Bamboo pencil board softening modification production method

Abstract

The invention relates to the technical field of pencil board processing, and particularly discloses a bamboo pencil board softening and modifying production method which comprises the steps of cutting off, subdivision, fragmentation, rough planing, high-temperature softening of rectangular bamboo chips, high-pressure dipping, heating and softening, drying and finish planing and automatic gluing, blank assembling and flat splicing and gluing. In addition, free acetic acid generated through high-temperature treatment can inhibit growth of decay fungi and improve decay resistance and durability, bamboo fibers are softened and fluffy and wettability is improved by preferably selecting a penetrating softener, and therefore permeability of other agents is improved, and the effect of preventing and treating the bamboo fibers is achieved. According to the high-hardness bamboo pencil material, the problem that the bamboo pencil material is difficult to roll and cut due to high hardness is completely solved. According to the method, rapid and automatic mass production of the pencil board with the antibacterial function can be achieved, the daily output can be greatly improved, the labor efficiency is improved, and therefore the cost is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of pencil board processing, and in particular to a softening and modified production method of a bamboo pencil board. Background Art

[0002] my country is a major manufacturer of wooden pencils in the world, with an annual output of more than 50 billion pencils, accounting for 47.2% of the total output of pens in my country. The pencil industry uses about 900,000 to 1.1 million cubic meters of wood per year. At present, the commercially available pencils are made of basswood and poplar. Basswood has a long growth cycle and cannot be planted artificially, and excessive logging is becoming increasingly scarce. Bamboo, as a green, low-carbon, and degradable biomass material, has great potential in responding to global plastic bans, plastic restrictions, low-carbon, and green development, especially in the field of pencil manufacturing.

[0003] Bamboo is the fastest growing plant in the world, with a maximum growth rate of 1.21m per 24 hours. It can complete high and thick growth in 2-3 months, and can become a forest in 3-5 years. Once planted, it can be used sustainably. Natural bamboo has high density and hardness. In particular, it is affected by its own structure, bamboo age, location, soil and climate of the origin. The density of each bamboo varies greatly, making it difficult to roll and cut. In addition, the existing bamboo pieces are small in width, with low yield and high cost of preparing pencils. Therefore, a new preparation method for bamboo pencil boards is needed to solve the above problems. Summary of the invention

[0004] The purpose of the present invention is to provide a method for softening and modifying a bamboo pencil board to solve the problems raised in the above background technology. To achieve the above purpose, the present invention provides the following technical solutions:

[0005] A method for softening and modifying a bamboo pencil board comprises the following steps:

[0006] S1: Cutting, splitting, slicing, and rough planing: Select a bamboo tube with a small end outer diameter greater than 90 mm, saw a length of 1.6 to 2.1 m, and then split the bamboo tube into two bamboo slices with a width of 19 to 25 mm and 35 to 43 mm. Use a wire drawing bamboo slice rough planing machine to slice the 19 to 25 mm wide bamboo slices into two pieces of bamboo green and bamboo yellow. The thickness of the bamboo green is 2 to 4 mm, and it is cut into green silk with a width of 2 to 4 mm; the thickness of the bamboo yellow is 5.5 to 7 mm and it is cut into rough planed rectangular bamboo slices with a width of 18 to 24 mm; the bamboo slices with a width of 35 to 43 mm are sliced ​​into two pieces of bamboo green and bamboo yellow by rough planing. The thickness of the bamboo green is 2 to 3 mm and it is used to prepare knife, fork and spoon slices with a width of 33 to 40 mm; the thickness of the bamboo yellow is 5.5 to 7 mm and it is used to prepare rough planed rectangular bamboo slices with a width of 33 to 40 mm;

[0007] S2: high temperature softened rectangular bamboo pieces;

[0008] S3: High-pressure impregnation heating softening: Put the high-temperature softened rectangular bamboo pieces into the high-pressure impregnation tank, and use vacuum to suck the osmotic softener mixture at a temperature of 40-60°C into the high-pressure impregnation tank, and keep it at an impregnation pressure of 5-20Mpa for 10-20min. This process mainly uses high pressure to fully penetrate the softener into the bamboo. In order to prevent the high-pressure bamboo cells from collapsing, the pressure is adjusted to 2-5Mpa and kept for 1-2h. The bamboo fiber is first infiltrated with the fiber softener to fully soften under the action of the penetrant. After the pressure is released, the osmotic softener is drained and the excess osmotic softener in the bamboo cell channel is sucked away by vacuum pressurization. The vacuum degree is -0.98Mpa and the vacuum time is 0.5-1h. The softener is then vacuum-adsorbed and introduced into the high-pressure impregnation tank, and the temperature is 60-80°C and the impregnation pressure is 10-20Mpa for 10-20min. The pressure is then released to 2-5Mpa and kept for 2-3h before being released and taken out;

[0009] S4: Drying and fine planing: Air-dry the high-pressure impregnated and heated softened rectangular bamboo strips for 7 to 10 days, dry them at a temperature of 65 to 80°C to a moisture content of 8 to 12%, and then fine plan them into rectangular bamboo strips with a width of 16 to 23 mm and a thickness of:

[0010] 4.2~5.5mm finely planed rectangular bamboo pieces, width: 31~38mm, thickness: 4.5~6mm;

[0011] S5: Automatic gluing and flat gluing of bamboo pieces: Place the planed rectangular bamboo pieces into the automatic bamboo piece assembly line, apply pencil glue on the side, and the glue application amount is 100-135g / m 3 , turn the bamboo strips over and flatten them with the width facing upwards, and then put them into a continuous hot press. Under the positive unit pressure: 1~1.5Mpa, side pressure: 2~3Mpa, hot pressing temperature: 80~100℃; hot pressing time: 30~120s, the finely planed rectangular bamboo strips are side-jointed into pencil-sized boards with a width of 1.15~1.25m.

[0012] Preferably, in step S2, the high-temperature softening method of the rectangular bamboo chips is one of the following: high-temperature softening by restrained drying and high-temperature and high-humidity softening, wherein the high-temperature softening by restrained drying is as follows: 200 to 400 roughly planed rectangular bamboo chips are formed into a layer, dried in a tunnel-type ventilated drying kiln at 50 to 60°C for 6 to 7 days, and then placed on a drying high-temperature integrated drying bracket, the drying bracket having a side locking device, and treated at a temperature of 65 to 80°C and a humidity of 65 to 80% for 6 to 8 hours to absorb moisture and rebound, and when the moisture content of the rectangular bamboo chips reaches 5 to 10%, the temperature is increased to 90 to 100°C and dried to absolute dryness, and then the temperature is increased at a rate of 2 to 4°C / min to 110 to 120°C, 130 to 140°C, 150 to 160°C, and 165 to 170°C, respectively, for 2 to 3 hours, and then softened at a high temperature of 180 to 200°C for 4 to 6 hours.

[0013] Preferably, high temperature and high humidity softening: 200 to 400 roughly planed rectangular bamboo pieces are placed in a layer on a drying high temperature integrated drying rack with a side locking device at a steam pressure of 4 to 6 kg / cm 2 Treat for 3-5 minutes, then steam pressure 12-15Kg / cm 2 Process for 5 to 12 minutes.

[0014] Preferably, in step S3, the osmotic softener consists of a osmotic agent with a mass fraction of 0.2-1%, a fiber softener with a mass fraction of 1-2.5%, an antibacterial agent with a mass fraction of 0.2-1%, and the balance is water; the softener consists of an emulsifier with a mass fraction of 10-15%, a fiber softener with a mass fraction of 1-2.5%, and the balance is water.

[0015] Preferably, the emulsifier is one or two of emulsified paraffin, food-grade water-soluble wax emulsion and aqueous phase change wax.

[0016] Preferably, the fiber softener is one or two of sodium sulfate, sodium sulfite, sodium carbonate and urea.

[0017] Preferably, the penetrant is one or more of sodium dodecyl sulfate, fatty alcohol polyoxyalkyl ether, alkylphenol polyoxyethylene ether, sodium secondary alkyl sulfonate, and polyethylene glycol fatty acid ester.

[0018] Preferably, the antibacterial agent is one or more of chitosan, quaternary ammonium salt, nanosilver, titanium dioxide, zinc oxide, plant extract, ZnO@Ag, Ag@AgCl, nanosilver / titanium dioxide-chitosan, and nanosilver / titanium dioxide.

[0019] Preferably, in step S5, the pencil glue is: modified vinyl acetate emulsion, and the performance requirement is that it can be glued and formed by hot pressing for 30 to 120 seconds at a temperature of 60 to 80°C, wherein the modified vinyl acetate emulsion is: milky white viscous liquid, solid content 35 to 55%, viscosity 2500 to 5000 / mPa·s, pH value 4.5-6.5, and curing at room temperature for 2 to 3 hours.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] First, in view of the shortcomings of traditional bamboo units, such as small width, high hardness and high cost, a technology for grading bamboo filaments and bamboo slices to optimize the use of materials was invented, which reduced the cost of bamboo for pencils. In view of the high hardness of the yellow part of bamboo, which is easy to mold and bend, a high-temperature softening technology was invented, which can eliminate the hydrophilic hydroxyl groups in the bamboo and generate other hydrophobic groups, which helps to improve the dimensional stability of the bamboo. In addition, the free acetic acid generated by high-temperature treatment can inhibit the growth of decay fungi, improve decay resistance and durability, and prepare bamboo slices into pencil bamboo units that are not easy to warp and deform and have a brittle texture. In view of the poor permeability of bamboo and the difficulty of impregnation and softening, a special softener for pencils was invented. The preferred penetration softener helps to soften, fluff and improve the wettability of bamboo fibers, thereby improving the permeability of other agents, which is conducive to the absorption of softeners to further reduce the strength of the fibers. The ultra-high pressure technology uses a pressure of 10 to 20 MPa to break through the limitation of the traditional impregnation pressure of 2 MPa, and the difficult-to-penetrate emulsifiers, fiber softeners, and antibacterial agents are fully impregnated and filled into the bamboo cell cavity and its cell gaps. The technical improvement of this invention further reduces the cutting resistance of bamboo pencils and increases the smoothness of tool cutting. Through the dual softening technology of high temperature softening and high-pressure impregnation softening, the present invention completely solves the pain point of bamboo pencils being hard and difficult to cut. The present invention preferably selects rapid prototyping pencil glue and antibacterial agent, which can realize the rapid and automated mass production of pencil boards with antibacterial functions, greatly increase daily output, improve labor efficiency and thus reduce costs. DETAILED DESCRIPTION

[0022] The following is a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with specific embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] Example 1.

[0024] The invention provides a method for softening and modifying a bamboo pencil board, comprising the following steps:

[0025] S1: Cutting, splitting, slicing, and rough planing: Select bamboo tubes with a small end outer diameter greater than 90 mm, saw the length of the bamboo tube to 1.6-2.1 m, split the bamboo tube into pieces with a width of 22-25 mm, and then slice the bamboo pieces into bamboo green and bamboo yellow pieces through a wire drawing bamboo rough planing machine. The green bamboo is 2-4 mm thick and cut into green bamboo with a width of 2-4 mm; the yellow bamboo is 5.5-7 mm thick and cut into rough planed rectangular bamboo pieces with a width of 21-24 mm;

[0026] S2: high temperature softened rectangular bamboo pieces;

[0027] S3: High-pressure impregnation heating softening: put the high-temperature softened rectangular bamboo pieces into the high-pressure impregnation tank, and use vacuum to suck the osmotic softener mixture at a temperature of 60°C into the high-pressure impregnation tank, and keep it at an impregnation pressure of 5-20Mpa for 15 minutes. This process mainly uses high pressure to fully penetrate the softener into the bamboo. In order to prevent the high-pressure bamboo cells from collapsing, the pressure is adjusted to 4Mpa and kept for 2 hours. The bamboo fiber is first infiltrated with the fiber softener under the action of the penetrant to fully soften. After the pressure is released, the osmotic softener is drained and the excess osmotic softener in the bamboo cell channel is sucked away by vacuum pressurization. The vacuum degree is -0.98Mpa and the vacuum time is 1h. The softener is then vacuum-adsorbed and introduced into the high-pressure impregnation tank, and the temperature is 80°C and the impregnation pressure is 10Mpa for 10 minutes. The pressure is then released to 5Mpa and kept for 3 hours before being released and taken out;

[0028] S4: Drying and fine planing: The high-pressure impregnation and heating softened rectangular bamboo pieces are air-dried for 7 days, dried at a temperature of 65° C. to a moisture content of 8-12%, and are finely planed into a rectangular shape with a width of 22 mm and a thickness of 5 mm by a rectangular bamboo piece fine planing machine.

[0029] S5: Automatic gluing and flat gluing of bamboo pieces: Place the planed rectangular bamboo pieces into the automatic bamboo paneling line, apply pencil glue on the side, and the glue amount is 120g / m 3 , turn the bamboo strips over and flatten them with the width facing upwards, and then put them into a continuous hot press. Under the positive pressure unit pressure: 1Mpa, side pressure: 2Mpa, hot pressing temperature: 100℃; hot pressing time: 90s, the finely planed rectangular bamboo strips are side-jointed into pencil-sized boards with a width of 1210mm.

[0030] In the present embodiment, in step S2, the high-temperature softening method of the rectangular bamboo pieces is one of the following: high-temperature softening by restrained drying and high-temperature and high-humidity softening, wherein the high-temperature softening by restrained drying is as follows: 200 to 400 roughly planed rectangular bamboo pieces are dried as a layer in a tunnel-type ventilated drying kiln at 50 to 60°C for 7 days, and then placed on a drying high-temperature integrated drying bracket, the drying bracket has a side locking device, and is treated at a temperature of 65°C and a humidity of 80% for 8 hours to absorb moisture and rebound. When the moisture content of the rectangular bamboo pieces reaches 5 to 10%, the temperature is increased to 90 to 100°C and dried until absolutely dry, and then the temperature is increased at a rate of 2 to 4°C / min to 120°C, 140°C, 160°C, and 170°C, respectively, for 2.5 hours, and then softened at 190°C for 4 hours.

[0031] In this embodiment, high temperature and high humidity softening: 200 to 400 roughly planed rectangular bamboo pieces are placed in a layer on a drying high temperature integrated drying bracket, which has a side locking device, at a steam pressure of 6Kg / cm 2 Treat for 5 minutes, then steam pressure 12Kg / cm 2 Process for 10 minutes.

[0032] In this embodiment, in step S3, the osmotic softener is composed of 0.5% of osmotic agent by mass, 2.5% of fiber softener by mass, 1% of antibacterial agent by mass and the balance is water; the softener is composed of 15% of emulsifier by mass, 2.5% of fiber softener by mass and the balance is water.

[0033] In this embodiment, the emulsifier is one or two of emulsified paraffin wax, food-grade water-soluble wax emulsion and aqueous phase change wax.

[0034] In this embodiment, the fiber softener is one or two of sodium sulfate, sodium sulfite, sodium carbonate and urea.

[0035] In this embodiment, the penetrant is one or more of sodium dodecyl sulfate, fatty alcohol polyoxyalkyl ether, alkylphenol polyoxyethylene ether, sodium secondary alkyl sulfonate, and polyethylene glycol fatty acid ester.

[0036] In this embodiment, the antibacterial agent is one or more of chitosan, quaternary ammonium salt, nanosilver, titanium dioxide, zinc oxide, plant extract, ZnO@Ag, Ag@AgCl, nanosilver / titanium dioxide-chitosan, and nanosilver / titanium dioxide.

[0037] In the present embodiment, in step S5, the pencil glue is: modified vinyl acetate emulsion, and the performance requirement is that it can be glued into shape by hot pressing for 120 seconds at a temperature of 80°C, wherein the modified vinyl acetate emulsion is: milky white viscous liquid, solid content 35-55%, viscosity 2500-5000 / mPa·s, pH value 4.5-6.5, and curing at room temperature for 2-3 hours.

[0038] The performance of the bamboo pencil board prepared in the embodiment of the present invention and the existing bamboo pencil board on the market were tested, and the test results are shown in Table 1.

[0039] Table 1

[0040]

[0041]

[0042] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

[0043] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A method for softening and modifying a bamboo pencil board, characterized in that: The following steps are involved: S1: Cutting, splitting, slicing, and rough planing: Select bamboo tubes with a small end outer diameter greater than 90 mm, saw the tubes to a length of 1.6 to 2.1 m, and then split the bamboo tubes into bamboo slices of two specifications with a width of 19 to 25 mm and 35 to 43 mm. Use a wire drawing bamboo slice rough planer to slice the 19 to 25 mm wide bamboo slices into bamboo green and bamboo yellow. The thickness of the bamboo green is 2 to 4 mm, and the bamboo green is cut into green silk with a width of 2 to 4 mm. The bamboo yellow has a thickness of 5.5-7 mm and is cut into roughly planed rectangular bamboo pieces with a width of 18-24 mm; the bamboo pieces with a width of 35-43 mm are roughly planed into two pieces, bamboo green and bamboo yellow. The bamboo green with a thickness of 2-3 mm is used to prepare knife, fork and spoon pieces with a width of 33-40 mm; the bamboo yellow with a thickness of 5.5-7 mm is used to prepare roughly planed rectangular bamboo pieces with a width of 33-40 mm; S2: high temperature softened rectangular bamboo pieces; S3: High-pressure impregnation heating softening: Put the high-temperature softened rectangular bamboo pieces into a high-pressure impregnation tank, and use a vacuum method to suck the osmotic softener mixture at a temperature of 40-60°C into the high-pressure impregnation tank, and keep it at an impregnation pressure of 5-20Mpa for 10-20min, and then adjust the pressure to 2-5Mpa and keep it for 1-2h. After decompression, drain the osmotic softener and absorb the excess osmotic softener in the bamboo cell channel by vacuum pressurization, at a vacuum degree of -0.98Mpa and a vacuum time of 0.5-1h, and then vacuum absorb the softener into the high-pressure impregnation tank, at a temperature of 60-80°C and an impregnation pressure of 10-20Mpa, and keep it for 10-20min, and then decompress it to 2-5Mpa and keep it for 2-3h before decompressing and taking it out; S4: Drying and fine planing: air-drying the high-pressure impregnated heated and softened rectangular bamboo pieces for 7 to 10 days, drying at a temperature of 65 to 80° C. to a moisture content of 8 to 12%, and then using a rectangular bamboo piece fine planing machine to form finely planed rectangular bamboo pieces with a width of 16 to 23 mm and a thickness of 4.2 to 5.5 mm, and finely planed rectangular bamboo pieces with a width of 31 to 38 mm and a thickness of 4.5 to 6 mm; S5: Automatic gluing and flat gluing of bamboo pieces: Place the planed rectangular bamboo pieces into the automatic bamboo piece assembly line, apply pencil glue on the side, and the glue application amount is 100-135g / m 3 , turn the bamboo strips over and flatten them with the width facing upwards, and then put them into a continuous hot press. Under the positive unit pressure: 1~1.5Mpa, side pressure: 2~3Mpa, hot pressing temperature: 80~100℃; hot pressing time: 30~120s, the finely planed rectangular bamboo strips are side-jointed into pencil-sized boards with a width of 1.15~1.25m.

2. The method for softening and modifying a bamboo pencil board according to claim 1, characterized in that: In step S2, the high-temperature softening method of the rectangular bamboo pieces is one of the following: high-temperature softening by restrained drying and high-temperature high-humidity softening. In the case of restrained drying and high-temperature softening, 200 to 400 roughly planed rectangular bamboo pieces are dried as a layer in a tunnel-type ventilated drying kiln at 50 to 60°C for 6 to 7 days, and then placed on a high-temperature integrated drying bracket, the drying bracket is provided with a side locking device, and treated at a temperature of 65 to 80°C and a humidity of 65 to 80% for 6 to 8 hours to absorb moisture and rebound. When the moisture content of the rectangular bamboo pieces reaches 5 to 10%, the temperature is increased to 90 to 100°C and dried to absolute dryness, and then the temperature is increased at a rate of 2 to 4°C / min to 110 to 120°C, 130 to 140°C, 150 to 160°C, and 165 to 170°C, respectively, for 2 to 3 hours, and then softened at a high temperature of 180 to 200°C for 4 to 6 hours.

3. The method for softening and modifying a bamboo pencil board according to claim 2, characterized in that: High temperature and high humidity softening: Place 200 to 400 roughly planed rectangular bamboo pieces in a layer on a high temperature integrated drying rack with a side locking device at a steam pressure of 4 to 6 kg / cm 2 Treat for 3-5 minutes, then steam pressure 12-15Kg / cm 2 Process for 5 to 12 minutes.

4. The method for softening and modifying a bamboo pencil board according to claim 1, characterized in that: In step S3, the osmotic softener is composed of a osmotic agent with a mass fraction of 0.2-1%, a fiber softener with a mass fraction of 1-2.5%, an antibacterial agent with a mass fraction of 0.2-1%, and the balance is water; the softener is composed of an emulsifier with a mass fraction of 10-15%, a fiber softener with a mass fraction of 1-2.5%, and the balance is water.

5. The method for softening and modifying a bamboo pencil board according to claim 4, characterized in that: The emulsifier is one or two of emulsified paraffin, food-grade water-soluble wax emulsion and aqueous phase-change wax.

6. The method for softening and modifying a bamboo pencil board according to claim 4, characterized in that: The fiber softener is one or two of sodium sulfate, sodium sulfite, sodium carbonate and urea.

7. The method for softening and modifying a bamboo pencil board according to claim 4, characterized in that: The penetrant is one or more of sodium dodecyl sulfonate, fatty alcohol polyoxyalkyl ether, alkylphenol polyoxyethylene ether, secondary alkyl sulfonate sodium, and polyethylene glycol fatty acid ester.

8. The method for softening and modifying a bamboo pencil board according to claim 4, characterized in that: The antibacterial agent is one or more of chitosan, quaternary ammonium salt, nano silver, titanium dioxide, zinc oxide, plant extract, ZnO@Ag, Ag@AgCl, nano silver / titanium dioxide-chitosan, and nano silver / titanium dioxide.

9. The method for softening and modifying a bamboo pencil board according to claim 1, characterized in that: In step S5, the pencil glue is: modified vinyl acetate emulsion, and the performance requirement is that it can be glued and formed by hot pressing for 30 to 120 seconds at a temperature of 60 to 80° C., wherein the modified vinyl acetate emulsion is: milky white viscous liquid, solid content 35 to 55%, viscosity 2500 to 5000 / mPa·s, pH value 4.5-6.5, and curing at room temperature for 2 to 3 hours.

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