CN110587749B - Complexing wood shavings, complexing shaving board and manufacturing method thereof - Google Patents

Abstract

The invention relates to a complex wood shavings, a complex shaving board and a manufacturing method thereof, belonging to the technical field of artificial board processing. The complex shaving board is composed of complex shavings and an adhesive, wherein a plant polyphenol metal salt complex is introduced into the complex shavings, and metal ions are fixed on the surfaces, cell walls, cell cavities and/or cell gaps of the shavings through plant polyphenol, so that the color of the shaving board is effectively changed, and the performances of the shaving board, such as water resistance, corrosion resistance, mildew resistance and the like, are improved.

Description

Complexing wood shavings, complexing shaving board and manufacturing method thereof

Technical Field

The invention relates to the technical field of artificial board processing, in particular to a complex wood shavings, a complex shaving board and a manufacturing method thereof.

Background

Particle board, also called particle board, is a wood composite material made by wood or other wood materials after being made into wood shavings, applying adhesive and then gluing under the action of heat and pressure. Because of the characteristics of good physical and mechanical properties, easy processing and the like, the material has wide application in the fields of plate furniture, building structural materials and decorative materials. With the continuous development of shaving boards in the field of home decoration and the continuous pursuit of people for beautiful life. During decoration, the pursuit of wooden products is greatly changed from practicability to individuation, functionalization and the like, the existing shaving board processing technology is difficult to realize the unification of the individuation and the functionalization, for example, the shaving board needs to be dyed when the color of the shaving board is increased; the water resistance of the shaving board is improved by mainly adding water-proofing agents such as paraffin and the like; increasing preservative performance requires the addition of preservatives; a mildew preventive is required for increasing the mildew resistance; and it is difficult to superimpose the above functions simultaneously in the same product or in the same process.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides a complex wood shaving, a complex shaving board and a manufacturing method thereof. The complex shaving board prepared by the method not only effectively changes the color of the shaving board, but also has the advantages of improving the performances of water resistance, corrosion resistance, mildew resistance and the like of the shaving board, and can effectively prevent the shaving board from cracking.

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

in one aspect, the invention provides a complex wood shaving, prepared from wood shavings, a plant polyphenol and a metal salt; the plant polyphenol and metal salt are present in the strands in a complex form and distributed on the strand surface, cell walls, cell cavities and/or intercellular spaces.

Further, the plant polyphenol is polygallate and/or polyflavan plant polyphenol; the gallate polyphenol comprises at least one polyalcohol and a plurality of phenolic carboxylic acids, wherein the polyalcohol is connected with the phenolic carboxylic acids through ester bonds; the molecular weight of the polyflavan polyphenol is 500-3000, the polymer is 2-10, the units are connected by C-C bonds, and the molecular skeleton is C₆·C₃·C₆The structure is that two phenol rings (ring A and ring B) are connected by a three-carbon chain (C-2, C-3 and C-4), wherein one carbon atom is connected with an oxygen atom at the position of ring A8 a to form a pyran ring (ring C).

In another aspect, the invention also provides a preparation method of the complex wood shavings, which comprises the steps of

Step 1: preparing a proper amount of wood shavings;

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

and step 3: introducing metal salt into the polyphenol wood shavings to obtain polyphenol metal salt wood shavings;

and 4, step 4: and drying the wood shavings to obtain the complex wood shavings.

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 wood shavings in plant polyphenol water solution;

23) drying the wood shavings impregnated with the aqueous solution of plant polyphenols.

Preferably, 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; soaking the wood shavings in plant polyphenol water solution for 10min-48h at 0-80 deg.C under normal pressure or under pressure;

the plant polyphenol is one or more of tannin extract, tannin, tannic acid, terminal food acid, and charred terminal food acid.

Soaking the wood shavings in a polyphenol solution, wherein the wood shavings gradually swell by the action of water, and the plant polyphenol is gradually introduced to the surfaces, cell walls, cell cavities and/or cell gaps of the wood shavings until a preset impregnation amount is reached; and taking out the wood shavings, placing the wood shavings in a drying kiln or air to gradually evaporate water in the wood shavings, 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 wood shavings under the action of hydrogen bonds and/or hydrophobic bonds to form the polyphenol wood shavings.

Further, the step 3 is:

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

32) immersing the polyphenol wood shavings into a metal salt aqueous solution.

Preferably, the concentration of the metal salt aqueous solution is 0.3 g/L-30.0 g/L; soaking the wood shavings in a metal salt aqueous solution for 10min-24h at the temperature of 0-80 ℃, wherein the soaking method is normal pressure or pressurization;

the metal salt is one or a mixture of iron salt, copper salt and borate metal salt.

Soaking polyphenol wood shavings in metal salt, gradually swelling wood shavings cell walls under the action of water, and gradually introducing the metal salt to the surfaces, cell walls, cell cavities and/or cell gaps of the wood shavings until a preset impregnation amount is reached; the plant polyphenol and the metal salt are complexed in the wood shavings, the wood shavings and the plant polyphenol metal salt complex are combined through hydrogen bonds, defibering bonds and covalent bonds, and the polyphenol metal salt complex is chelated by five-membered rings formed by ortho-diphenol hydroxyl of the plant polyphenol and ions.

On the other hand, the invention also provides a complex shaving board which comprises 1-95% of the complex shaving boards.

Plant polyphenol metal salt is arranged on the surfaces of the wood shavings and/or cell cavities, cell walls and/or cell gaps in the wood shavings, and the wood shavings are directionally arranged along the grains and/or randomly arranged and are glued into a whole through an adhesive.

In another aspect, the present invention also provides a method for preparing a complex particle board, comprising the above complex particle board, comprising:

101) drying

Drying the complex wood shavings by adopting an airflow method until the moisture content is 2-5%, wherein the temperature of the airflow at the inlet is 370-400 ℃, the temperature of the drying medium is 160-190 ℃, and the oxygen content of the drying medium is 13-18%;

102) sizing

Uniformly spraying phenolic resin or urea-formaldehyde resin on the surface of the complex wood shavings by adopting a spray sizing method, wherein the sizing amount of the phenolic resin is 5-10%; if the urea-formaldehyde resin is adopted, the glue application amount is 8-12%

103) Paving and forming

Spreading the dried wood shavings by air flow spreading to obtain a surface density of 0.15-0.45g/cm²The slab of (1);

104) hot pressing

Feeding the plate blank into a multi-layer hot press or a continuous hot press, and hot-pressing to obtain the plate blank with the density of 0.65-1.10g/cm³The particle board.

The existing research considers that the particleboard cracks for a plurality of reasons, wherein the main factor is that polysaccharides (cellulose, hemicellulose and the like) in the particleboards absorb or release water in the processes of moisture absorption and desorption to cause the particleboards to expand or contract, thereby causing the size instability of the particleboards.

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

the method comprises the steps of firstly, introducing plant polyphenol into wood shavings, wherein the phenolic hydroxyl group of the plant polyphenol is combined with the alcoholic hydroxyl groups in cellulose and hemicellulose in the wood shavings through hydrogen bonds, untwining bonds and covalent bonds, so that hydrophilic groups in the wood shavings are reduced, and the phenolic hydroxyl group and benzene ring of the plant polyphenol enable the wood shavings to have hydrophilicity and hydrophobicity;

meanwhile, the introduction of the metal salt can effectively increase the properties of the shaving board such as corrosion resistance and mildew resistance, and the color of the shaving board is changed to a certain extent, so that the shaving board has the color of the metal salt, and the metal salt ions and the plant polyphenol are complexed in wood, so that the metal salt ion complex wood is stable and is not easy to fade.

According to the invention, plant polyphenol and metal salt are introduced into the cell wall of the wood shavings, the plant polyphenol and the metal salt are complexed in the wood shavings, the wood shavings and the plant polyphenol metal salt complex are mainly combined through hydrogen bonds, defibering bonds and covalent bonds, and the polyphenol metal salt complex is chelated by five-membered rings formed by ortho-position diphenol hydroxyl of the plant polyphenol and ions. The molecular chains of adjacent cellulose/hemicellulose are crosslinked into a net structure, just as a plurality of supports are supported on the molecular chain branches of the cellulose/hemicellulose, so that the molecular chains of the cellulose/hemicellulose are reduced or even do not expand or contract when absorbing or desorbing moisture; on the basis, a large number of multiple sacrificial bond networks consisting of hydrogen bonds (the plant polyphenol phenolic hydroxyl groups are combined with the hydroxyl groups in the wood shavings to form multi-point hydrogen bonds) and coordination bonds (the ortho hydroxyl groups on the plant polyphenol phenolic rings are complexed with metal salts to form coordination bonds) are formed in the cellulose skeleton. Because the sacrificial bond energy is less than the covalent bonds (a network of covalent bonds is formed between the cellulose, hemicellulose, lignin, and phenolic resin), when the strands are subjected to internal or external stresses, the sacrificial bonds break 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 wood shaving system, eliminates or weakens internal stress, and protects the integrity of a cellulose skeleton covalent bond network. This provides a new approach to solving the problem of wood chip cracking.

Firstly, plant polyphenol is introduced into wood shavings to ensure that the wood shavings are swollen; then introducing metal salt into the wood shavings, combining the plant polyphenol with cellulose and hemicellulose in the wood shavings 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 cellulose skeleton molecules; then, accompanied by evaporation and oxidation reaction of water, the "cellulose-plant polyphenol-metal salt" is further cross-linked and oxidized, finally forming a complex wood wool. 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 wood shavings at the molecular level is solved.

Drawings

FIG. 1 shows the condition of wood shavings before and after treatment in example 1 of the present invention;

FIG. 2 is a graph showing the contact angles of water on the surface of radiata pine wood shavings before and after treatment in example 1 of the present invention;

FIG. 3 shows the condition of wood shavings before and after treatment in example 2 of the present invention;

FIG. 4 shows the contact angles of water on the surface of eucalyptus strands before and after the treatment in example 2 of the present invention;

FIG. 5 is an oriented strand board made according to example 4 of the present invention;

figure 6 shows a particle board made according to example 5 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.

Example 1

A method for preparing complexed radiata pine wood shavings comprises

Step 1: preparing a proper amount of radiata pine wood shavings;

cutting the radiata pine into wood sections with the length of 1000-; after drying, the flat strands are obtained by air-flow separation, as shown in fig. 1(a), which is prior art.

Step 2: introducing plant polyphenol into wood shavings to obtain polyphenol wood shavings;

21) dissolving tannin with average molecular weight of 170 and polymer of 1 in water, and stirring to obtain tannin water solution with concentration of 1.0 g/L;

22) soaking the wood shavings in tannin water solution at normal pressure for 48h at 25 deg.C;

23) drying the strands impregnated with the aqueous tannin solution.

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

31) dissolving ferric chloride in water, and uniformly stirring to form a ferric chloride aqueous solution with the concentration of 1.0 g/L;

32) soaking the polyphenol wood shavings in a ferric chloride aqueous solution at normal pressure for 24 hours at a soaking temperature of 25 ℃.

And 4, step 4: and drying the wood shavings to obtain the complex wood shavings.

The above complex wood shavings were dried by air flow method to a moisture content of 3%, the inlet air flow temperature during drying was 400 ℃, the drying medium temperature was 160 ℃, and the oxygen content of the drying medium was 13%, as shown in fig. 1 (b).

The color difference meter is adopted for analysis, the Lab values of the wood shavings before treatment are respectively 67.90, 2.71 and 20.49, the wood shavings are shown to be light yellow, and the Lab values of the wood shavings after complexation treatment are respectively 47.87, 0.14 and 8.80, and the wood shavings are black.

The contact angle was used to analyze the strands before and after treatment, as shown in fig. 2, the contact angle of the complexed radiata pine strands increased and the water resistance increased.

Example 2

A method for preparing complex eucalyptus shavings comprises

Step 1: preparing a proper amount of wood shavings;

cutting eucalyptus into 1300mm wood segments, rotary cutting into 1.0mm single plates by a rotary cutter, cutting to form regular large shavings, drying, and making into eucalyptus shavings as shown in fig. 3 (a).

Step 2: introducing cortex Nerii tannin extract (polyflavanoid plant polyphenol) into wood shavings to obtain polyphenol wood shavings;

21) dissolving a black wattle bark tannin extract in water, and uniformly stirring to form a black wattle bark tannin extract water solution with the concentration of 1 g/L;

22) soaking the wood shavings in a tanning extract solution of black wattle bark at 20 deg.C for 10min under 0.4 MPa;

23) drying the strands impregnated with the aqueous extract solution of Acacia Negra bark.

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

31) dissolving ferrous sulfate in water, and stirring uniformly to form a ferrous sulfate aqueous solution with the concentration of 3.0 g/L;

32) soaking the above polyphenol wood shavings in ferrous sulfate water solution at 0.4MPa for 30min at 20 deg.C.

And 4, step 4: and drying the wood shavings to obtain the complex wood shavings.

The above complex wood shavings were dried by air flow method to a moisture content of 3%, the inlet air flow temperature during drying was 400 ℃, the drying medium temperature was 160 ℃, and the oxygen content of the drying medium was 13%, as shown in fig. 3 (b).

The color difference meter is adopted for analysis, the Lab values of the wood shavings before treatment are 82.21, 1.48 and 23.41 respectively, the wood shavings are pink, and the Lab values of the wood shavings after complexation treatment are 50.73, 0.16 and 1.26 respectively, and the wood shavings are dark black.

The wood shavings before and after treatment were analyzed by contact angle, as shown in fig. 4, the contact angle of the poplar wood shavings after complexation treatment was increased and the water resistance was enhanced.

Example 3

A method for preparing complex poplar wood shavings comprises

Step 1: preparing a proper amount of poplar wood shavings;

the method comprises the following steps of (1) slicing poplar or poplar branches into wood chips by a chipping machine, and then planing the wood chips into rod-shaped wood chips by a double-drum wheel planer, belonging to the prior art;

step 2: introducing fructus Myricae Rubrae tannin extract (polygallate plant polyphenol) into wood shavings to obtain polyphenol wood shavings;

21) dissolving the bayberry tannin extract in water, and uniformly stirring to form a bayberry tannin extract water solution with the concentration of 3.0 g/L;

22) soaking the wood shavings in plant polyphenol water solution at normal pressure for 8h and at 25 ℃;

23) drying the strands impregnated with the aqueous extract of a bayberry extract.

And step 3: introducing metal salt into the bayberry tannin extract shavings to obtain bayberry tannin extract metal salt shavings;

31) dissolving 500g of zinc borate and 500g of copper sulfate in 1000L of water, and uniformly stirring to form a zinc borate and copper sulfate mixed salt solution;

32) soaking the polyphenol wood shavings in a metal salt aqueous solution at normal pressure for 4h at the soaking temperature of 25 ℃.

And 4, step 4: and drying the wood shavings to obtain the complex wood shavings.

Example 4

A complex oriented strand board comprising the complex strands prepared in example 1, wherein tannic acid salt is disposed on the surface of the strands and/or in the cavities, walls, and/or spaces of the strands, and the strands are oriented and glued together by adhesive to form a unitary body, as shown in fig. 5.

The preparation method of the complex particle board comprises the following steps:

101) drying

Drying the complex wood shavings by adopting an airflow method until the water content is 3 percent, wherein the temperature of inlet airflow is 400 ℃, the temperature of a drying medium is 160 ℃, and the oxygen content of the drying medium is 13 percent;

102) sizing

Uniformly spraying phenolic resin on the surface of the complex wood shavings by adopting a spray sizing method, wherein the sizing amount of the phenolic resin is 8%;

103) paving and forming

The dried wood shavings are directionally paved into pieces with surface density of 0.15g/cm by an air flow paving method²The slab of (1);

104) hot pressing

Feeding the plate blank into a continuous hot press, and hot-pressing to obtain the product with density of 0.65g/cm³The oriented strand board of (1).

The physical and mechanical properties of the complex oriented strand board were measured according to GB/T4897 2015, and the results are shown in Table 1. As can be seen from Table 1, all properties of the board meet the requirements of national standards, and after the complexing treatment, the expansion rate value of the 24-hour water absorption thickness is obviously reduced, which proves that the dimensional stability of the complex particle board prepared by the invention is obviously improved.

TABLE 1 comparison of oriented strand board Performance before and after complexing

Example 5

A composite particle board comprised of 45% of the composite strands prepared in example 3, 45% of ordinary strands and 10% of phenolic resin; mixing common wood shavings and the complex wood shavings uniformly; the wood shavings are overlapped and stacked randomly, a phenolic adhesive is arranged at the overlapped part and is glued into a whole through the adhesive, and the density of the complex shaving board is 0.90g/cm³As shown in fig. 6.

The preparation method of the complex particle board comprises the following steps:

101) drying

Drying the glued complex wood shavings by adopting an air flow method until the moisture content is 5%, wherein the inlet air flow temperature is 370-400 ℃ during drying, the drying medium temperature is 160-190 ℃, and the oxygen content of the drying medium is 13-18%;

102) sizing

Respectively and uniformly spraying phenolic resin on the surfaces of the complexing wood shavings and the common wood shavings by adopting a spray sizing method, wherein the sizing amount of the complexing wood shavings is 12%; the glue application amount of the common wood shavings is 8 percent;

103) paving and forming

Adopting an air flow paving method, weighing the glued complex wood shavings and common wood shavings according to a set density, uniformly mixing, and adopting random paving with a paving density of 0.30g/cm²The slab of (1);

104) hot pressing

Feeding the plate blank into a multi-layer hot press, and hot-pressing to obtain the plate blank with the density of 0.90g/cm³The particle board.

The physical and mechanical properties of the particle board are tested according to GB/T4897-2003, and the results are shown in Table 2, and it can be seen from Table 2 that the density, strength and elastic modulus of the material are basically kept unchanged after the complexing treatment; the dimensional stability is greatly increased; the corrosion resistance, mildew resistance and flame retardant property of the material are greatly improved, and the loss of introduced metal ions (zinc ions and copper ions) is greatly reduced.

TABLE 2 comparison of particle board Properties of poplar before and after complexing

Performance index	Common shaving board	Complexing shaving board
			Density (g/cm)3)	0.90	0.90
Flexural Strength (MPa)	48.2	48.6
			Flexural modulus of elasticity (MPa)	5400	5300
Internal bond Strength (MPa)	1.10	1.12
			Surface bonding Strength (MPa)	1.23	1.25
Internal bond Strength after 2h boiling Water (MPa)	0.42	0.48
			Swelling ratio in thickness after 24h absorption (%)	6.7	4.3
Flame retardant properties	B2	B1
			Mildew resistance	4 stage	Stage 2
Corrosion resistance	Grade IV (decay-free)	II level (Corrosion resistant)
			Loss of copper ion	-	15％
Loss of zinc ion	-	17％

To sum up, the complex shaving board that utilizes the complex wood shavings preparation of this application possesses the colour of metal salt, and metal salt ion and plant polyphenol complex in timber, exist comparatively stably, and difficult the fading has performances such as anticorrosive, mould proof, fire-retardant concurrently.

The foregoing is a preferred embodiment of the present invention, and 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 are intended to be within the scope of the invention.

Claims (9)

1. A method of making a complex wood chip comprising:

step 1: preparing a proper amount of wood shavings;

step 2: introducing plant polyphenol into wood shavings: soaking the wood shavings in a plant polyphenol solution, and gradually introducing plant polyphenol into the surfaces, cell walls, cell cavities and/or cell gaps of the wood shavings to obtain polyphenol wood shavings; 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 polymers;

and step 3: introducing a metal salt into the polyphenol shavings: soaking the polyphenol wood shavings in a metal salt aqueous solution, and gradually introducing metal salt into the surfaces, cell walls, cell cavities and/or cell gaps of the wood shavings to obtain polyphenol metal salt wood shavings; the concentration of the metal salt water solution is 0.3 g/L-30.0 g/L; the metal salt is one or a mixture of iron salt, copper salt and borate metal salt;

and 4, step 4: and drying the wood shavings to obtain the complex wood shavings.

2. The method of making a complex wood wool according to claim 1 comprising wood wool, a plant polyphenol and a metal salt; the plant polyphenol and metal salt are present in the strands in a complex form and distributed on the surface, cell walls, cell cavities and/or interstitial spaces of the strands.

3. The method of making a complexed shaving according to claim 1, wherein step 2 is:

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

22) soaking the wood shavings in plant polyphenol water solution;

23) drying the wood shavings impregnated with the aqueous solution of plant polyphenols.

4. The method for preparing the complex wood shavings according to claim 3 wherein the wood shavings are immersed in the aqueous solution of plant polyphenol for 10min to 48h at a temperature of 0 to 80 ℃ under normal pressure or under pressure;

the plant polyphenol is one or more of tannin extract, tannin, tannic acid, gallic acid and pyrogallic acid.

5. The method of making a complexed shaving according to claim 1, wherein step 3 is:

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

32) immersing the polyphenol wood shavings into a metal salt aqueous solution.

6. The method for preparing the complex wood shavings according to claim 5 wherein the wood shavings are immersed in the aqueous solution of the metal salt at a temperature of 0-80 ℃ for a period of 10min-24h, and the immersion is carried out under normal pressure or under pressure.

7. A complex wood wool produced by the method of any one of claims 1 to 6.

8. A method of making a composite particle board from the composite particles of claim 7, comprising:

101) drying

Drying the complex wood shavings by adopting an airflow method until the moisture content is 2-5%, wherein the temperature of the airflow at the inlet is 370-400 ℃, the temperature of the drying medium is 160-190 ℃, and the oxygen content of the drying medium is 13-18%;

102) sizing

Uniformly spraying phenolic resin or urea-formaldehyde resin on the surface of the complex wood shavings by adopting a spray sizing method, wherein the sizing amount of the phenolic resin is 5-10%; if the urea resin is used, the glue application amount is 8-12%;

103) paving and forming

Spreading the dried wood shavings by air flow spreading to obtain a surface density of 0.15-0.45g/cm²The slab of (1);

104) hot pressing

Feeding the plate blank into a multi-layer hot press or a continuous hot press, and hot-pressing to obtain the plate blank with the density of 0.65-1.10g/cm³The particle board.

9. A composite particle board made by the process of claim 8.

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