阅读说明：本技术 一种络合锯材、络合胶合木及其制备方法 (Complexing sawn timber, complexing laminated wood and preparation method thereof ) 是由 余养伦 于文吉 吕斌 张耀明 于 2019-09-20 设计创作，主要内容包括：本发明涉及一种络合锯材、络合胶合木及其制备方法,属于木材加工技术领域。上述络合胶合木的制备方法包括：步骤1：准备适量锯材；步骤2：把植物多酚导入锯材,得到多酚锯材；步骤3：在多酚锯材中导入金属盐,得到多酚金属盐锯材；步骤4：干燥多酚金属盐锯材,得到络合锯材；步骤5：对上述络合锯材进行基材加工；步骤6：层板加工；步骤7：层积加工；步骤8：制品加工。本发明通过在胶合木中引入“纤维素-植物多酚-金属盐”动态多重牺牲键网络结构,使其具有减少开裂甚至不开裂、增加尺寸稳定、防腐、防霉、防火等优点。(The invention relates to a complex sawn timber, a complex laminated wood and a preparation method thereof, belonging to the technical field of wood processing. The preparation method of the complex laminated wood comprises the following steps: step 1: preparing a proper amount of sawn timber; step 2: introducing plant polyphenol into sawn timber to obtain polyphenol sawn timber; and step 3: introducing metal salt into the polyphenol sawn timber to obtain polyphenol metal salt sawn timber; and 4, step 4: drying the polyphenol metal salt sawn timber to obtain complex sawn timber; and 5: processing the base material of the complexing sawn timber; step 6: processing a laminate; and 7: lamination processing; and 8: and (5) processing the product. According to the invention, the cellulose-plant polyphenol-metal salt dynamic multi-sacrifice bond network structure is introduced into the laminated wood, so that the laminated wood has the advantages of cracking reduction, even no cracking, size increase, stability, corrosion resistance, mildew resistance, fire resistance and the like.)

1. The preparation method of the complexing sawn timber is characterized by comprising the following steps:

step 1: preparing a proper amount of sawn timber;

step 2: introducing plant polyphenol into sawn timber to obtain polyphenol sawn timber;

and step 3: introducing metal salt into the polyphenol sawn timber to obtain polyphenol metal salt sawn timber;

and 4, step 4: and drying the polyphenol metal salt sawn timber to obtain the complex sawn timber.

2. The method for preparing the complexing sawn timber according to the claim 1, characterized in that the step 1 is:

11) sawing the log into wood sections with certain length;

12) sawing the wood sections into sawn timber with certain width and thickness;

13) drying the sawn timber until the relative water content is 6-30%.

3. The method for preparing the complexing sawn timber according to the 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 sawn timber in plant polyphenol water solution;

23) drying the sawn timber dipped with the plant polyphenol water solution.

4. The method for preparing the complexing sawn timber as claimed in claim 3, wherein the concentration of the plant polyphenol water solution is 1 g/L-25.0 g/L, the average molecular weight is 170-50000, and the plant polyphenol water solution is 1-40 polymer; the dipping time of the sawn timber in the plant polyphenol water solution is 10min-48h, the dipping temperature is 0-80 ℃, and the dipping method is normal pressure, pressurization or pressurization after vacuum pumping; the plant polyphenol is one or more of tannin extract, tannin, tannic acid, terminal food acid, and charred terminal food acid.

5. The method for preparing the complexing sawn timber according to the claim 1, characterized in that the step 3 is:

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

32) the polyphenol sawn timber is soaked in metal salt water solution.

6. The method for preparing the complexing sawn timber according to the claim 5, characterized in that the concentration of the metal salt water solution is 0.3g/L to 30.0 g/L; soaking the polyphenol sawn timber in a metal salt water 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, copper salt, aluminum salt, zinc salt, titanium salt, calcium salt, molybdenum salt, tungsten salt, chromium salt, magnesium salt, potassium salt and complex salt thereof.

7. The complexing sawn timber 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 distributed on the surface, cell walls, cell cavities and/or intercellular spaces of the sawn timber and exist in the form of a complex.

8. A method for preparing a laminated wood complex, comprising: the complexing sawn timber obtained by the method of any one of claims 1 to 6 or the complexing sawn timber of claim 7 is taken as a raw material, and comprises the following components:

step 1: complex sawn timber processing

After the complexing sawn material is divided into grades, the complexing sawn material with certain width and thickness is processed by planing, and the two ends of the complexing sawn material are subjected to tooth punching, slotting or cutting to be processed into fingers, inclined planes, step surfaces or planes;

step 2: processing of complex laminates

Coating resorcinol adhesive, water-based polymer-isocyanate adhesive or polyvinyl acetate adhesive on finger joint surfaces, inclined surfaces, step surfaces or planes at two ends of the complexing sawn timber, extending the complexing sawn timber through finger joint, inclined joint, lap joint or end joint, coating the adhesive on the thickness and width directions of the complexing sawn timber, splicing the complexing sawn timber into a certain width by adopting flat splicing or side splicing, and planing the complexing sawn timber into a complexing laminated board with a certain thickness after curing;

and step 3: lamination processing

Coating resorcinol adhesive, aqueous polymer-isocyanate adhesive or polyvinyl acetate adhesive on the upper and lower surfaces of a laminated board, assembling the laminated board in parallel or in a crossed manner, and pressurizing and curing to obtain a complex glued wood blank board;

and 4, step 4: article processing

The complex laminated wood slab is processed into complex laminated wood after edge cutting, saw cutting, sanding and inspection.

9. The complex laminated wood is characterized in that the complex laminated wood is formed by assembling a plurality of layers of complex laminated plates according to a straight line or cross structure, and an adhesive is arranged between each layer of complex laminated plate;

the adhesive is resorcinol adhesive, aqueous polymer-isocyanate adhesive or polyvinyl acetate adhesive;

the laminated board is formed by longitudinally lengthening and/or transversely splicing complexing sawn materials;

the complexing laminated plate contains 0.3-15 wt% of plant polyphenol and 0.1-12 wt% of metal salt, and the plant polyphenol and the metal salt are distributed on the surface, cell walls, cell cavities and/or intercellular spaces of the sawn timber and exist in the form of a complex.

10. The laminated composite board of claim 9, wherein the sawn timber of the laminated composite board is one or more of pinus sylvestris, larch, masson pine, radiata pine, fir, oak, poplar, birch, beech, ash, and white wax.

Technical Field

The invention relates to the technical field of wood processing, in particular to a complex sawn timber, a complex laminated wood and a preparation method thereof.

Background

The laminated wood (also called as laminated wood or finger joint wood) is an engineering wood which is formed by using sawn timber as a basic unit and gluing the sawn timber by using an adhesive, and mainly comprises parallel structure laminated wood (Glulam) and cross structure laminated wood (CLT). Compared with raw wood, the laminated wood has the advantages of attractive appearance, high strength, large allowable bending stress, uniform structure, small internal stress, difficulty in cracking and warping deformation and the like, is widely applied to the engineering fields of furniture, floor panels, wall panels, bridges, buildings and the like, and is one of effective ways for efficiently utilizing artificial forest wood. However, as a biomass material, like other woody materials, the laminated wood has problems of swelling, drying, shrinkage, cracking, decay, mildew, discoloration and the like, and thus, the application of the laminated wood is greatly limited. Aiming at the main defects of the laminated wood in the using process, people adopt physical and chemical technologies to carry out functional improvement, and the functional improvement comprises a wood strengthening technology, a wood size stability enhancing technology, a wood anticorrosion and mildew-proof technology, a wood discoloration prevention and dyeing technology and the like.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides a complexing sawn timber, a complexing laminated wood and a preparation method thereof. The complex sawn timber and the complex laminated wood prepared by the invention and the preparation method thereof have the advantages of reducing cracking even not cracking, improving the dimensional stability, preventing corrosion, mildew and fire, and the like.

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

in one aspect, the invention provides a preparation method of a complexing sawn timber, which comprises the following steps:

step 1: preparing a proper amount of sawn timber;

step 2: introducing plant polyphenol into sawn timber to obtain polyphenol sawn timber;

and step 3: introducing metal salt into the polyphenol sawn timber to obtain polyphenol metal salt sawn timber;

and 4, step 4: and drying the polyphenol metal salt sawn timber to obtain the complex sawn timber.

Further, the step 1 is as follows:

11) sawing the log into wood sections with certain length;

12) sawing the wood sections into sawn timber with certain width and thickness;

13) drying the sawn timber until the relative water content is 6-30%.

Further, the step 2 is as follows:

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

22) immersing the sawn timber in a plant polyphenol aqueous solution, and introducing the polyphenol aqueous solution into the surface, cell walls, cell cavities and/or cell gaps of the sawn timber;

23) drying the sawn timber dipped with the plant polyphenol water solution.

Further, the concentration of the plant polyphenol water solution is 1-25.0 g/L, the average molecular weight is 170-50000, and the plant polyphenol water solution is 1-40 polymers; the dipping time of the sawn timber in the plant polyphenol water solution is 10min-48h, the dipping temperature is 0-80 ℃, and the dipping method is normal pressure, pressurization or pressurization after vacuum pumping; the plant polyphenol is one or more of tannin extract, tannin, tannic acid, terminal food acid, and charred terminal food acid.

Soaking sawn timber in polyphenol solution, gradually swelling sawn timber cell walls under the action of water, and gradually introducing the plant polyphenol into the surfaces, cell walls, cell cavities and/or intercellular spaces of the sawn timber until a preset impregnation amount is reached; and taking out the sawn timber, placing the sawn timber in a drying kiln or air to gradually evaporate water in the sawn timber, 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 sawn timber under the action of hydrogen bonds and/or hydrophobic bonds to form the polyphenol sawn timber.

Further, the step 3 is:

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

32) the polyphenol sawn timber is immersed in a metal salt aqueous solution, and the metal salt aqueous solution is introduced into the surface, cell walls, cell cavities and/or intercellular spaces of the sawn timber.

Further, the concentration of the metal salt water solution is 0.3 g/L-30.0 g/L; soaking the polyphenol sawn timber in a metal salt water 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, copper salt, aluminum salt, zinc salt, titanium salt, calcium salt, molybdenum salt, tungsten salt, chromium salt, magnesium salt, potassium salt and complex salt thereof.

Soaking the prepared polyphenol sawn timber in a metal salt solution, wherein the metal salt solution is gradually introduced to the surface, cell walls, cell cavities and/or cell gaps of the sawn timber, and the polyphenol aqueous solution is introduced into the surfaces, cell walls, cell cavities and/or cell gaps of the sawn timber until a preset impregnation 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 sawn timber is taken out and placed in a drying kiln or air, so that the water in the sawn timber is gradually evaporated, and the sawn timber, the plant polyphenol and the metal ions form a whole.

In another aspect, the present invention provides a complexed sawn timber, wherein the complexed sawn timber comprises 0.3-15% by weight of plant polyphenol and 0.1-12% by weight of metal salt, and the plant polyphenol and the metal salt are distributed on the surface, cell walls, cell cavities and/or intercellular spaces of the sawn timber and exist in the form of a complex.

In another aspect, the present invention further provides a method for preparing a laminated wood board, which uses the above laminated wood board as a raw material, and comprises:

step 1: complex sawn timber processing

After the complexing sawn material is divided into grades, the complexing sawn material with certain width and thickness is processed by planing, and the two ends of the complexing sawn material are subjected to tooth punching, slotting or cutting to be processed into fingers, inclined planes, step surfaces or planes;

step 2: processing of complex laminates

Coating resorcinol adhesive, water-based polymer-isocyanate adhesive or polyvinyl acetate adhesive on finger joint surfaces, inclined surfaces, step surfaces or planes at two ends of the complexing sawn timber, extending the complexing sawn timber through finger joint, inclined joint, lap joint or end joint, coating the adhesive on the thickness and width directions of the complexing sawn timber, splicing the complexing sawn timber into a certain width by adopting flat splicing or side splicing, and planing the complexing sawn timber into a complexing laminated board with a certain thickness after curing;

and step 3: lamination processing

Coating resorcinol adhesive, aqueous polymer-isocyanate adhesive or polyvinyl acetate adhesive on the upper and lower surfaces of a laminated board, assembling the laminated board in parallel or in a crossed manner, and pressurizing and curing to obtain a complex glued wood blank board;

and 4, step 4: article processing

The complex laminated wood slab is processed into complex laminated wood after edge cutting, saw cutting, sanding and inspection.

On the other hand, the invention also provides a complexing laminated wood which is formed by assembling a plurality of layers of complexing laminated plates according to a straight line or cross structure, and an adhesive is arranged between each layer of complexing laminated plate;

the adhesive is resorcinol adhesive, aqueous polymer-isocyanate adhesive or polyvinyl acetate adhesive;

the laminated board is formed by longitudinally lengthening and/or transversely splicing complexing sawn materials;

the complexing sawn timber contains 0.3-15 wt% of plant polyphenol and 0.1-12 wt% of metal salt, and the plant polyphenol and the metal salt are distributed on the surface, cell walls, cell cavities and/or intercellular spaces of the sawn timber and exist in the form of a complex.

Further, the complexing sawn timber is one or more of pinus sylvestris, larch, masson pine, radiata pine, fir, oak, poplar, birch, beech, ash bark, and white wax.

The complexing sawn timber comprises sawn timber, plant polyphenol and metal salt, the plant polyphenol and sawn timber components are fixed in the sawn timber through the action of multi-point hydrogen bonds and/or multi-point hydrophobic bonds, and the polyphenol and metal ions are complexed into a polyphenol-metal ion complex, so that the sawn timber, the plant polyphenol and the metal ions form a whole. The hydrogen bond is mainly generated by the combination of phenolic hydroxyl in polyphenol and hydroxyl and carbonyl in sawn timber cellulose and hemicellulose; the hydrophobic bond is mainly generated by the combination of the benzene ring in the polyphenol and the benzene ring in the lignin in the sawn timber; the complexation is mainly generated by chelating vicinal diphenol hydroxyl in the plant polyphenol with metal ions.

The existing research considers that the cracking of the laminated wood is caused by a plurality of reasons, wherein the main factor is that polysaccharides (cellulose, hemicellulose and the like) in the wood absorb or release water in the processes of moisture absorption and desorption to cause the expansion or shrinkage of the wood, so that the dimension of the laminated wood is unstable and the laminated wood cracks, and the figure 1 shows.

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 sawn timber, phenolic hydroxyl of the plant polyphenol is combined with hydroxyl of cellulose and hemicellulose, meanwhile, ortho 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 sawn timber) 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 skeleton. Because the bond energy of the sacrificial bonds is less than that of the covalent bonds (a network of covalent bonds is formed between the cellulose, hemicellulose, lignin and phenolic resin), the sacrificial bonds break in preference to the covalent bonds when the sawn timber is subjected to internal stress or external force. The dynamic action of the continuous breakage and reconstruction of the sacrificial bonds dissipates a large amount of energy in a sawn timber 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 problem of cracking of sawn timber.

Firstly, introducing plant polyphenol into sawn timber to swell the sawn timber; then introducing metal salt into the saw, combining plant polyphenol with cellulose and hemicellulose in the saw material to form a multi-point hydrogen bond, complexing the plant polyphenol with the metal salt to combine the cellulose-plant polyphenol-metal salt into a whole just like forming a plurality of bracket 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, finally forming the complex sawn timber. 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 continuous fracture and reconstruction of sacrifice bonds is reduced or even not generated when the cellulose and/or hemicellulose absorbs moisture or desorbs, 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 that sawn wood is easy to crack is solved from the molecular level, which is shown in figure 2.

The invention complexes the metal salt in situ through the plant polyphenol, is fixed in the wooden material cell in situ, the prepared complex sawn timber and complex glued wood have the advantages of reducing cracking even not cracking, improving the dimensional stability, being antiseptic, mildew-proof, fireproof 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 dry and wet states of the complex sawn cellulose skeleton of the present invention;

FIG. 3 is a photograph of a compounded oak sawn timber prepared in example 1 of the present invention;

FIG. 4 is a schematic view of a process for preparing a laminated veneer in example 3 of the present invention;

FIG. 5 is a schematic view of the procedure for gluing wood with an orthogonal structure in example 4 of the present invention;

FIG. 6 is a photograph of a complexed pinus sylvestris sawn timber prepared in example 4 of the present invention;

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.