A cross-laminated timber balanced engineered wood panel and a process for producing the same

Abstract

The present application relates to a kind of longitudinal and transverse vertical wood fiber balanced artificial board and its production process, belong to solid wood composite board technical field.The artificial board is obtained by rotary cutting of log and has oriented wood fiber, and is made into good processability square material by longitudinal laminating glue, longitudinal veneer and rotary laminating, so that wood fiber is transverse, and forms interwoven wood fiber network in space, when being subjected to external force, stress is evenly dispersed, so that board has higher mechanical strength and structural stability, in test, the rigidity and warping resistance of board are significantly improved;Interlamination is bonded by lignin adhesive, lignin adhesive uses traditional PMDI prepolymer as gluing matrix, and the water resistance of adhesive layer is improved by introducing self-developed modified lignin.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of solid wood composite board, and particularly relates to a longitudinal and transverse vertical wood fiber balanced artificial board and a production process thereof. BACKGROUND

[0002] Traditional wood balance boards are made of solid wood, and the utilization rate of wood is low and the price is high. With the progress of science and technology and the innovation of process, multi-layer artificial boards are used to replace the existing technology, which not only reduces the cost but also can be diversified according to the demand. Artificial boards are favored due to their unique advantages. However, the multi-layer artificial board is prone to deformation and warping, which seriously limits the application of the board. SUMMARY

[0003] In order to solve the technical problems mentioned in the background art, the purpose of the present application is to provide a longitudinal and transverse vertical wood fiber balanced artificial board and a production process thereof.

[0004] The purpose of the present application can be achieved by the following technical solutions:

[0005] A production process of a longitudinal and transverse vertical wood fiber balanced artificial board, comprising the following steps:

[0006] Step S1: cutting and drying the logs, and then coating with lignin adhesive, longitudinal stacking and pressure curing in sequence to obtain square material;

[0007] Step S2: longitudinal planing the square material to obtain blanks, rotating the adjacent blanks longitudinally, and then coating the blanks with lignin adhesive, transverse stacking and pressure curing in sequence to obtain a longitudinal and transverse vertical wood fiber balanced artificial board.

[0008] Preferably, the longitudinal rotation angle is 90°, and in this state, the wood fibers of the blank are easy to form a uniform longitudinal and transverse vertical structure, which is beneficial to improve the mechanical property stability of the board.

[0009] Preferably, the lignin adhesive comprises PMDI prepolymer 100 parts, modified lignin 18-26 parts, metal oxide filler 5-8 parts, leveling agent 0.4-0.5 parts and diluent 10-15 parts by weight.

[0010] Preferably, the -NCO content of the PMDI prepolymer is 30-35%, and the adhesive prepared in this state has good coatability and curing activity.

[0011] Preferably, the metal oxide filler is one or more of zinc oxide, titanium oxide and aluminum oxide, which can be chelated with modified lignin to strengthen and has good antibacterial and mildewproof effect.

[0012] The modified lignin is prepared by the following method:

[0013] Step A1: ultrasonic dispersion of lignin, tetrafluorobutylene glycol and anhydrous dioxane, dry nitrogen protection, temperature rise to 85-95 DEG C, apply 90-120 rpm stirring, intermittent addition of methyl vinyl dichlorosilane reaction 5-7h, reaction end spin-off dioxane, get fluorosilicon lignin;

[0014] Further, the amount ratio of lignin, tetrafluorobutylene glycol, methyl vinyl dichlorosilane and anhydrous dioxane is 50g: 15-20mmol: 30-40mmol: 80-100mL, the high activity methyl vinyl dichlorosilane reacts with the hydroxyl group on the lignin molecule and tetrafluorobutylene glycol, and the fluorosilicon structure and unsaturated double bond are introduced into the lignin molecule.

[0015] Step A2: ultrasonic pre-mixing of fluorosilicon lignin, benzoin dimethyl ether and dimethylacetamide, nitrogen protection, then adding mercaptoethanol and mixing, heating to 60-80 DEG C, applying 180-240 rpm stirring and 200-300W / m 2 UV irradiation, reaction 3.5-5h, reaction end centrifugal taking lignin precipitate layer, washing, drying, to get modified lignin;

[0016] Further, the amount ratio of fluorosilicon lignin, mercaptoethanol, benzoin dimethyl ether and dimethylacetamide is 50g: 35-45mmol: 8-12mg: 60-70mL, under the light initiation, mercaptoethanol and unsaturated double bond grafted on fluorosilicon lignin click reaction, active hydroxyl group is introduced into fluorosilicon lignin.

[0017] The beneficial effects of the present application are:

[0018] The application discloses a kind of artificial board of vertical and horizontal vertical structure, and the slice with directional wood fiber is obtained using rotary cutting process along the growth direction of log fiber, and good processability square material is made by longitudinal laminated gluing, longitudinal veneer is sliced and rotated laminated, so that wood fiber is interlaced, and interwoven wood fiber network is formed in space, when being subjected to external force, stress is evenly dispersed, so that the board has higher mechanical strength and structural stability, in test, the rigidity and warpage resistance of the board are significantly improved.

[0019] The present application discloses a lignin adhesive suitable for artificial balance plate, which takes traditional PMDI prepolymer as adhesive matrix, introduces self-developed modified lignin to improve the water resistance of adhesive layer, and reacts high-activity methyl vinyl dichlorosilane with hydroxyl on lignin molecule and tetrafluorobutanediol to introduce fluorosilicon structure and unsaturated double bond to lignin molecule, then reacts mercaptoethanol with the unsaturated double bond grafted on fluorosiliconated lignin by click reaction to introduce active hydroxyl to fluorosiliconated lignin, in the adhesive curing process, the active hydroxyl in modified lignin can be effectively crosslinked with PMDI prepolymer, at the same time, the thioether structure introduced by mercaptothiol and the oxygen and nitrogen structures in the curing chain form chelation, and form chelation strengthening with metal oxide filler, make up the problem of decreased adhesion caused by fluorosiliconated lignin, so that the adhesive maintains excellent bonding performance, and also has good waterproofness. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0021] Embodiment 1, preparation of vertical lignocellulose balance artificial plate, the specific implementation process is as follows:

[0022] (1) Preparation of lignin adhesive

[0023] 1.1, preparation of modified lignin

[0024] Step A1: take lignin, tetrafluorobutanediol and anhydrous dioxane, and ultrasonic dispersion for 10 min, protect by introducing dry nitrogen, heat to 95℃, apply 120rpm stirring, take methyl vinyl dichlorosilane and divide it into four equal parts, add intermittently for 30 min, continue constant temperature stirring reaction after complete addition, control the total reaction time of methyl vinyl dichlorosilane addition reaction to be 5h, wherein the amount ratio of lignin, tetrafluorobutanediol, methyl vinyl dichlorosilane and anhydrous dioxane is 50g:20mmol:40mmol:100mL, after reaction, remove dioxane by rotary evaporation to obtain fluorosiliconated lignin.

[0025] Step A2: take fluorosiliconated lignin, benzoin dimethyl ether and dimethylacetamide, ultrasonic pre-mix for 10 min, protect by introducing nitrogen, then add mercaptoethanol and mix well, heat to 80℃, apply 240rpm stirring and 300W / m 2UV irradiation, reaction 3.5h, wherein the amount ratio of fluorosiliconized lignin, mercaptoethanol, benzoin dimethyl ether and dimethylacetamide is 50g:45mmol:8mg:70mL, after reaction, centrifugal separation, water washing and drying of lignin precipitate layer, modified lignin is obtained.

[0026] 1.2, glue preparation

[0027] Raw materials are taken according to parts by weight: PMDI prepolymer 100 parts, Lupranate WBP type raw material is used in the implementation process, -NCO content is 31.2%; modified lignin 18 parts, prepared by this embodiment; metal oxide filler 5 parts, 500 mesh zinc oxide powder is used in the implementation process; leveling agent 0.4 parts, KMT-5502 type silicone leveling agent is used in the implementation process; diluent 10 parts, industrial grade ethyl acetate is used in the implementation process;

[0028] PMDI prepolymer, leveling agent and diluent are premixed at 120 rpm for 30 min, and then modified lignin and metal oxide filler are added at a uniform speed under the condition of 30 rpm stirring for 10 min, to obtain lignin adhesive.

[0029] (2) Preparation of vertical and horizontal lignocellulose balanced wood-based panel

[0030] Step S1: rotary cutting of raw wood and drying of the slice, controlling the drying moisture content of the slice to be 12%, coating the lignin adhesive on the surface, stacking the slice vertically after coating, applying 1.5 MPa pressure perpendicular to the stacking direction, and curing at 80℃ for 5 min, to obtain square material.

[0031] Step S2: longitudinal planing of the square material to obtain blank, longitudinal rotation of adjacent blanks, controlling the rotation angle to be 90°, coating the lignin adhesive on the planed surface of the blank, stacking the blank horizontally after coating, applying 2 MPa pressure perpendicular to the stacking direction, and curing at 100℃ for 15 min, to obtain vertical and horizontal lignocellulose balanced wood-based panel.

[0032] Example 2, preparation of vertical and horizontal lignocellulose balanced wood-based panel, the specific implementation process is as follows:

[0033] (1) Preparation of lignin adhesive

[0034] 1.1, preparation of modified lignin

[0035] Step A1: Take lignin, tetrafluorobutandiol and anhydrous dioxane as raw materials and ultrasonic dispersion for 10 min, protect with dry nitrogen, heat to 85℃, apply 90 rpm stirring, take methyl vinyl dichlorosilane as an equivalent and divide into four parts, add intermittently for 30 min, continue constant temperature stirring after complete addition, control methyl vinyl dichlorosilane addition reaction total time for 7 h, wherein, the amount ratio of lignin, tetrafluorobutandiol, methyl vinyl dichlorosilane and anhydrous dioxane is 50 g: 15 mmol: 30 mmol: 80 mL, remove dioxane by rotary evaporation after reaction is completed, and fluorosiliconized lignin is obtained.

[0036] Step A2: Take fluorosiliconized lignin, benzoin dimethyl ether and dimethylacetamide as raw materials and ultrasonic pre-mixing for 10 min, protect with nitrogen, then add mercaptoethanol and mix well, heat to 60℃, apply 180 rpm stirring and 200 W / m 2 UV irradiation, react for 5 h, wherein, the amount ratio of fluorosiliconized lignin, mercaptoethanol, benzoin dimethyl ether and dimethylacetamide is 50 g: 35 mmol: 12 mg: 60 mL, after reaction is completed, centrifuge to take lignin precipitate layer, wash with water and dry, and modified lignin is obtained.

[0037] 1.2, glue preparation

[0038] Take raw materials according to weight parts: PMDI prepolymer 100 parts, use Lupranate WBP type raw material in the implementation process, -NCO content is 31.2%; modified lignin 26 parts, prepared by this embodiment; metal oxide filler 8 parts, use 500 mesh zinc oxide powder in the implementation process; leveling agent 0.5 parts, use KMT-5502 type silicone leveling agent in the implementation process; diluent 15 parts, use industrial grade ethyl acetate in the implementation process;

[0039] Pre-mix PMDI prepolymer, leveling agent and diluent at 120 rpm for 30 min, then add modified lignin and metal oxide filler at a constant speed under 30 rpm stirring state for 10 min, and get lignin adhesive.

[0040] (2) Preparation of vertical lignocellulose balanced engineered wood

[0041] Process S1: Rotary cut raw wood and dry the slices, control the drying moisture content of the slices to be 12%, coat the lignin adhesive on the surface, stack the slices vertically after coating, apply 1.5 MPa pressure perpendicular to the stacking direction, and solidify at 80℃ for 5 min, and get square material.

[0042] Process S2: The square material is longitudinally sliced into blanks, the adjacent blanks are rotated longitudinally, the rotation angle is controlled to be 90°, then the lignin adhesive is coated on the sliced surface of the blank, after coating, the blanks are stacked transversely, a pressure of 2 MPa is applied perpendicular to the stacking direction, and the pressure is cured at 100℃ for 15 min to obtain the longitudinal and transverse vertical wood fiber balanced wood-based panel.

[0043] Example 3, preparation of longitudinal and transverse vertical wood fiber balanced wood-based panel, the specific implementation process is as follows:

[0044] (1) Preparation of lignin adhesive

[0045] 1.1 Preparation of modified lignin

[0046] Step A1: Take lignin, tetrafluorobutylene glycol and anhydrous dioxane and ultrasonic dispersion for 10 min, protect with dry nitrogen, heat to 90℃, apply 90rpm stirring, take methyl vinyl dichlorosilane and divide it into four equal parts, add intermittently for 30 min, after complete addition, continue constant temperature stirring reaction, control the total reaction time of methyl vinyl dichlorosilane addition to be 6h, wherein the amount ratio of lignin, tetrafluorobutylene glycol, methyl vinyl dichlorosilane and anhydrous dioxane is 50g:18mmol:35mmol:90mL, after reaction, remove dioxane by rotary evaporation to obtain fluorosiliconized lignin.

[0047] Step A2: Take fluorosiliconized lignin, benzoin dimethyl ether and dimethylacetamide and ultrasonic pre-mixing for 10 min, protect with nitrogen, then add mercaptoethanol and mix well, heat to 70℃, apply 180rpm stirring and 260W / m 2 UV irradiation, react for 4h, wherein the amount ratio of fluorosiliconized lignin, mercaptoethanol, benzoin dimethyl ether and dimethylacetamide is 50g:40mmol:10mg:65mL, after reaction, centrifuge to take lignin precipitate layer, wash with water and dry to obtain modified lignin.

[0048] 1.2 Glue preparation

[0049] According to the weight parts, take raw materials: PMDI prepolymer 100 parts, in the implementation process, use Lupranate WBP type raw material, -NCO content is 31.2%; modified lignin 20 parts, prepared by this embodiment; metal oxide filler 7 parts, in the implementation process, use 500 mesh aluminum oxide and titanium oxide powder compounded according to the mass ratio of 2:1; leveling agent 0.4 parts, in the implementation process, use KMT-5502 type silicone leveling agent; diluent 12 parts, in the implementation process, use industrial grade ethyl acetate;

[0050] The PMDI prepolymer, leveling agent and diluent were premixed at 120 rpm for 30 min, then the modified lignin and metal oxide filler were added at a uniform speed under stirring at 30 rpm for 10 min to obtain the lignin adhesive.

[0051] (2) Preparation of vertical and horizontal lignocellulose balanced wood-based panel

[0052] Step S1: The logs were rotary cut and the slices were dried, the drying moisture content of the slices was controlled to be 12%, the lignin adhesive was coated on the surface, the slices were stacked vertically after coating, 1.5 MPa pressure was applied perpendicular to the stacking direction, and the pressure was cured at 80°C for 5 min to obtain the square material.

[0053] Step S2: The square material was longitudinally sliced to obtain the blank, the adjacent blanks were rotated longitudinally, the rotation angle was controlled to be 90°, the lignin adhesive was coated on the sliced surface of the blank, the blanks were stacked transversely after coating, 2 MPa pressure was applied perpendicular to the stacking direction, and the pressure was cured at 100°C for 15 min to obtain the vertical and horizontal lignocellulose balanced wood-based panel.

[0054] Example 4, preparation of vertical and horizontal lignocellulose balanced wood-based panel, the specific implementation process is as follows:

[0055] (1) Preparation of lignin adhesive

[0056] 1.1, preparation of modified lignin

[0057] Step A1: lignin, tetrafluorobutylene glycol and anhydrous dioxane were taken and ultrasonically dispersed for 10 min, dry nitrogen was introduced for protection, the temperature was raised to 90°C, stirring was applied at 120 rpm, an equal amount of methyl vinyl dichlorosilane was taken and divided into four portions, and was added intermittently for 30 min, after complete addition, constant temperature stirring reaction was continued, the total reaction time of methyl vinyl dichlorosilane addition was controlled to be 6.5 h, wherein the amount ratio of lignin, tetrafluorobutylene glycol, methyl vinyl dichlorosilane and anhydrous dioxane was 50 g:20 mmol:35 mmol:90 mL, after reaction, dioxane was removed by rotary evaporation to obtain fluorosiliconized lignin.

[0058] Step A2: fluorosiliconized lignin, benzoin dimethyl ether and dimethylacetamide were ultrasonically premixed for 10 min, nitrogen was introduced for protection, then mercaptoethanol was added and mixed, the temperature was raised to 65°C, stirring was applied at 240 rpm and 220 W / m 2 UV irradiation, reaction for 4.5 h, wherein the amount ratio of fluorosiliconized lignin, mercaptoethanol, benzoin dimethyl ether and dimethylacetamide was 50 g:40 mmol:12 mg:70 mL, after reaction, the lignin precipitate layer was taken by centrifugation, washed with water and dried to obtain modified lignin.

[0059] 1.2, glue preparation

[0060] The raw materials were taken by weight parts: PMDI prepolymer 100 parts, Lupranate WBP type raw material was used in the implementation process, -NCO content was 31.2%; modified lignin 23 parts, prepared by this embodiment; metal oxide filler 6 parts, 500 mesh aluminum oxide and titanium oxide powder were compounded in a mass ratio of 2:1 to form the metal oxide filler in the implementation process; leveling agent 0.5 parts, KMT-5502 type silicone leveling agent was used in the implementation process; diluent 13 parts, industrial grade ethyl acetate was used in the implementation process;

[0061] The PMDI prepolymer, leveling agent and diluent were premixed at 120 rpm for 30 min, and then the modified lignin and metal oxide filler were added at a uniform speed under the condition of stirring at 30 rpm for 10 min to obtain the lignin adhesive.

[0062] (2) Preparation of vertical and horizontal lignin fiber balanced wood-based panel

[0063] Step S1: The logs were rotary cut and the slices were dried, the drying moisture content of the slices was controlled to be 12%, the lignin adhesive was coated on the surface, the slices were stacked vertically after coating, 1.5 MPa pressure was applied perpendicular to the stacking direction, and the pressure was cured at 80°C for 5 min to obtain the square material.

[0064] Step S2: The square material was longitudinally sliced to obtain the blank, the adjacent blanks were rotated longitudinally, the rotation angle was controlled to be 90°, the lignin adhesive was coated on the sliced surface of the blank, the blanks were stacked transversely after coating, 2 MPa pressure was applied perpendicular to the stacking direction, and the pressure was cured at 100°C for 15 min to obtain the vertical and horizontal lignin fiber balanced wood-based panel.

[0065] Comparative Example 1

[0066] This comparative example is a commercially available multi-layer solid wood balanced panel.

[0067] Comparative Example 2

[0068] This comparative example refers to Example 4, the modified lignin is replaced by lignin raw material, and the rest of the implementation process is exactly the same.

[0069] The balanced panel was taken as above, the stiffness of the balanced panel was tested according to the ASTM D1037-12 standard; the warping of the balanced panel was tested according to the ISO 23999-2021 standard, the heat resistance warping was tested after being baked at 70°C for 3h, and the water resistance warping was tested after being soaked in room temperature water for 24h; the water absorption thickness expansion rate of the balanced panel was tested according to the NALFA LF01 standard; the specific test results are shown in the following table:

[0070] Stiffness / N Heat warpage resistance / % Water warpage resistance / % Thickness expansion rate / % Example 1 379.2 0.19 0.16 0.29 Example 2 415.5 0.12 0.11 0.35 Example 3 391.0 0.15 0.14 0.25 Example 4 402.9 0.11 0.08 0.21 Comparative Example 1 286.4 0.69 0.53 1.27 Comparative Example 2 337.5 0.31 0.38 1.08

[0071] From the test results of the above table, the balance plate of the embodiment has higher rigidity, and is resistant to heat warping, water warping and water swelling, and has excellent structural stability.

[0072] In the description of the specification, the description referring to the terms "one embodiment", "an example", "a specific example" and the like means that the specific feature, structure, material or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present application. In the specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Also, the specific feature, structure, material or characteristic described can be combined in any suitable manner in any one or more embodiments or examples.

[0073] The above is only an example and description of the present application, and those skilled in the art can make various modifications or supplements to the described specific embodiments or replace them with similar ways, as long as they do not deviate from the invention or exceed the scope defined by the claims.

Claims

1. A production process for a longitudinally and transversely oriented wood fiber balanced engineered wood panel, characterized in that, The process includes the following steps: Process S1: The logs are rotary-cut and the slices are dried. Then, lignin adhesive is applied, the slices are stacked longitudinally, and pressure is applied for curing to obtain square timber. Process S2: The square material is longitudinally sliced ​​into blanks, adjacent blanks are longitudinally rotated, and then the blanks are coated with lignin adhesive, transversely stacked and pressure cured in sequence to obtain longitudinal and transverse wood fiber balanced engineered wood panels. The lignin adhesive comprises, by weight: 100 parts PMDI prepolymer, 18-26 parts modified lignin, 5-8 parts metal oxide filler, 0.4-0.5 parts leveling agent, and 10-15 parts diluent; The modified lignin is prepared by the following method: Step A1: Disperse lignin, tetrafluorobutane and anhydrous dioxane by ultrasonication, purge with dry nitrogen, heat to 85-95℃, stir at 90-120 rpm, add methyl vinyl dichlorosilane at intervals and react for 5-7 hours. After the reaction is complete, remove anhydrous dioxane by rotary evaporation to obtain fluorosilicified lignin. Step A2: Fluorosilicon-modified lignin, benzoin dimethyl ether, and dimethylacetamide are ultrasonically premixed, protected with nitrogen gas, then mercaptoethanol is added and mixed thoroughly. The mixture is heated to 60-80℃ and stirred at 180-240 rpm. The lignin was irradiated with ultraviolet light at a certain intensity for 3.5-5 hours. After the reaction was completed, the lignin precipitate was collected by centrifugation, washed with water, and dried to obtain modified lignin.

2. The production process of a longitudinally and transversely oriented wood fiber balanced engineered wood panel according to claim 1, characterized in that, The ratio of lignin, tetrafluorobutane, methyl vinyl dichlorosilane and anhydrous dioxane is 50g: 15-20mmol: 30-40mmol: 80-100mL.

3. The production process of a longitudinally and transversely oriented wood fiber balanced engineered wood panel according to claim 2, characterized in that, The ratio of fluorosilicified lignin, mercaptoethanol, benzoin dimethyl ether and dimethylacetamide is 50g: 35-45mmol: 8-12mg: 60-70mL.

4. The production process of a longitudinally and transversely oriented wood fiber balanced engineered wood panel according to claim 1, characterized in that, The -NCO content of PMDI prepolymer is 30-35%.

5. The production process of a longitudinally and transversely oriented wood fiber balanced engineered wood panel according to claim 1, characterized in that, The metal oxide filler is one or more of zinc oxide, titanium oxide, and aluminum oxide.

6. The production process of a longitudinally and transversely oriented wood fiber balanced engineered wood panel according to claim 1, characterized in that, The longitudinal rotation angle between adjacent blanks is 90°.