A frost resistant polyurethane sealant for low temperature areas and method of use

Abstract

The application discloses a kind of anti-freezing polyurethane sealant special for low temperature area, it includes following weight parts of each component: polypropylene glycol 25-35 parts, polypropylene glycol 15-25 parts, hexamethylene diisocyanate 10-15 parts, phenyl methyl phenyl phosphate 15-20 parts, filler 10-14 parts, curing agent 1.5-2.5 parts, catalyst 1-3 parts, tetrafluoroethanol 4-8 parts, 2-isopropyl-3-oxazolidine ethanol 1.5-2 parts, air entraining agent 6-8 parts and aluminium hydroxide modified nano calcium carbonate 2-3.5 parts.The application has the advantages that the anti-freezing performance is good, and the bonding strength is high.The phenyl methyl phenyl phosphate is used as plasticizer, which improves the low temperature resistance and saponification resistance of polyurethane adhesive product.The addition of air entraining agent can improve the flowability and cohesiveness of sealant, and tetrafluoroethanol is used for sealant with high anti-freezing requirement, which can significantly improve the low temperature resistance and anti-freezing performance of sealing material.

Description

Technical Field

[0001] This invention relates to the field of polyurethane sealant technology, and in particular to an antifreeze polyurethane sealant specifically for low-temperature regions and its application method. Background Technology

[0002] Polyurethane sealant is a type of sealant primarily composed of polyurethane rubber and polyurethane prepolymer. This type of sealant possesses high tensile strength, excellent elasticity, abrasion resistance, oil resistance, and cold resistance. Polyurethane sealant is widely used in buildings, plazas, and highways as a caulking and sealing material, as well as in automobile manufacturing, glass installation, and electronic filling. In some special operating environments, polyurethane sealant requires specific performance characteristics, such as low-temperature resistance and freeze-thaw resistance. While polyurethane sealant is typically not used in extremely low temperatures, winter temperatures can drop to around -20 to -30 degrees Celsius. This necessitates that polyurethane sealant used as a caulking and sealing material exhibit good low-temperature freeze-thaw resistance, meaning it can still perform normally as a caulking and sealing material in low-temperature environments. A polyurethane sealant, authorized by publication number CN110684501, uses alkyl sulfonate plasticizer (mesamoll) to replace the phthalic acid plasticizer in existing polyurethane or silane-modified sealants, significantly improving the weather resistance, saponification resistance, and migration and exudation resistance of the polyurethane sealant product. However, it does not have good freeze-thaw resistance for winter temperatures around -20 to -30 degrees Celsius. Existing ordinary polyurethane sealants have poor low-temperature resistance, thus limiting their application in low-temperature environments. Summary of the Invention

[0003] The purpose of this invention is to provide an antifreeze polyurethane sealant specifically for low-temperature regions and its application method, addressing the aforementioned deficiencies.

[0004] An antifreeze polyurethane sealant specifically for low-temperature regions, comprising the following components in parts by weight:

[0005] 25-35 parts of polypropylene glycol

[0006] 15-25 parts of polypropylene glycol

[0007] 10-15 parts of hexamethylene diisocyanate

[0008] 15-20 parts of phenyl methyl phenyl phosphate

[0009] 10-14 parts of filler

[0010] 1.5-2.5 parts of curing agent

[0011] 1-3 parts catalyst

[0012] 4-8 parts of tetrafluoroethanol

[0013] 1.5-2 parts of 2-isopropyl-3-oxazolidineethanol

[0014] 6-8 parts of entraining agent

[0015] 2-3.5 parts of aluminum hydroxide-modified nano-calcium carbonate.

[0016] Preferably, it comprises the following components in parts by weight:

[0017] 30 parts of polypropylene glycol

[0018] 20 parts of polypropylene glycol

[0019] 12 parts hexamethylene diisocyanate

[0020] 18 parts of phenyl methyl phenyl phosphate

[0021] 12 parts of filler

[0022] 2 parts of curing agent

[0023] 2 parts catalyst

[0024] 6 parts of tetrafluoroethanol

[0025] 1.8 parts of 2-isopropyl-3-oxazolidineethanol

[0026] 7 parts of entraining agent

[0027] 3.2 parts of aluminum hydroxide-modified nano-calcium carbonate.

[0028] Preferably, the method of using aluminum hydroxide modified nano-calcium carbonate is as follows: prepare a suspension of nano-calcium carbonate with a volume fraction of 0.5-0.8%, then add sodium hydroxide to control the pH value of the suspension between 8 and 9, then add aluminum chloride solution dropwise and stir. After the reaction is completed, centrifuge, wash with water and alcohol, and dry to obtain aluminum hydroxide modified nano-calcium carbonate.

[0029] Preferably, the filler is one or a mixture of heavy calcium carbonate, light calcium carbonate, kaolin, or talc.

[0030] Preferably, the filler is rigid polyurethane foam powder, which is obtained by crushing and pulverizing waste rigid polyurethane foam.

[0031] Preferably, the curing agent is one or a mixture of two of 4,4′-bis-sec-butylaminodiphenylmethane and 1,4-bis-sec-butylaminobenzene.

[0032] Preferably, the air-entraining agent is a triterpenoid saponin air-entraining agent.

[0033] A method for using an antifreeze polyurethane sealant specifically designed for low-temperature regions includes the following steps:

[0034] The above-mentioned parts by weight of polypropylene glycol, polypropylene glycol, hexamethylene diisocyanate, and phenyl methyl phenyl phosphate are added sequentially to a mixer and stirred for 10-30 minutes at room temperature under a vacuum of no more than -0.08 MPa, and then the pressure is released to atmospheric pressure. Then, the above-mentioned parts by weight of filler, curing agent, catalyst, tetrafluoroethanol, 2-isopropyl-3-oxazolidineethanol, air-entraining agent, and aluminum hydroxide-modified nano-calcium carbonate are added, and the mixture is stirred thoroughly at 60-70℃ for 4-6 hours. The mixture is then degassed using a negative pressure device and then embedded into the building cracks to be repaired, and cured into a gel-like elastomer.

[0035] The advantages of this invention are: good antifreeze performance and high bonding strength. Phenylmethylphenyl phosphate, as a plasticizer, replaces commonly used phthalic acid plasticizers, improving the low-temperature resistance and saponification resistance of polyurethane adhesives. The addition of an air-entraining agent improves the flowability and cohesiveness of the sealant. Combined with tetrafluoroethanol for sealants requiring high antifreeze properties, it significantly improves the low-temperature antifreeze performance of the sealing material, making it particularly suitable for use in large-area, easily frozen cracks in concrete dams, roads, bridge decks, airport runways, and other applications. Aluminum hydroxide-modified nano-calcium carbonate, due to the outer aluminum hydroxide film, prevents the combination of electrons and holes with water and oxygen, thereby reducing the photochemical properties of the sealant, improving the product's weather resistance, and further enhancing the sealant's low-temperature antifreeze performance. Implementation

[0036] The following will describe preferred embodiments of the invention in detail. These embodiments are provided to better illustrate the invention and are not intended to limit the invention to these examples. Non-essential improvements and adjustments to the embodiments based on the invention's description still fall within the scope of the invention.

[0037] <Example 1>

[0038] An antifreeze polyurethane sealant specifically for low-temperature regions, comprising the following components in parts by weight:

[0039] 25 parts of polypropylene glycol

[0040] 15 parts of polypropylene glycol

[0041] 10 parts hexamethylene diisocyanate

[0042] 15 parts of phenyl methyl phenyl phosphate

[0043] 10 parts of filler

[0044] 1.5 parts of curing agent

[0045] 1 part catalyst

[0046] Four parts of tetrafluoroethanol

[0047] 1.5 parts of 2-isopropyl-3-oxazolidine ethanol

[0048] 6 parts of entraining agent

[0049] Two parts of aluminum hydroxide-modified nano-calcium carbonate.

[0050] The method of using aluminum hydroxide modified nano-calcium carbonate is as follows: prepare a suspension of nano-calcium carbonate with a volume fraction of 0.5%, then add sodium hydroxide to control the pH value of the suspension between 8 and 9, then add aluminum chloride solution dropwise and stir. After the reaction is completed, separate by centrifugation, wash with water and alcohol, and dry to obtain aluminum hydroxide modified nano-calcium carbonate.

[0051] The filler is heavy calcium carbonate powder.

[0052] The curing agent is 4,4′-bis-sec-butylaminodiphenylmethane.

[0053] The air-entraining agent is a triterpenoid saponin air-entraining agent.

[0054] A method for using an antifreeze polyurethane sealant specifically designed for low-temperature regions includes the following steps:

[0055] The above-mentioned parts by weight of polypropylene glycol, polypropylene glycol, hexamethylene diisocyanate, and phenyl methyl phenyl phosphate were sequentially added to a mixer and stirred for 10 minutes at room temperature under a vacuum of no more than -0.08 MPa. The pressure was then released to atmospheric pressure. Then, the above-mentioned parts by weight of filler, curing agent, tetrafluoroethanol, 2-isopropyl-3-oxazolidineethanol, air-entraining agent, and aluminum hydroxide-modified nano-calcium carbonate were added. The mixture was stirred thoroughly at 60°C for 4 hours. The mixture was then degassed using a negative pressure device and then embedded into the building cracks to be repaired, and cured into a gel-like elastomer.

[0056] <Example 2>

[0057] An antifreeze polyurethane sealant specifically for low-temperature regions, comprising the following components in parts by weight:

[0058] 35 parts of polypropylene glycol

[0059] 25 parts of polypropylene glycol

[0060] 15 parts hexamethylene diisocyanate

[0061] 20 parts of phenyl methyl phenyl phosphate

[0062] 14 parts of filler

[0063] 2.5 parts of curing agent

[0064] 3 parts catalyst

[0065] 8 parts of tetrafluoroethanol

[0066] 2 parts of 2-isopropyl-3-oxazolidine ethanol

[0067] 8 parts of entraining agent

[0068] 3.5 parts of aluminum hydroxide-modified nano-calcium carbonate.

[0069] The method of using aluminum hydroxide modified nano-calcium carbonate is as follows: prepare a suspension of nano-calcium carbonate with a volume fraction of 0.8%, then add sodium hydroxide to control the pH value of the suspension between 8 and 9, then add aluminum chloride solution dropwise and stir. After the reaction is completed, separate by centrifugation, wash with water and alcohol, and dry to obtain aluminum hydroxide modified nano-calcium carbonate.

[0070] The filler is talc.

[0071] The curing agent is 4,4′-bis-sec-butylaminodiphenylmethane.

[0072] The air-entraining agent is a triterpenoid saponin air-entraining agent.

[0073] A method for using an antifreeze polyurethane sealant specifically designed for low-temperature regions includes the following steps:

[0074] The above-mentioned parts by weight of polypropylene glycol, polypropylene glycol, hexamethylene diisocyanate, and phenyl methyl phenyl phosphate were sequentially added to a mixer and stirred for 30 minutes at room temperature under a vacuum of no more than -0.08 MPa. The pressure was then released to atmospheric pressure. Then, the above-mentioned parts by weight of filler, curing agent, catalyst, tetrafluoroethanol, 2-isopropyl-3-oxazolidineethanol, air-entraining agent, and aluminum hydroxide-modified nano-calcium carbonate were added. The mixture was then stirred thoroughly at 60°C for 6 hours. The mixture was then degassed using a negative pressure device and then embedded into the building cracks to be repaired, and cured into a gel-like elastomer.

[0075] <Example 3>

[0076] An antifreeze polyurethane sealant specifically for low-temperature regions, comprising the following components in parts by weight:

[0077] 30 parts of polypropylene glycol

[0078] 20 parts of polypropylene glycol

[0079] 12 parts hexamethylene diisocyanate

[0080] 18 parts of phenyl methyl phenyl phosphate

[0081] 12 parts of filler

[0082] 2 parts of curing agent

[0083] 2 parts catalyst

[0084] 6 parts of tetrafluoroethanol

[0085] 1.8 parts of 2-isopropyl-3-oxazolidineethanol

[0086] 7 parts of entraining agent

[0087] 3.2 parts of aluminum hydroxide-modified nano-calcium carbonate.

[0088] The method of using aluminum hydroxide modified nano-calcium carbonate is as follows: prepare a suspension of nano-calcium carbonate with a volume fraction of 0.6%, then add sodium hydroxide to control the pH value of the suspension between 8 and 9, then add aluminum chloride solution dropwise and stir. After the reaction is completed, centrifuge, wash with water and alcohol, and dry to obtain aluminum hydroxide modified nano-calcium carbonate.

[0089] The filler is rigid polyurethane foam powder, which is obtained by crushing and pulverizing waste rigid polyurethane foam.

[0090] The curing agent is a mixture of 4,4′-bis-sec-butylaminodiphenylmethane and 1,4-bis-sec-butylaminobenzene.

[0091] The air-entraining agent is a triterpenoid saponin air-entraining agent.

[0092] A method for using an antifreeze polyurethane sealant specifically designed for low-temperature regions includes the following steps:

[0093] The above-mentioned parts by weight of polypropylene glycol, polypropylene glycol, hexamethylene diisocyanate, and phenyl methyl phenyl phosphate were sequentially added to a mixer and stirred for 20 minutes at room temperature under a vacuum of no more than -0.08 MPa. The pressure was then released to atmospheric pressure. Then, the above-mentioned parts by weight of filler, curing agent, catalyst, tetrafluoroethanol, 2-isopropyl-3-oxazolidineethanol, air-entraining agent, and aluminum hydroxide-modified nano-calcium carbonate were added. The mixture was stirred thoroughly at 65°C for 5 hours. The mixture was then degassed using a negative pressure device and then embedded into the building cracks to be repaired, and cured into a gel-like elastomer.

[0094] <Comparative Example 1>

[0095] The commercially available polyurethane sealant was purchased from Hengshui Hongji Rubber & Plastic Co., Ltd.

[0096] <Comparative Example 2>

[0097] The flexible sealing material obtained does not contain air-entraining agents or aluminum hydroxide-modified nano-calcium carbonate, and all other components are the same as in Example 3 and are used in the same way.

[0098] <Detection Experiment>

[0099] The comprehensive performance tests of the sealing materials prepared by this method are shown in the table below. The test data for each embodiment and comparative example are compared.

[0100]

[0101]

[0102] The antifreeze multi-component polyurethane sealant of this invention exhibits excellent antifreeze properties and high adhesive strength. Phenylmethylphenyl phosphate, as a plasticizer, replaces commonly used phthalic acid plasticizers, improving the low-temperature resistance and saponification resistance of the polyurethane sealant. The addition of an air-entraining agent improves the sealant's flowability and cohesiveness. When used in conjunction with aluminum hydroxide-modified nano-calcium carbonate, it significantly enhances the low-temperature antifreeze performance of sealant materials, especially suitable for use in large-area, easily frozen cracks in concrete dams, roads, bridge decks, airport runways, and other applications. The aluminum hydroxide-modified nano-calcium carbonate, due to the outer aluminum hydroxide film, prevents the combination of electrons and holes with water and oxygen, thereby reducing the photochemical properties of the sealant, improving its weather resistance, and further enhancing its low-temperature antifreeze performance.

[0103] The above embodiments are only for illustrating the technical solutions and features of the present invention, and are intended to enable those skilled in the art to implement them better. They should not be used to limit the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention are within the scope of protection of the present invention. The parts not described in detail are prior art.

Claims

1. A freeze-resistant polyurethane sealant specifically for low-temperature regions, characterized in that... It comprises the following components in parts by weight: 25-35 parts of polypropylene glycol 15-25 parts of polypropylene glycol 10-15 parts of hexamethylene diisocyanate 15-20 parts of phenyl methyl phenyl phosphate 10-14 parts of filler 1.5-2.5 parts of curing agent 1-3 parts catalyst 4-8 parts of tetrafluoroethanol 1.5-2 parts of 2-isopropyl-3-oxazolidineethanol 6-8 parts of entraining agent 2-3.5 parts of aluminum hydroxide-modified nano-calcium carbonate; The preparation method of aluminum hydroxide modified nano-calcium carbonate is as follows: prepare a suspension of nano-calcium carbonate with a volume fraction of 0.5-0.8%, then add sodium hydroxide to control the pH value of the suspension between 8 and 9, then add aluminum chloride solution dropwise and stir. After the reaction is completed, centrifuge, wash with water and alcohol, and dry to obtain aluminum hydroxide modified nano-calcium carbonate. The air-entraining agent is a triterpenoid saponin air-entraining agent.

2. The antifreeze polyurethane sealant for low-temperature regions according to claim 1, characterized in that... It comprises the following components in parts by weight: 30 parts of polypropylene glycol 20 parts of polypropylene glycol 12 parts hexamethylene diisocyanate 18 parts of phenyl methyl phenyl phosphate 12 parts of filler 2 parts of curing agent 2 parts catalyst 6 parts of tetrafluoroethanol 1.8 parts of 2-isopropyl-3-oxazolidineethanol 7 parts of entraining agent 3.2 parts of aluminum hydroxide-modified nano-calcium carbonate.

3. The antifreeze polyurethane sealant for low-temperature regions according to claim 1, characterized in that... The filler is one or more of heavy calcium carbonate, light calcium carbonate, kaolin, or talc.

4. The antifreeze polyurethane sealant for low-temperature regions according to claim 1, characterized in that... The filler is rigid polyurethane foam powder, which is obtained by crushing and pulverizing waste rigid polyurethane foam.

5. The antifreeze polyurethane sealant for low-temperature regions according to claim 1, characterized in that... The curing agent is one or a mixture of two of 4,4′-bis-sec-butylaminodiphenylmethane and 1,4-bis-sec-butylaminobenzene.

6. The method of using the antifreeze polyurethane sealant for low-temperature areas according to claim 1, characterized in that... Includes the following steps: The above-mentioned parts by weight of polypropylene glycol, polypropylene glycol, hexamethylene diisocyanate, and phenyl methyl phenyl phosphate are added sequentially to a mixer and stirred for 10-30 minutes at room temperature under a vacuum of no more than -0.08 MPa, and then the pressure is released to atmospheric pressure. Then, the above-mentioned parts by weight of filler, curing agent, catalyst, tetrafluoroethanol, 2-isopropyl-3-oxazolidineethanol, air-entraining agent, and aluminum hydroxide-modified nano-calcium carbonate are added, and the mixture is stirred thoroughly at 60-70℃ for 4-6 hours. The mixture is then degassed using a negative pressure device and then embedded into the building cracks to be repaired, and cured into a gel-like elastomer.

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