CN114260987A - Preparation method of formaldehyde-free high-strength microwave-cured plywood - Google Patents
Preparation method of formaldehyde-free high-strength microwave-cured plywood Download PDFInfo
- Publication number
- CN114260987A CN114260987A CN202111626578.4A CN202111626578A CN114260987A CN 114260987 A CN114260987 A CN 114260987A CN 202111626578 A CN202111626578 A CN 202111626578A CN 114260987 A CN114260987 A CN 114260987A
- Authority
- CN
- China
- Prior art keywords
- microwave
- plywood
- curing
- formaldehyde
- free high
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Abstract
The invention relates to the technical field of wood plywood, and discloses a preparation method of formaldehyde-free high-strength microwave curing plywood, which comprises the steps of bonding wood plates together by using an adhesive to prepare the plywood, then placing the plywood on a platform in a curing area of a microwave curing device, and closing a door of the microwave curing device; starting the microwave curing device, performing microwave irradiation on the plywood, and applying pressure to the board blank while receiving microwave heating to finish curing; the microwave curing method provided by the invention can quickly raise the temperature of the irradiated body, namely the wood board and each adhesive layer, and the curing degree, so that the strength of the finished board is improved, the formaldehyde release of the finished board is eliminated, the preparation time is shortened, and the energy consumption is reduced.
Description
Technical Field
The invention relates to the technical field of plywood, in particular to a preparation method of formaldehyde-free high-strength microwave cured plywood.
Background
The plate-type furniture is more and more inclined by the market due to high cost performance, rich appearance and convenient assembly and disassembly. The plywood is the main material of panel furniture, and the plywood board is different from the wood material, can make full use of timber such as path timber, practices thrift forest resources, also has the texture and the colour of natural wood simultaneously, does to supply effect material such as aircraft, boats and ships, train, car, building and packing box.
The common plywood is a three-layer or multi-layer plate material formed by rotary cutting wood sections into veneers or slicing battens into thin wood and gluing the veneers with an adhesive, and is usually formed by using odd number of veneers and mutually and vertically gluing the fiber directions of the veneers of the adjacent layers. The difference of physical and mechanical properties in the longitudinal and transverse directions is small. The types of plywood commonly used are plywood, plywood and the like. The plywood can improve the utilization rate of the wood and is a main way for saving the wood.
Typical length and width specifications are: 1220X 2440mm, and the thickness specification is generally: 3. 5, 9, 12, 15, 18mm, etc. The main tree species are: beech, cinnamomum camphora, willow, poplar, eucalyptus, and the like.
The invention improves the important link of the plywood preparation subversively and adopts the microwave curing mode to replace the hot pressing process under the background of the prior art, so that the finished board has the advantage of no aldehyde naturally, the bonding strength can be greatly improved, and the consumed energy is obviously reduced.
Based on the above, we provide a preparation method of formaldehyde-free high-strength microwave-cured plywood, and hopefully solve the defects in the prior art.
Disclosure of Invention
Technical problem to be solved
The invention aims to solve the problems and develop a preparation method of formaldehyde-free high-strength microwave cured plywood.
(II) technical scheme
In order to achieve the purpose, the invention provides the following technical scheme:
a method for preparing formaldehyde-free high-strength microwave curing plywood comprises the steps of bonding wood plates together by using an adhesive to prepare the plywood, then placing the plywood on a platform in a curing area of a microwave curing device, and closing a door of the microwave curing device; and starting the microwave curing device, performing microwave irradiation on the plywood, and applying pressure to the board blank while receiving microwave heating to finish curing.
As a further technical scheme: the plywood comprises 3 layers, 5 layers, 7 layers or other layers;
the adhesive is a reinforced phenolic resin adhesive.
As a further technical scheme, the preparation method of the reinforced phenolic resin adhesive comprises the following steps:
(1) sequentially adding sodium cyanate, dimethylformamide, sodium bromide and calcium chloride into a reaction kettle, adjusting the temperature to 95 ℃, then dropwise adding chloropropene while stirring, heating to 110 ℃ after dropwise adding, keeping the temperature for reaction for 3 hours, cooling after the reaction is finished, filtering to remove salt, and recovering dimethylformamide from filtrate through reduced pressure distillation to obtain a reinforcing agent; the mixing molar ratio of sodium cyanate, dimethylformamide, sodium bromide and calcium chloride is 3:5:2: 1;
(2) sequentially adding phenol, sodium hydroxide and water into a reaction kettle, then adjusting the temperature to 92 ℃, preserving heat and stirring for 40min, then dropwise adding a formaldehyde solution, continuously stirring for 50min, then adding the reinforcing agent, continuously stirring for 20min, then performing ultrasonic treatment for 10min, then cooling, washing and drying to obtain the composite material;
the mass ratio of the phenol to the water is 1: 1;
the mass ratio of the sodium hydroxide to the water is 0.15: 1;
the mass ratio of the formaldehyde solution to the phenol is 1.5:1, wherein the mass fraction of the formaldehyde solution is 12%;
the phenol and the reinforcing agent are mixed according to the mass ratio: 10:1-3.
As a further technical scheme, the power of the microwave irradiation is 1-10kw, the irradiation time is 0.5-5min, and the applied pressure is 0.5 MPa-2.5 MPa.
As a further technical scheme: the microwave curing device comprises: the device comprises a power system, a pressure applying unit 1, a microwave transmitting unit 2, a cooling unit 3, an air circulating system and a steel strip transmission unit 4;
a pressing unit 1 for pressing a slab directly or indirectly, which is provided with a pressure generator;
microwave transmitting unit 2: which is provided with a microwave generator;
cooling unit 3: the function of the cooling device is cooling;
steel strip conveying unit 4: the system is provided with a transmission system which is used for connecting all units in series;
an electric power system: power is provided.
As a further technical scheme: the cooling unit 3 contains a heat dissipation system.
As a further technical scheme, the heat dissipation system comprises a heat dissipation system of equipment and a heat dissipation system of plywood.
As a further technical solution, the power system includes a power supply system and a control system of the device.
As a further technical solution, the air circulation system includes a circulation fan disposed on the air circulation pipeline, preferably, disposed at an end of the air circulation pipeline near an air outlet of the air circulation system.
As a further technical scheme, the transportation system comprises the transportation of the plate blank and the transportation of the finished plate.
The wood board is a single-layer wood board with the thickness of about 3mm, including but not limited to beech, cinnamomum camphora, willow, poplar and eucalyptus, the raw wood is rotationally cut into large single boards along the annual ring direction, and the single boards are dried and cut to obtain raw materials for preparing the aldehyde-free plywood by microwave curing. The drying method is a common drying method, such as solar irradiation, normal temperature drying, high temperature drying, dehumidification drying, vacuum drying, etc., and the cutting method is a common cutting method. The water content and the size of the raw material veneer are determined according to specific conditions. The water content of the single-layer wood board is about 8% usually.
Operation S1: the number of the wood boards is odd; principle one: the symmetry principle, the details of which are as follows: the veneers on both sides of the symmetrical center plane of the plywood are required to be mutually symmetrical no matter the wood property, the veneer thickness, the number of layers, the fiber direction, the water content and the like;
principle two: the vertical principle, the details of which are as follows: the single board fibers of the adjacent layers are vertical to each other. Finishing and stacking are unnecessary operations, and in some cases, conditions are not suitable or do not require operation 1.
Operation S2: and (4) sizing. And conveying the raw materials which are well arranged and stacked to a sizing table for sizing, wherein the used glue is a reinforced phenolic resin adhesive, and the sizing parts are the inner side of the surface plate, the two sides of the core plate and the inner side of the back plate. The amount of glue application is determined according to specific requirements and the variety of glue, and the unit of quantization can be gram per square meter, and the general amount of glue application is about 50 grams per square meter. The terms "inside", "outside" and "both sides" express an orientation or positional relationship based on common sense, and for example, "both sides" refer to "both faces of the core plate contacting the upper and lower plate layers" for convenience of describing the present invention and simplifying the description, and thus the above terms should not be construed as limiting the present invention. The sizing process should still follow principles 1 and 2 described above.
Operation S3: and (5) microwave curing. And (3) transporting the plate blank subjected to the operation 2 to a microwave curing area, finishing microwave curing in the area, applying pressure while performing microwave curing, wherein the pressure application range can be 0.5-2.5 MPa to optimize the microwave heating curing effect, and cooling to obtain the aldehyde-free high-strength microwave curing plywood.
According to an aspect of the present invention, other heating methods, such as hot air assisted heating and infrared radiation heating, may be added in an auxiliary manner while the microwave heating is performed. An air circulation system can also be added to optimize the curing effect of the adhesive layer.
According to an aspect of the present invention, when performing microwave irradiation, a method of performing multiple intermittent microwave irradiation may be adopted, for example, after operating the microwave curing device to perform one microwave irradiation on the slab, turning off the one microwave irradiation, and turning on the microwave curing device again to perform the microwave irradiation.
According to one aspect of the invention, the emitting direction of the microwave device is aligned with the slab during microwave irradiation to ensure that the slab is irradiated with the most sufficient microwave. But the specific orientation of the microwave emitting device relative to the slab is not particularly critical.
According to one aspect of the invention, the platform on which the slab is placed during the microwave irradiation may be a rotating platform in order to better receive the microwave irradiation.
According to one scheme of the invention, when the slab is subjected to microwave irradiation, the slab can be a single slab or a plurality of slabs which are stacked, and the microwave has better penetrating power to a wood board layer.
At the moment of carrying out plywood heating curing, the temperature that promotes each glue film has the promotion effect by a wide margin to the quality of finished product board, if each glue film is complete solidification, then the finished product panel does not possess the nature of releasing formaldehyde. Traditional hot pressing technology mainly by heating system, the effect of the system performance hot pressing solidification glue film of exerting pressure, to heating system, promote the temperature of exerting heat, just be expected to shorten the heating time, promote the solidification degree on glue film, and then promote the whole quality of plywood. The wood board layer naturally has no good heat transfer performance, and the heat conductivity coefficient of the common wood board layer is less than 1. When the heating temperature is increased, the temperature of the plywood core layer is actually increased, the curing degree of each glue layer is optimized, but the physical performance of the heated surface of the wood board which is directly contacted with the heating element is reduced, and even the phenomenon of overheating and carbonization occurs. Therefore, a common solution in the industry is to conservatively limit the application temperature and extend the press time. In the case of the multi-ply plywood, in order to reduce damage of physical properties of the surface of the plywood which is in direct contact or indirect contact with a heat-applying body, the core temperature is increased, and the hot-press application time is even more than 1200 seconds. Therefore, the traditional hot pressing process has great energy demand, low production efficiency and low curing degree of the central glue layer, and is very easy to release free formaldehyde in the glue layer which is not completely cured.
(III) advantageous effects
Compared with the prior art, the invention provides the preparation method of the formaldehyde-free high-strength microwave cured plywood, which has the following beneficial effects:
the microwave curing method provided by the invention can quickly raise the temperature of the irradiated body, namely the wood board and each adhesive layer, and the curing degree, so that the strength of the finished board is improved, the formaldehyde release of the finished board is eliminated, the preparation time is shortened, and the energy consumption is reduced.
Drawings
FIG. 1 is a flow chart of the method of the present invention;
fig. 2 is a structural layout diagram of the microwave curing device.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
A method for preparing formaldehyde-free high-strength microwave curing plywood comprises the steps of bonding wood plates together by using an adhesive to prepare the plywood, then placing the plywood on a platform in a curing area of a microwave curing device, and closing a door of the microwave curing device; and starting the microwave curing device, performing microwave irradiation on the plywood, and applying pressure to the board blank while receiving microwave heating to finish curing.
The plywood comprises 3 layers, 5 layers, 7 layers or other layers;
the adhesive is a reinforced phenolic resin adhesive.
The preparation method of the reinforced phenolic resin adhesive comprises the following steps:
(1) sequentially adding sodium cyanate, dimethylformamide, sodium bromide and calcium chloride into a reaction kettle, adjusting the temperature to 95 ℃, then dropwise adding chloropropene while stirring, heating to 110 ℃ after dropwise adding, keeping the temperature for reaction for 3 hours, cooling after the reaction is finished, filtering to remove salt, and recovering dimethylformamide from filtrate through reduced pressure distillation to obtain a reinforcing agent; the mixing molar ratio of sodium cyanate, dimethylformamide, sodium bromide and calcium chloride is 3:5:2: 1;
(2) sequentially adding phenol, sodium hydroxide and water into a reaction kettle, then adjusting the temperature to 92 ℃, preserving heat and stirring for 40min, then dropwise adding a formaldehyde solution, continuously stirring for 50min, then adding the reinforcing agent, continuously stirring for 20min, then performing ultrasonic treatment for 10min, then cooling, washing and drying to obtain the composite material;
the mass ratio of the phenol to the water is 1: 1;
the mass ratio of the sodium hydroxide to the water is 0.15: 1;
the mass ratio of the formaldehyde solution to the phenol is 1.5:1, wherein the mass fraction of the formaldehyde solution is 12%;
the phenol and the reinforcing agent are mixed according to the mass ratio: 10:1-3.
The power of the microwave irradiation is 1-10kw, the irradiation time is 0.5-5min, and the applied pressure is 0.5 MPa-2.5 MPa.
The microwave curing device comprises: the device comprises a power system, a pressure applying unit 1, a microwave transmitting unit 2, a cooling unit 3, an air circulating system and a steel strip transmission unit 4;
a pressing unit 1 for pressing a slab directly or indirectly, which is provided with a pressure generator;
microwave transmitting unit 2: which is provided with a microwave generator;
cooling unit 3: the function of the cooling device is cooling;
steel strip conveying unit 4: the system is provided with a transmission system which is used for connecting all units in series;
an electric power system: power is provided.
The cooling unit 3 contains a heat dissipation system.
The heat dissipation system comprises a heat dissipation system of the equipment and a heat dissipation system of the plywood.
The power system comprises a power supply system and a control system of the equipment.
The air circulation system includes a circulation fan disposed on the air circulation line, preferably, at an end of the air circulation line near an air outlet of the air circulation system.
The transportation system comprises the transportation of the plate blank and the transportation of the finished plate.
FIG. 1 is a flow chart schematically illustrating the method of the present invention. Fig. 2 is a view schematically showing the structural arrangement of the microwave curing apparatus according to the present invention. As shown in fig. 1, in the present embodiment, the process of manufacturing the plywood includes four steps of finishing and stacking, sizing, microwave curing, and cooling and shaping.
As shown in fig. 2, in the present embodiment, the microwave curing machine for manufacturing plywood includes a power system, a pressing unit 1, a microwave emitting unit 2, a cooling unit 3, an air circulation system, and a steel strip transfer unit 4.
In the present embodiment, the pressing unit 1 and the microwave emitting unit 2 are main working units of microwave curing. The steel strip transmission unit 4 is used for connecting the pressing unit 1, the microwave emitting unit 2 and the cooling unit 3 in series, and the microwave emitting unit 2 and the cooling unit 3 are both positioned in the steel strip transmission unit 4. In the present embodiment, the working portions of the pressing unit 1, the microwave emitting unit 2, the cooling unit 3, the air circulation system, and the steel strip transferring unit 4 are operated in synchronization.
With reference to fig. 1 and 2, in this embodiment, the raw materials to be processed are stacked and glued in the microwave curing device, and then pass through the pressing unit 1, the microwave emitting unit 2 and the cooling unit 3, so that the plywood production process in the heating and pressing stage and the cooling and thickness setting stage in the plywood manufacturing method can be realized, no other processes are required for processing, and the process from blank to finished product is completed in one step, so that the production period is shortened, the efficiency of plywood production is improved, the molding quality is good, and the phenomena of core stacking and seam separation are not generated.
The preparation method of the plywood is specifically explained according to the preparation flow of the plywood and the microwave curing device, and the preparation method comprises the following specific steps:
firstly, drying, cutting, arranging and stacking production raw materials, and then gluing the raw materials to prepare the plywood. The microwave curing device is operated when the plywood blank enters the beginning of the steel strip transfer unit 4. The pressure applying unit 1 applies pressure to the plywood blank, the microwave emitting unit 2 performs microwave curing on the plywood blank, and then the steel strip transmission unit 4 transports the plywood to be cooled to the cooling unit 3, so that the processing technology of the microwave curing of the plywood is completed.
The following are specific examples:
example 1
A method for preparing formaldehyde-free high-strength microwave curing plywood comprises the steps of bonding wood plates together by using an adhesive to prepare the plywood, then placing the plywood on a platform in a curing area of a microwave curing device, and closing a door of the microwave curing device; and starting the microwave curing device, performing microwave irradiation on the plywood, and applying pressure to the board blank while receiving microwave heating to finish curing.
The plywood comprises 5 layers;
the adhesive is a reinforced phenolic resin adhesive.
The preparation method of the reinforced phenolic resin adhesive comprises the following steps:
(1) sequentially adding sodium cyanate, dimethylformamide, sodium bromide and calcium chloride into a reaction kettle, adjusting the temperature to 95 ℃, then dropwise adding chloropropene while stirring, heating to 110 ℃ after dropwise adding, keeping the temperature for reaction for 3 hours, cooling after the reaction is finished, filtering to remove salt, and recovering dimethylformamide from filtrate through reduced pressure distillation to obtain a reinforcing agent; the mixing molar ratio of sodium cyanate, dimethylformamide, sodium bromide and calcium chloride is 3:5:2: 1;
(2) sequentially adding phenol, sodium hydroxide and water into a reaction kettle, then adjusting the temperature to 92 ℃, preserving heat and stirring for 40min, then dropwise adding a formaldehyde solution, continuously stirring for 50min, then adding the reinforcing agent, continuously stirring for 20min, then performing ultrasonic treatment for 10min, then cooling, washing and drying to obtain the composite material;
the mass ratio of the phenol to the water is 1: 1;
the mass ratio of the sodium hydroxide to the water is 0.15: 1;
the mass ratio of the formaldehyde solution to the phenol is 1.5:1, wherein the mass fraction of the formaldehyde solution is 12%;
the phenol and the reinforcing agent are mixed according to the mass ratio: 10:1.
The power of the microwave irradiation is 1kw, the irradiation time is 0.5min, and the applied pressure is 0.5 MPa.
Example 2
A method for preparing formaldehyde-free high-strength microwave curing plywood comprises the steps of bonding wood plates together by using an adhesive to prepare the plywood, then placing the plywood on a platform in a curing area of a microwave curing device, and closing a door of the microwave curing device; and starting the microwave curing device, performing microwave irradiation on the plywood, and applying pressure to the board blank while receiving microwave heating to finish curing.
The plywood comprises 5 layers;
the adhesive is a reinforced phenolic resin adhesive.
The preparation method of the reinforced phenolic resin adhesive comprises the following steps:
(1) sequentially adding sodium cyanate, dimethylformamide, sodium bromide and calcium chloride into a reaction kettle, adjusting the temperature to 95 ℃, then dropwise adding chloropropene while stirring, heating to 110 ℃ after dropwise adding, keeping the temperature for reaction for 3 hours, cooling after the reaction is finished, filtering to remove salt, and recovering dimethylformamide from filtrate through reduced pressure distillation to obtain a reinforcing agent; the mixing molar ratio of sodium cyanate, dimethylformamide, sodium bromide and calcium chloride is 3:5:2: 1;
(2) sequentially adding phenol, sodium hydroxide and water into a reaction kettle, then adjusting the temperature to 92 ℃, preserving heat and stirring for 40min, then dropwise adding a formaldehyde solution, continuously stirring for 50min, then adding the reinforcing agent, continuously stirring for 20min, then performing ultrasonic treatment for 10min, then cooling, washing and drying to obtain the composite material;
the mass ratio of the phenol to the water is 1: 1;
the mass ratio of the sodium hydroxide to the water is 0.15: 1;
the mass ratio of the formaldehyde solution to the phenol is 1.5:1, wherein the mass fraction of the formaldehyde solution is 12%;
the phenol and the reinforcing agent are mixed according to the mass ratio: 10:2.
The power of the microwave irradiation is 5kw, the irradiation time is 3min, and the applied pressure is 1.5 MPa.
Example 3
A method for preparing formaldehyde-free high-strength microwave curing plywood comprises the steps of bonding wood plates together by using an adhesive to prepare the plywood, then placing the plywood on a platform in a curing area of a microwave curing device, and closing a door of the microwave curing device; and starting the microwave curing device, performing microwave irradiation on the plywood, and applying pressure to the board blank while receiving microwave heating to finish curing.
The plywood comprises 5 layers;
the adhesive is a reinforced phenolic resin adhesive.
The preparation method of the reinforced phenolic resin adhesive comprises the following steps:
(1) sequentially adding sodium cyanate, dimethylformamide, sodium bromide and calcium chloride into a reaction kettle, adjusting the temperature to 95 ℃, then dropwise adding chloropropene while stirring, heating to 110 ℃ after dropwise adding, keeping the temperature for reaction for 3 hours, cooling after the reaction is finished, filtering to remove salt, and recovering dimethylformamide from filtrate through reduced pressure distillation to obtain a reinforcing agent; the mixing molar ratio of sodium cyanate, dimethylformamide, sodium bromide and calcium chloride is 3:5:2: 1;
(2) sequentially adding phenol, sodium hydroxide and water into a reaction kettle, then adjusting the temperature to 92 ℃, preserving heat and stirring for 40min, then dropwise adding a formaldehyde solution, continuously stirring for 50min, then adding the reinforcing agent, continuously stirring for 20min, then performing ultrasonic treatment for 10min, then cooling, washing and drying to obtain the composite material;
the mass ratio of the phenol to the water is 1: 1;
the mass ratio of the sodium hydroxide to the water is 0.15: 1;
the mass ratio of the formaldehyde solution to the phenol is 1.5:1, wherein the mass fraction of the formaldehyde solution is 12%;
the phenol and the reinforcing agent are mixed according to the mass ratio: 10:2.5.
The power of the microwave irradiation is 8kw, the irradiation time is 4min, and the applied pressure is 2 MPa.
Example 4
A method for preparing formaldehyde-free high-strength microwave curing plywood comprises the steps of bonding wood plates together by using an adhesive to prepare the plywood, then placing the plywood on a platform in a curing area of a microwave curing device, and closing a door of the microwave curing device; and starting the microwave curing device, performing microwave irradiation on the plywood, and applying pressure to the board blank while receiving microwave heating to finish curing.
The plywood comprises 5 layers;
the adhesive is a reinforced phenolic resin adhesive.
The preparation method of the reinforced phenolic resin adhesive comprises the following steps:
(1) sequentially adding sodium cyanate, dimethylformamide, sodium bromide and calcium chloride into a reaction kettle, adjusting the temperature to 95 ℃, then dropwise adding chloropropene while stirring, heating to 110 ℃ after dropwise adding, keeping the temperature for reaction for 3 hours, cooling after the reaction is finished, filtering to remove salt, and recovering dimethylformamide from filtrate through reduced pressure distillation to obtain a reinforcing agent; the mixing molar ratio of sodium cyanate, dimethylformamide, sodium bromide and calcium chloride is 3:5:2: 1;
(2) sequentially adding phenol, sodium hydroxide and water into a reaction kettle, then adjusting the temperature to 92 ℃, preserving heat and stirring for 40min, then dropwise adding a formaldehyde solution, continuously stirring for 50min, then adding the reinforcing agent, continuously stirring for 20min, then performing ultrasonic treatment for 10min, then cooling, washing and drying to obtain the composite material;
the mass ratio of the phenol to the water is 1: 1;
the mass ratio of the sodium hydroxide to the water is 0.15: 1;
the mass ratio of the formaldehyde solution to the phenol is 1.5:1, wherein the mass fraction of the formaldehyde solution is 12%;
the phenol and the reinforcing agent are mixed according to the mass ratio: 10:3.
The power of the microwave irradiation is 10kw, the irradiation time is 5min, and the applied pressure is 2.5 MPa.
Test of
The plywood prepared in the examples and the comparative examples were subjected to an aging resistance test; the accelerated aging method refers to the 4.17 dipping stripping performance measurement in GB/T17657-1999 test method for physical and chemical properties of artificial boards and veneered artificial boards, and adjusts the method to simulate the use conditions of indoor plywood, and to make the plywood extremely end (extremely wet and extremely dry state), accelerate the aging of test pieces: completely soaking the test piece in water at the temperature of (25 +/-3) DEG for 24 hours, then taking out the test piece, and wiping the surface moisture; drying at 100 ℃ for 10h, which is a cycle, comparing the bonding strength change after 10 cycles:
TABLE 1
| Initial bond strength/MPa | Bonding Strength/MPa after circulation | |
| Example 1 | 1.68 | 0.99 |
| Example 2 | 1.62 | 0.94 |
| Example 3 | 1.66 | 0.97 |
| Example 4 | 1.63 | 0.95 |
| Comparative example 1 | 1.22 | 0.50 |
| Comparative example 2 | 1.43 | 0.69 |
Comparative example 1: the difference from example 1 is that no reinforcing agent is added;
comparative example 2: the difference from the example 1 is that dimethylformamide is not added in the preparation of the enhancer;
as can be seen from Table 1, the aging resistance of the plywood prepared by the invention is greatly improved.
Further experiments, based on the sample of example 1, on the effect of conventional drying and microwave curing drying on the bond strength, compare:
conventional drying (control): drying the plywood at 80 ℃ for 5 hours, naturally cooling to room temperature, and detecting:
TABLE 2
| Bonding strength/MPa | |
| Example 1 | 1.68 |
| Control group | 1.32 |
As can be seen from table 2, the wood plywood prepared by the present invention adopts the microwave drying treatment, which can significantly improve the bonding strength.
Further experiments, formaldehyde detection refers to GB/T9846-2004 standard;
TABLE 3
| Formaldehyde release/classification | |
| Example 1 | E0 |
| Example 2 | E0 |
| Example 3 | E0 |
| Example 4 | E0 |
As can be seen from Table 3, the formaldehyde emission test of the plywood prepared by the invention is qualified.
Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.
Claims (10)
1. A preparation method of formaldehyde-free high-strength microwave curing plywood is characterized in that wood boards are bonded together by using an adhesive to prepare the plywood, then the plywood is placed on a platform in a curing area of a microwave curing device, and a door of the microwave curing device is closed; and starting the microwave curing device, performing microwave irradiation on the plywood, and applying pressure to the board blank while receiving microwave heating to finish curing.
2. The method for preparing aldehyde-free high-strength microwave-cured plywood according to claim 1, wherein the method comprises the following steps: the plywood comprises 3 layers, 5 layers, 7 layers or other layers;
the adhesive is a reinforced phenolic resin adhesive.
3. The method for preparing the formaldehyde-free high-strength microwave-cured plywood according to claim 2, wherein the method for preparing the reinforced phenolic resin adhesive comprises the following steps:
(1) sequentially adding sodium cyanate, dimethylformamide, sodium bromide and calcium chloride into a reaction kettle, adjusting the temperature to 95 ℃, then dropwise adding chloropropene while stirring, heating to 110 ℃ after dropwise adding, keeping the temperature for reaction for 3 hours, cooling after the reaction is finished, filtering to remove salt, and recovering dimethylformamide from filtrate through reduced pressure distillation to obtain a reinforcing agent; the mixing molar ratio of sodium cyanate, dimethylformamide, sodium bromide and calcium chloride is 3:5:2: 1;
(2) sequentially adding phenol, sodium hydroxide and water into a reaction kettle, then adjusting the temperature to 92 ℃, preserving heat and stirring for 40min, then dropwise adding a formaldehyde solution, continuously stirring for 50min, then adding the reinforcing agent, continuously stirring for 20min, then performing ultrasonic treatment for 10min, then cooling, washing and drying to obtain the composite material;
the mass ratio of the phenol to the water is 1: 1;
the mass ratio of the sodium hydroxide to the water is 0.15: 1;
the mass ratio of the formaldehyde solution to the phenol is 1.5:1, wherein the mass fraction of the formaldehyde solution is 12%;
the phenol and the reinforcing agent are mixed according to the mass ratio: 10:1-3.
4. The method for preparing the formaldehyde-free high-strength microwave cured plywood according to claim 1, wherein the microwave irradiation power is 1-10kw, the irradiation time is 0.5-5min, and the applied pressure is 0.5-2.5 MPa.
5. The method for preparing aldehyde-free high-strength microwave-cured plywood according to claim 1, wherein the method comprises the following steps: the microwave curing device comprises: the device comprises a power system, a pressure applying unit 1, a microwave transmitting unit 2, a cooling unit 3, an air circulating system and a steel strip transmission unit 4;
a pressing unit 1 for pressing a slab directly or indirectly, which is provided with a pressure generator;
microwave transmitting unit 2: which is provided with a microwave generator;
cooling unit 3: the function of the cooling device is cooling;
steel strip conveying unit 4: the system is provided with a transmission system which is used for connecting all units in series;
an electric power system: power is provided.
6. The method for preparing aldehyde-free high-strength microwave-cured plywood according to claim 5, wherein the method comprises the following steps: the cooling unit 3 contains a heat dissipation system.
7. The method as claimed in claim 6, wherein the heat dissipation system comprises a heat dissipation system of a device and a heat dissipation system of a plywood.
8. The method for preparing aldehyde-free high-strength microwave cured plywood according to claim 5, wherein the power system comprises a power supply system and a control system of equipment.
9. The method for preparing formaldehyde-free high-strength microwave cured plywood according to claim 5, wherein the air circulation system comprises a circulating fan which is arranged on the air circulation pipeline, preferably on one end of the air circulation pipeline close to an air outlet of the air circulation system.
10. The method for preparing aldehyde-free high-strength microwave-cured plywood according to claim 5, wherein the transportation system comprises slab transportation and finished board transportation.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111626578.4A CN114260987B (en) | 2021-12-28 | 2021-12-28 | Preparation method of formaldehyde-free high-strength microwave-cured plywood |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111626578.4A CN114260987B (en) | 2021-12-28 | 2021-12-28 | Preparation method of formaldehyde-free high-strength microwave-cured plywood |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114260987A true CN114260987A (en) | 2022-04-01 |
| CN114260987B CN114260987B (en) | 2022-07-15 |
Family
ID=80830771
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111626578.4A Active CN114260987B (en) | 2021-12-28 | 2021-12-28 | Preparation method of formaldehyde-free high-strength microwave-cured plywood |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114260987B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114654607A (en) * | 2022-03-28 | 2022-06-24 | 广东高景太阳能科技有限公司 | Method for quickly sticking silicon rod to crystal |
Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19737593C1 (en) * | 1997-08-28 | 1999-03-04 | Kuper Heinrich Gmbh Co Kg | Joining wood veneer strips at their edges and process equipment |
| DE19835988A1 (en) * | 1997-05-03 | 2000-02-10 | Dieffenbacher Gmbh Maschf | Method for producing layered boards uses RF to preheat the layers and with a higher moisture content in the middle layers to concentrate the RF heating |
| CN102653667A (en) * | 2012-04-09 | 2012-09-05 | 北京林业大学 | Water-soluble non-formaldehyde wood adhesive and method for preparing same |
| CN102703007A (en) * | 2012-04-30 | 2012-10-03 | 苏州信邦绿色新材料科技有限公司 | Preparation method of polyvinyl alcohol modified phenolic resin adhesive |
| CN202862316U (en) * | 2012-10-18 | 2013-04-10 | 上海秋林机械有限公司 | Microwave thermocompressor |
| CN103991111A (en) * | 2014-06-03 | 2014-08-20 | 李茂林 | Large-scale high-density wood-based material and method for manufacturing same through microwave heating, pressing and gluing |
| CN104178059A (en) * | 2014-08-24 | 2014-12-03 | 侯梦斌 | Production process for formaldehyde-free plywood |
| CN105754527A (en) * | 2016-03-21 | 2016-07-13 | 常州大学 | Phenolic resin adhesive containing demethylated lignin and preparation method of phenolic resin adhesive |
| CN106903761A (en) * | 2017-03-08 | 2017-06-30 | 中国福马机械集团有限公司 | The preparation method of glued board |
| CN110405872A (en) * | 2019-06-28 | 2019-11-05 | 中南林业科技大学 | A kind of quick hot-press molding method of integrated timber |
| CN113831490A (en) * | 2021-09-17 | 2021-12-24 | 安徽弘源化工科技有限公司 | High-strength water-based phenolic resin and preparation method thereof |
-
2021
- 2021-12-28 CN CN202111626578.4A patent/CN114260987B/en active Active
Patent Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19835988A1 (en) * | 1997-05-03 | 2000-02-10 | Dieffenbacher Gmbh Maschf | Method for producing layered boards uses RF to preheat the layers and with a higher moisture content in the middle layers to concentrate the RF heating |
| DE19737593C1 (en) * | 1997-08-28 | 1999-03-04 | Kuper Heinrich Gmbh Co Kg | Joining wood veneer strips at their edges and process equipment |
| CN102653667A (en) * | 2012-04-09 | 2012-09-05 | 北京林业大学 | Water-soluble non-formaldehyde wood adhesive and method for preparing same |
| CN102703007A (en) * | 2012-04-30 | 2012-10-03 | 苏州信邦绿色新材料科技有限公司 | Preparation method of polyvinyl alcohol modified phenolic resin adhesive |
| CN202862316U (en) * | 2012-10-18 | 2013-04-10 | 上海秋林机械有限公司 | Microwave thermocompressor |
| CN103991111A (en) * | 2014-06-03 | 2014-08-20 | 李茂林 | Large-scale high-density wood-based material and method for manufacturing same through microwave heating, pressing and gluing |
| CN104178059A (en) * | 2014-08-24 | 2014-12-03 | 侯梦斌 | Production process for formaldehyde-free plywood |
| CN105754527A (en) * | 2016-03-21 | 2016-07-13 | 常州大学 | Phenolic resin adhesive containing demethylated lignin and preparation method of phenolic resin adhesive |
| CN106903761A (en) * | 2017-03-08 | 2017-06-30 | 中国福马机械集团有限公司 | The preparation method of glued board |
| CN110405872A (en) * | 2019-06-28 | 2019-11-05 | 中南林业科技大学 | A kind of quick hot-press molding method of integrated timber |
| CN113831490A (en) * | 2021-09-17 | 2021-12-24 | 安徽弘源化工科技有限公司 | High-strength water-based phenolic resin and preparation method thereof |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114654607A (en) * | 2022-03-28 | 2022-06-24 | 广东高景太阳能科技有限公司 | Method for quickly sticking silicon rod to crystal |
Also Published As
| Publication number | Publication date |
|---|---|
| CN114260987B (en) | 2022-07-15 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN100393493C (en) | Manufacturing method of high wear resistant dyed poplar wood floor | |
| CN203380976U (en) | Plywood for bamboo-wood composite container baseplate | |
| CN101508124B (en) | Preparation method of plywood for full-bamboo or bamboo wood composite container | |
| CN206937527U (en) | A kind of energy-saving type plywood hot-pressing machine | |
| CN201677368U (en) | Bamboo composite plywood used for container floor | |
| CN114260987B (en) | Preparation method of formaldehyde-free high-strength microwave-cured plywood | |
| CN101100086A (en) | Method for manufacturing high-strength anti-corrosion integrated material | |
| CN109366656B (en) | Control method for density peak shape of single-side compressed wood | |
| CN1331644C (en) | Production process of long material in composite bamboo-timber structure | |
| CN106003283B (en) | A kind of recombination bamboo and wood composite decoration veneer and its manufacturing method | |
| CN105965616B (en) | The manufacturing method of veneer base composite board | |
| CN104002340A (en) | Method for manufacturing long structural bamboo skin curtain laminated lumber | |
| CN101915049A (en) | Flame-retardant veneer laminated fireproof door frame and manufacturing method | |
| CN106013715A (en) | A composite floor board produced by using eucalypt wood laminated veneer lumber and a preparation process therefor | |
| CN113290657A (en) | Plywood processing technology | |
| WO2014090165A1 (en) | Compressed laminated timber and manufacturing method thereof | |
| CN113478592A (en) | Hexagonal solid wood splicing structure and processing method thereof | |
| US11123894B2 (en) | Method for quick hot-press forming of laminated wood | |
| JPH0716964A (en) | Laminated material and its manufacture | |
| CN103692502B (en) | As the manufacture method of the non-woven fabrics enhancement mode laminated veneer lumber of decoration bar section base material | |
| CN101973051A (en) | Production method of poplar laminated veneer lumber composite decorative plate | |
| CN101725216A (en) | Unsaturated polyester-bonded and glass fiber-reinforced beam and implementation method thereof | |
| CN104385386A (en) | Full fast-growing tree timber composite plywood for container soleplate | |
| CN114919031A (en) | Pre-pressed ultrathin large shaving board composite block board capable of facing and manufacturing method thereof | |
| CN102909761B (en) | Homogeneous container bottom board production method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |