阅读说明：本技术 一种络合竹材、络合竹材人造板及其制备方法 (Complex bamboo, complex bamboo artificial board and preparation method thereof ) 是由 余养伦 于文吉 李澍农 雷文成 于 2019-09-20 设计创作，主要内容包括：本发明涉及一种络合竹材、络合竹材人造板及其制备方法,属于竹材加工技术领域。上述络合竹材的制备方法,包括：步骤1：竹材的制备；步骤2：把植物多酚导入竹材,得到多酚竹材；步骤3：在多酚竹材中导入金属盐,得到多酚金属盐竹材；步骤4：干燥多酚金属盐竹材,得到络合竹材。本发明在竹材中导入植物多酚-金属盐,利用植物多酚与金属盐的络合反应,将植物多酚和金属盐固定在竹材细胞内,将所述的竹材制备成络合竹材,再通过复合或重组加工,制备成络合竹材人造板。本发明制备的络合竹材、络合竹材人造板具有减少开裂甚至不开裂、尺寸稳定、纹理美观、色泽丰富等优点。(the invention relates to a complex bamboo wood, a complex bamboo wood-based plate and a preparation method thereof, belonging to the technical field of bamboo wood processing. The preparation method of the complex bamboo material comprises the following steps: step 1: preparing bamboo wood; step 2: introducing plant polyphenol into bamboo wood to obtain polyphenol bamboo wood; and step 3: introducing metal salt into the polyphenol bamboo wood to obtain polyphenol metal salt bamboo wood; and 4, step 4: and drying the bamboo wood with the polyphenol metal salt to obtain the complex bamboo wood. The invention introduces plant polyphenol-metal salt into bamboo wood, fixes the plant polyphenol and the metal salt in bamboo wood cells by utilizing the complex reaction of the plant polyphenol and the metal salt, prepares the bamboo wood into complex bamboo wood, and prepares the complex bamboo wood artificial board by compounding or recombination processing. The complex bamboo wood and the complex bamboo wood-based board prepared by the invention have the advantages of cracking reduction, even no cracking, stable size, beautiful texture, rich color and the like.)

1. The preparation method of the complex bamboo is characterized by comprising the following steps:

step 1: preparing bamboo wood;

step 2: introducing plant polyphenol into bamboo wood to obtain polyphenol bamboo wood;

And step 3: introducing metal salt into the polyphenol bamboo wood to obtain polyphenol metal salt bamboo wood;

And 4, step 4: and drying the bamboo wood with the polyphenol metal salt to obtain the complex bamboo wood.

2. the method for preparing the complex bamboo material according to claim 1, wherein the step 1 is: the raw bamboo is processed into bamboo tubes, bamboo strips, bamboo filaments, bamboo fibers, bamboo shavings, bamboo splits or bamboo bundles by a certain processing mode.

3. The method for preparing the complex bamboo material according to claim 1, wherein the step 2 is:

21) Dissolving plant polyphenol in water, and stirring uniformly to form a plant polyphenol water solution;

22) soaking the bamboo material in plant polyphenol water solution;

23) and drying the bamboo impregnated with the plant polyphenol water solution to obtain the polyphenol bamboo.

4. the method for preparing the complex bamboo material according to claim 3, wherein the concentration of the plant polyphenol water solution is 1-250 g/L, the average molecular weight is 170-50000, and the plant polyphenol water solution is 1-40 polymers; the bamboo wood is soaked in the plant polyphenol water solution for 10min to 48h at the soaking temperature of 0 to 80 ℃, and the soaking method is normal pressure, pressurization or pressurization after vacuum pumping; the plant polyphenol is one or more of tea polyphenol, charred fruit juice, tannin, and tannin extract.

5. the method for preparing the complex bamboo material according to claim 1, wherein the step 3 is:

31) Dissolving metal salt in water, and stirring uniformly to form a metal salt water solution;

32) soaking the polyphenol bamboo wood in a metal salt aqueous solution.

6. The method for preparing the complex bamboo material according to claim 5, wherein the concentration of the metal salt aqueous solution is 0.3g/L to 300 g/L; soaking the polyphenol bamboo wood in a metal salt aqueous solution for 10min-180 days at the soaking temperature of 0-80 ℃, wherein the soaking method is normal pressure, pressurization or pressurization after vacuum pumping; the metal salt is one or more of iron salt, zinc salt, copper salt, aluminum salt, titanium salt, calcium salt, molybdenum salt, tungsten salt, chromium salt, magnesium salt and potassium salt.

7. The complex bamboo is characterized by comprising 0.3-15 wt% of plant polyphenol and 0.1-12 wt% of metal salt, wherein the plant polyphenol and the metal salt are arranged on the surface, cell walls, cell cavities and/or cell gaps of the bamboo and exist in a complex form; the bamboo is a bamboo tube, bamboo strips, bamboo filaments, bamboo fibers, bamboo shavings, bamboo splits or bamboo bundles.

8. A method for preparing complex bamboo artificial board, characterized in that, the complex bamboo obtained by the method of any claim 1-6 or the complex bamboo of claim 7 is used as raw material, and is formed by gluing phenolic resin, urea-formaldehyde resin or isocyanate resin, the glue layer of the gluing is in a layered structure and/or a dotted structure, comprising:

step 1: sizing

applying phenolic resin, urea-formaldehyde resin or isocyanate resin into the complex bamboo wood in a dipping, spraying or roll coating mode;

step 2: assembly

Forming a plate blank by the complex bamboo materials according to a certain assembly mode;

And step 3: slab processing

Hot-pressing the plate blank prepared in the step 2 into a complex bamboo wood-based plate blank;

And 4, step 4: article processing

And (3) cooling, cutting edges, sanding and quenching and tempering the blank plate of the complex bamboo wood-based panel in the step (3) to prepare the complex bamboo wood-based panel.

9. The method for preparing a complex bamboo-based artificial board according to claim 8, wherein in the step 1, if the complex bamboo-based artificial board is phenolic resin, the complex bamboo is adjusted to be weakly alkaline; in the case of urea resin, the complex bamboo material is adjusted to be weakly acidic.

10. the complex bamboo wood-based plate is characterized in that the complex bamboo wood-based plate is formed by stacking a plurality of layers of complex bamboos in a parallel grain or cross structure, an adhesive layer is arranged among the complex bamboos, and the adhesive is phenolic resin, urea resin or isocyanate resin; the complexing bamboo wood contains plant polyphenol with the weight ratio of 0.3-15% and metal salt with the weight ratio of 0.1-12%, and the plant polyphenol and the metal salt exist on the surface, cell walls, cell cavities and/or cell gaps of the bamboo wood in a complex form; the bamboo is a bamboo tube, bamboo strips, bamboo filaments, bamboo fibers, bamboo shavings, bamboo splits or bamboo bundles.

11. the complex bamboo-based board of claim 10, wherein the complex bamboo-based board comprises one or more layers of complex bamboo, such as bamboo laminated wood, bamboo recombined wood, bamboo fiber board, bamboo shaving board, bamboo filament board, bamboo curtain or bamboo plywood.

Technical Field

The invention relates to the technical field of bamboo processing, in particular to complex bamboo, a complex bamboo artificial board and a preparation method thereof.

background

Bamboo occupies a very important position in forest resources in the world and is known as a second forest, more than 70 bamboo plants belong to the world, more than 1200 bamboo plants belong to the world, and the area of the bamboo forest is 3200 hectares. The bamboo is mostly a cylindrical shell with joints, and is a natural polymer composite material with thin and hollow walls, no radial tissue and a gradient structure (the part close to the green of bamboo is compact in tissue, and the part close to the yellow of bamboo is loose in tissue). Because of the moisture absorption or desorption property of the components such as cellulose, hemicellulose and the like, the components are subjected to dry shrinkage and wet swelling due to moisture absorption or release from the environment during use and processing, and generate internal stress. In addition, compared with wood, the special structure is easier to crack. The bamboo is mainly light yellow and has single color, and is rich in abundant nutrient substances and easy to mildew and damage by worms. In order to solve the problems of cracking, single color, mildewing and the like of bamboo wood, heat treatment (commonly called carbonization) is mainly adopted to treat the bamboo wood at present. The thermal treatment can induce the pyrolysis of starch, hemicellulose and part of cellulose, so that the number of hydroxyl in the bamboo wood is reduced, and the dimensional stability is improved; the content of substances such as starch, low molecular weight polysaccharide and the like is reduced, the biological aging resistance is improved, and simultaneously, the color of lignin is changed under the action of damp heat, so that the color of bamboo is changed. But the intensity of the bamboo is reduced by heat treatment, and the mechanical intensity of the recombined bamboo prepared by the bamboo bundles treated at 200 ℃ is reduced by about 50 percent; meanwhile, the long-term action of damp and heat can cause products to have different odors, and waste liquid and waste gas can be generated in the heat treatment process to cause environmental pollution.

disclosure of Invention

the invention provides a complex bamboo wood, a complex bamboo wood artificial board and a preparation method thereof, aiming at solving the problems in the prior art, plant polyphenol-metal salt is introduced into bamboo wood, the plant polyphenol and the metal salt are fixed in bamboo wood cells by utilizing the complex reaction of the plant polyphenol and the metal salt, the bamboo wood is prepared into complex bamboo wood, and the complex bamboo wood artificial board is prepared by compounding or recombination processing. The complex bamboo wood and the complex bamboo wood-based board prepared by the invention have the advantages of cracking reduction, even no cracking, stable size, beautiful texture, rich color, mildew resistance, corrosion resistance and the like.

In order to solve the technical problems, the invention provides the following technical scheme:

On one hand, the invention provides a preparation method of complex bamboo wood, which comprises the following steps:

step 1: the preparation of bamboo wood, it is prior art;

step 2: introducing plant polyphenol into bamboo wood to obtain polyphenol bamboo wood;

And step 3: introducing metal salt into the polyphenol bamboo wood to obtain polyphenol metal salt bamboo wood;

And 4, step 4: and drying the bamboo wood with the polyphenol metal salt to obtain the complex bamboo wood.

Preferably, the bamboo is one or more of raw bamboo, bamboo strips, bamboo filaments, bamboo fibers, bamboo shavings, bamboo splits or bamboo bundles.

Further, the step 2 is as follows:

21) dissolving plant polyphenol in water, and stirring uniformly to form a plant polyphenol water solution;

22) Soaking the bamboo material in plant polyphenol water solution;

23) Drying the bamboo impregnated with the plant polyphenol water solution.

Preferably, the concentration of the plant polyphenol water solution is 1-250 g/L, the average molecular weight is 170-50000, and the plant polyphenol water solution is 1-40 polymers; the bamboo wood is soaked in the plant polyphenol water solution for 10min to 48h at the temperature of 0 to 80 ℃, and the soaking method is normal pressure, pressurization or pressurization after vacuum pumping;

The plant polyphenol is one or more of tea polyphenol, charred fruit juice, tannin, and tannin extract.

Soaking the bamboo wood prepared in the step 1 in the polyphenol solution in the step 2, gradually swelling the cell wall of the bamboo wood under the action of water, and gradually introducing the plant polyphenol into the bamboo wood cells until a preset impregnation amount is reached; and taking out the bamboo wood, placing the bamboo wood in a drying kiln or air to gradually evaporate water in the bamboo wood, increasing the concentration of the plant polyphenol in the cells, beginning to precipitate when the concentration of the plant polyphenol reaches an isoelectric point, and solidifying the plant polyphenol in the bamboo wood under the action of hydrogen bonds and/or hydrophobic bonds to form the polyphenol bamboo wood.

Further, the step 3 is:

31) dissolving metal salt in water, and stirring uniformly to form a metal salt water solution;

32) Soaking the polyphenol bamboo wood in a metal salt aqueous solution.

Preferably, the concentration of the metal salt aqueous solution is 0.3 g/L-300 g/L; the bamboo wood is soaked in the metal salt water solution for 10min to 180 days at the soaking temperature of 0 to 80 ℃, and the soaking method is normal pressure, pressurization or pressurization after vacuum pumping;

the metal salt is one or more of iron salt, zinc salt, copper salt, aluminum salt, titanium salt, calcium salt, molybdenum salt, tungsten salt, chromium salt, magnesium salt and potassium salt.

Soaking the polyphenol bamboo wood prepared in the step 2 in the metal salt solution in the step 3, and gradually introducing the metal salt solution into the polyphenol bamboo wood cells until a preset soaking amount is reached; in the process, the polyphenol and the metal ions are complexed into a polyphenol-metal ion complex under the action of water and air, the bamboo material is taken out and placed in a drying kiln or air, and water in the bamboo material is gradually evaporated, so that the bamboo material, the plant polyphenol and the metal ions form a whole.

On the other hand, the invention provides the complex bamboo material which is prepared by the method.

The complexing bamboo wood contains plant polyphenol with the weight ratio of 0.3-15% and metal salt with the weight ratio of 0.1-12%, and the plant polyphenol and the metal salt exist on the surface, cell walls, cell cavities and/or cell gaps of the bamboo wood in a complex form; the bamboo is a bamboo tube, bamboo strips, bamboo filaments, bamboo fibers, bamboo shavings, bamboo splits or bamboo bundles.

Specifically, plant polyphenol and bamboo components are fixed in the bamboo through the action of multipoint hydrogen bonds and/or multipoint hydrophobic bonds, and the polyphenol and metal ions are complexed into a polyphenol-metal ion complex, so that the bamboo, the plant polyphenol and the metal ions form a whole. The hydrogen bond is mainly generated by combining phenolic hydroxyl in polyphenol with hydroxyl and carbonyl in bamboo cellulose and hemicellulose; the hydrophobic bond is mainly generated by the combination of hydrophobic bonds formed between benzene rings in polyphenol and lignin in bamboo wood; the complexation is mainly generated by chelating vicinal diphenol hydroxyl in the plant polyphenol with metal ions.

On the other hand, the invention relates to a method for preparing a complex bamboo wood-based plate, which takes the complex bamboo wood as a raw material and is formed by gluing phenolic resin, urea-formaldehyde resin or isocyanate resin, wherein the glued glue layer has a laminated structure and/or a dotted structure and comprises the following steps:

Step 1: sizing

applying phenolic resin, urea-formaldehyde resin or isocyanate resin into the complex bamboo wood in a dipping, spraying or roll coating mode;

Step 2: assembly

Forming a plate blank by the complex bamboo materials according to a certain assembly mode;

and step 3: blank processing

The plate blank prepared in the step 2 is hot-pressed into a complex bamboo wood-based plate blank;

and 4, step 4: article processing

and (3) cooling, cutting edges, sanding and quenching and tempering the blank plate of the complex bamboo wood-based panel in the step (3) to prepare the complex bamboo wood-based panel.

In the step 1, the complexing bamboo wood is adjusted to be weakly alkaline when the phenolic resin is used; the complex bamboo material is adjusted to be weakly acidic when the urea resin is used.

In the step 2, if the bamboo strips are complex, flat splicing or side splicing is firstly carried out to form a laminated plate, and then the laminated plate is assembled in parallel or in a crossed way to form an integrated material or a plywood blank; if the bamboo bundles are complex bamboo bundles, stacking and assembling the bamboo bundles according to the grain to form a recombined bamboo board blank; if the bamboo filaments are complex bamboo filaments, assembling the bamboo filaments according to a smooth grain or random mode to form a bamboo filament plate blank or a bamboo curtain plate blank; if the bamboo shaving board is complex bamboo shavings, assembling the bamboo shavings according to an oriented or random paving mode to form a bamboo shaving board blank; if the complex bamboo fibers are formed, assembling the bamboo fibers according to an oriented or random paving mode to form a bamboo fiber board blank; if the bamboo strips are complex bamboo strips, assembling the bamboo strips in a parallel grain or cross mode to form a bamboo laminated material or a bamboo-woven plywood;

In the step 3, if the bamboo laminated wood is complex bamboo laminated wood, the bamboo laminated wood slab is sent into a hot press machine, and the complex bamboo laminated wood is manufactured through hot-pressing gluing; if the bamboo recombined material is the complex bamboo recombined square material, the bamboo recombined material plate blank is sent into a cold press to be pressed into a bamboo recombined material square material, and then the bamboo recombined material square material is put into curing equipment to be heated and cured into the complex bamboo recombined square material; or the bamboo recombined material plate blank is sent into a hot press to be hot-pressed into the complex bamboo recombined plate by adopting a cold-in cold-out process; if the complex bamboo plywood is the complex bamboo plywood, sending the plywood plate blank into a hot press, and synthesizing the complex bamboo plywood through hot-pressing gluing; if the bamboo fiber board is the complex bamboo fiber board, the fiber board blank is sent into a hot press machine and is glued by hot pressing to prepare the complex bamboo fiber board; if the complex bamboo shaving board is the complex bamboo shaving board, the board blank of the shaving board is sent into a hot press machine, and the complex bamboo shaving board is prepared by hot-press gluing; if the complex bamboo filament board is the complex bamboo filament board, the board blank of the bamboo filament board is sent into a hot press machine and is glued by hot pressing to prepare the complex bamboo filament board; if the bamboo laminated wood is complex bamboo laminated wood, the bamboo laminated wood plate blank is sent into a hot press machine and is subjected to hot pressing and gluing to prepare complex bamboo laminated wood; if the complex bamboo woven plywood is the complex bamboo woven plywood, the plate blank of the bamboo woven plywood is sent into a hot press machine, and the complex bamboo woven plywood is manufactured through hot-press gluing.

on the other hand, the invention also provides a complex bamboo wood-based board which is prepared by the method. The complex bamboo wood-based plate is formed by stacking a plurality of layers of complex bamboo wood through a parallel grain or cross structure, an adhesive layer is arranged between the complex bamboo wood, and the adhesive is phenolic resin, urea resin or isocyanate resin; the complexing bamboo wood contains plant polyphenol with the weight ratio of 0.3-15% and metal salt with the weight ratio of 0.1-12%, and the plant polyphenol and the metal salt exist on the surface, cell walls, cell cavities and/or cell gaps of the bamboo wood in a complex form; the bamboo is a bamboo tube, bamboo strips, bamboo filaments, bamboo fibers, bamboo shavings, bamboo splits or bamboo bundles.

Preferably, the complex bamboo-based artificial board at least comprises one or more layers of complex bamboo, and the complex bamboo-based artificial board comprises one or more layers of complex bamboo, such as a bamboo laminated wood, a bamboo recombined material, a bamboo fiber board, a bamboo shaving board, a bamboo filament board, a bamboo curtain or a bamboo plywood.

the existing research considers that the bamboo is cracked due to a plurality of reasons, wherein the main factor is that polysaccharides (cellulose, hemicellulose and other substances) in the bamboo absorb or release water in the processes of moisture absorption and desorption to cause the expansion or contraction of the bamboo, so that the bamboo is unstable in size and cracked, and the figure 1 shows that the bamboo is cracked.

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

according to the invention, plant polyphenol and metal salt are introduced into the cell wall of bamboo wood, phenolic hydroxyl of the plant polyphenol is combined with hydroxyl of cellulose and hemicellulose, meanwhile, ortho-position phenolic hydroxyl is complexed with metal ions, and molecular chains of adjacent cellulose/hemicellulose are crosslinked into a net structure, just as a plurality of supports are supported on the molecular chains of the cellulose/hemicellulose, so that the expansion or contraction of the molecular chains is reduced or even not generated during moisture absorption or desorption; on the basis, a large number of multiple sacrificial bond networks consisting of hydrogen bonds (multipoint hydrogen bonds are formed by combining plant polyphenol phenolic hydroxyl groups and hydroxyl groups in bamboo wood) and coordination bonds (coordination bonds are formed by complexing ortho-position hydroxyl groups on plant polyphenol phenolic rings and metal salts) are formed in the cellulose framework. Because the bond energy of the sacrificial bonds is less than that of the covalent bonds (a covalent bond network is formed among cellulose, hemicellulose, lignin and phenolic resin), when the bamboo is subjected to internal stress or external force, the sacrificial bonds are broken in preference to the covalent bonds. The dynamic action of the continuous breakage and reconstruction of the sacrificial bonds dissipates a large amount of energy in a bamboo wood system, eliminates or weakens internal stress, and protects the integrity of a cellulose skeleton covalent bond network. This provides a new method for solving the cracking problem of bamboo, as shown in fig. 2.

Firstly, introducing plant polyphenol into bamboo wood to swell the bamboo wood; then introducing metal salt into the bamboo wood, combining plant polyphenol with cellulose and hemicellulose in the bamboo wood to form a multi-point hydrogen bond, complexing the plant polyphenol with the metal salt, and combining the cellulose-plant polyphenol-metal salt into a whole just like forming a plurality of support supports in a cellulose skeleton molecule; then, accompanied by evaporation and oxidation reaction of water, the "cellulose-plant polyphenol-metal salt" is further cross-linked and oxidized, and finally the complex bamboo is formed. The dynamic multi-sacrifice bond network structure of the invention 'cellulose-plant polyphenol-metal salt' supports cellulose and/or hemicellulose, so that the dynamic effect of the repeated breakage and reconstruction of sacrifice bonds is reduced or even avoided when the cellulose and/or hemicellulose absorbs moisture or desorbs moisture, a large amount of energy in a wood recombination material system is dissipated, the internal stress is eliminated or weakened, the integrity of a cellulose skeleton covalent bond network is protected, and the problem of easy cracking of bamboo wood at the molecular level is solved.

the metal salt is in-situ complexed through the plant polyphenol and is in-situ fixed in the wood material cells, and the prepared complex bamboo wood and complex bamboo wood-based plates have the advantages of cracking reduction, even no cracking, stable size, beautiful texture, rich color, mildew resistance, corrosion resistance and the like.

Drawings

FIG. 1 is a diagram of a dry shrinkage and wet swelling molecular chain of a cell wall cellulose skeleton in the prior art;

FIG. 2 is a molecular chain structure diagram of the complex bamboo cellulose framework in dry and wet states;

Fig. 3 is a schematic view of the bamboo laminated wood blank in step 2 in example 2 of the present invention;

FIG. 4 is a schematic diagram of a slab of the complex bamboo-based artificial board obtained in step 3 of example 2 of the present invention;

FIG. 5 is a schematic structural diagram of a layer glue layer obtained in step 4 of example 2 of the present invention;

Fig. 6 is a schematic view of the reformed bamboo blank at step 2 in example 4 of the present invention;

FIG. 7 is a schematic diagram of the complex recombinant bamboo obtained in step 3 of example 4;

FIG. 8 is a SEM picture of the dot-shaped glue layer of step 4 in example 4 of the present invention;

FIG. 9 is a photograph of a complexed recombined bamboo in example 4 of the present invention;

FIG. 10 is a picture of a bamboo chip split by an untreated bamboo tube according to example 5 of the present invention after being subjected to mold treatment;

fig. 11 is a picture of a bamboo chip split by a complex bamboo tube prepared in example 5 of the present invention after being subjected to mold treatment.

Detailed Description

In order to make the technical problems, technical solutions and advantages to be solved by the present invention clearer, the following detailed description is given with reference to specific embodiments.

in the present invention, the materials and reagents used are not specifically described, and are commercially available.

The invention provides a complex bamboo wood, a complex bamboo wood-based plate and a preparation method thereof, and the specific embodiment is as follows.