CN109227839B - Bamboo drying and heat treatment method - Google Patents
Bamboo drying and heat treatment method Download PDFInfo
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- CN109227839B CN109227839B CN201811221293.0A CN201811221293A CN109227839B CN 109227839 B CN109227839 B CN 109227839B CN 201811221293 A CN201811221293 A CN 201811221293A CN 109227839 B CN109227839 B CN 109227839B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
- B27K—PROCESSES, APPARATUS OR SELECTION OF SUBSTANCES FOR IMPREGNATING, STAINING, DYEING, BLEACHING OF WOOD OR SIMILAR MATERIALS, OR TREATING OF WOOD OR SIMILAR MATERIALS WITH PERMEANT LIQUIDS, NOT OTHERWISE PROVIDED FOR; CHEMICAL OR PHYSICAL TREATMENT OF CORK, CANE, REED, STRAW OR SIMILAR MATERIALS
- B27K9/00—Chemical or physical treatment of reed, straw, or similar material
- B27K9/002—Cane, bamboo
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
- B27K—PROCESSES, APPARATUS OR SELECTION OF SUBSTANCES FOR IMPREGNATING, STAINING, DYEING, BLEACHING OF WOOD OR SIMILAR MATERIALS, OR TREATING OF WOOD OR SIMILAR MATERIALS WITH PERMEANT LIQUIDS, NOT OTHERWISE PROVIDED FOR; CHEMICAL OR PHYSICAL TREATMENT OF CORK, CANE, REED, STRAW OR SIMILAR MATERIALS
- B27K5/00—Treating of wood not provided for in groups B27K1/00, B27K3/00
- B27K5/0085—Thermal treatments, i.e. involving chemical modification of wood at temperatures well over 100°C
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Abstract
The invention discloses a bamboo drying and heat treatment method, wherein polyethylene wax is adopted to modify paraffin, and modified paraffin liquid is injected into a treatment tank filled with bamboo for drying treatment until the moisture content of the bamboo is reduced to 6-8%; heating the modified paraffin to 160-200 ℃, and keeping the temperature for 2-6 h; cooling the modified paraffin to 75-100 ℃, taking out the bamboo wood until the modified paraffin entering the bamboo wood is fully solidified; the invention adopts polyethylene wax modified paraffin as a medium to dry and thermally treat the bamboo, capillaries in the bamboo cell wall begin to expand continuously in the treatment process, and the modified paraffin with low molecular weight permeates into the capillaries of the bamboo to realize the replacement with moisture, so that the bamboo is quickly dried; in addition, under the action of high-temperature modified paraffin, organic substances such as hemicellulose, saccharides and the like in the bamboo cell wall are degraded to form a pore structure, and the modified paraffin can enter the cell wall structure and plays a role in physical filling and reinforcing after being cooled and solidified.
Description
Technical Field
The invention belongs to the technical field of bamboo processing, and particularly relates to a method for drying and thermally treating bamboo.
Background
The bamboo high-temperature heat treatment technology is a modification technology for performing short-term pyrolysis treatment on a bamboo material in a high-temperature oxygen-free or low-oxygen-content environment. Through degradation of hemicellulose in the bamboo wood, hydrophilic groups are reduced, and nutrient substances such as starch, saccharides and the like are pyrolyzed, so that the color, weather resistance and dimensional stability of the bamboo wood are effectively improved. No chemical modifier is added in the treatment process, so that the method has good environmental protection property, and in recent years, the industrial application of the bamboo heat treatment technology is realized. According to different heat treatment media, the processes which are researched more at present are mainly divided into three types: a steam treatment process, an inert gas treatment process, and a hot oil treatment process. The steam treatment process can obviously improve the dimensional stability, weather resistance and corrosion resistance of the bamboo, but high-temperature steam can generate strong pyrolysis, hydrolysis and acidolysis on hemicellulose and cellulose substances of the bamboo, so that the strength of the bamboo is obviously reduced. The inert gas treatment process mainly uses nitrogen as an oxygen-isolating protective medium, and can also improve the dimensional stability and the corrosion resistance of bamboo wood, but the nitrogen can cause surface hardening of wood, so that the brittleness of the wood is obviously increased. The hot oil medium in the hot oil treatment process has high heat transfer efficiency, short treatment time and less strength loss, but the method has high treatment cost, can pollute the surface of the material and has the problem of waste oil treatment. In addition, although the water absorption of the bamboo material after the heat treatment in the above manner is reduced, the bamboo material after the heat treatment still has a certain water absorption due to the micropores of the bamboo material itself and the pores formed by the degradation of the material. Particularly, when used outdoors, the dimensional stability and the anticorrosive effect thereof still need to be further improved.
The paraffin is a solid hydrocarbon mixture prepared from petroleum refining, is colorless or white and nearly semitransparent, has a melting point of 45-70 ℃, and has a molecular weight of 240-450. The paraffin has low chemical activity, is neutral, has stable chemical property, can be used as a heat transfer medium in the heat treatment of bamboo wood, and can be filled in the material after being cooled. However, paraffin has problems of low softening point (about 30 ℃ C.), large solidification shrinkage, low surface hardness, and the like. The polyethylene wax has high hardness and good compatibility with other types of wax; but its melting point is relatively high and its molecular weight is large. Based on the characteristics of the two types of wax, the polyethylene wax is used as the additive to modify the paraffin, so that the characteristics of small molecular weight and good fluidity and wettability of the paraffin are maintained, the hardness, toughness and adhesion of the paraffin are improved, and feasibility is provided for the application of the modified paraffin in bamboo heat treatment and enhanced modification.
Disclosure of Invention
The invention provides a bamboo drying and heat treatment method, which can obviously reduce the water absorption of bamboo, improve the dimensional stability of the bamboo and simultaneously solve the problem of the reduction of the mechanical property of the heat-treated bamboo.
In order to achieve the purpose, the invention adopts the technical scheme that:
a method for drying and heat-treating bamboo wood, which adopts modified paraffin as a medium to dry and heat-treat the bamboo wood, comprises the following steps:
s1, paraffin modification treatment: modifying paraffin wax by using polyethylene wax to obtain modified paraffin wax;
s2, bamboo drying: injecting the modified paraffin liquid obtained in the step S1 into a treatment tank filled with bamboo wood for drying treatment until the water content of the bamboo wood is reduced to 6-8%;
s3, bamboo heat treatment: continuously heating the modified paraffin in the step S2 at the speed of 10-15 ℃/h, and keeping the temperature for 2-6 h when the temperature of the modified paraffin is increased to 160-200 ℃;
s4, bamboo post-treatment: and (5) cooling the modified paraffin in the step (S3) until the temperature of the modified paraffin is reduced to 75-100 ℃, taking out the bamboo, and placing the bamboo in air or a refrigerating chamber until the modified paraffin entering the bamboo is fully solidified.
Further, the bamboo material is one or more of raw bamboo, bamboo sheet material, bamboo bundle material, bamboo board material and bamboo laminated material.
Further, in the step S1, the addition amount of the polyethylene wax is 3-10% of the mass of the paraffin wax, the polyethylene wax and the paraffin wax are mixed, the mixture is heated to 100 ℃ at a speed of 10 ℃/h, and the mixture is stirred for 2-4 h after the paraffin wax is fully melted.
Further, the molecular weight of the polyethylene wax is 1000-5000.
Furthermore, the modified paraffin wax obtained in the step S1 has fine crystals and a more compact structure, the dropping melting point is improved to 60-80 ℃, the molecular weight is increased to 600-800, and the hardness is improved by 20-30% compared with that of unmodified paraffin wax.
Further, in the step S2, the bamboo drying treatment is a segmented drying treatment, in the first stage, the temperature of the modified paraffin is controlled to be 100-120 ℃, the treatment time is 2-3 hours, in the second stage, the temperature of the modified paraffin is adjusted to be 80 ℃, and the treatment time is 16-24 hours until the moisture content of the bamboo is reduced to 6-8%.
Preferably, in the step S3, the modified paraffin in the step S2 is continuously heated at a speed of 12-14 ℃/h to raise the temperature to 170-180 ℃, and the temperature is maintained for 3-5 h.
Further, in the step S4, the cooling temperature of the modified paraffin when the modified paraffin is cooled is 5 to 10 ℃ higher than the melting point of the modified paraffin.
Furthermore, in the steps S1-S4, the heating during the bamboo wood processing adopts an oil bath heating mode; in the heat treatment process of the bamboo wood, the temperature reaches 160-200 ℃, and the water bath generally cannot meet the requirement, so the bamboo wood industry in the embodiment adopts an oil bath heating mode.
Compared with the prior art, the invention has the following beneficial effects:
the invention adopts polyethylene wax modified paraffin as a medium to dry and thermally treat the bamboo, capillaries in the bamboo cell wall begin to expand continuously in the treatment process, and the modified paraffin with low molecular weight permeates into the capillaries of the bamboo to realize the replacement with moisture, so that the bamboo is quickly dried; in addition, under the action of high-temperature modified paraffin, organic substances such as hemicellulose, saccharides and the like in the bamboo cell wall are degraded to form a pore structure, and the modified paraffin can enter the cell wall structure and can play a role in physical filling and reinforcing after being cooled and solidified.
The method has the following three characteristics: (1) the technological processes of drying, heat treatment and filling reinforcement are continuous and simple, and the production cost can be effectively reduced; (2) compared with the conventional drying process, the modified paraffin treatment heat utilization rate is higher, and the drying efficiency of bamboo wood can be effectively improved; (3) compared with other thermal modification media, due to the sealing effect of the modified paraffin on the bamboo gaps, the water absorption of the bamboo can be further reduced, and the dimensional stability of the bamboo is improved; after the wax liquid filled in the bamboo gaps is cooled and solidified, the modified paraffin has excellent hardness, toughness and adhesiveness, so that the cell wall reinforcing effect can be realized, and the problems of increased brittleness and reduced strength commonly existing in heat treatment of bamboo are effectively solved; in addition, the treated wax liquid can be recycled and gradually retained in the bamboo wood, so that the problem of waste treatment is avoided, and the environment-friendly and energy-saving effects are achieved. The method has the advantages of simple process, good controllability, low cost, simple equipment and easy industrialization, and the produced bamboo wood product has good dimensional stability and durability, high strength and wide application prospect.
Detailed Description
The present invention will be further described with reference to the following examples.
Example 1
S1, paraffin modification treatment, namely mixing L-912 polyethylene wax (with the molecular weight of 1000-2000) and paraffin solid, pouring the mixture into a mixing tank, wherein the addition amount of the polyethylene wax is 5% of the mass of the paraffin, heating to 100 ℃ after mixing, the heating speed is 10 ℃/h, stirring is carried out after the wax is fully melted, and the stirring time is 3 h;
s2, drying the bamboo chips: injecting the modified paraffin into a treatment tank filled with bamboo sheets with initial water content of 30% for drying treatment; the temperature of the modified paraffin in the first stage is 100 ℃, and the processing time is 2 hours; in the second stage, the degree of the modified paraffin is reduced to 80 ℃, the treatment time is 16h, and the water content of the bamboo chips is 7%;
s3, bamboo chip heat treatment: continuously heating the modified paraffin at the speed of 10 ℃/h, raising the temperature of the modified paraffin to 180 ℃, and keeping the temperature for 6 h;
s4, bamboo chip post-treatment: after the heat treatment process is finished, cooling, taking out the bamboo wood when the modified paraffin is cooled to 90 ℃, and placing the bamboo wood in a refrigerated cabinet until the modified paraffin is completely solidified;
the test result shows that: compared with the bamboo chips treated by the gas medium at high temperature, the equilibrium water content of the bamboo chips treated by the embodiment 1 is reduced from 11.5 percent to 2.7 percent, and the elastic modulus is improved by 12 percent.
Example 2
S1, paraffin modification treatment: mixing domestic H1001 polyethylene wax (with the molecular weight of 1500-3500) and paraffin wax solid, and pouring the mixture into a mixing tank, wherein the addition amount of the polyethylene wax is 5% of the mass of the paraffin wax; after mixing, heating to 100 ℃, wherein the heating speed is 10 ℃/h, and stirring is carried out after the wax liquid is fully melted for 4 h;
s2, drying the bamboo laminated wood: injecting the modified paraffin into a bamboo laminated wood treatment tank with initial water content of 40% for drying treatment; the temperature of the modified paraffin is 120 ℃ in the first stage, the processing time is 3h, the degree of the modified paraffin is reduced to 80 ℃ in the second stage, the moisture content is balanced, the processing time is 24h, and the moisture content of the bamboo laminated wood is 8%;
s3, bamboo laminated wood heat treatment: continuously heating the modified paraffin at the speed of 10 ℃/h, raising the temperature of the modified paraffin to 200 ℃, and keeping the temperature for 2 h;
s4, bamboo laminated wood post-treatment: and after the heat treatment process is finished, cooling, taking out the bamboo laminated wood when the modified paraffin is cooled to 80 ℃, and placing in the air until the modified paraffin is completely solidified.
The test result shows that: compared with the bamboo laminated wood treated by the gas medium at high temperature, the bamboo laminated wood treated by the embodiment 2 has the advantages that the equilibrium water content of the bamboo laminated wood treated by the modified paraffin is reduced to 2.3% from 11.5%, and the elastic modulus is improved by 10%.
Example 3
A method for drying and heat-treating bamboo wood, which adopts modified paraffin as medium to dry and heat-treat bamboo wood (raw bamboo), comprises the following steps:
s1, paraffin modification treatment: modifying paraffin by using polyethylene wax (with molecular weight of 3500-5000), mixing the polyethylene wax and the paraffin, wherein the addition amount of the polyethylene wax is 3% of the mass of the paraffin, heating the mixture to 100 ℃ at the speed of 10 ℃/h, and stirring for 2h after the paraffin is fully melted; the prepared modified paraffin wax has fine crystals and more compact structure, the dropping melting point is improved to 60-80 ℃, the molecular weight is increased to 600-800, and the hardness is improved by 20-30% compared with that of unmodified paraffin wax;
s2, bamboo drying: injecting the modified paraffin liquid obtained in the step S1 into a processing tank filled with bamboo (raw bamboo) for drying treatment, wherein the drying treatment of the bamboo adopts sectional drying treatment, the temperature of the modified paraffin is controlled at 100 ℃ in the first stage, the processing time is 2 hours, the temperature of the modified paraffin is adjusted to 80 ℃ in the second stage, and the processing time is 16 hours until the moisture content of the bamboo is reduced to 6%;
s3, bamboo heat treatment: continuously heating the modified paraffin in the step S2 at the speed of 10 ℃/h, and keeping the temperature for 2h when the temperature of the modified paraffin is increased to 160 ℃;
s4, bamboo post-treatment: and (5) cooling the modified paraffin in the step (S3) until the temperature of the modified paraffin is reduced to 75-100 ℃, taking out the bamboo, and placing the bamboo in air or a refrigerating chamber until the modified paraffin entering the bamboo is fully solidified. The cooling temperature of the modified paraffin is 5 ℃ higher than the melting point of the modified paraffin when the modified paraffin is cooled.
In the steps S1 to S4, the heating in the bamboo wood treatment is performed by an oil bath heating method: in the heat treatment process of the bamboo wood, the temperature reaches 160-200 ℃, and the water bath generally cannot meet the requirement, so the bamboo wood industry in the embodiment adopts an oil bath heating mode.
The test result shows that: compared with the raw bamboo treated by the gas medium at high temperature, the raw bamboo treated by the embodiment 3 has the advantages that the equilibrium moisture content of the raw bamboo treated by the modified paraffin is reduced to 2.5% from 11.5%, and the elastic modulus is improved by 11%.
Example 4
A method for drying and heat-treating bamboo wood, which adopts modified paraffin as a medium to dry and heat-treat the bamboo wood (bamboo bundle material), comprises the following steps:
s1, paraffin modification treatment: modifying paraffin by using domestic H1001 polyethylene wax (with the molecular weight of 1500-3500), mixing the polyethylene wax with the paraffin, wherein the addition amount of the polyethylene wax is 7% of the mass of the paraffin, heating the mixture to 100 ℃ at the speed of 10 ℃/H, and stirring for 3H after the paraffin is fully melted; the prepared modified paraffin wax has fine crystals and more compact structure, the dropping melting point is improved to 60-80 ℃, the molecular weight is increased to 600-800, and the hardness is improved by 20-30% compared with that of unmodified paraffin wax;
s2, bamboo drying: injecting the modified paraffin liquid obtained in the step S1 into a processing tank filled with bamboo (bamboo bundle) for drying, wherein the bamboo drying adopts sectional drying, the temperature of the modified paraffin is controlled at 110 ℃ in the first stage, the processing time is 2.5h, the temperature of the modified paraffin is adjusted to 80 ℃ in the second stage, and the processing time is 20h until the water content of the bamboo is reduced to 7%;
s3, bamboo heat treatment: continuously heating the modified paraffin in the step S2 at the speed of 12 ℃/h, and keeping the temperature for 3h when the temperature of the modified paraffin is raised to 170 ℃;
s4, bamboo post-treatment: and (5) cooling the modified paraffin in the step (S3) until the temperature of the modified paraffin is reduced to 85 ℃, taking out the bamboo, and placing the bamboo in air or a refrigerating chamber until the modified paraffin entering the bamboo is fully solidified. The cooling temperature of the modified paraffin is 8 ℃ higher than the melting point of the modified paraffin when the modified paraffin is cooled.
In the steps S1 to S4, the heating in the bamboo wood treatment is performed by an oil bath heating method: in the heat treatment process of the bamboo wood, the temperature reaches 160-200 ℃, and the water bath generally cannot meet the requirement, so the bamboo wood industry in the embodiment adopts an oil bath heating mode.
The test result shows that: compared with the bamboo bundle material treated by the gas medium at high temperature, the bamboo bundle material treated by the embodiment 4 has the advantages that the equilibrium water content of the bamboo bundle material treated by the modified paraffin is reduced to 2.4% from 11.5%, and the elastic modulus is improved by 11%.
Example 5
A method for drying and heat-treating bamboo wood, which adopts modified paraffin as medium to dry and heat-treat bamboo wood (bamboo plate), comprises the following steps:
s1, paraffin modification treatment, namely modifying paraffin by using L-912 polyethylene wax (with the molecular weight of 1000-2000), mixing the polyethylene wax with the paraffin, wherein the addition amount of the polyethylene wax is 10% of the mass of the paraffin, heating the mixture to 100 ℃ at the speed of 10 ℃/h, stirring for 4 hours after the paraffin is fully melted, and the prepared modified paraffin has the advantages of fine crystal and more compact structure, the dropping melting point of the modified paraffin is increased to 60-80 ℃, the molecular weight is increased to 600-800, and the hardness is increased by 20-30% relative to that of unmodified paraffin;
s2, bamboo drying: injecting the modified paraffin liquid obtained in the step S1 into a processing tank filled with bamboo (bamboo board) for drying, wherein the bamboo drying adopts sectional drying, the temperature of the modified paraffin is controlled at 120 ℃ in the first stage, the processing time is 3 hours, the temperature of the modified paraffin is adjusted to 80 ℃ in the second stage, and the processing time is 24 hours until the moisture content of the bamboo is reduced to 8%;
s3, bamboo heat treatment: continuously heating the modified paraffin in the step S2 at the speed of 14 ℃/h, and keeping the temperature for 5h when the temperature of the modified paraffin is increased to 180 ℃;
s4, bamboo post-treatment: and (5) cooling the modified paraffin in the step (S3) until the temperature of the modified paraffin is reduced to 75-100 ℃, taking out the bamboo, and placing the bamboo in air or a refrigerating chamber until the modified paraffin entering the bamboo is fully solidified. The cooling temperature of the modified paraffin is 10 ℃ higher than the melting point of the modified paraffin when the modified paraffin is cooled.
In the steps S1 to S4, the heating in the bamboo wood treatment is performed by an oil bath heating method: in the heat treatment process of the bamboo wood, the temperature reaches 160-200 ℃, and the water bath generally cannot meet the requirement, so the bamboo wood industry in the embodiment adopts an oil bath heating mode.
The test result shows that: compared with the bamboo board treated by the gas medium at high temperature, the bamboo board treated by the embodiment 5 has the advantages that the equilibrium moisture content of the bamboo board treated by the modified paraffin is reduced to 2.5% from 11.5%, and the elastic modulus is improved by 12%.
Example 6
A method for drying and heat-treating bamboo wood, which adopts modified paraffin as a medium to dry and heat-treat the bamboo wood (raw bamboo and bamboo laminated wood), comprises the following steps:
s1, paraffin modification treatment: modifying paraffin by using domestic H1001 polyethylene wax (with the molecular weight of 1500-3500), mixing the polyethylene wax with the paraffin, wherein the addition amount of the polyethylene wax is 8% of the mass of the paraffin, heating the mixture to 100 ℃ at the speed of 10 ℃/H, and stirring for 4H after the paraffin is fully melted; the prepared modified paraffin wax has fine crystals and more compact structure, the dropping melting point is improved to 60-80 ℃, the molecular weight is increased to 600-800, and the hardness is improved by 20-30% compared with that of unmodified paraffin wax;
s2, bamboo drying: injecting the modified paraffin liquid obtained in the step S1 into a processing tank filled with bamboo (raw bamboo and bamboo laminated wood) for drying, wherein the bamboo drying process adopts segmented drying process, the temperature of the modified paraffin is controlled at 120 ℃ in the first stage, the processing time is 3h, the temperature of the modified paraffin is adjusted to 80 ℃ in the second stage, and the processing time is 24h until the water content of the bamboo is reduced to 8%;
s3, bamboo heat treatment: continuously heating the modified paraffin in the step S2 at the speed of 15 ℃/h, and keeping the temperature for 6h when the temperature of the modified paraffin is raised to 200 ℃;
s4, bamboo post-treatment: and (5) cooling the modified paraffin in the step (S3) until the temperature of the modified paraffin is reduced to 100 ℃, taking out the bamboo, and placing the bamboo in air or a refrigerating chamber until the modified paraffin entering the bamboo is fully solidified. The cooling temperature of the modified paraffin is 10 ℃ higher than the melting point of the modified paraffin when the modified paraffin is cooled.
In the steps S1 to S4, the heating in the bamboo wood treatment is performed by an oil bath heating method: in the heat treatment process of the bamboo wood, the temperature reaches 160-200 ℃, and the water bath generally cannot meet the requirement, so the bamboo wood industry in the embodiment adopts an oil bath heating mode.
Example 7
A method for drying and heat-treating bamboo wood (raw bamboo, bamboo sheet, bamboo bundle, bamboo plate and bamboo laminated wood) by using modified paraffin as a medium comprises the following steps:
s1, paraffin modification treatment, namely modifying paraffin by using L-912 polyethylene wax (with the molecular weight of 1000-2000), and mixing the polyethylene wax and the paraffin, wherein the addition amount of the polyethylene wax is 10% of the mass of the paraffin, heating the mixture to 100 ℃ at the speed of 10 ℃/h, and stirring for 4 hours after the paraffin is fully melted, so that the prepared modified paraffin has the advantages of fine crystal and more compact structure, the dropping melting point of the modified paraffin is increased to 60-80 ℃, the molecular weight is increased to 600-800, and the hardness is increased by 20-30% relative to that of unmodified paraffin;
s2, bamboo drying: injecting the modified paraffin liquid obtained in the step S1 into a treatment tank filled with bamboo (raw bamboo, bamboo sheets, bamboo bundles, bamboo plates and bamboo integrated materials) for drying treatment, wherein the bamboo drying treatment adopts sectional drying treatment, the temperature of the modified paraffin is controlled at 120 ℃ in the first stage, the treatment time is 3 hours, and the temperature of the modified paraffin is adjusted to 80 ℃ in the second stage, the treatment time is 24 hours until the water content of the bamboo is reduced to 8%;
s3, bamboo heat treatment: continuing to heat the modified paraffin in the step S2 at the speed of 13 ℃/h, and keeping the temperature for 4h when the temperature of the modified paraffin is increased to 190180 ℃;
s4, bamboo post-treatment: and (5) cooling the modified paraffin in the step (S3) until the temperature of the modified paraffin is reduced to 75-100 ℃, taking out the bamboo, and placing the bamboo in air or a refrigerating chamber until the modified paraffin entering the bamboo is fully solidified. The cooling temperature of the modified paraffin is 8 ℃ higher than the melting point of the modified paraffin when the modified paraffin is cooled.
In the steps S1 to S4, the heating in the bamboo wood treatment is performed by an oil bath heating method: in the heat treatment process of the bamboo wood, the temperature reaches 160-200 ℃, and the water bath generally cannot meet the requirement, so the bamboo wood industry in the embodiment adopts an oil bath heating mode.
Example 8
A method for drying and heat-treating bamboo wood (bamboo sheets, bamboo bundles, bamboo plates and bamboo laminated wood) by using modified paraffin as a medium comprises the following steps:
s1, paraffin modification treatment: modifying paraffin by using domestic H1001 polyethylene wax (with the molecular weight of 1500-3500), mixing the polyethylene wax with the paraffin, wherein the addition amount of the polyethylene wax is 5% of the mass of the paraffin, heating the mixture to 100 ℃ at the speed of 10 ℃/H, and stirring for 3H after the paraffin is fully melted; the prepared modified paraffin wax has fine crystals and more compact structure, the dropping melting point is improved to 60-80 ℃, the molecular weight is increased to 600-800, and the hardness is improved by 20-30% compared with that of unmodified paraffin wax;
s2, bamboo drying: injecting the modified paraffin liquid obtained in the step S1 into a treatment tank filled with bamboo (bamboo sheets, bamboo bundles, bamboo plates and bamboo laminated wood) for drying treatment, wherein the bamboo drying treatment adopts segmented drying treatment, the temperature of the modified paraffin is controlled at 110 ℃ in the first stage, the treatment time is 2 hours, and the temperature of the modified paraffin is adjusted to 80 ℃ in the second stage, the treatment time is 18 hours until the water content of the bamboo is reduced to 6%;
s3, bamboo heat treatment: continuously heating the modified paraffin in the step S2 at the speed of 14 ℃/h, and keeping the temperature for 5h when the temperature of the modified paraffin is increased to 180 ℃;
s4, bamboo post-treatment: and (5) cooling the modified paraffin in the step (S3) until the temperature of the modified paraffin is reduced to 75-100 ℃, taking out the bamboo, and placing the bamboo in air or a refrigerating chamber until the modified paraffin entering the bamboo is fully solidified. The cooling temperature of the modified paraffin is 10 ℃ higher than the melting point of the modified paraffin when the modified paraffin is cooled.
In the steps S1 to S4, the heating in the bamboo wood treatment is performed by an oil bath heating method: in the heat treatment process of the bamboo wood, the temperature reaches 160-200 ℃, and the water bath generally cannot meet the requirement, so the bamboo wood industry in the embodiment adopts an oil bath heating mode.
The above description is only of the preferred embodiments of the present invention, and it should be noted that: it will be apparent to those skilled in the art that various modifications and adaptations can be made without departing from the principles of the invention and these are intended to be within the scope of the invention.
Claims (8)
1. A bamboo drying and heat treatment method is characterized in that: the method for drying and thermally treating bamboo wood by using modified paraffin as a medium comprises the following steps:
s1, paraffin modification treatment: modifying paraffin wax by using polyethylene wax to obtain modified paraffin wax;
s2, bamboo drying: injecting the modified paraffin liquid obtained in the step S1 into a treatment tank filled with bamboo wood for drying treatment until the water content of the bamboo wood is reduced to 6-8%;
s3, bamboo heat treatment: continuously heating the modified paraffin in the step S2 at the speed of 10-15 ℃/h, and keeping the temperature for 2-6 h when the temperature of the modified paraffin is increased to 160-200 ℃;
s4, bamboo post-treatment: cooling the modified paraffin in the step S3 until the temperature of the modified paraffin is reduced to 75-100 ℃, taking out the bamboo, and placing the bamboo in air or a refrigerating chamber until the modified paraffin entering the bamboo is fully solidified;
in the step S1, the addition amount of the polyethylene wax is 3-10% of the mass of the paraffin wax, the polyethylene wax and the paraffin wax are mixed, the mixture is heated to 100 ℃ at a speed of 10 ℃/h, and the mixture is stirred for 2-4 h after the paraffin wax is fully melted.
2. The bamboo drying and heat treatment method according to claim 1, characterized in that: the bamboo material is one or more of raw bamboo, bamboo sheet, bamboo bundle, bamboo board and bamboo laminated material.
3. The bamboo drying and heat treatment method according to claim 1, characterized in that: the molecular weight of the polyethylene wax is 1000-5000.
4. The bamboo drying and heat treatment method according to claim 1, characterized in that: the melting point of the modified paraffin prepared in the step S1 is 60-80 ℃, and the molecular weight is 600-800.
5. The bamboo drying and heat treatment method according to claim 1, characterized in that: in the step S2, the bamboo wood drying treatment adopts segmented drying treatment, the temperature of the modified paraffin is controlled to be 100-120 ℃ in the first stage, the treatment time is 2-3 h, and the temperature of the modified paraffin is adjusted to be 80 ℃ in the second stage, the treatment time is 16-24 h until the moisture content of the bamboo wood is reduced to 6-8%.
6. The bamboo drying and heat treatment method according to claim 1, characterized in that: in the step S3, the modified paraffin in the step S2 is continuously heated at a speed of 12-14 ℃/h to raise the temperature to 170-180 ℃, and the temperature is kept for 3-5 h.
7. The bamboo drying and heat treatment method according to claim 1, characterized in that: in the step S4, the cooling temperature of the modified paraffin is 5-10 ℃ higher than the melting point of the modified paraffin.
8. The bamboo drying and heat treatment method according to claim 1, characterized in that: in the steps S1 to S4, the heating in the bamboo wood processing is performed by oil bath heating.
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| CA1207952A (en) * | 1983-12-01 | 1986-07-22 | Stuart A. Eaton | Wood preservative composition |
| CN101116984B (en) * | 2007-08-15 | 2010-05-19 | 江阴市青阳世盛老红木家俱厂 | Method for reducing the moisture percentage of wood materials to zero by using paraffin wax heat-treated process |
| US20150132492A1 (en) * | 2012-04-18 | 2015-05-14 | Rohm And Haas Company | Wax-biocide wood treatment |
| DE102015006290B4 (en) * | 2015-05-15 | 2017-08-03 | Thomas Buchholz | Wax dispersions, use of wax dispersions as water repellents in wood-based materials and processes for the production of wood-based materials with these wax dispersions |
| CN107520932A (en) * | 2017-10-11 | 2017-12-29 | 南京林业大学 | Poplar hot wax are dried and high-temperature heat treatment integral process |
| CN108058251B (en) * | 2018-01-15 | 2019-11-29 | 北京林业大学 | A kind of preparation method of the timber and the two of compound wax emulsion waterproofing wood agent and its processing |
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2018
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