Dispersion liquid of polyurethane adhesive for wood artificial board production
By using a polyurethane adhesive dispersion containing water and surfactant, the problem of difficulty in uniform dispersion of pure adhesives in wooden units is solved, and the effect of reducing the amount of use and improving uniformity and bonding effect is achieved.
Patent Information
- Application Number
- CN202411798537.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-09
- Publication Date
- 2025-02-18
AI Technical Summary
In the prior art, direct spraying of pure polyurethane adhesive is difficult to disperse evenly in wooden units, resulting in uneven glue application, increasing the amount of adhesive used, affecting cost control and environmental protection.
A dispersion of polyurethane adhesive, including water and a surfactant dispersed in water, is provided, which is dispersed and diluted by mixing with pure polyurethane adhesive, reduces the amount used and improves uniformity.
Without affecting the adhesive bonding effect of the adhesive, the amount of polyurethane adhesive is used is reduced, its uniform dispersion in wooden units is improved, and the bonding effect to the board is enhanced.
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Figure CN119463782A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of polyurethane adhesive (MDI) for wood-based panels, and in particular to a dispersion of polyurethane adhesive (MDI) for producing and processing wood-based panels, wherein the dispersion can be used in combination with a polyurethane adhesive. Background Art
[0002] Wood-based panels are made by mixing wood fibers or wood shavings with adhesives and hot pressing. Currently, polyurethane adhesives are commonly used to bond wood fibers or wood shavings. When applying the adhesive, pure polyurethane adhesive is directly poured into the adhesive tank and then sprayed on the surface of the wood fibers or wood shavings through an output pump.
[0003] However, the technical solution of directly spraying pure polyurethane adhesive has the following problems: Pure polyurethane adhesive itself has a very high viscosity. Even if it is sprayed and stirred, it is not easy to disperse evenly in wood units (such as wood fibers, wood shavings, etc.), which easily leads to uneven application of glue.
[0004] The use of pure polyurethane adhesive results in a relatively large amount of adhesive, which is not conducive to cost control and environmental protection. At the same time, in the prior art, in order to overcome the problem of uneven glue application, the glue application amount is often increased. Although this problem can be overcome to a certain extent, it will increase production costs and cause the density of the board to be higher than the set value. Summary of the invention
[0005] In order to solve the above-mentioned problems, the present application provides a dispersion of a polyurethane adhesive for use in the production of wood-based panels and its use. The dispersion is used to disperse and dilute pure polyurethane adhesive, thereby reducing the amount of polyurethane adhesive used without affecting the bonding effect of the adhesive, and is more conducive to the uniform dispersion of the polyurethane adhesive in the wood unit.
[0006] In one aspect, the present application provides a dispersion of a polyurethane adhesive for use in the production of wood-based panels. By selecting the components of the dispersion, the polyurethane adhesive has an excellent dispersion effect and can assist the polyurethane adhesive in bonding the panel.
[0007] The specific technical solutions adopted are as follows: A dispersion of a polyurethane adhesive for producing wood-based panels, comprising water and a surfactant dispersed in the water.
[0008] Preferably, in the dispersion, the mass ratio of the water to the surfactant is (50-65):(1-5).
[0009] More preferably, the surfactant is calcium lignin sulfonate.
[0010] Preferably, the dispersion further comprises nano-silicon dioxide in an amount of 0.8%-2.0% of the mass of the dispersion.
[0011] More preferably, the particle size of the nano-silicon dioxide is 10nm-60nm.
[0012] More preferably, the nano-silicon dioxide in the dispersant is treated by plasticization modification.
[0013] More preferably, the nano-silicon dioxide in the dispersant is modified with a mixture of polylactic acid and polyurethane.
[0014] More preferably, the modification method of nano silicon dioxide comprises the following steps: S1. dissolving polylactic acid and polyurethane in a solvent to obtain a polylactic acid solution and a polyurethane solution; S2. The polylactic acid solution and the polyurethane solution are mixed in proportion to obtain a mixed solution; S3. Disperse the nano-silica in the mixed solution, and treat it under ultrasonic conditions for 5 min-10 min; then shake it for 3 h-5 h; S4. The solution obtained in S3 is spray-dried to obtain modified nano-silicon dioxide.
[0015] More preferably, the mass ratio of the polylactic acid, polyurethane, polylactic acid and nano-silicon dioxide is 1:1:(3-4).
[0016] The purpose of the dispersion provided in the present application is as follows: the dispersion is mixed with a pure polyurethane adhesive to obtain a polyurethane adhesive; in the polyurethane adhesive, the mass ratio of the pure polyurethane adhesive to the dispersion is (30-45):(55-70).
[0017] Preferably, the dispersion of the present application is prepared and used immediately.
[0018] The method for using the dispersion provided in the present application is as follows: the dispersion is mixed with a pure polyurethane adhesive, including a pre-mixing step and a main mixing step; The premixing step is performed in a premixing device, a unit volume of pure polyurethane adhesive is added to the premixing device, and when the pure polyurethane adhesive is stabilized at a stirring speed of 50 rpm to 70 rpm, water is added to the premixing device to obtain a premixed mixture; The main mixing step is carried out in a main mixing device, the premix is moved to the main mixing device, and when the premix is stabilized at a stirring speed of 300 rpm-350 rpm, the surfactant is added to the premix, and stirring is continued until a polyurethane adhesive suspension is formed.
[0019] More preferably, nano silicon dioxide is added to the premix at the same time as the surfactant is added to the premix.
[0020] Preferably, the amount of the premixture leaving the premixing device per unit time is the same as the amount of the premixture entering the main mixing device, and the amount of the polyurethane adhesive suspension leaving the main mixing device per unit time is the same as the amount of the polyurethane adhesive suspension sprayed onto the wood particles.
[0021] Among them, the wood particles are wood shavings or wood fibers.
[0022] Preferably, the dispersion of the present application and the pure polyurethane adhesive are mixed using a specific mixing device.
[0023] The dispersion provided in the present application is used in combination with a polyurethane adhesive to disperse and dilute the polyurethane adhesive, thereby reducing the usage of the polyurethane adhesive and increasing the uniformity of the polyurethane adhesive coating. It also further uses nano-silica / modified nano-silica to synergistically increase the bonding effect of the polyurethane adhesive on the plate, thereby ensuring that the bonding effect of the polyurethane adhesive is not reduced or even improved while reducing the usage of the polyurethane adhesive. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without paying any creative labor.
[0025] Figure 1 This is a schematic structural diagram of a dispersing device for a polyurethane adhesive for wood-based panels provided in Example 1 of the present application.
[0026] Figure 2 This is a schematic cross-sectional structure diagram of a dispersing device for a polyurethane adhesive for wood-based panels provided in Example 1 of the present application.
[0027] Figure 3 This is a schematic diagram of the structure of the main mixing tank provided in Example 1 of the present application.
[0028] Figure 4This is a schematic diagram of the structure of the main dispersion unit provided in Example 1 of the present application. DETAILED DESCRIPTION
[0029] In order to enable those skilled in the art to better understand the technical solutions in the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work should fall within the scope of protection of the present application. Example
[0030] A dispersion of a polyurethane adhesive for producing wood-based panels, the dispersion comprising water and a surfactant dispersed in the water, wherein the water comprises 90.9 g and the surfactant comprises 9.1 g, and the surfactant is calcium lignin sulfonate. Example
[0031] A dispersion of a polyurethane adhesive for producing wood-based panels, the dispersion comprising water and a surfactant dispersed in the water, wherein the water comprises 98.3 g and the surfactant comprises 1.7 g, and the surfactant is calcium lignin sulfonate. Example
[0032] A dispersion of a polyurethane adhesive for producing wood-based panels, the dispersion comprising water and a surfactant dispersed in the water, wherein the water comprises 98.5 g and the surfactant comprises 1.5 g, and the surfactant is calcium lignin sulfonate. Example
[0033] A dispersion of a polyurethane adhesive for producing wood-based panels, comprising ionized water, a surfactant and nano-silicon dioxide dispersed in the water, wherein the dispersion comprises 96.4 g of water, 1.6 g of a surfactant and 2 g of nano-silicon dioxide, wherein the surfactant is calcium lignin sulfonate and the particle size of the nano-silicon dioxide is 20 nm-60 nm. Example
[0034] A dispersion of a polyurethane adhesive for producing wood-based panels, the dispersion comprising ionized water, a surfactant and nano-silicon dioxide dispersed in the water, wherein the dispersion comprises 97.4 g of water, 1.6 g of a surfactant and 1 g of nano-silicon dioxide, the surfactant is calcium lignin sulfonate, and the particle size of the nano-silicon dioxide is 20 nm-60 nm. Example
[0035] A dispersion of a polyurethane adhesive for producing wood-based panels, comprising ionized water, a surfactant and nano-silicon dioxide dispersed in the water, wherein the dispersion comprises 97.5 g of water, 1.7 g of a surfactant and 0.8 g of nano-silicon dioxide, wherein the surfactant is calcium lignin sulfonate and the particle size of the nano-silicon dioxide is 20 nm-60 nm. Example
[0036] A dispersion of a polyurethane adhesive for the production of wood-based panels, the dispersion comprising ionized water, a surfactant and nano-silicon dioxide dispersed in the water, wherein the water comprises 96.4 g, the surfactant comprises 1.6 g, and the nano-silicon dioxide comprises 2 g, wherein the surfactant is calcium lignin sulfonate. The nano-silicon dioxide is modified nano-silicon dioxide obtained by the following modification process: S1. The polylactic acid and the polyurethane were dissolved in an acetone solvent to obtain a polylactic acid solution having a concentration of 5 mg / L and a polyurethane solution having a concentration of 5 mg / L; S2. The polylactic acid solution and the polyurethane solution were mixed in a ratio (the mass ratio of polylactic acid, polyurethane and nano-silica was 1:1:4) to obtain a mixed solution; S3. Disperse the nano-silica in the mixed solution, and treat it under ultrasonic conditions for 6 minutes; then shake it for 3 hours; S4. The solution obtained in S3 is spray-dried to obtain modified nano-silicon dioxide with a particle size controlled at 60nm-80nm. Example
[0037] A dispersion of a polyurethane adhesive for the production of wood-based panels, the dispersion comprising ionized water, a surfactant and nano-silicon dioxide dispersed in the water, wherein the water comprises 96.4 g, the surfactant comprises 1.6 g, and the nano-silicon dioxide comprises 2 g, wherein the surfactant is calcium lignin sulfonate. The nano-silicon dioxide is modified nano-silicon dioxide obtained by the following modification process: S1. The polylactic acid and the polyurethane were dissolved in an acetone solvent to obtain a polylactic acid solution having a concentration of 5 mg / L and a polyurethane solution having a concentration of 5 mg / L; S2. The polylactic acid solution and the polyurethane solution were mixed in a ratio (the mass ratio of polylactic acid, polyurethane and nano-silica was 1:1:3) to obtain a mixed solution; S3. Disperse the nano-silica in the mixed solution, and treat it under ultrasonic conditions for 5 minutes; then shake it for 4 hours; S4. The solution obtained in S3 is spray-dried to obtain modified nano-silicon dioxide with a particle size controlled at 60nm-80nm. Example
[0038] A dispersion of a polyurethane adhesive for the production of wood-based panels, the dispersion comprising ionized water, a surfactant and nano-silicon dioxide dispersed in the water, wherein the water comprises 96.4 g, the surfactant comprises 1.6 g, and the nano-silicon dioxide comprises 2 g, wherein the surfactant is calcium lignin sulfonate. The nano-silicon dioxide is modified nano-silicon dioxide obtained by the following modification process: S1. The polylactic acid and the polyurethane were dissolved in an acetone solvent to obtain a polylactic acid solution having a concentration of 5 mg / L and a polyurethane solution having a concentration of 5 mg / L; S2. The polylactic acid solution and the polyurethane solution were mixed in a ratio (the mass ratio of polylactic acid, polyurethane and nano-silica was 1:1:3.5) to obtain a mixed solution; S3. Disperse the nano-silica in the mixed solution, and treat it under ultrasonic conditions for 8 minutes; then shake it for 3 hours; S4. The solution obtained in S3 is spray-dried to obtain modified nano-silicon dioxide with a particle size controlled at 60nm-80nm. Example
[0039] This embodiment provides a method for preparing a dispersion of a polyurethane adhesive for use in the production of wood-based panels. Water is placed in a stirring tank, a surfactant is added at a stirring speed of 100 rpm, and stirring and dispersing is continued at a stirring speed of 200 rpm for more than 30 minutes. Example
[0040] This embodiment provides a method for preparing a dispersion of a polyurethane adhesive for use in the production of wood-based panels. Water is placed in a stirring tank, a surfactant and nano-silicon dioxide are added at a stirring speed of 100 rpm, and stirring and dispersing is continued at a stirring speed of 200 rpm for more than 30 minutes. Example
[0041] This embodiment provides a polyurethane adhesive suspension for the production of wood-based panels, which is obtained by mixing the above dispersion with pure polyurethane adhesive in the following manner, and the usage amount is: the mass ratio of the pure polyurethane adhesive to the dispersion is 40:60. The polyurethane adhesive suspensions corresponding to Examples 1-9 are respectively recorded as 1, 2, 3, 4, 5, 6, 7, 8, and 9.
[0042] The mixing method is as follows: the above dispersion and pure polyurethane adhesive are placed in a mixing kettle, and stirred and dispersed at a stirring speed of 200 rpm for more than 10 minutes. Example
[0043] This embodiment provides a polyurethane adhesive suspension for the production of wood-based panels, which is obtained by mixing the water and surfactant in the above dispersion with pure polyurethane adhesive in steps according to the following mixing method and device.
[0044] Mixing methods include premixing and main mixing.
[0045] Premixing: This step is carried out in a premixing device, into which a unit volume of pure polyurethane adhesive is added, and when the pure polyurethane adhesive is stabilized at a stirring speed of 60 rpm, water is added to the premixing device to obtain a premix; Main mixing: This step is carried out in a main mixing device. The premix is moved to the main mixing device. When the premix is stabilized at a stirring speed of 300 rpm, the surfactant is added to the premix, and stirring is continued until a polyurethane adhesive suspension is formed.
[0046] In some embodiments, nano-silica is added to the premix simultaneously with the addition of the surfactant.
[0047] Dispersion device Reference Figure 1 , Figure 2 A dispersing device for polyurethane adhesive for wood-based panels shown in the figure comprises a surfactant providing device 1, a water supply device 2, a glue supply device 3, a premixing device 4, a main mixing device 5 and a control system. The surfactant providing device 1, the water supply device 2 and the glue supply device 3 are configured to store surfactants, water and polyurethane adhesive (MDI) respectively, and can be controlled by the control system to provide the corresponding raw materials to the premixing device 4 in a quantitative and constant speed, and the three can be any feasible structure in the prior art. The control system can also be any one of the prior art, such as a PLC controller. In some embodiments, the surfactant providing device 1 stores surfactants and nano-silicon dioxide at the same time.
[0048] The premixing device 4 is vertically arranged, and includes a premixing tank 41, and a premixing inlet 44 and a flow port 46 are provided on the upper part of the premixing tank 41. The premixing inlet 44 is connected to the glue supply device 3 through necessary components such as a solenoid valve, a pump, and a pipeline, and is configured to allow the polyurethane adhesive (MDI) to enter the premixing tank 41. The flow port 46 is connected to the surfactant supply device 1 and the water supply device 2 through necessary components such as a solenoid valve, a pump, and a pipeline, and is configured to allow the dispersant and ionized water to enter the premixing tank 41. The premixing tank 41 has a cylindrical internal space, and a screw conveyor 42 is coaxially installed inside it. The high end of the screw conveyor 42 extends out of the top surface of the premixing tank 41 and is connected to the motor shaft of the premixing motor 43 through a coupling. The premixing motor 43 is any motor such as an auger motor or a servo motor that can drive the screw conveyor 42 to rotate. The lower end of the screw conveyor 42 is connected to the bottom surface of the premixing tank 41 through a flange. The outer edge of the spiral blade of the screw conveyor 42 abuts against the inner wall surface of the premixing tank 41. Preferably, the outer edge of the spiral blade has a wear-resistant gasket, such as a PP or PVC wear-resistant film. At this time, the premixing feed port 44 is located on the feeding side of the screw conveying rod 42.
[0049] The premixing motor 43 , the solenoid valve, the pump and other components of the premixing device 4 are all electrically connected to and controlled by the control system.
[0050] Combination Figure 3 , Figure 4 The main mixing device 5 is vertically arranged, and includes a main mixing tank body 51, which has a cylindrical internal space and a rectangular outer wall shape. A main mixing inlet 55 is provided at the lower part of the main mixing tank body 51, and a main mixing outlet 56 is provided at the upper part. A premixing outlet 45 is provided at the lower part of the premixing tank body 41, and the premixing outlet 45 is connected to the main mixing inlet 55 through a pressure pump 6, a pipeline, and in some cases, necessary components such as valves and pumps. The pressure pump 6 can be any one of the prior art that can pump the premixed mixed glue liquid to the main mixing tank body 51 until the mixed glue liquid leaves the main mixing tank body 51 through the main mixing outlet 56. A main dispersing unit 52 is coaxially installed inside the main mixing tank body 51. The main dispersing unit 52 includes a main dispersing shaft 521 coaxially arranged in the main mixing tank body 51, and the top end of the main dispersing shaft 521 extends out of the top surface of the main mixing tank body 51 and is connected to the motor shaft of the main dispersing motor 522 through a coupling. The main dispersing motor 522 is any motor such as a servo motor that can drive the main dispersing shaft 521 to rotate. The lower part of the main dispersing shaft 521 is welded or screwed with a main dispersing blade 523. In particular, the main dispersing blade 523 is arranged at a height higher than the main mixing inlet 55.
[0051] The upper part of the main dispersion shaft 521 has a chamber inside, and an electron generator 57 is arranged in the chamber, and the electron generator 57 is screwed and grounded on the coupling. The main dispersion shaft 521 has an upper through hole 524 coaxial with it, and the chamber is connected with the space below the main dispersion blade 523 through the upper through hole 524. Preferably, the bottom end of the upper through hole 524 is connected with a discharge chamber 526 through an upper expansion chamber 525, so that the thermal electrons generated by the electron generator are injected into the suspension through the upper through hole 524, the upper expansion chamber 525, and the discharge chamber 526.
[0052] An ultrasonic transducer 53 is installed on the outer facade of the main mixing tank body 51, and an ultrasonic generator 54 is installed below the main mixing tank body 51. The ultrasonic generator 54 and the electronic generator 57 are connected through a circuit. The main dispersion motor 522, the ultrasonic transducer 53, the ultrasonic generator 54 and the electronic generator 57 are electrically connected to and controlled by the control system.
[0053] The working principle of the dispersing device of the polyurethane adhesive for wood-based panels of this embodiment is as follows: The control system controls the surfactant providing device 1, the water supply device 2, and the adhesive supply device 3 to pass the surfactant, water, and polyurethane adhesive (MDI) into the premixing device 41 according to the set ratio, and the premixing motor 43 drives the screw conveyor 42 to premix the surfactant, water, and polyurethane adhesive (MDI) to obtain a mixed adhesive liquid, and intermittently pumps the mixed adhesive liquid into the main mixing tank 51, and the pumping amount each time does not exceed the capacity of the main mixing tank 51. Preferably, the capacity of the main mixing tank 51 is greater than or equal to the amount of the mixed adhesive liquid that can be accommodated in the gap between the spiral blades of the screw conveyor 42, and less than or equal to twice the amount. The mixed adhesive liquid is fully dispersed in the surfactant and water in the main mixing tank 51 by the action of the main dispersing unit 52, the ultrasonic transducer 53, the ultrasonic generator 54, and the electronic generator 57 to obtain a suspension of polyurethane adhesive (MDI). Finally, it is pumped and sprayed on the surface of wood fiber or wood shavings by the output pump of the prior art.
[0054] Since the main mixing tank 51 of this embodiment can disperse the polyurethane adhesive (MDI) in small amounts and multiple times, a suspension of the polyurethane adhesive (MDI) with good dispersion can be obtained, thereby achieving the technical purpose of online adhesive preparation.
[0055] Application Examples The dispersions in Examples 1-9 are used in combination with a polyurethane adhesive and mixed in the manner of Example 12 to obtain a polyurethane adhesive suspension for the production of wood-based panels (specifically wood fiberboards). The obtained polyurethane adhesive suspension is sprayed on the boards to achieve bonding between the boards, which are respectively recorded as 1, 2, 3, 4, 5, 6, 7, 8, and 9.
[0056] The dispersion of Example 9 is used in combination with a polyurethane adhesive and mixed according to the apparatus and method of Example 13 to obtain a polyurethane adhesive suspension for the production of wood-based panels (specifically wood fiberboards). The obtained polyurethane adhesive suspension is sprayed on the board to achieve bonding between the boards, which are respectively recorded as 10.
[0057] Comparative Example 1 In this comparative example, pure polyurethane adhesive is sprayed on the plate. This comparative example is denoted as A.
[0058] Comparative Example 2 A dispersion of a polyurethane adhesive for producing wood-based panels, the dispersion comprising ionized water, a surfactant and nano-silicon dioxide dispersed in the water, wherein the water comprises 88.5 g, the surfactant comprises 1.5 g, and the nano-silicon dioxide comprises 10 g, wherein the particle size of the nano-silicon dioxide is 10 nm-20 nm. This comparative example is denoted as B.
[0059] Comparative Example 3 A dispersion of a polyurethane adhesive for producing wood-based panels, the dispersion comprising ionized water, a surfactant and nano-silicon dioxide dispersed in the water, wherein the dispersion comprises 96.4 g of water, 1.6 g of a surfactant, and 2 g of nano-silicon dioxide, wherein the particle size of the nano-silicon dioxide is 100 nm-150 nm. This comparative example is denoted as C.
[0060] Comparative Example 4 This comparative example provides a dispersion liquid, wherein the dispersion liquid is water. This comparative example is correspondingly recorded as D.
[0061] The polyurethane adhesive suspension or polyurethane adhesive in each application example and comparative example is used for the production of wood fiberboard. The amount of polyurethane adhesive suspension or polyurethane adhesive used per unit area is the same. The relevant properties of the obtained wood fiberboard are tested, and the test results are as follows.
[0062] Table 1
[0063] It can be seen from Table 1 that the polyurethane adhesive suspensions corresponding to Examples 1-10, under the premise that the usage of pure polyurethane adhesive is 40%, the strength performance of the obtained panels is better than that of Comparative Example 1 using 100% pure polyurethane adhesive. It can be seen that the use of the dispersion of the present invention can greatly reduce the usage of the polyurethane adhesive while ensuring the bonding strength.
[0064] Specifically, the nano-silica in the dispersion corresponding to Examples 7-9 uses plasticized nano-silica. When the amount of pure polyurethane adhesive used is the same, the static bending strength and internal bonding strength are better than those of Examples 4-6.
[0065] In the dispersion corresponding to Comparative Example 2, compared with Example 1, the amount of nano-silicon dioxide added is too much, which has a negative impact on the static bending strength and the internal bonding strength.
[0066] In the dispersion corresponding to Comparative Example 3, compared with Example 1, the particle size of nano-silicon dioxide is too large, which has a negative impact on the static bending strength and the internal bonding strength.
[0067] Compared with Example 1, the dispersion corresponding to Control Example 4, which only uses water as a dispersant, fails to meet the requirements of the national standard for wood fiberboard in terms of static bending strength and internal bonding strength.
[0068] The present invention also conducts an experimental analysis on the effect of the amount of the dispersion used in Example 3 of the present invention on the results. See Table 2 for some experimental data.
[0069] Table 2
[0070] As can be seen from Table 2, when the polyurethane adhesive suspension corresponding to Example 3 is used and the amount of pure polyurethane adhesive used is 30%, the strength performance of the obtained board is equivalent to that of Comparative Example 1 using 100% pure polyurethane adhesive. It can be seen that by using the dispersion of Example 1 of the present invention, the amount of pure polyurethane adhesive used can be reduced by up to 70% while ensuring that the bonding strength is equivalent to that of pure polyurethane adhesive. However, when the amount of pure polyurethane adhesive used exceeds 50%, the contribution to the internal bonding strength and static bending strength is not large.
[0071] The above description is intended to be illustrative and not limiting. Upon reading the above description, many embodiments and many applications beyond the examples provided will be apparent to those skilled in the art. Therefore, the scope of the present teachings should not be determined with reference to the above description, but should be determined with reference to the appended claims and the full scope of equivalents to which such claims are entitled. For the purpose of comprehensiveness, all articles and references, including disclosures of patent applications and publications, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein in the preceding claims is not intended to be a waiver of the subject matter, nor should it be considered that the applicant has not considered the subject matter to be part of the disclosed application subject matter.
Claims
1. A dispersion of a polyurethane adhesive for use in the production of wood-based panels, characterized in that: The dispersion includes water and a surfactant dispersed in the water.
2. The dispersion of polyurethane adhesive for wood-based panel production according to claim 1, characterized in that: In the dispersion, the mass ratio of the water to the surfactant is (50-65):(1-5).
3. The dispersion of polyurethane adhesive for wood-based panel production according to claim 1, characterized in that: The surfactant is calcium lignin sulfonate.
4. The dispersion of polyurethane adhesive for wood-based panel production according to claim 1, characterized in that: The dispersion also includes nano silicon dioxide added in an amount of 0.8% to 2.0% of the mass of the dispersion.
5. The dispersion of polyurethane adhesive for wood-based panel production according to claim 4, characterized in that: The particle size of the nano silicon dioxide is 10nm-60nm.
6. The dispersion of polyurethane adhesive for wood-based panel production according to claim 4, characterized in that: The nano silicon dioxide in the dispersant is treated by plasticization modification.
7. The dispersion of polyurethane adhesive for wood-based panel production according to claim 6, characterized in that: The nano silicon dioxide in the dispersant is modified by a mixture of polylactic acid and polyurethane.
8. The dispersion of polyurethane adhesive for wood-based panel production according to claim 1, characterized in that: The method for using the dispersion is as follows: the dispersion is mixed with pure polyurethane adhesive to obtain a polyurethane adhesive; in the polyurethane adhesive, the mass ratio of the pure polyurethane adhesive to the dispersion is (30-45):(55-70).
9. The dispersion of polyurethane adhesive for wood-based panel production according to claim 8, characterized in that: The mass ratio of the pure polyurethane adhesive to the dispersion is 40:
60.
10. The dispersion of polyurethane adhesive for wood-based panel production according to claim 8, characterized in that: The particle size of the polyurethane adhesive particles is 1 μm-5 μm.