is generated during the production process, and the bamboo chips and wood powder produced can be recycled as biomass fuel, achieving clean production; 6. Safe to use: The surface is physically polished in multiple layers, without paint or wax, and does not release harmful substances at high temperatures, making it suitable for long-term repeated use. Detailed Implementation

[0011] The present invention will now be described in further detail with reference to specific embodiments. The embodiments of the present invention are given for illustrative and descriptive purposes only, and are not intended to be exhaustive or to limit the invention to the disclosed forms. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described to better illustrate the principles and practical application of the invention, and to enable those skilled in the art to understand the invention and design various embodiments with various modifications suitable for a particular purpose.

[0012] Example 1: The present invention provides a technical solution: a method for preparing chopsticks using a purely physical carbonization process is described below.

[0013] Includes the following steps: Step 1: Raw material screening. Select high-quality 3-year-old moso bamboo, and remove materials with insect holes, mold, and cracks to ensure the quality of the raw materials; Step 2: Bamboo splitting and filament drawing. The screened raw bamboo is split into bamboo strips, which are then processed into bamboo filaments or strips of specified dimensions using a filament drawing machine. The initial moisture content is 12%. Step 3: High-temperature carbonization. Place the blank in a high-temperature carbonization furnace, heat it to 180°C, introduce saturated steam, and continue processing for 3.5 hours to perform one carbonization. Step 4: Dry until 0% moisture content; Step 5: Re-moisturize and balance moisture. After removing it, re-moisturize it in a constant temperature and humidity room (temperature 25℃, relative humidity 60%) for 48 hours until the moisture content returns to 9%. Step Six: Re-carbonization and conditioning. The re-moistened blanks are sent back into the carbonization furnace for secondary carbonization. The temperature is raised to 170℃ and maintained for 2 hours for secondary carbonization, followed by constant temperature conditioning for 24 hours. Step 7: Segmentation and sharpening / beveling. Cut the chopsticks into segments according to their length specifications, and then use a sharpening machine to shape the chopstick tips, ensuring that the tips are rounded and free of burrs. Step 8: Polishing and grinding. Use fine physical polishing and sanding machine to make the surface of chopsticks smooth and delicate. Use sanding machine grit from 150 grit to 600 grit to finely grind each chopstick. Step Nine: Sorting and sterilization, selecting those with carbonized color differences; physical sterilization is carried out using ultraviolet light or ozone before leaving the factory to prevent secondary pollution; manual sorting is used to ensure uniform color before packaging.

[0014] The chopsticks produced are a uniform dark brown color with a smooth surface free of paint film. Testing revealed no detectable sulfur dioxide or hydrogen peroxide, formaldehyde migration was <0.5 mg / kg, and heavy metal migration met national standards. After being placed in an environment with 85% relative humidity and 30℃ for 90 consecutive days, no mold was observed. They are packaged in plastic-free, environmentally friendly cardboard boxes.

[0015] Example 2: The present invention provides a technical solution: a method for preparing chopsticks using a purely physical carbonization process is described below.

[0016] Includes the following steps: Step 1: Raw material screening. Select high-quality 5-year-old moso bamboo, and remove materials with insect holes, mold, and cracks to ensure the quality of the raw materials; Step 2: Bamboo splitting and filament drawing. The screened raw bamboo is split into bamboo strips, which are then processed into bamboo filaments or strips of specified dimensions using a filament drawing machine. The initial moisture content of the filaments is 35%. Step 3: High-temperature carbonization. Place the blank in a high-temperature carbonization furnace, heat it to 200°C, introduce saturated steam, and maintain it for 2.5 hours to perform one carbonization cycle. Step 4: Dry until 0% moisture content; Step 5: Rehydration and moisture balance. Place the carbonized blank in a constant temperature and humidity environment and let it stand until the moisture content reaches 10%. Step Six: Re-carbonization and Curing. The re-moistened blank is sent back into the carbonization furnace for secondary carbonization to further stabilize the material. The secondary carbonization is carried out at 190℃ for 1.5 hours, and then placed in a constant temperature environment for curing for 15 days to fully release internal stress and eliminate the risk of deformation. Step 7: Segmentation and sharpening / beveling. Cut the chopsticks into segments according to their length specifications, and then use a sharpening machine to shape the chopstick tips, ensuring that the tips are rounded and free of burrs. Step 8: Polishing and grinding. Use fine physical polishing and sanding machine to make the surface of the chopsticks smooth and delicate. Step Nine: Sorting and sterilization, selecting for carbonization color differences; physical sterilization is carried out before leaving the factory using ultraviolet light or ozone to prevent secondary pollution; manual sorting is used to ensure uniform color; no surface coating is applied, and the product is directly sterilized and packaged.

[0017] The chopsticks produced have a slightly darker color and a good smoothness. Tests showed that no chemical residues were detected. Under normal household use conditions (daily washing and natural drying), they showed no mold or deformation after 6 months of continuous use.

[0018] Example 3: The present invention provides a technical solution: a method for preparing chopsticks using a purely physical carbonization process is described below.

[0019] Includes the following steps: Step 1: Raw material screening. Select high-quality 4-year-old chicken wing wood, and remove materials with insect holes, mold, and cracks to ensure the quality of the raw materials; Step 2: The screened logs are split into wood chips, which are then processed into wood fibers or strips of specified dimensions using a wire drawing machine. The initial moisture content is 12%. Step 3: High-temperature carbonization. Place the blank in a high-temperature carbonization furnace, heat it to 200°C, introduce saturated steam, and continue processing for 4 hours to perform one carbonization. Step 4: Dry until 0% moisture content; Step 5: Re-moisturize and balance moisture. After removing it, re-moisturize it in a constant temperature and humidity room (temperature 25℃, relative humidity 60%) for 48 hours until the moisture content returns to 9%. Step Six: Re-carbonization and conditioning. The re-moistened blanks are sent back into the carbonization furnace for secondary carbonization. The temperature is raised to 190℃ and maintained for 2 hours for secondary carbonization, followed by constant temperature conditioning for 24 hours. Step 7: Segmentation and sharpening / beveling. Cut the chopsticks into segments according to their length specifications, and then use a sharpening machine to shape the chopstick tips, ensuring that the tips are rounded and free of burrs. Step 8: Polishing and grinding. Use fine physical polishing and sanding machine to make the surface of chopsticks smooth and delicate. Use sanding machine grit from 150 grit to 600 grit to finely grind each chopstick. Step Nine: Sorting and sterilization, selecting those with carbonized color differences; physical sterilization is carried out using ultraviolet light or ozone before leaving the factory to prevent secondary pollution; manual sorting is used to ensure uniform color before packaging.

[0020] Example 4: The present invention provides a technical solution: a method for preparing chopsticks using a purely physical carbonization process is described below.

[0021] Includes the following steps: Step 1: Raw material screening. Select high-quality 3-year-old ironwood, and remove materials with insect holes, mold, and cracks to ensure the quality of the raw materials; Step 2: The screened logs are split into wood chips, which are then processed into wood fibers or strips of specified dimensions using a wire drawing machine. The initial moisture content is 12%. Step 3: High-temperature carbonization. Place the blank in a high-temperature carbonization furnace, heat it to 220°C, introduce saturated steam, and continue processing for 2.5 hours to perform one carbonization. Step 4: Dry until 0% moisture content; Step 5: Re-moisturize and balance moisture. After removing it, re-moisturize it in a constant temperature and humidity room (temperature 25℃, relative humidity 60%) for 48 hours until the moisture content returns to 9%. Step Six: Re-carbonization and conditioning. The re-moistened blanks are sent back into the carbonization furnace for secondary carbonization. The temperature is raised to 210℃ and maintained for 2 hours for secondary carbonization, followed by constant temperature conditioning for 24 hours. Step 7: Segmentation and sharpening / beveling. Cut the chopsticks into segments according to their length specifications, and then use a sharpening machine to shape the chopstick tips, ensuring that the tips are rounded and free of burrs. Step 8: Polishing and grinding. Use fine physical polishing and sanding machine to make the surface of chopsticks smooth and delicate. Use sanding machine grit from 150 grit to 600 grit to finely grind each chopstick. Step Nine: Sorting and sterilization, selecting those with carbonized color differences; physical sterilization is carried out using ultraviolet light or ozone before leaving the factory to prevent secondary pollution; manual sorting is used to ensure uniform color before packaging.

[0022] Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art and related fields based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention. Structures, devices, and operating methods not specifically described and explained in the present invention, unless otherwise specified or limited, shall be implemented according to conventional means in the art.

Claims

1. A method for manufacturing chopsticks using a purely physical charring process, characterized by, Includes the following steps: Step 1: Raw material selection, choosing bamboo or hardwood; Step 2: Splitting and drawing bamboo into strips, the raw bamboo is split into strips and then drawn into rough blanks; Step 3: High-temperature carbonization, treating the blanks in an oxygen-free or oxygen-deficient environment at 160℃-220℃ for 2-6 hours; Step 4: Re-moisten and balance the water absorption, restoring the moisture content of the carbonized blank to 8%-12%; Step 5: Return to charcoal and health preservation, and perform a second carbonization process followed by constant temperature health preservation; Step Six: Segmentation and sharpening / beveling, segmenting according to specifications and processing the chopstick tips; Step 7: Polishing and grinding, the product is shaped after multiple rounds of physical polishing; Step 8: Sorting and sterilization. After color sorting, the product is physically sterilized and packaged.

2. The method of claim 1, wherein the chopstick is prepared by a pure physical charring process, and the method is characterized in that: In step three, the high-temperature carbonization uses saturated steam as the heat transfer medium.

3. The method as claimed in claim 1, wherein the process of making chopsticks using pure physical charring process is characterized by: In step five, the re-carbonization treatment temperature is 160℃-200℃, and the treatment time is 1-3 hours.

4. The method for preparing chopsticks using a purely physical carbonization process according to claim 1, characterized in that: The multiple physical polishing steps described in step seven are performed by gradually grinding with a sander ranging from 150 grit to 600 grit.

5. The method for preparing chopsticks using a purely physical carbonization process according to claim 1, characterized in that: In step eight, the sterilization method is physical sterilization using ultraviolet light or ozone.

6. The method for preparing chopsticks using a purely physical carbonization process according to claim 1, characterized in that: The raw material is 3-5 year old moso bamboo with a moisture content of 35% before carbonization.