Preparation method of waterborne polyurethane dispersion galling ceramic tile back adhesive

Abstract

The invention discloses a preparation method of a waterborne polyurethane dispersion galling ceramic tile back adhesive, and relates to the technical field of ceramic tile back adhesives, and the preparation method of the ceramic tile back adhesive comprises the steps of raw material preparation, prepolymer synthesis, waterborne dispersion preparation, viscosity adjustment, filler addition and performance test. The method has the advantages that the ultrasonic dispersion device is introduced to treat the polyurethane prepolymer, so that the agglomeration structure in the prepolymer can be effectively destroyed, the polyurethane prepolymer can be more uniformly dispersed in water, the full reaction of the cross-linking agent and the prepolymer can be promoted, the layering and precipitation phenomena are reduced, the stability and the performance of the water-based dispersion are improved, and the service life of the water-based dispersion is prolonged. The anti-ultraviolet agent and the antioxidant effectively cooperate with the prepolymer obtained through ultrasonic dispersion treatment and a strict preparation process and other components under the specific step-by-step stirring condition, and highly uniform dispersion of the additive in a gum system is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of tile adhesive, in particular to a method for preparing a roughened tile adhesive using a waterborne polyurethane dispersion. Background Art

[0002] In the tile pasting industry, adhesive is a key auxiliary material, and its performance directly affects the firmness and durability of tile pasting;

[0003] As one of the main components of adhesive, the dispersibility and cross-linking reaction degree of polyurethane prepolymer directly determine the performance of the adhesive. However, traditional dispersion methods often make it difficult to evenly disperse polyurethane prepolymer in water, resulting in the existence of agglomerate structure, which affects the uniformity and stability of the adhesive. Therefore, we propose a method for preparing roughened tile adhesive using water-based polyurethane dispersion. Summary of the invention

[0004] The purpose of the invention is to provide a method for preparing a roughened tile backing adhesive made of waterborne polyurethane dispersion.

[0005] In order to solve the problems raised in the above background technology, the present invention provides the following technical solution: a method for preparing a roughened tile adhesive of a waterborne polyurethane dispersion, comprising the following steps:

[0006] Step 1, raw material preparation, by weight, prepare 40-50 parts of polyester polyol, 15-20 parts of diphenylmethane diisocyanate, 1-3 parts of surfactant, 0.5-1.5 parts of thickener, 20-30 parts of silica sand, 0.1-1 parts of defoamer, 0.2-1.5 parts of preservative, 0.5-2 parts of crosslinking agent, 0.1-1 parts of UV inhibitor, 0.1-1 parts of antioxidant;

[0007] Step 2, prepolymer synthesis, after adding polyester polyol into the reactor, turn on the stirrer and gradually increase the temperature, slowly drip the polyisocyanate into the polyol in the reactor, turn on the cooling device of the reactor to maintain the temperature, after the reaction is completed, stop stirring and heating, and introduce nitrogen protection;

[0008] Step 3, preparing an aqueous dispersion, adding deionized water and a surfactant into a stainless steel stirring tank for preliminary stirring, slowly adding a defoaming agent into the aqueous solution in the stainless steel stirring tank, continuing stirring, slowly adding a preservative into the stainless steel stirring tank, stirring again, pretreating the polyurethane prepolymer, adding a crosslinking agent into the treated polyurethane prepolymer, after the addition is completed, slowly dropping the polyurethane prepolymer into the stainless steel stirring tank through a dropping device, after the prepolymer is dropped, slowly adding an anti-ultraviolet agent and an antioxidant into the stainless steel stirring tank and stirring to obtain an aqueous polyurethane dispersion;

[0009] Step 4: Viscosity adjustment: add thickener to adjust the viscosity of the adhesive;

[0010] Step 5: Add filler, dry, grind and sieve the silica sand, slowly add the treated silica sand into the aqueous polyurethane dispersion with adjusted viscosity, and stir for 30-60 minutes;

[0011] Step six: Performance test: perform performance test on the prepared tile adhesive.

[0012] As a further scheme of the present invention: in the step 1, the molecular weight of the polyester polyol is 1000-3000, the surfactant is polyoxyethylene sorbitan fatty acid ester, the thickener is hydroxyethyl cellulose, the defoamer is a silicone defoamer, the cross-linker is ethylenediamine, the anti-ultraviolet agent is a benzotriazole ultraviolet absorber, and the antioxidant is a hindered phenol antioxidant.

[0013] As a further scheme of the present invention: In the step 2, the specific method of synthesizing the prepolymer is: adding polyester polyol to a reactor equipped with a stirrer, a thermometer, a condenser and a nitrogen protection device, turning on the stirrer and heating to 80°C, placing polyisocyanate in a separate glass dropping funnel and preheating to 50°C, slowly dropping the preheated polyisocyanate into the reactor, turning on the cooling device of the reactor, maintaining the temperature in the reactor to 60°C-90°C, reacting for 2h-5h, sampling every 30min to determine the isocyanate group content of the reaction system, and after the reaction is completed, stopping stirring and heating, continuing nitrogen protection, and cooling the prepolymer in the reactor to 30°C-40°C.

[0014] As a further scheme of the present invention: in the step three, the specific method for preparing the aqueous dispersion is to add deionized water and a surfactant into a stainless steel stirring tank and stir for 10 min-15 min, slowly add a defoaming agent into the aqueous solution in the stainless steel stirring tank and stir for 5 min-10 min, slowly add a preservative into the stainless steel stirring tank and stir for 3 min-5 min, pretreat the polyurethane prepolymer, add a crosslinking agent into the polyurethane prepolymer cooled by 30°C-40°C, react at 40°C-60°C for 30 min-60 min, then slowly drop the polyurethane prepolymer treated by the crosslinking reaction into the stainless steel stirring tank through a dropping device, increase the stirring speed to 800-1500 rpm, adjust the water temperature to 20°C-30°C during the dropping process, and slowly add an anti-ultraviolet agent and an antioxidant into the stainless steel stirring tank and stir.

[0015] As a further solution of the present invention: in the step three, the polyurethane prepolymer is pretreated by treating the polyurethane prepolymer through an ultrasonic dispersion device for 10 min-20 min, and the ultrasonic frequency is set to 20 kHz-40 kHz.

[0016] As a further solution of the present invention: the specific method of slowly adding the anti-ultraviolet agent and the antioxidant into the stainless steel stirring tank and stirring is to slowly add the anti-ultraviolet agent and the antioxidant into the stainless steel stirring tank, stir at a speed of 300-500rpm for 15min-30min, and then stir at a speed of 800-1500rpm for 30min-60min.

[0017] As a further solution of the present invention: in the step 4, the specific method of adjusting the viscosity is to slowly add the thickener to the aqueous polyurethane dispersion, stir for 15 minutes to 30 minutes, and after the stirring is completed, let it stand for 5 minutes to 10 minutes.

[0018] As a further solution of the present invention: in the step 5, the specific method of adding filler is to place the silica sand in an oven and dry it for 2h-4h, the drying temperature is set to 100℃-120℃, and after drying, it is placed in a ball mill and ground to 10μm-15μm, and after grinding, it is placed in a 100-200 mesh screen for sieving, and the aqueous polyurethane dispersion with adjusted viscosity is placed in a stirring tank with a stirring device, and stirring is started, and the speed is set to 400rpm-800rpm, and the treated silica sand filler is slowly poured into the stirring tank, and stirred at a speed of 400rpm-800rpm for 30min-60min.

[0019] As a further solution of the present invention: in step six, the specific method of the performance test is to prepare multiple groups of tile samples coated with adhesive, take out a group of samples, and cure them at 20℃-25℃ for one week. After the curing is completed, the samples are installed on a viscosity strength tester to test the viscosity strength, take a group of samples, soak them in a container filled with deionized water for one week, observe the changes in the adhesive, take a group of samples and put them into a wear resistance testing machine for testing, and record the wear resistance.

[0020] By adopting the above technical solution, compared with the prior art, the beneficial effects of the present invention are:

[0021] 1. The present invention introduces an ultrasonic dispersion device to treat the polyurethane prepolymer, which can effectively destroy the agglomeration structure in the prepolymer, making it more evenly dispersed in water, and can also promote the full reaction of the crosslinking agent and the prepolymer, reduce the occurrence of stratification and precipitation, thereby improving the stability and performance of the water-based dispersion, and further improving the viscosity strength of the backing glue;

[0022] 2. The present invention realizes highly uniform dispersion of the additives in the adhesive system by effectively coordinating the anti-ultraviolet agent and the antioxidant with the prepolymer and other components obtained through ultrasonic dispersion treatment and strict preparation process under specific step-by-step stirring conditions. This fine dispersion and mixing not only enhances the resistance of the adhesive to ultraviolet radiation and oxidation, but also improves the durability and stability of the adhesive during long-term use;

[0023] 3. In the present invention, by drying, grinding and sieving the silica sand in step five, the consistency and stability of the filler quality are ensured, and the slow addition method combined with appropriate stirring speed and time effectively prevents the occurrence of silica sand agglomeration, ensures the uniform distribution of the silica sand filler in the aqueous polyurethane dispersion, enables the back glue to evenly withstand external force at all positions, and further improves its mechanical properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Schematic diagram of the steps of the method for preparing tile adhesive in an embodiment of the present invention. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] Embodiment 1:

[0027] Please see attached Figure 1 The present invention provides a method for preparing a roughened tile adhesive using a waterborne polyurethane dispersion, comprising the following steps:

[0028] Step 1, raw material preparation, by weight, prepare 40-50 parts of polyester polyol, 15-20 parts of diphenylmethane diisocyanate, 1-3 parts of surfactant, 0.5-1.5 parts of thickener, 20-30 parts of silica sand, 0.1-1 parts of defoamer, 0.2-1.5 parts of preservative, 0.5-2 parts of crosslinking agent, 0.1-1 parts of UV inhibitor, 0.1-1 parts of antioxidant;

[0029] Step 2, prepolymer synthesis, after adding polyester polyol into the reactor, turn on the stirrer and gradually increase the temperature, slowly drip the polyisocyanate into the polyol in the reactor, turn on the cooling device of the reactor to maintain the temperature, after the reaction is completed, stop stirring and heating, and introduce nitrogen protection;

[0030] Step 3, preparing an aqueous dispersion, adding deionized water and a surfactant into a stainless steel stirring tank for preliminary stirring, slowly adding a defoaming agent into the aqueous solution in the stainless steel stirring tank, continuing stirring, slowly adding a preservative into the stainless steel stirring tank, stirring again, pretreating the polyurethane prepolymer, adding a crosslinking agent into the treated polyurethane prepolymer, after the addition is completed, slowly dropping the polyurethane prepolymer into the stainless steel stirring tank through a dropping device, after the prepolymer is dropped, slowly adding an anti-ultraviolet agent and an antioxidant into the stainless steel stirring tank and stirring to obtain an aqueous polyurethane dispersion;

[0031] Step 4: Viscosity adjustment: add thickener to adjust the viscosity of the adhesive;

[0032] Step 5: Add filler, dry, grind and sieve the silica sand, slowly add the treated silica sand into the aqueous polyurethane dispersion with adjusted viscosity, and stir for 30-60 minutes;

[0033] Step 6: Performance test: perform performance test on the prepared tile adhesive;

[0034] In step 1, the molecular weight of the polyester polyol is 1000-3000, the surfactant is polyoxyethylene sorbitan fatty acid ester, the thickener is hydroxyethyl cellulose, the defoamer is an organosilicon defoamer, the cross-linker is ethylenediamine, the anti-ultraviolet agent is a benzotriazole ultraviolet absorber, and the antioxidant is a hindered phenol antioxidant;

[0035] In step 2, the specific method of prepolymer synthesis is: adding polyester polyol to a reactor equipped with a stirrer, a thermometer, a condenser and a nitrogen protection device, turning on the stirrer and heating to 80°C, placing polyisocyanate in a separate glass dropping funnel and preheating to 50°C, slowly dropping the preheated polyisocyanate into the reactor, turning on the cooling device of the reactor, maintaining the temperature in the reactor to 60°C-90°C, reacting for 2h-5h, sampling every 30min to determine the isocyanate group content of the reaction system, and after the reaction is completed, stopping stirring and heating, continuing nitrogen protection, and cooling the prepolymer in the reactor to 30°C-40°C;

[0036] In step 3, the specific method for preparing the aqueous dispersion is to add deionized water and a surfactant to a stainless steel stirring tank and stir for 10 min-15 min, slowly add a defoamer to the aqueous solution in the stainless steel stirring tank and stir for 5 min-10 min, slowly add a preservative to the stainless steel stirring tank and stir for 3 min-5 min, pretreat the polyurethane prepolymer, add a crosslinking agent to the polyurethane prepolymer cooled by 30°C-40°C, react at 40°C-60°C for 30 min-60 min, then slowly drop the polyurethane prepolymer treated by the crosslinking reaction into the stainless steel stirring tank through a dropping device, increase the stirring speed to 800-1500 rpm, adjust the water temperature to 20°C-30°C during the dropping process, and slowly add an anti-ultraviolet agent and an antioxidant to the stainless steel stirring tank and stir;

[0037] In step three, the polyurethane prepolymer is pretreated by subjecting the polyurethane prepolymer to an ultrasonic dispersion device for 10 min to 20 min, with the ultrasonic frequency set to 20 kHz to 40 kHz.

[0038] Specific workflow: Take two parts of raw materials of the same weight, one of which is synthesized according to the conventional method, that is, the polyurethane prepolymer is not treated with an ultrasonic dispersion device (control group), and the other is treated with an ultrasonic dispersion device for 15 minutes before adding the crosslinking agent to the polyurethane prepolymer, and the ultrasonic frequency is set to 30kHz (experimental group). Subsequent steps such as water-based dispersion preparation, viscosity adjustment, and filler addition are all operated according to the standard process;

[0039] Several groups of tile samples coated with two groups of back glue were made and cured at 20-25℃ for one week. After curing, the samples were installed on a viscosity strength tester to test the viscosity strength. The test results showed that the average viscosity strength of the back glue in the control group was 0.8MPa, while the average viscosity strength of the back glue in the experimental group after ultrasonic dispersion treatment reached 1.2MPa, an increase of about 50%. This shows that the ultrasonic dispersion device can destroy the agglomeration structure in the prepolymer, promote the cross-linking reaction, and significantly improve the viscosity strength of the back glue.

[0040] Furthermore, by introducing an ultrasonic dispersion device to treat the polyurethane prepolymer, the agglomeration structure in the prepolymer can be effectively destroyed, making it more evenly dispersed in water. It can also promote the full reaction between the crosslinker and the prepolymer, reduce the occurrence of stratification and precipitation, thereby improving the stability and performance of the water-based dispersion, and then improving the viscosity strength of the backing adhesive.

[0041] Embodiment 2:

[0042] Based on Example 1, the specific method of slowly adding the anti-ultraviolet agent and the antioxidant to the stainless steel stirring tank for stirring is to slowly add the anti-ultraviolet agent and the antioxidant to the stainless steel stirring tank, stir at a speed of 300-500 rpm for 15 min-30 min, and then stir at a speed of 800-1500 rpm for 30 min-60 min;

[0043] In step 4, the specific method of adjusting the viscosity is to slowly add the thickener to the aqueous polyurethane dispersion, stir for 15 minutes to 30 minutes, and after stirring, let it stand for 5 minutes to 10 minutes.

[0044] Specific work flow: two groups of raw materials are prepared to prepare the backing adhesive. Both groups adopt the same preliminary preparation process such as ultrasonic dispersion treatment of prepolymer. When adding the anti-ultraviolet agent and antioxidant, the control group adopts the conventional one-time rapid addition and uniform stirring for 45 minutes (rotation speed 600rpm), and the experimental group follows the specific step-by-step stirring conditions of the present invention, that is, stirring at a rotation speed of 400rpm for 20 minutes, and then stirring at a rotation speed of 1200rpm for 40 minutes;

[0045] Two groups of adhesives were coated on tile samples respectively. Some samples were exposed to the sun in the outdoor natural environment for 6 months, and the other samples were placed in an accelerated aging test chamber (simulating ultraviolet radiation and oxidation environment) for 1000 hours. It was observed that the adhesive in the control group began to show slight discoloration and surface powdering after 3 months of outdoor exposure. After running in the accelerated aging test chamber for 500 hours, the viscosity strength decreased by about 30%. The adhesive in the experimental group only had very slight discoloration after being exposed to the sun outdoors for 6 months, and the viscosity strength only decreased by about 15% after running in the accelerated aging test chamber for 1000 hours. This enhanced the adhesive's resistance to ultraviolet radiation and oxidation, and improved its durability and stability.

[0046] Furthermore, by effectively coordinating the anti-ultraviolet agent and antioxidant under specific step-by-step stirring conditions with the prepolymer and other ingredients obtained through ultrasonic dispersion treatment and strict preparation process, a highly uniform dispersion of the additives in the adhesive system is achieved. This fine dispersion and mixing not only enhances the adhesive's resistance to ultraviolet radiation and oxidation, but also improves the durability and stability of the adhesive during long-term use.

[0047] Embodiment three:

[0048] Based on the second embodiment, in step 5, the specific method of adding filler is to place the silica sand in an oven and dry it for 2h-4h, the drying temperature is set to 100°C-120°C, and after drying, it is placed in a ball mill and ground to 10μm-15μm, and after grinding, it is placed in a 100-200 mesh screen for sieving, and the aqueous polyurethane dispersion with adjusted viscosity is placed in a stirring tank with a stirring device, and stirring is started, and the speed is set to 400rpm-800rpm, and the treated silica sand filler is slowly poured into the stirring tank, and stirred at a speed of 400rpm-800rpm for 30min-60min;

[0049] In step six, the specific method of performance testing is to prepare multiple groups of tile samples coated with adhesive, take out a group of samples, and cure them at 20℃-25℃ for one week. After the curing is completed, the samples are installed on a viscosity strength tester to test the viscosity strength. Take a group of samples, soak them in a container filled with deionized water for one week, observe the changes in the adhesive, take a group of samples and put them into a wear resistance testing machine for testing, and record the wear resistance.

[0050] Specific work flow: two groups of silica sand treatment methods are used to prepare back glue. The silica sand of the control group is simply dried for 1 hour (without precise temperature control) and then directly added to the aqueous polyurethane dispersion without adjusting the viscosity, and a quick pouring method is adopted and stirred for 20 minutes (speed 300rpm). The experimental group is placed in an oven and dried for 3 hours according to the steps of the present invention, and the drying temperature is set to 110°C. After drying, it is placed in a ball mill and ground to 12μm. After grinding, it is placed in a 150-mesh screen for sieving. The aqueous polyurethane dispersion with adjusted viscosity is placed in a stirring tank with a stirring device, stirring is turned on, and the speed is set to 600rpm. The treated silica sand filler is slowly poured into the stirring tank and stirred at a speed of 600rpm for 45min.

[0051] The mechanical properties of the two groups of prepared adhesives were tested, including tensile strength and shear strength tests. The test results showed that the tensile strength of the adhesive in the control group was 2.5 MPa, and the shear strength was 1.8 MPa. The tensile strength of the adhesive in the experimental group reached 3.5 MPa, and the shear strength reached 2.5 MPa, which were increased by about 40% and 39%, respectively. This shows that the drying, grinding, sieving, slow addition and appropriate stirring of silica sand in the present invention can effectively prevent silica sand from agglomerating and ensure its uniform distribution, thereby improving the mechanical properties of the adhesive.

[0052] Furthermore, by drying, grinding and sieving the silica sand in step five, the consistency and stability of the filler quality are ensured, and the slow addition method combined with appropriate stirring speed and time effectively prevents the occurrence of silica sand agglomeration, ensuring the uniform distribution of the silica sand filler in the water-based polyurethane dispersion, so that the backing adhesive can evenly withstand external forces in all parts, further improving its mechanical properties.

[0053] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for preparing a roughened tile adhesive made of waterborne polyurethane dispersion, characterized in that: The following steps are involved: Step 1, raw material preparation, by weight, prepare 40-50 parts of polyester polyol, 15-20 parts of diphenylmethane diisocyanate, 1-3 parts of surfactant, 0.5-1.5 parts of thickener, 20-30 parts of silica sand, 0.1-1 parts of defoamer, 0.2-1.5 parts of preservative, 0.5-2 parts of crosslinking agent, 0.1-1 parts of UV inhibitor, 0.1-1 parts of antioxidant; Step 2, prepolymer synthesis, after adding polyester polyol into the reactor, turn on the stirrer and gradually increase the temperature, slowly drip the polyisocyanate into the polyol in the reactor, turn on the cooling device of the reactor to maintain the temperature, after the reaction is completed, stop stirring and heating, and introduce nitrogen protection; Step 3, preparing an aqueous dispersion, adding deionized water and a surfactant into a stainless steel stirring tank for preliminary stirring, slowly adding a defoaming agent into the aqueous solution in the stainless steel stirring tank, continuing stirring, slowly adding a preservative into the stainless steel stirring tank, stirring again, pretreating the polyurethane prepolymer, adding a crosslinking agent into the treated polyurethane prepolymer, after the addition is completed, slowly dropping the polyurethane prepolymer into the stainless steel stirring tank through a dropping device, after the prepolymer is dropped, slowly adding an anti-ultraviolet agent and an antioxidant into the stainless steel stirring tank and stirring to obtain an aqueous polyurethane dispersion; Step 4: Viscosity adjustment: add thickener to adjust the viscosity of the adhesive. Step 5: Add filler, dry, grind and sieve the silica sand, slowly add the treated silica sand into the aqueous polyurethane dispersion with adjusted viscosity, and stir for 30-60 minutes; Step six: Performance test: perform performance test on the prepared tile adhesive.

2. The method for preparing a roughened tile adhesive made of waterborne polyurethane dispersion according to claim 1, characterized in that: In the step 1, the molecular weight of the polyester polyol is 1000-3000, the surfactant is polyoxyethylene sorbitan fatty acid ester, the thickener is hydroxyethyl cellulose, the defoamer is an organosilicon defoamer, the crosslinker is ethylenediamine, the anti-ultraviolet agent is a benzotriazole ultraviolet absorber, and the antioxidant is a hindered phenol antioxidant.

3. The method for preparing a roughened tile adhesive made of waterborne polyurethane dispersion according to claim 1, characterized in that: In the step 2, the specific method of synthesizing the prepolymer is as follows: adding the polyester polyol to a reactor equipped with a stirrer, a thermometer, a condenser and a nitrogen protection device, turning on the stirrer and heating to 80°C, placing the polyisocyanate in a separate glass dropping funnel and preheating it to 50°C, slowly dropping the preheated polyisocyanate into the reactor, turning on the cooling device of the reactor, maintaining the temperature in the reactor to 60°C-90°C, reacting for 2h-5h, sampling every 30min to determine the isocyanate group content of the reaction system, and after the reaction is completed, stopping stirring and heating, continuing nitrogen protection, and cooling the prepolymer in the reactor to 30°C-40°C.

4. The method for preparing a roughened tile adhesive made of waterborne polyurethane dispersion according to claim 1, characterized in that: In the step 3, the specific method for preparing the aqueous dispersion is to add deionized water and a surfactant into a stainless steel stirring tank and stir for 10 min-15 min, slowly add a defoaming agent into the aqueous solution in the stainless steel stirring tank and stir for 5 min-10 min, slowly add a preservative into the stainless steel stirring tank and stir for 3 min-5 min, pretreat the polyurethane prepolymer, add a crosslinking agent into the polyurethane prepolymer cooled by 30° C.-40° C., react at 40° C.-60° C. for 30 min-60 min, then slowly drop the polyurethane prepolymer treated by the crosslinking reaction into the stainless steel stirring tank through a dropping device, increase the stirring speed to 800-1500 rpm, adjust the water temperature to 20° C.-30° C. during the dropping process, and slowly add an anti-ultraviolet agent and an antioxidant into the stainless steel stirring tank and stir.

5. The method for preparing a roughened tile adhesive made of waterborne polyurethane dispersion according to claim 1, characterized in that: In the step three, the polyurethane prepolymer is pretreated by subjecting the polyurethane prepolymer to an ultrasonic dispersion device for 10 min to 20 min, with the ultrasonic frequency set to 20 kHz to 40 kHz.

6. The method for preparing a roughened tile adhesive made of waterborne polyurethane dispersion according to claim 1, characterized in that: In the step three, the specific method of slowly adding the anti-ultraviolet agent and the antioxidant into the stainless steel stirring tank and stirring is to slowly add the anti-ultraviolet agent and the antioxidant into the stainless steel stirring tank, stir at a speed of 300-500rpm for 15min-30min, and then stir at a speed of 800-1500rpm for 30min-60min.

7. The method for preparing a roughened tile adhesive made of waterborne polyurethane dispersion according to claim 1, characterized in that: In the step 4, the specific method of adjusting the viscosity is to slowly add the thickener to the aqueous polyurethane dispersion, stir for 15 minutes to 30 minutes, and after the stirring is completed, let it stand for 5 minutes to 10 minutes.

8. The method for preparing a roughened tile adhesive made of waterborne polyurethane dispersion according to claim 1, characterized in that: In the step 5, the specific method of adding filler is to place the silica sand in an oven and dry it for 2h-4h, the drying temperature is set to 100℃-120℃, and after drying, it is placed in a ball mill and ground to 10μm-15μm, and after grinding, it is placed in a 100-200 mesh screen for sieving, and the aqueous polyurethane dispersion with adjusted viscosity is placed in a stirring tank with a stirring device, and stirring is started, and the speed is set to 400rpm-800rpm, and the treated silica sand filler is slowly poured into the stirring tank, and stirred at a speed of 400rpm-800rpm for 30min-60min.

9. The method for preparing a roughened tile adhesive made of waterborne polyurethane dispersion according to claim 1, characterized in that: In step six, the specific method of the performance test is to prepare multiple groups of tile samples coated with adhesive, take out a group of samples, and cure them at 20°C-25°C for one week. After the curing is completed, the samples are installed on a viscosity strength tester to test the viscosity strength, take a group of samples, soak them in a container filled with deionized water for one week, observe the changes in the adhesive, take a group of samples and put them into a wear resistance testing machine for testing, and record the wear resistance.

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