阅读说明：本技术 一种木材增重增硬方法 (Wood weight increasing and hardening method ) 是由 韦鹏练 符韵林 黄腾华 刘明德 康成芳 周劲航 于 2021-08-24 设计创作，主要内容包括：本发明公开了一种木材增重增硬的方法：(1)选择观光木人工林木材,锯成板材,自然干燥,刨光；(2)配置氯化钙溶液,倒入试件,常温浸泡；(3)取出试件,低温干燥；(4)配置碳酸钠溶液,倒入试件,先真空后加压；(5)放置,取出试件浸泡清水,干燥；(6)将干燥好的试件进行压缩密实化；(7)将试件变形固定,完成试件的密实化处理。本发明通过原位生成碳酸钙和物理压缩提高木材的密度和硬度,充分发挥碳酸钙密度大,来源广,价格便宜,解决树脂类填充剂的价格偏高,浸渍困难,存在游离甲醛等环境问题；并且填充后可以降低木材压缩率,减少木材材积损失,达到较好的增重增硬效果,解决人工林木材材质松软的问题。(The invention discloses a method for increasing weight and hardening of wood, which comprises the following steps: (1) selecting timber of the sightseeing wood artificial forest, sawing the timber into boards, naturally drying the boards and planing the boards; (2) preparing a calcium chloride solution, pouring the calcium chloride solution into a test piece, and soaking at normal temperature; (3) taking out the test piece, and drying at low temperature; (4) preparing a sodium carbonate solution, pouring the sodium carbonate solution into a test piece, and pressurizing after vacuum; (5) standing, taking out the test piece, soaking in clear water, and drying; (6) compressing and densifying the dried test piece; (7) and (5) deforming and fixing the test piece to finish the densification treatment of the test piece. The invention improves the density and hardness of the wood by in-situ generation of calcium carbonate and physical compression, gives full play to the large density, wide source and low price of the calcium carbonate, and solves the environmental problems of high price, difficult impregnation, free formaldehyde and the like of resin fillers; and after filling, the wood compression rate can be reduced, the volume loss of wood is reduced, a better weight increasing and hardening effect is achieved, and the problem that the material of the artificial forest wood is soft is solved.)

1. A method for increasing the weight and the hardness of wood is characterized by comprising the following operation steps:

(1) selecting timber of the sightseeing wood artificial forest, sawing the timber into a plate, naturally drying the plate, planing the plate, and sawing the plate into a test piece with the length of 300mm to 370mm and the width of natural width;

(2) preparing a calcium chloride solution with the mass concentration of 30-45%, pouring the calcium chloride solution into the test piece obtained in the step (1), and soaking at normal temperature;

(3) taking out the test piece, naturally drying, and then drying at low temperature;

(4) preparing a sodium carbonate solution, wherein the mass concentration of the solution is 20-30%, pouring the solution into the test piece obtained in the step (3) after low-temperature drying, and then carrying out vacuum and pressurization;

(5) standing for 24-48 h until the calcium chloride solution and the sodium carbonate solution fully react, taking out the test piece, soaking in clear water, air-drying, and drying to keep the water content of the test piece at 8-12%;

(6) compressing and densifying the dried test piece, wherein the compression parameter is compression ratio of 5-15%, the compression temperature is 160-180 ℃, and the pressure maintaining time is 15-45 min;

(7) and (5) deforming and fixing the test piece, and then carrying out moisture content balance treatment to finish the densification treatment of the test piece.

2. The method of claim 1, wherein: and (2) sawing into a plate with the thickness of 20mm in the step (1), and naturally drying for 30 d.

3. The method of claim 1, wherein: and (3) soaking for 5d at normal temperature in the step (2).

4. The method of claim 1, wherein: and (4) naturally drying for 1d in the step (3), wherein the low-temperature drying is drying for 2-3d at 50 ℃.

5. The method of claim 1, wherein: in the step (4), the vacuum condition of the vacuum degree of 0.08Mpa is kept for 30min, then the pressure is kept for 1h, and the pressure is 1 Mpa.

6. The method of claim 1, wherein: the drying in the step (5) is carried out at a temperature of less than or equal to 50 ℃, the temperature is gradually increased to 80 ℃, and the temperature increasing rate is 10 ℃/day.

7. The method of claim 1, wherein: the pressure of the pressure maintaining in the step (6) is 14 Bar.

8. The method of claim 1, wherein: and (4) fixing the denaturation in the step (7) at 180 ℃ for 3 h.

Technical Field

The invention relates to the technical field of wood processing, in particular to a wood weight increasing and hardening method.

Background

The artificial forest wood has the advantages of high growth speed, short growth period, low wood density, soft material, low strength, easy buckling deformation and great limitation on application. In order to overcome the inherent defects of the wood of the artificial forest and expand the application range, the wood density is improved by adopting a wood strengthening and compacting treatment technology in production, and further the strength and the stability of the wood are improved. The weight increasing treatment adopted at present has two types, one is compression densification, namely, the physical modification technology of reducing the volume of a wood cavity by adopting a mechanical compression method through hydrothermal action so as to improve the density and the wood property of the wood, and the effect of densification is realized, and the method can be divided into integral compression densification and surface compression densification according to the effect of densification. The other method is impregnation filling densification, namely, the impregnant is added to fill substances into the gaps in the wood, so that the effects of volume saturation and quality improvement are achieved, and the purpose of densification is met. Additives which improve or enhance certain properties of the material are referred to as modifiers. At present, impregnants for weight increment and reinforcement of wood are mainly resins, such as low-molecular urea-formaldehyde resin, phenolic resin, furfural resin and the like.

The physical compression densification is an environment-friendly wood densification technology, the key technology of the physical compression densification is mainly softening and deformation fixation, the softening is to improve the plasticity of lignin and semi-fibers in the wood through heat and moisture so as to enable the wood to be easily compressed, in order to prevent the surface of the wood from exploding due to overlarge water vapor pressure in the compression process, the water content of the wood needs to be controlled to be lower (generally below 8%), so that the softening time of the wood is prolonged, and the interior of the wood has larger compression stress, so that the compression rebound rate is higher, and the use is influenced. Therefore, deformation stability treatment is needed after compression and densification, the compression stress in the wood is usually released in a high-temperature heat treatment mode, so that the dimension is stable, and if deformation and fixation are not good, dimension rebound can be caused in the later use process. On the other hand, the compression and densification are realized by compressing the volume of the cavity inside the wood to improve the density of the wood, the density is not obviously improved when the compression ratio is small, and the large volume loss and the wood resource waste are caused when the compression ratio is high. The wood density is increased by adding the impregnant, so that the volume loss of the wood can be avoided, and the wood can be endowed with functions of corrosion prevention, hydrophobicity and the like, but the commonly used impregnant is mainly resins which mainly use fossil resources as raw materials and contain harmful substances such as free formaldehyde, free phenol and the like, the production and use processes are harmful to the environmental safety, and meanwhile, the impregnant has large molecular weight, is difficult to impregnate the wood, and has large using amount and high cost.

The information disclosed in this background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.

Disclosure of Invention

Aiming at the technical problems, the invention provides a method for increasing weight and hardening of wood, which selects calcium carbonate as an external impregnant, has wide source, sufficient raw materials and economy, overcomes the environmental problems of high cost, free formaldehyde and the like existing in the existing resin impregnation reinforcement, adopts a method for generating nano calcium carbonate in situ, generates calcium carbonate precipitates in the wood by respectively entering calcium ions and carbonate ions, is easier to permeate into the interior compared with the method of directly adding nano calcium carbonate, and overcomes the problem of difficult medicament permeation existing in the resin impregnation reinforcement. Meanwhile, filling, compressing and compacting are adopted, and calcium carbonate inorganic matter is used for filling, so that on one hand, gaps of wood cell cavities are filled, the weight is increased, and on the other hand, the volume loss caused by compression is effectively reduced, so that the availability range of the wood cell cavities can be enlarged, the waste of wood resources is reduced, and the function value of the wood cell cavities is fully played.

In order to achieve the purpose, the technical scheme provided by the invention is as follows:

a method for increasing the weight and the hardness of wood comprises the following operation steps:

(1) selecting timber of the sightseeing wood artificial forest, sawing the timber into a plate, naturally drying the plate, planing the plate, and sawing the plate into a test piece with the length of 300mm to 370mm and the width of natural width;

(2) preparing a calcium chloride solution, wherein the mass concentration of the solution is 30-45%, pouring the calcium chloride solution into the test piece obtained in the step (1), preferably to submerge the wood test piece, adding a heavy object on the test piece to enable the test piece to sink, and soaking at normal temperature;

(3) taking out the test piece, naturally drying, and then drying at low temperature;

(4) preparing a sodium carbonate solution, wherein the mass concentration of the solution is 20-30%, pouring the solution into the test piece obtained in the step (3) after low-temperature drying, and then carrying out vacuum and pressurization;

(5) placing for 24-48 h until the calcium chloride solution and the sodium carbonate solution fully react, taking out the test piece, soaking in clear water, washing to remove salt and unstable calcium carbonate on the surface layer, placing in a room for air drying for 1d, and then placing in an oven for drying to keep the water content of the test piece at 8-12%;

(6) compressing and densifying the dried test piece, wherein the compression parameter is compression ratio of 5-15%, the compression temperature is 160-180 ℃, and the pressure maintaining time is 15-45 min;

(7) and (5) deforming and fixing the test piece, and then carrying out moisture content balance treatment to finish the densification treatment of the test piece.

Preferably, the plate with the thickness of 20mm is sawed in the step (1) and naturally dried for 30 d.

Preferably, in the step (2), the soaking is carried out for 5d at normal temperature.

Preferably, the drying step (3) is carried out naturally for 1d, and the low-temperature drying step is carried out at 50 ℃ for 2-3 d.

Preferably, in step (4), the vacuum condition of 0.08MPa is maintained for 30min, and then the pressure is maintained for 1h, and the pressure is 1 MPa.

Preferably, the drying in the step (5) is carried out at a temperature of less than or equal to 50 ℃, the temperature is gradually increased to 80 ℃, and the temperature increasing rate is 10 ℃/day.

Preferably, the pressure of the pressure holding 14Bar in the step (6).

Preferably, the denaturation step described in step (7) is fixed at 180 ℃ for 3 h.

Compared with the prior art, the invention has the following beneficial effects:

according to the invention, calcium carbonate is generated in situ, calcium ions and carbonate ions are brought into wood through the solution, and compared with resin impregnant, the impregnation agent is easier to enter wood, so that the impregnation efficiency is improved; furthermore, the density and hardness of the wood are improved through calcium carbonate filling and physical compression, the large density, wide source and low price of the calcium carbonate are fully exerted, and the environmental problems of high price, free formaldehyde and the like of the resin filler are solved; and after filling, the wood compression rate can be reduced, the volume loss of wood is reduced, a better weight increasing and hardening effect is achieved, and the problem that the material of the artificial forest wood is soft is solved.

Detailed Description

The following detailed description is to be read in connection with specific embodiments, but it should be understood that the scope of the invention is not limited to the specific embodiments. The raw materials and reagents used in the examples were all commercially available unless otherwise specified.

Example 1

A method for increasing weight and hardening of wood comprises the following operation steps:

(1) selecting sightseeing wood, sawing into plates with the thickness of 20mm, placing the plates in an indoor ventilation position for natural drying for 30 days, then planing the plates by a planing machine, sawing into test pieces with the length of 300-370 mm and the width of natural width, and placing the test pieces into a processing groove;

(2) preparing a calcium chloride solution (solution A) with the mass concentration of 35%, pouring the calcium chloride solution (solution A) into the treatment tank in the step (1), preferably submerging a wood test piece, adding a heavy object on the test piece to enable the test piece to sink, and soaking for 5d at normal temperature;

(3) taking out the test piece, placing the test piece in a room for natural drying for 1d, then placing the test piece in an oven, and drying the test piece for 2d at a low temperature of 50 ℃;

(4) placing the test piece dried at low temperature into a treatment tank, preparing a sodium carbonate solution (solution B) with the mass concentration of 30%, pouring the sodium carbonate solution into the treatment tank, then placing the treatment tank into a vacuum treatment tank, firstly vacuumizing the treatment tank at the vacuum degree of 0.08MPa, pressurizing for 30min, and then keeping for 1h at the pressurizing pressure of 1.0 MPa;

(5) taking the treatment tank out of the vacuum treatment tank, standing for 48 hours until the solution A and the solution B fully react, taking out a test piece, soaking in clear water, washing to remove salt and unstable calcium carbonate on the surface layer, placing the test piece in a room for air drying for 1d, then placing the test piece in an oven, keeping the temperature to be less than or equal to 50 ℃ for drying for 1d, and gradually heating to 80 ℃ at the heating rate of 10 ℃/day for drying to keep the water content of the test piece at 8-12%;

(6) putting the dried test piece into a press, setting compression parameters for compression and densification, wherein the compression parameters are 5% of the compression rate, the compression temperature is 180 ℃, the pressure maintaining time is 45min, and the pressure maintaining pressure is 14 Bar;

(7) transferring the test piece into an oven, baking for 3h at 180 ℃ for deformation and fixation, and then placing the test piece in a room for moisture content balance treatment to complete densification treatment of the test piece; the weight gain of the test piece after the densification treatment is detected to be 51.32%, and the wood hardness is improved by 27.51%.

Example 2

A method for increasing weight and hardening of wood comprises the following operation steps:

(1) selecting sightseeing wood, sawing into plates with the thickness of 20mm, placing the plates in an indoor ventilation position for natural drying for 30 days, then planing the plates by a planing machine, sawing into test pieces with the length of 300-370 mm and the width of natural width, and placing the test pieces into a processing groove;

(2) preparing a calcium chloride solution (solution A) with the mass concentration of 40%, pouring the calcium chloride solution (solution A) into the treatment tank in the step (1), preferably submerging a wood test piece, adding a heavy object on the test piece to enable the test piece to sink, and soaking for 5d at normal temperature;

(3) taking out the test piece, placing the test piece in a room for natural drying for 1d, then placing the test piece in an oven, and drying the test piece for 2d at a low temperature of 50 ℃;

(4) placing the test piece dried at low temperature into a treatment tank, preparing a sodium carbonate solution (solution B) with the mass concentration of 20%, pouring the sodium carbonate solution into the treatment tank, then placing the treatment tank into a vacuum treatment tank, firstly vacuumizing the treatment tank at the vacuum degree of 0.08MPa, pressurizing for 30min, and then keeping for 1h at the pressurizing pressure of 1.0 MPa;

(5) taking the treatment tank out of the vacuum treatment tank, standing for 36h until the solution A and the solution B fully react, taking out a test piece, soaking in clear water, washing to remove salt and unstable calcium carbonate on the surface layer, placing the test piece in a room for air drying for 1d, then placing the test piece in an oven, keeping the temperature to be less than or equal to 50 ℃ for drying for 1d, and gradually heating to 80 ℃ at the heating rate of 10 ℃/day for drying to keep the water content of the test piece at 8-12%;

(6) putting the dried test piece into a press, setting compression parameters for compression and densification, wherein the compression parameters are compression rate 10%, the compression temperature is 160 ℃, the pressure maintaining time is 30min, and the pressure maintaining pressure is 14 Bar;

(7) transferring the test piece into an oven, baking for 3h at 180 ℃ for deformation and fixation, and then placing the test piece in a room for moisture content balance treatment to complete densification treatment of the test piece; the weight gain of the test piece after the densification treatment is detected to be 48.19%, and the wood hardness is improved by 27.93%.

Example 3

A method for increasing weight and hardening of wood comprises the following operation steps:

(1) selecting sightseeing wood, sawing into plates with the thickness of 20mm, placing the plates in an indoor ventilation position for natural drying for 30 days, then planing the plates by a planing machine, sawing into test pieces with the length of 300-370 mm and the width of natural width, and placing the test pieces into a processing groove;

(2) preparing a calcium chloride solution (solution A) with the mass concentration of 45%, pouring the calcium chloride solution (solution A) into the treatment tank in the step (1), preferably submerging a wood test piece, adding a heavy object on the test piece to enable the test piece to sink, and soaking for 5d at normal temperature;

(3) taking out the test piece, placing the test piece in a room for natural drying for 1d, then placing the test piece in an oven, and drying the test piece for 3d at a low temperature of 50 ℃;

(4) placing the test piece dried at low temperature into a treatment tank, preparing a sodium carbonate solution (solution B) with the mass concentration of 25%, pouring the sodium carbonate solution into the treatment tank, placing the treatment tank into a vacuum treatment tank, vacuumizing to the vacuum degree of 0.08Mpa, pressurizing for 30min, and keeping for 1h, wherein the pressurizing pressure is 1.0 Mpa;

(5) taking the treatment tank out of the vacuum treatment tank, standing for 24 hours until the solution A and the solution B fully react, taking out a test piece, soaking in clear water, washing to remove salt and unstable calcium carbonate on the surface layer, placing the test piece in a room for air drying for 1d, then placing the test piece in an oven, keeping the temperature to be less than or equal to 50 ℃ for drying for 1d, and gradually heating to 80 ℃ at the heating rate of 10 ℃/day for drying to keep the water content of the test piece at 8-12%;

(6) putting the dried test piece into a press, setting compression parameters for compression and densification, wherein the compression parameters are 15% of the compression rate, the compression temperature is 170 ℃, the pressure maintaining time is 15min, and the pressure maintaining pressure is 14 Bar;

(7) transferring the test piece into an oven, baking for 3h at 180 ℃ for deformation and fixation, and then placing the test piece in a room for moisture content balance treatment to complete densification treatment of the test piece; the weight gain of the test piece after the densification treatment is detected to be 21.81%, and the wood hardness is improved by 64.93%.

The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. It is not intended to limit the invention to the precise form disclosed, and obviously many modifications and variations are possible in light of the above teaching. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and its practical application to enable one skilled in the art to make and use various exemplary embodiments of the invention and various alternatives and modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims and their equivalents.