Continuous processing method of bamboo fiber composite board

Abstract

According to the continuous processing method of the bamboo fiber composite board, the bamboo fibers subjected to special flame retardant treatment and the synthetic fibers with the low melting point are ingeniously combined, an adhesive does not need to be added, and the high-performance flame-retardant bamboo fiber composite board is produced through a blending felt forming process and a continuous laminating process of a double-belt type hot press. The board is green and low-carbon, has the advantages of light weight, high strength, no formaldehyde, favorable flame retardancy, excellent biological erosion resistance, excellent sound insulation effect, excellent compression resistance, favorable plasticity and favorable machining adaptability, and can be used for furniture, architectural decoration, automotive trim, electronic circuit boards and the like. Wide application prospects are also shown in the fields of municipal administration, water conservancy, traffic, low-altitude economy, new energy and the like.

Description

Technical field

[0001] The invention belongs to the technical field of application and processing of natural bamboo fibers, and particularly relates to a continuous processing method for a bamboo fiber composite board. [Background Technology]

[0002] Traditional bamboo fiberboard processing technology mostly uses intermittent pressurized production methods, which not only has low production efficiency, but also often requires reliance on adhesives for bonding, which undoubtedly increases the risk of formaldehyde residues and affects the environmental performance of the board. For example, a bamboo fiber composite board formula and production process CN202411035157.8 "heats the mold cavity to 220 degrees Celsius, and then lays the bamboo fiber raw material, bamboo fiber raw material, PET mixture, adhesive and auxiliary materials in a uniform layer in the molded mold cavity by a layering method." Various adhesives and chemical auxiliary materials are added during the manufacturing process. In addition, traditional processes also have bottlenecks in improving flame retardant properties, making it difficult to meet the high standards of safety performance required by modern life. [Summary of the invention]

[0003] To address the shortcomings of existing technologies, this paper proposes a continuous processing method for bamboo fiber composite boards. This method uses flame-retardant high-strength bamboo fiber as the primary raw material. This method involves blending it with low-melting-point synthetic fibers, carding it into felt, and then continuously hot-pressing it into boards. Without the addition of adhesives, this method successfully addresses the problems of low production efficiency, poor environmental performance, and inadequate flame retardancy associated with conventional technologies.

[0004] The invention uses high-strength bamboo fiber that has been flame-retardant treated as a main raw material, blends it with low-melting-point synthetic fiber, and carding it into felt, which is then continuously hot-pressed into a board.

[0005] The present invention is achieved by the following steps:

[0006] Step 1: Pretreatment: Degumming and drying the natural bamboo fiber to control its moisture content between 8% and 12%.

[0007] Step 2, flame retardant solution preparation: potassium dihydrogen phosphate (18% to 25%), boric acid (6% to 10%), surfactant (sodium lignin sulfonate, 2% to 3%) and an appropriate amount of deionized water are mixed uniformly according to specific weight percentages to form a flame retardant solution.

[0008] Step 3: Flame retardant treatment: The bamboo fiber is immersed in the flame retardant solution and maintained at a temperature of 60°C to 80°C for 30 to 60 minutes, with the liquid-to-solid ratio controlled between 8 and 12:1. The fiber is then dehydrated and dried to obtain flame retardant bamboo fiber.

[0009] Step 4, blending into felt: uniformly mix the flame-retardant bamboo fiber and the low-melting-point synthetic fiber in a weight ratio of 60% to 80% and 40% to 20%, and form a flame-retardant blended felt with a density of 80 to 150 g / m2 through a carding and laying process.

[0010] Step 5: Preheating: stack multiple layers of flame-retardant blended felt and introduce them into a hot air drying tunnel for heating. The heating temperature must reach the melting point of the low-melting-point synthetic fiber, but must not exceed 180°C to avoid negatively affecting the strength of the bamboo fiber.

[0011] Step 6, continuous hot pressing molding: Use a double-belt hot press to continuously press the preheated flame retardant blended felt. The temperature of the hot pressing zone is also set to the melting point of the low-melting-point synthetic fiber, and it is shaped and output through the pressure-maintaining cooling zone.

[0012] Step 7: Cut the finished product: Use the laser cutting system to cut the pressed sheet to a fixed length to obtain the finished product of the predetermined size.

[0013] The above method is characterized in that the low-melting-point synthetic fiber is a synthetic fiber with a melting point below 180° C., such as modified polyester fiber, polyolefin fiber, polyvinyl chloride, polylactic acid (PLA), etc.

[0014] In the above method, the total duration of heating and hot pressing in steps 5 and 6 shall not exceed 30 minutes.

[0015] The above method is characterized in that the hot pressing pressure in step 6 is 0.8 to 1.5 MPa.

[0016] The bamboo fiber composite board of the present invention is green and low-carbon. It is not only light, high-strength, formaldehyde-free, has good flame retardant properties and outstanding resistance to biological erosion, but also has excellent sound insulation and compression resistance, good plasticity and mechanical processing adaptability. It can be used for furniture, building decoration, automobile interiors, electronic circuit boards, and also shows broad application prospects in municipal administration, water conservancy, transportation, low-altitude economy, new energy and other fields. [Specific implementation method]

[0017] Example 1:

[0018] Bamboo fiber and polyester fiber composite board. The polyester fiber has a LOI value of 24-26, and a flame retardant is used at the lower limit. The hot pressing pressure is 1.5 MPa.

[0019] Step 1: Pretreatment: Degumming and drying the natural bamboo fiber to a moisture content of 8%.

[0020] Step 2, flame retardant solution preparation: flame retardant solution is prepared by weight percentage: 18% potassium dihydrogen phosphate, 6% boric acid, 2% surfactant (sodium lignin sulfonate), and deionized water to make 100%;

[0021] Step 3, flame retardant treatment: soak the bamboo fiber in a flame retardant solution at 60-80°C for 30 minutes, with a liquid-to-solid ratio of 8-12:1, dehydrate and dry to obtain flame retardant bamboo fiber;

[0022] Step 4, blending into felt: the flame-retardant bamboo fiber and the modified polyester fiber with a melting point of 120° C. are mixed in a weight ratio of 60:40, and the mixture is carded and laid to form a flame-retardant blended felt of 80-150 g / m2;

[0023] Step 5: Preheating: stack multiple layers of flame retardant blended felt and introduce them into a hot air drying tunnel to heat them to 120°C;

[0024] Step 6: Continuous hot pressing: Use a double-belt hot press to continuously press, the temperature of the hot pressing zone is 120°C, and then pass through the pressure-maintaining cooling zone to finalize the shape and output;

[0025] Step 7: Cut the finished product: After the sheet is formed, the laser cutting system will cut it to the predetermined size to complete the production.

[0026] Example 2:

[0027] Bamboo fiber and polyolefin fiber composite board. The LOI value of polyolefin fiber (such as polyethylene and polypropylene) is 17-18, and the flame retardant is at the upper limit. The hot pressing pressure is 1MPa.

[0028] Step 1, pretreatment: degumming and drying the natural bamboo fiber to a moisture content of 10%;

[0029] Step 2, flame retardant solution preparation: prepare flame retardant solution by weight percentage: 25% potassium dihydrogen phosphate, 10% boric acid, 3% surfactant (sodium lignin sulfonate), and add deionized water to make 100%;

[0030] Step 3, flame retardant treatment: soak the bamboo fiber in a flame retardant solution at 60-80°C for 60 minutes, with a liquid-to-solid ratio of 8-12:1, dehydrate and dry to obtain flame retardant bamboo fiber;

[0031] Step 4, blending into felt: the flame-retardant bamboo fiber and the modified polyolefin fiber with a melting point of 138° C. are mixed in a weight ratio of 80:20, and the mixture is carded and laid to form a flame-retardant blended felt of 80-150 g / m2;

[0032] Step 5: Preheating: stack multiple layers of flame retardant blended felt and introduce them into a hot air drying tunnel to heat them to 138°C;

[0033] Step 6: Continuous hot pressing: Use a double-belt hot press to continuously press, the temperature of the hot pressing zone is 138°C, and then pass through the pressure-maintaining cooling zone to finalize the shape and output;

[0034] Step 7: Cut the finished product: After the sheet is formed, the laser cutting system will cut it to the predetermined size to complete the production.

[0035] Example 3:

[0036] Bamboo fiber and PVC fiber composite board. The LOI value of the PVC fiber is 18-20, and the flame retardant is a medium value. The hot pressing pressure is 0.8 MPa.

[0037] Step 1, pretreatment: degumming and drying the natural bamboo fiber to a moisture content of 12%;

[0038] Step 2, flame retardant solution preparation: prepare flame retardant solution by weight percentage: 20% potassium dihydrogen phosphate, 8% boric acid, 2.5% surfactant (sodium lignin sulfonate), and add deionized water to make 100%;

[0039] Step 3, flame retardant treatment: soak the bamboo fiber in a flame retardant solution at 60-80°C for 40 minutes, with a liquid-to-solid ratio of 8-12:1, dehydrate and dry to obtain flame retardant bamboo fiber;

[0040] Step 4, blending into felt: flame-retardant bamboo fiber and modified polyvinyl chloride fiber with a melting point of 175°C are mixed in a weight ratio of 70:30, and the mixture is carded and laid to form a flame-retardant blended felt of 80-150g / m2;

[0041] Step 5: Preheating: stack multiple layers of flame retardant blended felt and introduce them into a hot air drying tunnel to heat them to 175°C;

[0042] Step 6: Continuous hot pressing: Use a double-belt hot press to continuously press, the temperature of the hot pressing zone is 175°C, and then it is shaped and output in the pressure-maintaining cooling zone;

[0043] Step 7: Cut the finished product: After the sheet is formed, the laser cutting system will cut it to the predetermined size to complete the production.

[0044] Although the specific embodiments of the present invention are described above, those skilled in the art should understand that the specific embodiments described are merely illustrative and are not intended to limit the scope of the present invention. Equivalent modifications and changes made by those skilled in the art in accordance with the spirit of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A continuous processing method for bamboo fiber composite board, characterized in that: The following steps are included in sequence: Step 1: Pretreatment: Degumming and drying the natural bamboo fiber to control its moisture content between 8% and 12%. Step 2, flame retardant solution preparation: potassium dihydrogen phosphate (18% to 25%), boric acid (6% to 10%), surfactant (sodium lignin sulfonate, 2% to 3%) and an appropriate amount of deionized water are mixed uniformly according to specific weight percentages to form a flame retardant solution. Step 3: Flame retardant treatment: The bamboo fiber is immersed in the flame retardant solution and maintained at a temperature of 60°C to 80°C for 30 to 60 minutes, with the liquid-to-solid ratio controlled between 8 and 12:

1. The fiber is then dehydrated and dried to obtain flame retardant bamboo fiber. Step 4, blending into felt: uniformly mix the flame-retardant bamboo fiber and the low-melting-point synthetic fiber in a weight ratio of 60% to 80% and 40% to 20%, and form a flame-retardant blended felt with a density of 80 to 150 g / m2 through a carding and laying process. Step 5: Preheating: stack multiple layers of flame-retardant blended felt and introduce them into a hot air drying tunnel for heating. The heating temperature must reach the melting point of the low-melting-point synthetic fiber, but must not exceed 180°C to avoid negatively affecting the strength of the bamboo fiber. Step 6, continuous hot pressing molding: Use a double-belt hot press to continuously press the preheated flame retardant blended felt. The temperature of the hot pressing zone is also set to the melting point of the low-melting-point synthetic fiber, and it is shaped and output through the pressure-maintaining cooling zone. Step 7: Cut the finished product: Use the laser cutting system to cut the pressed sheet to a fixed length to obtain the finished product of the predetermined size.

2. The method according to claim 1, wherein: The low-melting-point synthetic fiber is a synthetic fiber with a melting point lower than 180°C. Such as modified polyester fiber, polyolefin fiber, polyvinyl chloride, polylactic acid PLA, etc.

3. As described in claim 1, the total duration of heating and hot pressing in steps 5 and 6 shall not exceed 30 minutes.

4. The method according to claim 1, wherein: Hot pressing pressure in step 6: 0.8-1.5 MPa.