A forming device and manufacturing method for sewing particle sandwich panels

Abstract

The present invention relates to a forming device and manufacturing method for sewing particle sandwich panels, belonging to the technical field of manufacturing of biomass-based composite product forming technology. In the present invention, the fiber cloth after applying glue and the biomass particles after mixing with glue are respectively laid in a preform forming device, and a preform is made after pre-pressing and hot-pressing. Then the preform is sewn with the impregnated sewing thread, and finally cured and formed by a hot press. This technology extends the preparation method of sewing sandwich composites to the field of biomass composite forming technology, and compared with the prior art, the drilling step is omitted. Its finished product has high mechanical strength, high anti-creep performance, and also significantly reduces the water absorption thickness swelling rate. When the core layer is prepared with biomass materials such as straw, without chemical treatment and physical screening, commercial standard boards can still be prepared using low-cost urea-formaldehyde resin adhesives. And the manufacturing method can meet the preparation of boards with different size specifications, with low cost and easy to implement.

Description

Technical Field

[0001] The invention relates to a forming device and a manufacturing method of a sewing wood chip sandwich panel, belonging to the technical field of forming and manufacturing technology of biomass-based composite material products. Background Art

[0002] With the continuous development of urbanization and the increasing demand for food, a large amount of waste wood and crop residues such as straw are generated every year. However, the main way of disposal is still landfill or burning, which leads to the intensification of the greenhouse effect. my country has rich biomass resources, but the utilization rate is low, and a large amount of biomass energy is wasted. The production of particleboard is one of the effective ways to improve the utilization rate of biomass. According to statistics, by the end of 2020, my country's annual production capacity of particleboard is 36.91 million m 3 In 2020, the annual production capacity will increase by 3.09 million m 3 , the market demand for particleboard is huge.

[0003] The traditional preparation method of small-particle particleboard is often to lay, pre-press and hot-press the particles after mixing with glue. Due to the limitation of mechanical properties, most of the particleboards prepared by this process are still used in the furniture field, with low added value. Moreover, when the particles are made of biomass materials such as straw, the mechanical properties of straw-based particleboards are poor due to the waxy substances on the surface, and chemical treatment is often required. At the same time, there are many restrictions on the selection of straw raw materials and adhesives. For example, the raw material is the stem part, and the leaf part is not used as much as possible; the adhesive is not suitable for low-priced urea-formaldehyde resin or phenolic resin, etc. This leads to an increase in preparation costs and is not conducive to commodity conversion.

[0004] Sewing sandwich structures bring new ideas to how to improve material performance. The existing preparation methods of sewing sandwich composite materials often consist of drilling holes in the material first, and then going through the steps of sewing, dipping in glue, and curing and molding. However, when drilling holes in the material, if the material is very thin, flexible material or material with low lateral compression strength, such as thin urea-formaldehyde resin straw particleboard with poor mechanical properties, the material itself is prone to bending and deformation after being fixed, or cracks in the core layer during the drilling process, etc., which will lead to a decrease in the strength between the materials and even destroy the mechanical properties of the material itself. Therefore, the preparation of preforms for sewing particleboard sandwich panels by drilling is not suitable for all biomass materials, such as biomass straw. Summary of the invention

[0005] The purpose of the present invention is to extend the preparation method of sewing sandwich composite materials to the technical field of biomass-based composite material product molding, improve the method to remove the drilling step, and make it more suitable for biomass materials, such as small-particle biomass shavings, fiber cloth, etc., so as to design a molding device and provide a method for manufacturing a sewing shavings sandwich panel.

[0006] Technical solution of the present invention:

[0007] A manufacturing method of a sewn particle sandwich panel is as follows:

[0008] 1) Prepare the particles, adhesive, curing agent, fiber cloth, and sewing thread required for manufacturing the sewn particle sandwich panel;

[0009] 2) Coat the preforming device of the sewn particle sandwich panel with a release agent;

[0010] 3) Double-side coat the fiber cloth with glue and lay it on the small-hole plate. The fiber cloth is below the small-hole plate. Align the cylinders on the bottom plate with the corresponding holes on the small-hole plate, and then press the fiber cloth and the small-hole plate onto the bottom plate simultaneously;

[0011] 4) Remove the small-hole plate and assemble the mold onto the bottom plate;

[0012] 5) Stir the particles and the adhesive, and then lay them in the mold;

[0013] 6) Double-side coat the fiber cloth with glue again and lay it on the small-hole plate. The fiber cloth is below the small-hole plate. Align the holes, and then press the fiber cloth and the small-hole plate onto the laid particles simultaneously;

[0014] 7) Assemble the grid pressing plate onto the small-hole plate, and then put it into a pre-press for pre-pressing;

[0015] 8) After pre-pressing, remove the mold and take out the small-hole plate and the grid pressing plate. Assemble the large-hole plate and the grid pressing plate onto the top-layer fiber cloth respectively;

[0016] 9) Put the bottom plate, materials, large-hole plate, and grid pressing plate into a hot press for hot pressing to form a preform;

[0017] 10) Sew the preform with a sewing thread. The sewing method is an improved lockstitch sewing method. When sewing, first thread a glue-impregnated sewing thread from above, and then thread a glue-impregnated bobbin thread from below;

[0018] 11) Hot-press the sewn preform by hot pressing to form, and obtain a sewn particle sandwich composite board after curing.

[0019] The particles are broken from wood or biomass materials.

[0020] The bottom plate includes a metal plate and rows of cylinders. The top of the cylinder is conical. The bottom plate is prepared from a metal material.

[0021] The size of the small-hole plate is slightly smaller than the inner diameter of the mold. The hole positions on the hole plate are consistent with the center positions of the cylinders on the bottom plate. The hole diameter of the hole plate is slightly larger than the diameter of the cylinders on the bottom plate, with an error of 0.5 mm to 1.5 mm.

[0022] The size of the perforated plate is more than 60 mm larger than the inner diameter of the mold. The hole positions on the perforated plate are consistent with the center positions of the cylinders on the bottom plate. The aperture of the perforated plate is slightly larger than the diameter of the cylinders on the bottom plate, with an error of 0.5 mm to 1.5 mm. The perforated plate is made of metal material.

[0023] The grid pressing plate is made of metal material. The thickness of the grid plate is less than the net size between the cylinders on the bottom plate. The position of the grid plate is at the interval between the cylinders on the bottom plate. The height of the grid plate is higher than the heights of the mold and the cylinders on the bottom plate.

[0024] The thickness of the finished product after the second hot pressing is the same as that after the first hot pressing.

[0025] The beneficial effects of the present invention are as follows: The method for preparing the sewn particle sandwich board of the present invention is applicable to forming of different sizes. The particle core layer material can be any wood and biomass material. When the material is straw, the preform prepared by this method will not show the core layer cracking phenomenon caused by the previous drilling process, effectively reducing the requirements for the performance of raw materials (in the experiment, the straw was directly obtained from the farm and directly crushed with the connecting rod and leaves), and can greatly reduce the raw material acquisition cost. At the same time, during the preparation process, the finished product can obtain sufficient mechanical strength to meet the commercial standards without chemical treatment and physical screening. The cost is low and it is easy to implement. Compared with the existing particle board, the bending strength can be increased by more than 3 times, and the water absorption thickness swelling rate is also greatly reduced. It can be used as a load-bearing material in more fields such as construction, packaging, pallets, etc., not only improving the utilization rate of biomass materials, but also carbon sequestration, which is beneficial to achieving the carbon neutrality goal as soon as possible. Description of the Drawings

[0026] Figure 1 It is a forming device for the preform of the sewn particle sandwich board.

[0027] Figure 2 It is the preform of the sewn particle sandwich board. Detailed Embodiments

[0028] The present invention will be described in detail below with reference to specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made. These all belong to the protection scope of the present invention.

[0029] Embodiment 1

[0030] This embodiment provides a manufacturing method for a wood-based jute fiber sewn particle sandwich board. The forming device for the preform is as Figure 1 shown, and specifically includes the following steps:

[0031] In this embodiment, the product selects jute fiber cloth (25S*25S), and the fiber density is 1.5 g / cm3 ; The adhesive used is urea-formaldehyde resin adhesive, the curing temperature is 100°C to 170°C, and the curing agent is an aqueous ammonium chloride solution with a concentration of 20%. The sewing thread is jute fiber with a size of 1 mm. The wood shavings are ordinary wood shavings with the following dimensions: length 18 mm to 15 mm, width 3 mm to 6 mm, and thickness 0.2 mm to 0.6 mm.

[0032] The preform forming device is made of stainless steel and includes a bottom plate, a mold, a perforated plate, and a grid pressing plate. The specific dimensions are as follows: The outer dimensions of the bottom plate are 440 mm × 420 mm, with a row of stainless steel cylinders welded in the middle. The top of the cylinder is conical, the cylinder diameter is 2 mm, the total height is 150 mm, and the center distance between the cylinders is 10 mm × 10 mm; The outer dimensions of the mold are 440 mm × 420 mm, the inner dimensions are 340 mm × 320 mm, and the height is 150 mm; The outer dimensions of the small perforated plate are 338 mm × 318 mm, the outer dimensions of the large perforated plate are 438 mm × 418 mm, with a row of round holes in the middle, the hole diameter is 2.5 mm to 3 mm, and the center distance between the holes is 10 mm × 10 mm; The outer dimensions of the grid pressing plate are 440 mm × 420 mm, the height of the grid plate is 200 mm, and the thickness is 5 mm.

[0033] Apply a release agent to the preform forming device. Measure the moisture content of the wood shavings, cut the jute fiber cloth with dimensions of length 320 mm and width 340 mm. Weigh the jute fiber cloth, and then weigh the wood shavings, glue, and curing agent respectively, so that the density of the preform made after final hot pressing is 0.7 g / cm 3, with a thickness of 12 mm, the mass of the adhesive solid powder is 10% of the dry weight of the wood chips, and the mass of the 20% concentration ammonium chloride aqueous solution is 3.5% of the mass of the adhesive solid powder. Weigh the solid glue powder, curing agent and water and stir them to obtain a urea-formaldehyde resin adhesive solution. Then, by means of spraying glue, the glue solution and the wood chips are evenly mixed together under the action of a mixer to form a mixture. Weigh the urea-formaldehyde resin glue powder again, with a mass of 40% of the mass of the jute fiber cloth. Mix it with water in a ratio of 1:1 and add a 20% concentration ammonium chloride aqueous solution. Brush the obtained adhesive aqueous solution on both sides of the linen. Lay one of the brushed linens on the small hole plate, then invert the linen and the small hole plate, align the hole positions with the corresponding positions of the cylinders on the bottom plate, press down the small hole plate and lay the linen on the bottom plate. Remove the small hole plate and assemble the mold on the bottom plate. Lay the wood chip mixture in the mold. Lay the other linen brushed with the adhesive on the small hole plate, invert it, align the hole positions with the cylinders on the bottom plate, and press down the small hole plate to press the linen and the small hole plate above the mixture at the same time. Place the grid pressing plate on the small hole plate. Put the bottom plate, materials, small hole plate and grid pressing plate into a pre-press for pre-pressing, with a pressure of 1.5 MPa and a time of 30 s. After pre-pressing, remove the grid pressing plate, small hole plate and mold, align the large hole plate with the hole positions and place it on the linen, and then place the grid pressing plate. Put the bottom plate, materials, large hole plate and grid pressing plate into a hot press for hot pressing, with a hot pressing pressure of 10 MPa, a hot pressing temperature of 150 °C and a hot pressing time of 8 min. After hot pressing and taking out, cut it, cut off the edge part to make a preform, as Figure 2 shown. Use jute fiber sewing thread with a thickness of 1 mm to sew the preform by an improved lockstitch sewing method. The thread needs to be impregnated with glue before sewing, and the glue is urea-formaldehyde resin adhesive. After sewing, put it into a hot press for hot pressing, and ensure that the thickness of the specimen remains unchanged before and after hot pressing. The hot pressing temperature is 120 °C and the time is 3 min. After the specimen is cured and formed, a wood-based jute fiber sewn wood chip sandwich panel can be obtained.

[0034] Example 2

[0035] This example provides a manufacturing method of a biomass-based basalt fiber sewn wood chip sandwich panel. The preform forming device is as Figure 1 shown, and specifically includes the following steps:

[0036] For the product of this example, basalt fiber cloth (25S*25S) is selected; the adhesive is phenolic resin adhesive, and the curing temperature is 100 °C to 170 °C; the sewing thread is basalt fiber with a size of 1 mm; the wood chips are corn straw wood chips, and the size of the wood chips is: length 18 mm to 15 mm, width 3 mm to 6 mm, thickness 0.2 mm to 0.6 mm.

[0037] The preform forming device is the same as that in Example 1.

[0038] Apply a release agent to the preform forming device. Measure the moisture content of the wood chips, cut the basalt fiber cloth with dimensions of 320 mm in length and 340 mm in width. Weigh the basalt fiber cloth, and then weigh the wood chips and the glue separately, so that the density of the finally hot-pressed preform is 0.7 g / cm 3 , with a thickness of 12 mm. The mass of the phenolic resin solid powder is 10% of the dry weight of the wood chips. Stir the weighed solid glue powder with water to obtain a phenolic resin adhesive solution, and make the glue solution and the wood chips evenly mixed together under the action of a mixer by means of spraying glue. Weigh the phenolic resin solid powder, and its mass is 40% of the mass of the basalt fiber cloth. Apply the aqueous phenolic resin adhesive solution to both sides of the basalt fiber cloth. Lay one of the coated fiber cloths on the small hole plate, then invert the fiber cloth and the small hole plate, align the hole positions with the corresponding positions of the cylinders on the bottom plate, press down the small hole plate and lay the fiber cloth on the bottom plate. Remove the small hole plate, and assemble the mold onto the bottom plate. Lay the wood chip mixture in the mold. Lay the other fiber cloth coated with the adhesive on the small hole plate, invert it, align the hole positions with the holes of the cylinders on the bottom plate, and press down the small hole plate to press the fiber cloth and the small hole plate above the mixture at the same time. Place the grid pressing plate on the small hole plate. Put the bottom plate, the material, the small hole plate and the grid pressing plate into a pre-press for pre-pressing, with a pressure of 1.5 MPa and a time of 30 s. After pre-pressing, remove the grid pressing plate, the small hole plate and the mold, align the large hole plate with the hole positions and place it on the fiber cloth, and put on the grid pressing plate. Put the bottom plate, the material, the large hole plate and the grid pressing plate into a hot press for hot pressing, with a hot pressing pressure of 10 MPa, a hot pressing temperature of 150 °C and a hot pressing time of 20 min. After hot pressing and taking out, cut it, cut off the edge part, and make a preform, as Figure 2 shown. Use basalt fiber sewing thread with a thickness of 1 mm to sew the preform by an improved lockstitch sewing method. The thread needs to be impregnated with glue before sewing, and the glue is a phenolic resin adhesive. After sewing, put it into a hot press for hot pressing, and ensure that the thickness of the specimen remains unchanged before and after hot pressing. The hot pressing temperature is 120 °C and the time is 3 min. After the specimen is cured and formed, a biomass-based basalt fiber sewn wood chip sandwich panel can be obtained.

Claims

1. A forming device and manufacturing method for sewing particle sandwich panels, characterized in that, The steps are as follows: 1) Prepare the wood chips, adhesive, curing agent, fiber cloth, and sewing thread required for manufacturing the sewn particle sandwich board; 2) Coat the preforming device of the sewn particle sandwich board with a release agent; 3) Double-side coat the fiber cloth with adhesive and lay it on the small hole plate. The fiber cloth is below the small hole plate. Align the cylinders on the bottom plate with the corresponding holes on the small hole plate, and then press the fiber cloth and the small hole plate onto the bottom plate simultaneously; 4) Remove the small hole plate and assemble the mold onto the bottom plate; 5) Stir the wood chips and the adhesive, and then lay them in the mold; 6) Double-side coat another fiber cloth with adhesive and lay it on the small hole plate. The fiber cloth is below the small hole plate. Align the holes and then press the fiber cloth and the small hole plate onto the laid wood chips simultaneously; 7) Assemble the grid pressing plate onto the small hole plate, and then place it in a pre-press for pre-pressing; 8) After pre-pressing, remove the mold and take out the small hole plate and the grid pressing plate. Assemble the large hole plate and the grid pressing plate onto the top layer fiber cloth respectively; 9) Put the bottom plate, large hole plate, grid pressing plate, the wood chip and adhesive mixture obtained in step 8, and the adhesive-coated fiber cloth into a hot press for hot pressing to form a preform; 10) Sew the preform with sewing thread. The sewing method is an improved lockstitch sewing method. When sewing, first thread a glue-impregnated sewing thread from above, and then thread a glue-impregnated bobbin thread from below; 11) Hot press the sewn preform by hot pressing to form it, and obtain the sewn particle sandwich board after curing.

2. The manufacturing method according to claim 1, characterized in that, The wood chips are made by crushing biomass materials.

3. The manufacturing method according to claim 1, characterized in that, The bottom plate includes a metal plate and rows of cylinders. The top of the cylinder is conical. The bottom plate is made of metal materials.

4. The manufacturing method according to claim 1, characterized in that, The size of the small hole plate is slightly smaller than the inner diameter of the mold. The hole positions on the hole plate are consistent with the central positions of the cylinders on the bottom plate. The hole diameter of the hole plate is slightly larger than the diameter of the cylinders on the bottom plate, with an error of 0.5 mm to 1.5 mm.

5. The manufacturing method according to claim 1, characterized in that, The size of the large hole plate is more than 60 mm larger than the inner diameter of the mold. The hole positions on the hole plate are consistent with the central positions of the cylinders on the bottom plate. The hole diameter of the hole plate is slightly larger than the diameter of the cylinders on the bottom plate, with an error of 0.5 mm to 1.5 mm. The hole plate is made of metal materials.

6. The manufacturing method according to claim 1, characterized in that, The grid pressing plate is made of metal materials. The thickness of the grid plate is less than the net size between the cylinders on the bottom plate. The position of the grid plate is at the intervals between the cylinders on the bottom plate. The height of the grid plate is higher than the heights of the mold and the cylinders on the bottom plate.

7. The manufacturing method according to claim 1, characterized in that, The thickness of the finished product after the second hot pressing is the same as that after the first hot pressing.

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