High-water-absorption polyacrylamide-based two-component polyurethane material and preparation method thereof

Abstract

The invention relates to the technical field of high polymer material synthesis, and discloses a high-water-absorption polyacrylamide-based bi-component polyurethane material and a preparation method thereof.The material comprises 10-20 parts of a polyacrylamide component, 80-100 parts of an isocyanate component and 80-100 parts of a polyol component, and polyacrylamide is powdery, has the density of 1.30 g / cm < 3 > and is evenly dispersed in the isocyanate component. The grouting mode is adopted for construction, the construction process is simple and convenient, the material can be rapidly permeated into the deep position of the crack, and the beneficial effects of being rapid, environmentally friendly, durable, small in damage and the like are achieved. According to the invention, the polyacrylamide powder with high water absorption is uniformly embedded in the polyurethane open-cell foam, so that the material is endowed with extremely high water absorption performance, erosion of residual moisture at a leakage disease part to a building material can be effectively avoided, the bonding strength, flame retardance and other properties of the material are enhanced, the problems of core burning and the like of the material are effectively avoided, and the service life of the material is prolonged. And the restoration and treatment effect on the leakage water disease of the underground engineering structure can be further improved.

Description

Technical Field

[0001] The invention relates to the technical field of polymer material synthesis, and in particular to a highly water-absorbent polyacrylamide-based two-component polyurethane material and a preparation method thereof. Background Art

[0002] Tunnels and underground projects in my country are generally built in rock and soil, with huge scale. After years of service, underground project diseases have gradually increased. Since their structures, whether brick or reinforced concrete, are inevitably soaked and infiltrated by water for a long time, leakage has become one of the prominent problems affecting their service effect, especially for underground projects such as dams and urban underground pipelines, which are in a water-rich environment. The leakage problem is more serious. Leakage not only affects the use function and life of the building, but may also affect the bearing capacity of the structure in serious cases, causing engineering accidents. In order to ensure the safety and durability of underground projects, it is necessary to detect and control the leakage of underground projects in a timely manner. At present, grouting is a simple and effective means of plugging and reinforcing underground projects, and it is also one of the most commonly used plugging methods. The so-called grouting method is to configure a certain material into a slurry, inject it into the gap or hole with a grouting equipment, so that it can diffuse, gel or solidify, and use the slurry to adhere to, solidify and fill the leakage channel to repair the leakage site. Among the many grouting materials, polyurethane grouting materials have been widely used in grouting and plugging due to their good expansion, high early strength, strong adhesion, fast curing speed, good durability and simple grouting operation.

[0003] However, polyurethane materials still have some shortcomings in practical applications, which limits their scope of use. For example, Chinese patent publication No. CN 109679052 A discloses a double-slurry fast-setting polymer repair material suitable for underground pipeline grouting repair and its preparation method, but does not involve the water absorption of the grouting material itself; in practical applications, after grouting is completed, cracks in tunnels and urban underground projects will still retain moisture that has not been discharged. The presence of these moisture will cause secondary erosion to building materials, which may cause cracks, mildew spots and steel corrosion in the structure again. Due to its poor water absorption performance, polyurethane materials are difficult to effectively solve the above problems. In addition, the reaction of isocyanate and water and polyol components in polyurethane materials will release a large amount of heat, and the resulting polymer material has a large density, a fast solidification speed, and a solidification time of ≤10s. In order to achieve the repair effect, more grouting raw materials may be needed. The combined effect of these factors leads to an increase in the internal temperature of the material, which easily leads to yellowing and burning of the foam. Once the foam turns yellow and burns, its compressive strength decreases significantly, far below 0.8MPa, thereby weakening the repair effect of the polyurethane grouting material to a certain extent.

[0004] Therefore, in this field, there is an urgent need to develop a grouting plugging material with ideal strength, good durability and strong water absorption to meet the needs of plugging and reinforcing tunnels and underground projects. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a highly water-absorbent polyacrylamide-based two-component polyurethane material and a preparation method thereof, wherein polyacrylamide powder with high water absorption is embedded into the open-cell polyurethane foam pores to synthesize a foam product with ideal strength, good durability and strong water absorption.

[0006] The highly water-absorbent polyacrylamide-based two-component polyurethane material and the preparation method thereof provided by the present invention include two components A and B, wherein component A includes:

[0007] 10-20 parts of polyacrylamide component;

[0008] 80-100 parts of modified isocyanate component;

[0009] Component B includes:

[0010] 80-100 parts of polyol component;

[0011] 5-20 parts of physical foaming agent;

[0012] The surfactant accounts for 2-3% of component B;

[0013] The pore opener accounts for 2-3% of the B component.

[0014] Preferably, the modified isocyanate in the A component is obtained by prepolymerization of a hydrophilic polyol and an isocyanate, wherein the hydrophilic polyol is at least one of polyethylene glycol 200, polyethylene glycol 40, and diethylene glycol; and the isocyanate is at least one of polymethylene polyphenyl isocyanate, modified diphenylmethane diisocyanate, and modified toluene diisocyanate.

[0015] Preferably, the polyols in the polyol component in the B component are polyether polyols and polyester polyols, wherein the polyether polyol is at least one of sucrose polyether polyols or sorbitol polyether polyols, and has a hydroxyl value of 150 to 700 mgKOH / g, and the polyester polyol is a polyester polyol produced by a condensation reaction of phthalic anhydride or phthalic acid and diethylene glycol, ethylene glycol or butanediol.

[0016] Preferably, the polyacrylamide is in powder form with a density of 1.32 g / cm 3 .

[0017] Preferably, the physical foaming agent in the B component is at least one of n-butane (boiling point -0.5°C), isobutane (boiling point -11.8°C), heptafluoropropane (boiling point -16.4°C), 1,-1-difluoroethane (boiling point -24.7°C), and dimethyl ether (boiling point -24.9°C), accounting for 5 to 20% of the total weight of the polyol component.

[0018] Preferably, the surfactant in the B component is a non-silicone surfactant, which may be at least one of LK221, LK443, and LK665, accounting for 2-3% of the total weight of the polyol component to ensure the uniformity and fineness of the pore structure.

[0019] Preferably, the cell opener in the B component is at least one of polyoxypropylene-oxyethylene copolyether and polyoxyalkylene-polysiloxane copolymer, accounting for 2-3% of the total weight of the polyol component.

[0020] The present invention provides a preparation method and application of a highly water-absorbent polyacrylamide-based two-component polyurethane material, which is applied to the preparation and application of the highly water-absorbent polyacrylamide-based two-component polyurethane material, and comprises the following steps:

[0021] Step 1: Heat the reactor to 40-50° C., add the polyol and isocyanate in the proportions described in claim 2 in sequence, and then heat the reactor to 78-82° C. and react for 1.5-2.5 hours.

[0022] Step 2: After cooling the modified isocyanate obtained in step 1, add polyacrylamide powder, stir for 20 minutes to mix evenly, so that the polyacrylamide powder is evenly dispersed in the isocyanate to form a liquid A component;

[0023] Step 3, prepare component B, add 80-100 parts of polyol component, 5-20 parts of physical foaming agent, 2-3% of surfactant in component B, and 2-3% of cell opener in component B;

[0024] Step 4: Detect the leakage site, arrange grouting holes according to the on-site detection results, mix component A and component B in a grouting machine, and use the reaction of isocyanate groups (-NCO) and hydroxyl groups (-OH) to embed highly absorbent polyacrylamide resin into the open-cell polyurethane foam to synthesize a grouting material with strong water absorption. The highly absorbent resin is then delivered to the service location using a grouting transportation method, which is convenient and quick.

[0025] Preferably, the stirring temperature in step 2 is room temperature, and the stirring time is not less than 20 min.

[0026] Preferably, the material is composed of open-cell foam, and the combination of the water absorption of the open-cell foam and the water absorption of the polyacrylamide powder makes the grouting material have super strong water absorption.

[0027] Compared with the related art, the highly water-absorbent polyacrylamide-based two-component polyurethane material and the preparation method thereof provided by the present invention have the following beneficial effects:

[0028] 1. The present invention uniformly embeds highly absorbent polyacrylamide powder into polyurethane open-cell foam, and combines the water absorption of polyurethane open-cell foam and highly absorbent polyacrylamide. The generated grouting material is a solid honeycomb structure with ultra-long and ultra-strong water absorption and dewatering effects. The moisture at the leakage site can be wrapped in the polyurethane foam, which can not only enhance the strength of the polyurethane foam, but also keep the leakage site dry, avoid the re-erosion of building materials by moisture, and avoid the re-occurrence of cracks, mildew spots, steel bar corrosion and other problems, which can further improve the repair and control effect of water leakage diseases in underground engineering structures.

[0029] 2. Polyacrylamide powder gives the material extremely strong water absorption, which can prevent the polyurethane material from reacting too much with water, causing the material volume to expand excessively and resulting in too low compressive strength of the foam.

[0030] 3. Improving the water absorption of polyurethane grouting materials is not only beneficial for it to absorb moisture from leakage defects, but also helps to enhance the bonding strength between the polyurethane material and the defective part, which can further improve the repair effect.

[0031] 4. Polyurethane materials will react and release heat during the curing process. Polyacrylamide powder gives the material strong water absorption, which can effectively reduce the formation of pores and channels caused by structural deformation and temperature difference, enhance the durability of the material, and reduce the possibility of repeated leakage. At the same time, it also effectively avoids the problem of yellowing and burning of the foam.

[0032] 5. Embed highly water-absorbent polyacrylamide in polyurethane foam. Polyacrylamide can absorb dozens to thousands of times its own water, which can effectively improve the overall flame retardant properties of the material.

[0033] 6. The urban ground environment is complex and often does not have the conditions for pipeline excavation and maintenance. Most of the current trenchless repairs abroad involve replacing the entire pipeline, which is costly and has high requirements for the pipeline construction environment. This project has developed an environmentally friendly, early-strengthening, corrosion-resistant, and highly water-absorbent polyacrylamide-based two-component polyurethane grouting material. The construction process is convenient and fast, which can not only quickly realize road grouting repairs, but also effectively solve the foundation degassing and loosening problems caused by leakage in tunnels, basements, and underground pipeline projects.

[0034] 7. During grouting, the isocyanate component and the polyol component react rapidly to form a high-strength polymer skeleton in a short period of time. The highly absorbent resin is evenly embedded in the high-strength polymer skeleton, which effectively makes up for the lack of strength and poor durability of general highly absorbent resins. While ensuring the water absorption and dehydration effect, it can also provide support for the repair site and improve the stability of the repair structure. DETAILED DESCRIPTION

[0035] The specific implementation of the present invention is given below to further illustrate the present invention. Obviously, the examples described below are part of the embodiments of the present invention, rather than 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.

[0036] Embodiment 1:

[0037] The highly water-absorbent polyacrylamide-based two-component polyurethane material provided by the present invention comprises the following components:

[0038] Polyol components:

[0039] Table 1-1 Mass fraction of each component of polyol

[0040]

[0041]

[0042] Isocyanate component:

[0043] Polymethylene polyphenyl isocyanate PM-200, 90 parts by mass.

[0044] Polyacrylamide:

[0045] Polyacrylamide powder, 10 parts by mass.

[0046] The preparation method and application of the highly water-absorbent polyacrylamide-based two-component polyurethane material provided by the present invention include the following steps:

[0047] Putting polymethylene polyphenyl isocyanate and polyacrylamide particles in a magnetic stirrer and stirring for more than 20 minutes to make the polyacrylamide powder evenly dispersed in the polymethylene polyphenyl isocyanate, thus obtaining an isocyanate component containing polyacrylamide;

[0048] Putting the raw materials contained in the polyol component in a magnetic stirrer and stirring evenly to obtain the polyol component;

[0049] The prepared isocyanate component containing polyacrylamide and the polyol component are mixed and grouting is performed using a high-pressure grouting machine. After the slurry solidifies, the mechanical properties and water absorption properties of the material are tested. Various physical properties are shown in Table 1-2:

[0050] Table 1-2 Various physical properties

[0051]

[0052]

[0053] Embodiment 2:

[0054] The highly water-absorbent polyacrylamide-based two-component polyurethane material provided by the present invention comprises the following components:

[0055] Polyol components:

[0056] Table 2-1 Mass fraction of each component of polyol

[0057]

[0058] Isocyanate component:

[0059] Diphenylmethane diisocyanate, 90 parts by mass.

[0060] Polyacrylamide:

[0061] Polyacrylamide powder, 10 parts by mass

[0062] The preparation method and application of the highly water-absorbent polyacrylamide-based two-component polyurethane material provided by the present invention include the following steps:

[0063] Place diphenylmethane diisocyanate and polyacrylamide powder in a magnetic stirrer and stir for more than 20 minutes to evenly disperse the polyacrylamide powder in the diphenylmethane diisocyanate to obtain an isocyanate component containing polyacrylamide;

[0064] Putting the raw materials contained in the polyol component in a magnetic stirrer and stirring evenly to obtain the polyol component;

[0065] The prepared isocyanate component containing polyacrylamide and the polyol component are mixed and grouting is performed using a high-pressure grouting machine. After the slurry solidifies, the mechanical properties and water absorption properties of the material are tested. Various physical properties are shown in Table 2-2:

[0066] Table 2-2 Various physical properties

[0067] Physical properties unit Test Results Test Standards Solidification time s 9.5 Visual inspection Appearance - Uniform light yellow solid Visual inspection density <![CDATA[Kg / m 3 ]]> 145 GB / T6343-2009 Compressive strength MPa 1.45 GB / T8813-2009 Water absorption g / g 559.6 GB / T1034-2008

[0068] Embodiment 3:

[0069] The highly water-absorbent polyacrylamide-based two-component polyurethane material provided by the present invention comprises the following components:

[0070] Polyol components:

[0071] Table 3-1 Mass fraction of each component of polyol

[0072]

[0073]

[0074] Isocyanate component:

[0075] Polymethylene polyphenyl isocyanate PM-200, 90 parts by mass.

[0076] Polyacrylamide:

[0077] Polyacrylamide powder, 20 parts by mass

[0078] The preparation method and application of the highly water-absorbent polyacrylamide-based two-component polyurethane material provided by the present invention include the following steps:

[0079] Putting polymethylene polyphenyl isocyanate and polyacrylamide powder in a magnetic stirrer and stirring for more than 20 minutes to make the polyacrylamide powder evenly dispersed in the polymethylene polyphenyl isocyanate, thus obtaining an isocyanate component containing polyacrylamide;

[0080] Putting the raw materials contained in the polyol component in a magnetic stirrer and stirring evenly to obtain the polyol component;

[0081] The prepared isocyanate component containing polyacrylamide and the polyol component are mixed and grouting is performed using a high-pressure grouting machine. After the slurry solidifies, the mechanical properties and water absorption properties of the material are tested. Various physical properties are shown in Table 3-2:

[0082] Table 3-2 Various physical properties

[0083] Physical properties unit Test Results Test Standards Solidification time s 9 Visual inspection Appearance - Uniform light yellow solid Visual inspection density <![CDATA[Kg / m 3 ]]> 186 GB / T6343-2009 Compressive strength MPa 1.62 GB / T8813-2009 Water absorption g / g 591.3 GB / T1034-2008

[0084] Embodiment 4:

[0085] The highly water-absorbent polyacrylamide-based two-component polyurethane material provided by the present invention comprises the following components:

[0086] Polyol components:

[0087] Table 4-1 Mass fraction of each component of polyol

[0088]

[0089] Isocyanate component:

[0090] Diphenylmethane diisocyanate, 90 parts by mass.

[0091] Polyacrylamide:

[0092] Polyacrylamide powder, 20 parts by mass

[0093] Production steps:

[0094] Place diphenylmethane diisocyanate and polyacrylamide powder in a magnetic stirrer and stir for more than 20 minutes to evenly disperse the polyacrylamide powder in the diphenylmethane diisocyanate to obtain an isocyanate component containing polyacrylamide;

[0095] Putting the raw materials contained in the polyol component in a magnetic stirrer and stirring evenly to obtain the polyol component;

[0096] The prepared isocyanate component containing polyacrylamide and the polyol component are mixed and grouting is performed using a high-pressure grouting machine. After the slurry solidifies, the mechanical properties and water absorption properties of the material are tested. Various physical properties are shown in Table 4-2:

[0097] Table 4-2 Various physical properties

[0098] Physical properties unit Test Results Test Standards Solidification time s 9.5 Visual inspection Appearance - Uniform light yellow solid Visual inspection density <![CDATA[Kg / m 3 ]]> 215 GB / T6343-2009 Compressive strength MPa 1.54 GB / T8813-2009 Water absorption g / g 582.4 GB / T1034-2008

[0099] Compared with the related art, the highly water-absorbent polyacrylamide-based two-component polyurethane material and the preparation method thereof provided by the present invention have the following beneficial effects:

[0100] The present invention provides a highly absorbent polyacrylamide-based two-component polyurethane material and a preparation method thereof, by wrapping a highly absorbent polyacrylamide component in a polyurethane material, and constructing by grouting, the construction process is simple and convenient, the material can be quickly infiltrated into the depth of the crack, and has the advantages of being fast, environmentally friendly, durable, slightly damaged, highly absorbent, and having good adhesion. The present invention uniformly embeds highly absorbent polyacrylamide powder in polyurethane open-cell foam, retaining the advantages of good expansibility, high early strength, strong adhesion, fast curing speed, good durability, and simple grouting operation of polyurethane materials, and giving the material extremely high water absorption performance, effectively avoiding the problems of yellowing and burning of the material core, and can effectively enhance the bonding strength, foam structural strength, flame retardant and other properties of the material, and prevent foam shrinkage. At the same time, the presence of highly absorbent resin in the material can quickly absorb the moisture at the leakage disease, enhance the bonding strength of the polyurethane material and the disease, and further improve the repair effect.

[0101] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A highly water-absorbent polyacrylamide-based two-component polyurethane material, characterized in that: It includes two components, A and B, of which component A includes: 10-20 parts of polyacrylamide component; 80-100 parts of modified isocyanate component; Component B includes: 80-100 parts of polyol component; 5-20 parts of physical foaming agent; The surfactant accounts for 2-3% of component B; The pore opener accounts for 2-3% of the B component.

2. The highly water-absorbent polyacrylamide-based two-component polyurethane material according to claim 1, characterized in that: The modified isocyanate in the A component is obtained by prepolymerization of a hydrophilic polyol and an isocyanate, wherein the hydrophilic polyol is at least one of polyethylene glycol 200, polyethylene glycol 40, and diethylene glycol; and the isocyanate is at least one of polymethylene polyphenyl isocyanate, modified diphenylmethane diisocyanate, and modified toluene diisocyanate.

3. The highly water-absorbent polyacrylamide-based two-component polyurethane material according to claim 1, characterized in that: The polyols in the polyol component in the B component are polyether polyols and polyester polyols, wherein the polyether polyol is at least one of sucrose polyether polyols or sorbitol polyether polyols, and the hydroxyl value is 150-700 mgKOH / g, and the polyester polyol is a polyester polyol produced by a condensation reaction of phthalic anhydride or phthalic acid and diethylene glycol, ethylene glycol or butanediol.

4. The highly water-absorbent polyacrylamide-based two-component polyurethane material according to claim 1, characterized in that: The polyacrylamide is in powder form with a density of 1.32 g / cm 3 .

5. The highly water-absorbent polyacrylamide-based two-component polyurethane material according to claim 1, characterized in that: The physical foaming agent in the B component is at least one of n-butane, isobutane, heptafluoropropane, 1,-1-difluoroethane and dimethyl ether, accounting for 5-20% of the total weight of the polyol component.

6. The highly water-absorbent polyacrylamide-based two-component polyurethane material according to claim 1, characterized in that: The surfactant in the B component is a non-silicone surfactant, which may be at least one of LK221, LK443, and LK665, accounting for 2-3% of the total weight of the polyol component.

7. The highly water-absorbent polyacrylamide-based two-component polyurethane material and the preparation method thereof according to claim 1, characterized in that: The cell opener in the B component is at least one of polyoxypropylene-oxyethylene copolyether and polyoxyolefin-polysiloxane copolymer, accounting for 2-3% of the total weight of the polyol component.

8. A method for preparing a highly water-absorbent polyacrylamide-based two-component polyurethane material and its application, which is applied to the preparation and application of the highly water-absorbent polyacrylamide-based two-component polyurethane material according to claims 1-7, characterized in that: The following steps are involved: Step 1: Heat the reactor to 40-50° C., add the polyol and isocyanate in the proportions described in claim 2 in sequence, and then heat the reactor to 78-82° C. and react for 1.5-2.5 hours. Step 2: After cooling the modified isocyanate obtained in step 1, add polyacrylamide powder, stir for 20 minutes to mix evenly, so that the polyacrylamide powder is evenly dispersed in the isocyanate to form a liquid A component; Step 3, prepare component B, add 80-100 parts of polyol component, 5-20 parts of physical foaming agent, 2-3% of surfactant in component B, and 2-3% of cell opener in component B; Step 4: Detect the leakage site, arrange grouting holes according to the on-site detection results, mix component A and component B in a grouting machine, and use the reaction of isocyanate groups (-NCO) and hydroxyl groups (-OH) to embed highly absorbent polyacrylamide resin into the open-cell polyurethane foam to synthesize a grouting material with strong water absorption. The highly absorbent resin is then delivered to the service location using a grouting transportation method, which is convenient and quick.

9. The preparation method and application of the highly water-absorbent polyacrylamide-based two-component polyurethane material according to claim 8, characterized in that: The stirring temperature in the step 2 is room temperature, and the stirring time is not less than 20 min.

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