High-strength adhesive with waste polyurethane foam as raw material, preparation method and application thereof

Abstract

This invention belongs to the field of thermosetting plastic recycling technology, specifically relating to a high-strength adhesive made from waste polyurethane foam, its preparation method, and its application. The preparation method of the high-strength adhesive of this invention includes the following steps: (1) dissolving an aldehyde-containing bio-based monomer and a diamine containing disulfide bonds in a solvent, and refluxing at 60-90℃ for 3-8 h to obtain a dynamic crosslinking agent; (2) placing waste polyurethane foam powder into a ball mill jar, adding an organic base catalyst and the dynamic crosslinking agent obtained in step (1), ball milling for 1-2 h at a speed of 500-650 rpm, and obtaining the high-strength adhesive after ball milling. This invention introduces a dynamic crosslinking agent into waste polyurethane foam, promoting the construction of a multiple dynamic covalent network between the urethane bonds and the reversible covalent bonds in the dynamic crosslinking agent under the catalytic action of the organic base, synergistically improving the reprocessing mechanical properties of the waste polyurethane foam.

Description

Technical Field

[0001] This invention belongs to the field of thermosetting plastic recycling technology, specifically relating to a high-strength adhesive made from waste polyurethane foam, its preparation method, and its application. Background Technology

[0002] Polyurethane foam, one of the world's six major synthetic polymers, has a global annual production exceeding 28 million tons and continues to grow steadily. With its excellent lightweight and thermal insulation properties, it is widely used in building insulation, cold chain transportation, industrial pipelines, and home appliances. However, its massive production also brings significant environmental challenges. Due to its three-dimensional cross-linked network, polyurethane foam is chemically stable and extremely difficult to degrade in nature. It is estimated that more than 10 million tons of waste polyurethane foam are generated globally each year, the vast majority of which is disposed of through landfill or incineration, causing a severe environmental burden. With the advancement of global "dual carbon" goals and increasingly stringent circular economy regulations, how to efficiently and effectively treat waste polyurethane foam has become a key bottleneck restricting the sustainable development of the entire industry.

[0003] Currently, the recycling of waste polyurethane foam faces two major technological challenges: First, physical recycling methods, while low-cost, suffer from low added value and are considered typical "downgraded recycling," unable to handle large-scale waste disposal. Second, chemical recycling methods (such as alcoholysis and ammonolysis), while theoretically capable of depolymerizing polyurethane into small-molecule polyols, face challenges in industrial practice including complex processes, high costs, high energy consumption, cumbersome subsequent separation and purification, difficulty in controlling the composition of recycled products, unstable performance, and inefficient utilization.

[0004] Upgrading and recycling waste polyurethane foam into high-performance adhesives is a highly promising recycling pathway. Its potential lies in the strong demand and high added value of high-performance structural adhesives in high-end sectors such as automotive and wind power, enabling the development of products that achieve a win-win situation for both the environment and the economy. However, the overall performance of adhesives prepared from waste polyurethane foam using existing technologies is not ideal, limiting their widespread application. Summary of the Invention

[0005] The first objective of this invention is to provide a method for preparing a high-strength adhesive using waste polyurethane foam as raw material; the second objective of this invention is to provide a high-strength adhesive obtained by the method; and the third objective of this invention is to provide applications of the high-strength adhesive.

[0006] According to a first aspect of the present invention, a method for preparing a high-strength adhesive using waste polyurethane foam as a raw material is provided, comprising the following steps:

[0007] (1) Dissolve the aldehyde-containing bio-based monomer and the diamine containing disulfide bond in a solvent, reflux at 60-90℃ for 3-8 h, and after the reaction is complete, cool the reaction product at -15-0℃ to crystallize, remove the supernatant and remove the solvent by rotary evaporation to obtain the dynamic crosslinking agent.

[0008] (2) The waste polyurethane foam is crushed into powder to obtain waste polyurethane foam powder. The waste polyurethane foam powder is placed in a ball mill jar, and an organic base catalyst and the dynamic crosslinking agent prepared in step (1) are added. The ball mill is performed for 1-2 hours at a speed of 500-650 rpm. After the ball milling is completed, a high-strength adhesive is obtained.

[0009] This invention utilizes the Schiff base reaction between the aldehyde group of a bio-based monomer containing an aldehyde group and the amino group of a diamine containing a disulfide bond to prepare a dynamic crosslinking agent containing single or multiple reversible covalent bonds such as imine bonds and disulfide bonds. Then, through a mechanochemical ball milling dispersion pretreatment, the dynamic crosslinking agent is introduced into waste polyurethane foam. Under the catalysis of an organic base, the isocyanate (-NCO) or urethane (-NHCOO-) bonds in the waste polyurethane foam are promoted to form a multiple dynamic covalent network with the reversible covalent bonds such as imine bonds and disulfide bonds in the dynamic crosslinking agent. This synergistic effect improves the mechanical properties of the waste polyurethane foam for recycling and reprocessing, and upgrades it to manufacture high-strength adhesives, turning waste into treasure.

[0010] In some embodiments, in step (1), the aldehyde-containing bio-based monomer is vanillin and / or syringaldehyde.

[0011] In some embodiments, in step (1), the diamine containing a disulfide bond is 4,4'-diaminodiphenyl disulfide and / or 2,2'-dithiodimethyldiethylamine.

[0012] In some embodiments, in step (1), the solvent is ethanol and / or methanol.

[0013] In some embodiments, in step (1), the molar ratio of the aldehyde-containing bio-based monomer to the diamine containing disulfide bonds is (0.01-0.2) mol: (0.005-0.1) mol.

[0014] In some embodiments, in step (1), the ratio of the amount of aldehyde-containing bio-based monomer to the volume of solvent is (0.01-0.2) mol: (100-200) mL.

[0015] In some embodiments, in step (2), the particle size of the waste polyurethane foam powder is 100-1000 μm.

[0016] In some embodiments, in step (2), the organic base catalyst is 1,5,7-triazabicyclo[4.4.0]dec-5-ene and / or 1,8-diazabicyclo[5.4.0]undecene.

[0017] In some embodiments, in step (2), the amount of organic base catalyst added is 1-10 wt% of the mass of waste polyurethane foam powder.

[0018] In some embodiments, in step (2), the amount of dynamic crosslinking agent added is 1-10 wt% of the mass of waste polyurethane foam powder.

[0019] According to a second aspect of the present invention, a high-strength adhesive made from waste polyurethane foam prepared by the above-described preparation method is provided.

[0020] According to a third aspect of the present invention, the application of the above-mentioned high-strength adhesive made from waste polyurethane foam in the preparation of dry-mixed mortar, tile adhesive, wall and floor leveling agent, bonding mortar for external wall insulation systems, joint filler, artificial board, and wood splicing products is provided. When the high-strength adhesive made from waste polyurethane foam of the present invention is used to bond substrates, an appropriate amount of high-strength adhesive is placed on the surface of the substrate to be bonded, and the substrate surfaces are kept with a suitable overlap area according to actual needs. Then, the substrate is placed in a hot press and hot-pressed for 20-60 minutes, maintaining a temperature of 150-200°C and a pressure of 25-35 MPa.

[0021] The beneficial effects of this invention include:

[0022] (1) This invention introduces dynamic covalent bonds such as imine bonds and disulfide bonds into the dynamic crosslinking agent through molecular structure design, and then introduces the dynamic crosslinking agent containing N, O and S atoms with high electronegativity into the waste polyurethane foam, so that the waste polyurethane foam can obtain better reprocessing and recycling performance. The modified waste polyurethane foam enhances the interaction force with the adhesive substrate through hydrogen bonds, coordination bonds, etc., and the adhesive performance is significantly improved. It also has excellent corrosion resistance and broad application range, good comprehensive performance, and has the conditions for high-value application as a high-strength adhesive powder.

[0023] (2) The present invention adopts a mechanochemical ball milling dispersion pretreatment method to make the organic base catalyst and dynamic crosslinking agent more uniformly dispersed and have a larger loading in the waste polyurethane foam. At the same time, this pretreatment method can activate the surface of the waste polyurethane foam powder and generate more crosslinking sites. Thus, a denser crosslinking network structure can be obtained through hot pressing molding process, resulting in recycled polyurethane (PU) sheets with excellent reprocessing mechanical properties.

[0024] (3) The present invention designs and constructs a reversible dynamic crosslinking network in waste polyurethane foam molecular chain segments to prepare a high-strength adhesive. When the high-strength adhesive of the present invention is used as a powder adhesive, it can generate various interactions with the bonding substrate such as hydrogen bonds, covalent bonds and complex coordination bonds, and has excellent adhesive shear properties; it also has good resistance to corrosion by acids, alkalis and salts, and can be adapted to the bonding of various substrates, and has resilience and wide application range.

[0025] (4) This invention uses a one-pot polycondensation reaction to synthesize a dynamic crosslinking agent containing reversible covalent bonds. It is a one-step reaction, which is simple, environmentally friendly, and has a simple synthesis route with inexpensive raw materials. The preparation method of this invention is simple to operate and can be continuously produced using existing industrial equipment, thus having the potential for industrial production applications. Attached Figure Description

[0026] Figure 1 Fourier transform infrared spectra of the adhesive powders prepared in Comparative Examples 1-2 and Examples 2-3.

[0027] Figure 2 Fourier transform infrared spectra of the overlapping shear sheet samples obtained by applying Comparative Examples 1-2 and Application Examples 2-3.

[0028] Figure 3 The bonding strength of the lapped shear joint obtained in Example 2 after immersion in water, acidic liquid, alkaline liquid and artificial seawater for 24 hours is measured.

[0029] Figure 4 The results show the adhesion test results of the adhesive prepared in Example 2 on different substrates.

[0030] Figure 5 The tensile properties of the lap shear members prepared using Comparative Examples 1-2 and Application Examples 1-3 are presented. Detailed Implementation

[0031] The present invention will be further described in detail below with reference to specific embodiments, but the implementation of the present invention is not limited thereto. The materials involved in the following embodiments are all commercially available. Unless otherwise specified, the process steps employ conventional methods known in the art.

[0032] In the following examples and comparative examples, the waste rigid polyurethane foam used was manufactured by Fujian Zhouning County Hongshun Composite Materials Business Department, and the model was 65 density.

[0033] Example 1

[0034] The method for preparing a high-strength adhesive using waste polyurethane foam as raw material in this embodiment includes the following steps:

[0035] (1) Weigh 0.084 mol vanillin and 0.042 mol 4,4'-diaminodiphenyl disulfide into a three-necked flask, add 150 mL of ethanol to dissolve, reflux at 80℃ for 4 h, and after the reaction is complete, cool the reaction product at -8℃ to crystallize, remove the supernatant and remove the solvent by rotary evaporation to obtain a dynamic crosslinking agent containing diimine bonds and disulfide bonds, denoted as APDV.

[0036] (2) Chop the waste rigid polyurethane foam into small cubes of 1×1×1 cm, weigh 300 g of the cubes and put them into a small pulverizer. Cover the pulverizer and pulverize for 5 min to obtain powder with a particle size of about 500 μm. Take it out for later use.

[0037] (3) Weigh 30g of the powder obtained in step (2) and put it into a ball mill jar. At the same time, add 3wt% of 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) and 1wt% of APDV obtained in step (1) into the ball mill jar. Then add zirconia grinding beads, cover the jar, and place it in a planetary ball mill for 1.5 h. Keep the speed at 600 rpm. After the ball milling is completed, the modified ultrafine polyurethane powder is obtained, which is a high-strength adhesive made from waste polyurethane foam.

[0038] Example 2

[0039] The preparation method of the high-strength adhesive using waste polyurethane foam as raw material in this embodiment is basically the same as that in Example 1, except that in step (3), the amount of APDV added is 3wt% of the powder mass.

[0040] Example 3

[0041] The preparation method of the high-strength adhesive using waste polyurethane foam as raw material in this embodiment is basically the same as that in Example 1, except that in step (3), the amount of APDV added is 5 wt% of the powder mass.

[0042] Comparative Example 1

[0043] The comparative example of the preparation method of the adhesive using waste polyurethane foam as raw material includes the following steps:

[0044] (1) Chop the waste rigid polyurethane foam into small cubes of 1×1×1 cm, weigh 300 g of the small cubes and put them into a small pulverizer, cover the pulverizer and pulverize for 5 min to obtain powder with a particle size of about 500 μm, and take it out for use.

[0045] (2) Weigh 30g of the powder obtained in step (1), put it into a ball mill jar, add zirconia grinding beads, cover the jar, and place it in a planetary ball mill for 1.5 h at a speed of 600 rpm. After the ball milling is completed, ultrafine polyurethane powder is obtained, which is an adhesive made from waste polyurethane foam.

[0046] Comparative Example 2

[0047] The comparative example of the preparation method of the adhesive using waste polyurethane foam as raw material includes the following steps:

[0048] (1) Chop the waste rigid polyurethane foam into small cubes of 1×1×1 cm, weigh 300 g of the small cubes and put them into a small pulverizer, cover the pulverizer and pulverize for 5 min to obtain powder with a particle size of about 500 μm, and take it out for use.

[0049] (2) Weigh 30g of the powder obtained in step (1) and put it into a ball mill jar. At the same time, add 3wt% of 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) of the powder mass into the ball mill jar, add zirconium oxide ball milling beads, cover the jar, and place it in a planetary ball mill for 1.5 h at a speed of 600 rpm. After the ball milling is completed, ultrafine polyurethane powder loaded with organic base catalyst is obtained, which is the adhesive made from waste polyurethane foam.

[0050] Then, the adhesives prepared in Examples 1-3 and Comparative Examples 1-2 were used to prepare overlapping shear parts.

[0051] Application Example 1

[0052] The method for preparing the lap joint shearing component in this application embodiment includes the following steps:

[0053] Weigh 0.03 g of the adhesive prepared in Example 1 and place it in a custom-made stainless steel sheet (100 mm long, 25 mm wide, and 2 mm thick), with an overlap area of ​​25 mm × 12.5 mm. Then place it in a hot press and hot press for 30 min, maintaining the temperature at 170°C and the pressure at 30 MPa to obtain the overlapping sheared part, denoted as PTA-1wt.

[0054] Application Example 2

[0055] The method for preparing the lap joint shearing component in this application embodiment includes the following steps:

[0056] Weigh 0.03 g of the adhesive prepared in Example 2 and place it in a custom-made stainless steel sheet (100 mm long, 25 mm wide, and 2 mm thick), with an overlap area of ​​25 mm × 12.5 mm. Then place it in a hot press and hot press for 30 min, maintaining the temperature at 170°C and the pressure at 30 MPa to obtain the overlapping sheared part, denoted as PTA-3wt.

[0057] Application Example 3

[0058] The method for preparing the lap joint shearing component in this application embodiment includes the following steps:

[0059] Weigh 0.03 g of the adhesive prepared in Example 3 and place it in a custom-made stainless steel sheet (100 mm long, 25 mm wide, and 2 mm thick), with an overlap area of ​​25 mm × 12.5 mm. Then place it in a hot press and hot press for 30 min, maintaining the temperature at 170°C and the pressure at 30 MPa to obtain the overlapping sheared part, denoted as PTA-5wt.

[0060] Application Comparative Example 1

[0061] The preparation method of the lapped shear joint in this application includes the following steps:

[0062] Weigh 0.03 g of the adhesive prepared in Comparative Example 1 and place it in a custom-made stainless steel sheet (100 mm long, 25 mm wide, and 2 mm thick), with an overlap area of ​​25 mm × 12.5 mm. Then place it in a hot press and hot press for 30 min, maintaining the temperature at 170℃ and the pressure at 30 MPa to obtain the lapped sheared part, denoted as rePUF.

[0063] Application Comparative Example 2

[0064] The preparation method of the lapped shear joint in this application includes the following steps:

[0065] Weigh 0.03 g of the adhesive prepared in Comparative Example 2 and place it in a custom-made stainless steel sheet (100 mm long, 25 mm wide, and 2 mm thick), with an overlap area of ​​25 mm × 12.5 mm. Then place it in a hot press and hot press for 30 min, maintaining the temperature at 170℃ and the pressure at 30 MPa to obtain the overlapping sheared part, denoted as PTA-0wt%.

[0066] Then, the performance of the prepared adhesive powder and the overlapping sheared parts was tested.

[0067] 1. Adhesion strength

[0068] The adhesive properties were evaluated by testing the shear strength under uniaxial tensile strain, and the test method followed the national standard GB / T 7124-2008. The adhesive strength test results of the lapped shear joints of Comparative Example 2 and Application Examples 1-3 are shown in Table 1.

[0069] Table 1. Test results of adhesive strength of lapped shear joints

[0070]

[0071] Note: APDV content refers to the percentage of APDV in the waste rigid polyurethane foam powder in the examples or comparative examples.

[0072] As shown in Table 1, the adhesive strength of the prepared powder adhesive first increases and then decreases with the increase of crosslinking agent APDV content, reaching its highest value at 3 wt%. This is mainly because with the increase of APDV content, the content of reversible covalent bonds further increases, generating more active crosslinking sites, which increases the cohesive energy of the material and enables it to form more interactions with the surface of the adhesive substrate. However, excessive APDV leads to the presence of excessive hydroxyl groups. These hydroxyl groups can undergo dissociation reactions with the urethane bonds in the molecular chains of waste polyurethane foam, initiating partial depolymerization and thus reducing adhesive performance.

[0073] 2. Infrared spectroscopy test

[0074] Fourier transform infrared spectroscopy was used to perform infrared spectroscopy tests on the adhesive powders prepared in Comparative Examples 1-2 and Examples 2-3, and the overlapping shear sheet samples prepared in Comparative Examples 1-2 and Examples 2-3. Figure 1 Fourier transform infrared spectra of the adhesive powders prepared in Comparative Examples 1-2 and Examples 2-3. Figure 2 Fourier transform infrared spectra of the overlapping shear sheet samples obtained by applying Comparative Examples 1-2 and Application Examples 2-3.

[0075] from Figures 1-2 It can be seen that the characteristic absorption peaks of C=N and SS bonds in APDV are not clearly identified in the spectrum, which may be attributed to their relatively low concentration and the possibility that the signal overlaps with the dominant polyurethane matrix. In the analysis of adhesive powder and lap-jointed shear sheet samples, a peak at 3430 cm⁻¹ was found. -1 The absorption peak at 3200 cm⁻¹ is related to the vibrational mode of the -OH group. Furthermore, the absorption peak at 3200 cm⁻¹... -1 and 1527 cm -1 The peak at 1724 cm⁻¹ belongs to the NH stretching vibration, while the peak at 1724 cm⁻¹ belongs to the NH stretching vibration. -1 The characteristic peak detected at 1220 cm⁻¹ corresponds to the C=O stretching vibration in the urethane chain. -1A distinct and strong absorption band appears at [location], corresponding to the COC bond. The spectra of the powder and sheet did not show significant changes, indicating that the chemical structure was maintained during high-temperature processing. However, compared to the application of rePUF in Comparative Example 1, the introduction of TBD and APDV resulted in -NH (3200 cm⁻¹) […]. -1 ) and -OH (3430 cm -1 The absorption peak intensity increased significantly. This enhancement indicates the presence of phenolic hydroxyl groups in APDV and suggests the formation of additional hydrogen bonds. After high-temperature processing, the intensity of the -NH and -OH peaks decreased, indicating that TBD and APDV promoted dynamic reactive exchange, resulting in a denser cross-linked network. Furthermore, the ether bond peak (1220 cm⁻¹) in the sheet sample... -1 The significant enhancement suggests that high-temperature processing may have induced a dehydration reaction between -OH groups, leading to the formation of additional ether bonds.

[0076] 3. Corrosion resistance

[0077] The lap-sheared joints (PTA-3wt%) prepared in Application Example 2 were immersed in water, acidic liquid (pH=3), alkaline liquid (pH=12), and artificial seawater (20wt% NaCl) for 24 hours, respectively. Afterward, the samples were removed, the liquid on the surface was wiped dry, and the adhesive strength was tested according to the national standard GB / T 7124-2008. The test results are shown in Table 2 and... Figure 3 As shown.

[0078] Table 2. Adhesive strength of the lapped shear joints in Application Example 2 after immersion in different liquids for 24 hours.

[0079]

[0080] From Table 2 and Figure 3 It can be seen that the bonding strength of the lap shear joint prepared in Example 2 remained above 8 MPa after being immersed in water, acidic liquid (pH=3), alkaline liquid (pH=12), and artificial seawater (20wt% NaCl) for 24 hours, indicating that it has strong corrosion resistance.

[0081] 4. Adhesion on different substrates

[0082] 0.03 g of the adhesive prepared in Example 2 was weighed and placed into custom-made stainless steel, copper, aluminum, and wood sheets, respectively. Each sheet was 100 mm long, 25 mm wide, and 2 mm thick, with an overlap area of ​​25 mm × 12.5 mm. The sheets were then placed in a hot press and hot-pressed for 30 min at 170°C and 30 MPa to obtain overlapping sheared parts from the stainless steel, copper, aluminum, and wood sheets. The adhesive performance on different substrates was evaluated by testing the shear strength under uniaxial tensile strain, following the national standard GB / T 7124-2008. The test results are shown in Table 3 and... Figure 4 As shown.

[0083] Table 3. Adhesive strength of the adhesive in Example 2 on different substrates

[0084]

[0085] From Table 3 and Figure 4 It can be seen that the adhesive prepared in Example 2 has strong adhesion to a variety of substrates, indicating that the adhesive prepared in this invention has broad-spectrum adhesion.

[0086] 5. Tensile properties

[0087] Test method: The tensile strength of the lap-shear sheets prepared using Comparative Examples 1-2 and Application Examples 1-3 was tested using an electronic universal testing machine (MTS E44.104) at a tensile speed of 10 mm / min. The final tensile strength and elongation at break data of the samples are the average values ​​of at least three parallel samples.

[0088] Figure 5 The tensile properties of the lap shear joints prepared using Comparative Examples 1-2 and Application Examples 1-3 are presented. Figure 5 It can be seen that the tensile strength of the sheet first increases and then decreases with the increase of APDV content. When the APDV content is 3wt%, the tensile strength is the highest at 81.5 MPa, and the elongation at break is 18.63%. This is because the introduction of APDV, in which the imine bonds and disulfide bonds synergistically enhance the urethane bonds in the waste polyurethane foam, promotes the movement of its chain segments, making the crosslinked network more compact. However, excessive APDV leads to an excessive amount of free hydroxyl groups in the crosslinked network. These free hydroxyl groups will undergo a dissociation reaction with the urethane bonds in the waste polyurethane foam chain segments, leading to chain segment depolymerization and thus a decrease in strength.

[0089] The above descriptions are merely some embodiments of the present invention. Those skilled in the art can make various modifications and improvements without departing from the inventive concept of the present invention, and these all fall within the scope of protection of the present invention.

Claims

1. A method for preparing a high-strength adhesive using waste polyurethane foam as raw material, characterized in that, Includes the following steps: (1) Dissolve the aldehyde-containing bio-based monomer and the diamine containing disulfide bonds in a solvent, reflux at 60-90℃ for 3-8h, and after the reaction is complete, cool the reaction product at -15-0℃ to crystallize, remove the supernatant and remove the solvent by rotary evaporation to obtain a dynamic crosslinking agent; the aldehyde-containing bio-based monomer is vanillin and / or syringaldehyde; the diamine containing disulfide bonds is 4,4'-diaminodiphenyl disulfide and / or 2,2'-dithiodimethyldiethylamine; (2) The waste polyurethane foam is crushed into powder to obtain waste polyurethane foam powder. The waste polyurethane foam powder is placed in a ball mill jar, and an organic base catalyst and the dynamic crosslinking agent prepared in step (1) are added. The amount of dynamic crosslinking agent added is 1-10 wt% of the mass of the waste polyurethane foam powder. The ball mill is performed for 1-2 hours at a speed of 500-650 rpm. After the ball milling is completed, a high-strength adhesive is obtained.

2. The preparation method according to claim 1, characterized in that, In step (1), the solvent is ethanol and / or methanol.

3. The preparation method according to claim 1 or 2, characterized in that, In step (1), the molar ratio of the aldehyde-containing bio-based monomer to the diamine containing disulfide bonds is (0.01-0.2):(0.005-0.1). The ratio of the amount of aldehyde-containing bio-based monomer to the volume of solvent is (0.01-0.2):(100-200).

4. The preparation method according to claim 1 or 2, characterized in that, In step (2), the particle size of the waste polyurethane foam powder is 100-1000 μm.

5. The preparation method according to claim 1 or 2, characterized in that, In step (2), the organic base catalyst is 1,5,7-triazabicyclo[4.4.0]dec-5-ene and / or 1,8-diazabicyclo[5.4.0]undecene.

6. The preparation method according to claim 1 or 2, characterized in that, In step (2), the amount of organic base catalyst added is 1-10 wt% of the mass of waste polyurethane foam powder.

7. A high-strength adhesive made from waste polyurethane foam prepared by the preparation method according to any one of claims 1-6.

8. The application of the high-strength adhesive made from waste polyurethane foam as described in claim 7 in the preparation of dry-mixed mortar, tile adhesive, wall and floor leveling agent, bonding mortar for external wall insulation system, joint filler, artificial board, and wood splicing products.

Images