Modified polycaprolactone polyols, methods of making and using the same

Abstract

The application discloses a modified polycaprolactone polyol, a preparation method and application thereof. The modified polycaprolactone polyol is formed by ester exchange polymerization reaction of polycarbonate diol as a starting agent and caprolactone under a catalyst and high temperature. The preparation method comprises the following steps: blending and dehydrating the polycarbonate diol and the caprolactone, then adding a catalyst and an antioxidant, and performing polymerization reaction by heating to obtain the modified polycaprolactone polyol. The application also provides application of the modified polycaprolactone polyol in sealing paint. The sealing paint provided by the application has a block structure, and has flexibility and strength, and has excellent gamma ray irradiation resistance, hydrolysis resistance and shielding and blocking performance, and can keep the paint film complete and air-tight in the case that the base material is deformed and cracked.

Description

TECHNICAL FIELD

[0001] The present application relates to a modified polycaprolactone polyol, a preparation method thereof, and an application thereof in sealing coatings, and belongs to the technical field of coatings. BACKGROUND

[0002] At present, the containment structure of Hualong type adopts the cooperation of concrete containment and steel lining to realize sealing. However, the assembly and construction of the steel lining material have problems such as large welding workload, high difficulty of non-destructive testing, and complex operation environment, which are major constraints of construction progress, quality and cost. Due to the porous nature of concrete itself, cracking may occur during use, resulting in a decrease in air tightness. The concrete of the containment without steel lining is difficult to meet the sealing performance of the containment structure. A special coating system can be brushed on the surface of the concrete to realize the sealing performance of the containment together with the concrete containment. The optimization of the technical scheme can realize the sealing function of the containment by replacing the steel lining with a special coating to meet the requirements of the containment leakage rate, thereby reducing the cost, shortening the construction period, and improving the construction convenience. The traditional epoxy has a large rigidity, and with the increase of the use time, cracking may occur at the joint, resulting in leakage, and the air tightness continuously decreases with the increase of the use time. Therefore, the coating needs to have sufficient elasticity to ensure that the air tightness of the coating is not damaged when the concrete cracks. In addition, the coating needs to have good radiation resistance and aging resistance to ensure the sealing performance during the service life of the nuclear power plant.

[0003] Although the traditional elastic polyurethane coating has a certain elasticity, a large number of urethane bonds exist in the molecular chain, and the urethane bonds are prone to hydrolysis under the conditions of high temperature and high humidity in the nuclear accident, resulting in a decrease in the strength of the coating and even cracking. Therefore, a material is urgently needed to have sufficient strength and elongation to ensure the air tightness of the paint film when the substrate deforms or cracks, and to have radiation resistance and hydrolysis resistance to ensure the sealing performance of the coating under normal use and under the conditions of high temperature and high humidity in the accident. SUMMARY

[0004] The main purpose of the present application is to provide a modified polycaprolactone polyol and a preparation method thereof to overcome the deficiencies of the prior art.

[0005] Another purpose of the present application is to provide an application of the modified polycaprolactone polyol in sealing coatings.

[0006] To achieve the above-mentioned purposes, the technical scheme adopted by the present application comprises:

[0007] The modified polycaprolactone polyol provided by the embodiments of the present application is formed by ester exchange polymerization reaction of polycarbonate diol as a starter and caprolactone under the action of a catalyst and at high temperature.

[0008] The application also provides a preparation method of the modified polycaprolactone polyol, which comprises the following steps:

[0009] S1. A mixture of polycarbonate diol and caprolactone is blended and dehydrated under the protection of nitrogen to form a mixed reaction system;

[0010] S2. A catalyst and an antioxidant are added into the mixed reaction system, and after uniform stirring, a polymerization reaction is carried out under heating to obtain the modified polycaprolactone polyol.

[0011] The application also provides an application of the modified polycaprolactone polyol in a sealing coating.

[0012] Correspondingly, the application also provides an elastic polyurethane sealing coating, which comprises the modified polycaprolactone polyol, a reaction-type phosphate ester flame retardant, reinforcing fibers, boron nitride, an amine chain extender, an auxiliary agent, a filler, a plasticizer and a curing agent.

[0013] The application also provides a sealing coating layer formed by curing the elastic polyurethane sealing coating.

[0014] Compared with the prior art, the application has at least the following technical effects:

[0015] 1) The modified polycaprolactone polyol provided by the application is modified by using polycarbonate diol as a starting agent and caprolactone, wherein the caprolactone has good flexibility, elasticity and mechanical strength; the polycarbonate structure is relatively complex and stable, the bond energy of the carbonate ester bond is relatively high, and the regularity and steric hindrance of the molecular chain make it difficult for water molecules to attack, thereby improving the hydrolysis resistance and thermal stability of the coating and further improving the mechanical properties;

[0016] 2) The carbonized diimide is added to the main agent of the sealing coating, and the carbonized diimide modified MDI is contained in the curing agent, which plays a role in resisting hydrolysis and radiation decomposition in the coating. In polyurethane, there are ester bonds and urethane bonds that are prone to hydrolysis. In a humid environment or high-temperature conditions, these bonds are prone to react with water, resulting in a decrease in the performance of polyurethane. The functional groups in the carbonized diimide can react with the carboxyl groups generated by hydrolysis to form stable ureide structures, thereby preventing the carboxyl groups from further catalyzing the hydrolysis reaction, effectively improving the hydrolysis resistance and stability of the polyurethane. In addition, improving the stability of the molecular structure also improves the radiation resistance of the coating, greatly reducing the decrease in the tensile strength of the coating after radiation.

[0017] In addition, the carbonized diimide can also participate in some crosslinking reactions, enhance the network structure of the polyurethane, and further improve its physical properties.

[0018] 3) The reaction type phosphate ester flame retardant in the sealing paint provided by the present application is crosslinked with the curing agent to form a film, unlike the non-reaction type flame retardant which will migrate from the coating and cause the problem of free coating film with the increase of service life, reducing the flame retardancy and the film density. The coating layer of the paint has durable flame retardancy, and still has strong flame propagation resistance and air tightness after irradiation. Moreover, the sealing paint has a block structure, and has flexibility and strength, and has excellent resistance to gamma ray irradiation and shielding and blocking performance, and can keep the film complete and air tightness in the case of deformation and cracking of the base material. DETAILED DESCRIPTION

[0019] In view of the poor hydrolysis stability of the polyurethane elastomer in the prior art, the present inventors have long-term researched and proposed the technical concept of the present application, which mainly provides a preparation method of modified polycaprolactone polyol and application thereof in containment sealing paint of nuclear power plant, so as to optimize the technical improvement of high-temperature hydrolysis resistance of the product.

[0020] The technical scheme, implementation process and principles thereof will be further explained and described as follows.

[0021] As an aspect of the technical scheme of the present application, the modified polycaprolactone polyol is formed by ester exchange polymerization of polycarbonate diol as a starter and caprolactone under the action of a catalyst and at high temperature.

[0022] In some specific embodiments, the structural formula of the modified polycaprolactone polyol is shown as formula (I):

[0023]

[0024] In formula (I), R includes a polyalkylene group or a bisphenol A group, a is 2-10, b is 2-8, and c is 2-10.

[0025] Further, the weight average molecular weight of the modified polycaprolactone polyol is 2000-2400.

[0026] In summary, the modified polycaprolactone polyol provided by the present application is formed by ester exchange polycondensation of polycarbonate diol as a starter and caprolactone, wherein the polycaprolactone has good flexibility, elasticity and mechanical strength, the polytetrahydrofuran provides excellent fatigue resistance, wear resistance, chemical stability, water resistance and the like. The polycarbonate improves the hydrolysis resistance and thermal stability of the resin and further improves the mechanical properties.

[0027] As another aspect of the technical scheme of the present application, the preparation method of the modified polycaprolactone polyol comprises the following steps:

[0028] The polycarbonate diol and caprolactone are blended and dehydrated to form a mixed reaction system, then a catalyst and an antioxidant are added, and the temperature is raised to perform a transesterification polymerization reaction to obtain the modified polycaprolactone polyol.

[0029] In some embodiments, the method for preparing the modified polycaprolactone polyol specifically comprises the following steps:

[0030] S1. The mixture of polycarbonate diol and caprolactone is heated to 110-130°C under nitrogen protection to form a mixed reaction system;

[0031] S2. A catalyst and an antioxidant are added to the mixed reaction system, and after stirring, the temperature is raised to perform a polymerization reaction to obtain the modified polycaprolactone polyol.

[0032] In some preferred embodiments, in S1, the mass ratio of the polycarbonate diol to caprolactone is 1:1.8-2.2.

[0033] In some preferred embodiments, in S1, the mixture of polycarbonate diol and caprolactone is heated to 110-130°C and dehydrated for 0.5-2h.

[0034] In some preferred embodiments, in S1, the polycarbonate diol can include at least any one of polyalkylene carbonate diol (such as polyhexamethylene carbonate diol), polybisphenol A carbonate diol, etc., but is not limited thereto.

[0035] In some preferred embodiments, in S2, the temperature of the polymerization reaction is 150-200°C, and the time is 2-6h.

[0036] Further, in S2, the catalyst can include any one or a combination of butyl titanate, dibutyltin dilaurate, stannous octoate, dibutyltin diacetate, and tetraphenyltin, but is not limited thereto.

[0037] Further, the mass of the catalyst accounts for 0.03-0.1% of the total mass of the mixed reaction system.

[0038] Further, in S2, the antioxidant includes any one or a combination of triphenyl phosphite and p-phenylenediamine, but is not limited thereto.

[0039] Further, the mass of the antioxidant accounts for 0.2-0.4% of the total mass of the mixed reaction system.

[0040] In some more specific embodiments, the method for preparing the modified polycaprolactone polyol comprises the following steps:

[0041] S1: Under nitrogen protection, polycarbonate diol and caprolactone are blended and heated to 110℃~130℃ to dehydrate for 0.5~2h.

[0042] S2: Add appropriate amounts of catalyst and antioxidant to the mixed reaction system.

[0043] S3: Heat to 150-200℃ and stir the reaction, then distill under reduced pressure to remove water from the byproduct. Maintain the reaction temperature for 2-6 hours until the solution is clear, free of steam and bubbles, then allow it to stand to obtain the modified polycaprolactone polyol.

[0044] As another aspect of the technical solution of the present invention, it also relates to modified polycaprolactone polyol prepared by the aforementioned preparation method.

[0045] As another aspect of the technical solution of the present invention, it also relates to the application of the aforementioned modified polycaprolactone polyol in sealing coatings.

[0046] Furthermore, the modified polycaprolactone polyol can be applied to containment sealing coatings for nuclear power plants.

[0047] As another aspect of the technical solution of the present invention, it also relates to an elastic polyurethane sealing coating, which includes: a main agent composed of the modified polycaprolactone polyol, a reactive phosphate flame retardant, reinforcing fibers, boron nitride, an amine chain extender, additives, fillers, and a plasticizer, as well as a curing agent.

[0048] In some preferred embodiments, the elastic polyurethane sealant comprises the following main components by weight: 40-50 parts of modified polycaprolactone polyol, 3-10 parts of reactive phosphate flame retardant, 1-3 parts of reinforcing fiber, 2-5 parts of boron nitride, 10-20 parts of amine chain extender, 5-10 parts of additives, 10-20 parts of selected filler, 10-30 parts of plasticizer, and 200 parts of curing agent.

[0049] In some preferred embodiments, the reactive phosphate flame retardant comprises polyol phosphate ester or polyol phosphite ester, with a hydroxyl content of 2-8% by mass. The reactive phosphate flame retardant in the sealing coating of the present invention can crosslink with the curing agent to form a film. Unlike non-reactive flame retardants, which tend to migrate and become free from the coating film with increasing service life, reducing flame retardancy and film density, the coating of the present invention exhibits durable flame retardancy and retains strong resistance to flame propagation and airtightness even after irradiation.

[0050] Furthermore, the reinforcing fibers include, but are not limited to, mineral fibers.

[0051] In some preferred embodiments, the boron nitride comprises hexagonal boron nitride with a specific surface area of ​​7.0–9.0 m². 2 / g, with excellent balance of dispersion stability and barrier shielding ability. The sealing coating provided by the present application has high chain entanglement density and small intermolecular gap after curing and cross-linking, and high air tightness of the coating film; and the use of boron nitride powder provides excellent shielding and barrier properties, and filling in the intermolecular gap of the resin increases the air leakage prevention ability of the paint film.

[0052] In some preferred embodiments, the amine chain extender includes a combination of DMTDA and DETDA, preferably with a mass ratio of 2-4:1.

[0053] Further, the auxiliary agent includes an anti-degradation agent, and preferably can also include any one or a combination of a thickening agent, a defoaming agent, a dispersing agent, a drying agent, an antioxidant, etc.

[0054] Further, the thickening agent can be one or a combination of WACKER AEROSIL 200, Crayvallac ULTRA, BYK410, etc., with a mass ratio of 2-4%.

[0055] Further, the defoaming agent can be one or a combination of BYK-085, BYK-1790, XINNUO D980, AC300, etc., with a mass ratio of 1N3%.

[0056] Further, the dispersing agent can be BYK161, with a mass ratio of 0.2N0.5%.

[0057] Further, the drying agent can be 4A molecular sieve, with a mass ratio of 1-2%.

[0058] Further, the anti-degradation agent can include a carbodiimide, with a mass ratio of 0.3N1.5%, preferably 0.3-1%.

[0059] Further, the antioxidant can include any one or a combination of phenothiazine, sulfenamide, etc., with a mass ratio of 0.1-1.5% in the main agent.

[0060] Further, the plasticizer is an ester plasticizer, specifically including any one or a combination of dioctyl adipate (DOA), diisononyl phthalate, etc.; the mass ratio of the plasticizer in the main agent is 15-20%.

[0061] In some preferred embodiments, the selected filler includes at least one of talc, titanium white, etc., with a mass ratio of 10-20% in the main agent.

[0062] In some preferred embodiments, the curing agent comprises an isocyanate prepolymer, wherein the mass content of -NCO is 6.4% to 6.8%. The isocyanate prepolymer is mainly a combination of TDI prepolymer and carbodiimide modified MDI, and the mass ratio of the two is 100:0.5 to 5.

[0063] Further, the curing agent is Wanhua 3T6262 or a mixture of Mitsui TAKENATE MLT-8095 and Wanhua W1631, preferably in a mass ratio of 98.5:1.5.

[0064] The sealing coating provided by the present application has the carbon diimide added to the main agent and the carbon diimide modified MDI used in the curing agent, which can work under the conditions of high temperature and humidity, acid and alkali environment, irradiation, etc., remove water and acid, prevent autocatalytic degradation, resist ultraviolet rays, and especially reduce the degradation of the elastic polyurethane under the conditions of high temperature and high humidity in the accident working condition.

[0065] In summary, the sealing coating provided by the present application has the block structure, flexibility and strength, excellent Y-ray irradiation resistance and shielding and blocking performance, and can maintain the integrity of the paint film and air tightness even if the substrate is deformed and cracked.

[0066] Another aspect of the embodiment of the present application also provides a sealing coating formed by curing the aforementioned elastic polyurethane sealing coating.

[0067] Further, the advantages of the irradiation resistant high strength and high elasticity polyurethane sealing coating of the present application applied to the inner side of the concrete containment are as follows: the sealing coating has high strength (tensile strength of 27 to 31 MPa) and high elasticity (elongation at break of 550 to 600%). After the irradiation of 250 KGy γ-rays in the nuclear power plant, the surface has no powdering and cracking phenomenon, still has the tensile strength of 15.5 MPa and the elongation at break of 550%, and the air tightness is stable. The disadvantage of the high temperature hydrolysis of the elastic polyurethane material is overcome, and the coating sealing property can be maintained under the conditions of high temperature and high humidity (135℃, 100% for 30 min).

[0068] The following examples are provided to better further understand the present application, and do not limit the content and protection scope of the present application. Any person who obtains the same or similar products as the present application under the inspiration of the present application or by combining the present application with other prior art features falls within the protection scope of the present application.

[0069] The specific experimental steps or conditions are not specified in the examples, and can be performed according to the conventional experimental steps described in the literature in the art. The reagents or instruments used are not specified by the manufacturer, and are conventional reagent products that can be obtained by purchase.

[0070] The reactive phosphate ester flame retardant is a product of Clariant Company, model Exolit OP550, specifically a polyol phosphate ester.

[0071] The boron nitride powder is a product of Momentive Company, model CF500;

[0072] The reinforcing fiber is a product of Lapinus Company, model CF10, which is a mineral fiber;

[0073] The titanium white is a product of Jin-Titanium Company, model CR506, which is a silicon-aluminum and special organic surface treated chlorination method titanium white;

[0074] The wetting dispersant is a product of BYK Company, model DISPERBYK-161;

[0075] The TDI prepolymer in the curing agent is 3T6262 of Wanhua Company, and the modified MDI in the curing agent is WANNATE CDMDI-1631.

[0076] Example 1

[0077] The modified polycaprolactone polyol provided in this example has the following specific preparation method:

[0078] 1) Under nitrogen protection, polybisphenol A carbonate diol and caprolactone with a molar ratio of 1:1.8 were stirred and heated to 110°C in a reaction bottle for 2h to form a mixed reaction system.

[0079] 2) 0.03wt% butyl titanate catalyst and 0.2wt% triphenyl phosphite antioxidant were added to the mixed reaction system, and the temperature was raised to 160°C for stirring. The byproduct water was removed by distillation under reduced pressure, and the solution was fully reacted for 4h until it was clear, without steam and without foaming. After standing, the modified polycaprolactone polyol was obtained, with an acid value of 0.21mgKOH / g and a hydroxyl value of 54.5mgKOH / g. The product structure is shown in formula (II):

[0080]

[0081]

[0082] a is 5, b is 3, and c is 5;

[0083] The elastic polyurethane sealing paint provided in this embodiment has raw materials of 48 kg of modified polycaprolactone polyol, 3 kg of tris (1, 3-dichloropropyl) phosphate, 1.5 kg of mineral fiber, 2 kg of boron nitride powder, 11 kg of titanium white, 10 kg of DMTDA, 4 kg of DETDA, 20 kg of dioctyl adipate, 0.5 kg of carbodiimide, and a curing agent containing 197 kg of TDI prepolymer 3T6262 and 3 kg of modified MDI WANNATE CDMDI-1631. The preparation method is to mix the above raw materials sufficiently to obtain the product.

[0084] Example 2

[0085] The modified polycaprolactone polyol provided in this embodiment has the following specific preparation method:

[0086] 1) Under the protection of nitrogen, polybisphenol A carbonate diol and caprolactone with a molar ratio of 1:2 were stirred in a reaction bottle and blended and dehydrated at 130℃ for 1h to form a mixed reaction system.

[0087] 2) 0.03wt% butyl titanate catalyst and 0.2wt% triphenyl phosphite antioxidant were added to the mixed reaction system, and the temperature was raised to 180℃ for stirring. The byproduct water was removed by distillation under reduced pressure. After sufficient reaction for 4h until the solution was clear, there was no steam and no foaming, and then it was left standing to obtain the modified polycaprolactone polyol.

[0088] The elastic polyurethane sealing paint provided in this embodiment has raw materials of 48 kg of modified polycaprolactone polyol, 3 kg of tris (1, 3-dichloropropyl) phosphate, 1.5 kg of mineral fiber, 2 kg of boron nitride powder, 11 kg of titanium white, 16 kg of DMTDA, 4 kg of DETDA, 20 kg of dioctyl adipate, 0.3 kg of carbodiimide, and a curing agent containing 197 kg of TDI prepolymer 3T6262 and 3 kg of modified MDI WANNATE CDMDI-1631. The preparation method is to mix the above raw materials sufficiently to obtain the product.

[0089] Example 3

[0090] The modified polycaprolactone polyol provided in this embodiment has the following specific preparation method:

[0091] 1) Under the protection of nitrogen, polybisphenol A carbonate diol and caprolactone with a molar ratio of 1:2.2 were stirred in a reaction bottle and blended and dehydrated at 120℃ for 1h to form a mixed reaction system.

[0092] 2) To the mixed reaction system, 0.03wt% of tetraphenyl tin catalyst and 0.2wt% of triphenyl phosphite antioxidant were added, and the temperature was raised to 170°C for stirring. Byproduct water was removed by distillation under reduced pressure. After the solution was clear, vapor-free and bubble-free after 4h of sufficient reaction, it was left to stand, and the modified polycaprolactone polyol was obtained.

[0093] The raw materials of the elastic polyurethane sealing coating provided in this embodiment are 48 kg of modified polycaprolactone polyol, 3 kg of tris (1, 3-dichloropropyl) phosphate, 1.5 kg of mineral fiber, 2 kg of boron nitride powder, 11 kg of titanium white, 12 kg of DMTDA, 6 kg of DETDA, 20 kg of dioctyl adipate, 1.5 kg of carbodiimide, and the curing agent contains 197 kg of TDI prepolymer 3T6262 and 1 kg of modified MDI WANNATE CDMDI-1631. The preparation method is to mix the above raw materials thoroughly.

[0094] Example 4

[0095] The modified polycaprolactone polyol provided in this embodiment is prepared according to the following specific preparation method.

[0096] 1) Under the protection of nitrogen, polyhexamethylene carbonate diol and caprolactone with a molar ratio of 1:2.2 were stirred and blended in a reaction bottle and dehydrated by heating to 110°C for 2h to form a mixed reaction system.

[0097] 2) To the mixed reaction system, 0.06wt% of dibutyltin dilaurate catalyst and 0.3wt% of p-phenylenediamine antioxidant were added, and the temperature was raised to 150°C for stirring. Byproduct water was removed by distillation under reduced pressure. After the solution was clear, vapor-free and bubble-free after 6h of sufficient reaction, it was left to stand, and the modified polycaprolactone polyol was obtained. The test acid value was 0.18 mgKOH / g, the hydroxyl value was 56 mgKOH / g, and the product structure is shown in formula (III):

[0098]

[0099] a is 5, b is 5, and c is 5;

[0100] The raw materials of the elastic polyurethane sealing coating provided in this embodiment are 50 kg of modified polycaprolactone polyol, 5 kg of polyol phosphate (with a hydroxyl mass content of 2%), 1 kg of mineral fiber, 3 kg of boron nitride powder, 10 kg of titanium white, 6.6 kg of DMTDA, 3.3 kg of DETDA, 15 kg of diisononyl phthalate, 0.3 kg of carbodiimide, and the curing agent contains 190 kg of TDI prepolymer 3T6262 and 10 kg of modified MDI WANNATE CDMDI-1631. The preparation method is to mix the above raw materials thoroughly.

[0101] Example 5

[0102] The modified polycaprolactone polyol provided in this example has the following specific preparation method:

[0103] 1) Under the protection of nitrogen, polyhexamethylene carbonate diol and caprolactone with a molar ratio of 1:1.8 were stirred in a reaction bottle and blended and dehydrated at 130°C for 0.5h to form a mixed reaction system.

[0104] 2) 0.1wt% stannous octoate catalyst and 0.4wt% triphenyl phosphite antioxidant were added to the mixed reaction system, and the temperature was raised to 200°C for stirring. The byproduct water was removed by distillation under reduced pressure. After sufficient reaction for 2h until the solution was clear, without steam and without foaming, it was left to stand, and the modified polycaprolactone polyol was obtained.

[0105] The elastic polyurethane sealant provided in this example has raw materials of 40kg of modified polycaprolactone polyol, 10kg of polyol phosphate (hydroxyl mass content of 5%), 3kg of mineral fiber, 5kg of boron nitride powder, 3kg of talc powder, 7kg of titanium white powder, 12kg of DMTDA, 4kg of DETDA, 15kg of diisononyl phthalate, 1.5kg of carbodiimide, a curing agent containing 195kg of TDI prepolymer 3T6262, and 5kg of modified MDI WANNATE CDMDI-1631. The preparation method is to mix the above raw materials thoroughly to obtain the elastic polyurethane sealant.

[0106] Example 6

[0107] The modified polycaprolactone polyol provided in this example has the following specific preparation method:

[0108] 1) Under the protection of nitrogen, polyhexamethylene carbonate diol and caprolactone with a molar ratio of 1:2.0 were stirred in a reaction bottle and blended and dehydrated at 120°C for 1h to form a mixed reaction system.

[0109] 2) 0.08wt% dibutyltin diacetate catalyst and 0.4wt% triphenyl phosphite antioxidant were added to the mixed reaction system, and the temperature was raised to 180°C for stirring. The byproduct water was removed by distillation under reduced pressure. After sufficient reaction for 5h until the solution was clear, without steam and without foaming, it was left to stand, and the modified polycaprolactone polyol was obtained.

[0110] The embodiment provides a kind of elastic polyurethane seal coating, its raw material is 45kg modified polycaprolactone polyol, 8kg polyol phosphate (hydroxyl mass content is 8%), 2kg mineral fiber, 4kg boron nitride powder, 12kg talcum powder, 12kg DMTDA, 3kg DETDA, 15kg dioctyl adipate, 1.0kg carbodiimide, curing agent includes 198kg TDI prepolymer 3T6262, 2kg modified MDI WANNATE CDMDI-1631, its preparation method is that the above raw materials are mixed sufficiently, and obtained.

[0111] Comparative example 1

[0112] The comparative example provides a kind of modified polycaprolactone polyol, and the specific preparation method is as follows:

[0113] 1) under nitrogen protection, the polycarbonate diol and caprolactone with a molar ratio of 1:2 are stirred in a reaction bottle and blended and dehydrated by heating to 130 DEG C, to form a mixed reaction system.

[0114] 2) 0.03% butyl titanate catalyst and 0.2% triphenyl phosphite antioxidant are added to the reaction system, and the temperature is raised to 180 DEG C and stirred, and the by-product water is distilled off under reduced pressure, and after the solution is clear, no steam and no foaming, standing, the modified polycaprolactone polyol is obtained.

[0115] The comparative example provides a kind of elastic polyurethane coating, its raw material is 48kg modified polycaprolactone polyol, 3kg polyol phosphate (hydroxyl mass content is 5%), 1.5kg reinforcing fiber, 2kg boron nitride powder, 11.5kg filler, 10kg DMTDA, 4kg DETDA, 20kg dioctyl adipate, curing agent includes 200kg TDI prepolymer 3T6262, and its preparation method is that the above raw materials are mixed sufficiently, and obtained.

[0116] The comparative example is not added carbodiimide and carbodiimide modified MDI compared with example 2.

[0117] Comparative example 2

[0118] The comparative example provides a kind of modified polycaprolactone polyol, and the specific preparation method is as follows:

[0119] 1) under nitrogen protection, the polycarbonate diol and caprolactone with a molar ratio of 1:2 are stirred in a reaction bottle and blended and dehydrated by heating to 130 DEG C, to form a mixed reaction system.

[0120] 2) To the reaction system, 0.03% butyl titanate catalyst and 0.2% triphenyl phosphite antioxidant were added, and the temperature was raised to 180°C and stirred under reduced pressure to remove byproduct water. After the solution was clear, vapor-free and no foaming, standing was performed, and the modified polycaprolactone polyol was obtained.

[0121] The raw materials of the elastic polyurethane coating provided by the present comparative example were 48 kg of modified polycaprolactone polyol, 3 kg of reactive phosphate ester flame retardant, 1.5 kg of reinforcing fiber, 2 kg of boron nitride powder, 11 kg of filler, 10 kg of DMTDA, 4 kg of DETDA, 20 kg of dioctyl adipate, and 0.5 kg of carbodiimide. The curing agent was 200 kg of TDI prepolymer 3T6262, and the preparation method was to mix the above raw materials to obtain the elastic polyurethane coating.

[0122] The present comparative example was compared with example 2, and no carbodiimide modified MDI was added.

[0123] Comparative example 3

[0124] Commercially available elastic polyurethane coating

[0125] Comparative example 4

[0126] Commercially available asparto polyurea coating

[0127] Comparative example 5

[0128] The present comparative example was compared with example 2, and the difference was that no DETDA was added to the elastic polyurethane coating, and pure DMTDA was used as the chain extender.

[0129] Comparative example 6

[0130] The present comparative example was compared with example 2, and the difference was that no DMTDA was added to the elastic polyurethane coating, and pure DETDA was used as the chain extender.

[0131] Test example

[0132] The elastic polyurethane coatings obtained by examples 1-6 and comparative examples 1-4 were tested for performance, and the test results are shown in Tables 1 and 2:

[0133] The irradiation test was performed according to NB / T20133.3 procedure B, and the total irradiation dose was 300 KGy.

[0134] The tensile strength and elongation were tested according to GB / T528-2009.

[0135] The hydrolysis resistance test conditions were 135°C, 0.3 MPa, 100% humidity, and 3h.

[0136] Table 1 Performance test results of examples 1-6

[0137]

[0138] Table 2 Performance test results of Comparative Examples 1-4

[0139]

[0140]

[0141] From the above Table 1 and Table 2, it can be seen that the above examples of the present application all have very high mechanical properties, good high-temperature and high-humidity resistance and hydrolysis resistance, and the tensile properties after irradiation decrease less.

[0142] Comparative Example 1 is Example 2 without carbodiimide and carbodiimide modified MDI; the strength after irradiation decreases obviously, and it is not resistant to hydrolysis.

[0143] Comparative Example 2 is Example 2 without carbodiimide modified MDI; the strength performance after irradiation decreases less, but the hydrolysis resistance is insufficient, and there are fine cracks and bubbles after the hydrolysis resistance test.

[0144] Comparative Example 3 is a commercially available elastic polyurethane, which has lower high-temperature and high-humidity resistance and hydrolysis resistance than the present examples, and serious cracking and peeling occurs after the hydrolysis resistance test.

[0145] Comparative Example 4 is a commercially available aspartic polyurea coating, which has much lower tensile strength and elongation at break than the present application.

[0146] Comparative Example 5 uses single DETDA as a chain extender, and the coating performance is close to that of Example 2, but the coating construction pot life is too short, which is not convenient for construction operation.

[0147] Comparative Example 6 uses single DMTDA as a chain extender, and the coating performance is close to that of Example 2, but the coating construction pot life is too long, and the film open time is too long, so that water in the air can easily react with isocyanate in the curing agent to cause reactive foaming under high humidity.

[0148] In addition, the present inventors have also carried out tests with other raw materials, process operations and process conditions described in the present specification with reference to the foregoing examples, and all have obtained relatively ideal results.

[0149] Obviously, the above examples are merely examples for clarity, and are not limitations on the embodiments. Based on the above description, other different forms of changes or variations can be made by those of ordinary skill in the art. Here, it is not necessary and impossible to exhaust all embodiments. The obvious changes or variations derived therefrom are still within the protection scope of the present application.

Claims

1. An elastic polyurethane sealing coating, characterized in that, The main components, calculated by weight, are as follows: 40-50 parts modified polycaprolactone polyol, 3-10 parts reactive phosphate flame retardant, 1-3 parts reinforcing fiber, 2-5 parts boron nitride, 10-20 parts amine chain extender, 5-10 parts additives, 10-20 parts filler, 10-30 parts plasticizer, and 200 parts curing agent; the additives include anti-degradation agents. The modified polycaprolactone polyol has the structural formula shown in formula (Ⅰ): ; Wherein, R is a polyalkylene group or a bisphenol A group, a is 2~10, b is 2~8, and c is 2~10; the weight-average molecular weight of the modified polycaprolactone polyol is 2000~2400. The amine chain extender is a combination of DMTDA and DETDA, the anti-degradation agent is carbodiimide, and the curing agent is an isocyanate prepolymer, wherein the mass content of -NCO is 6.4%~6.8%; the isocyanate prepolymer is a combination of TDI prepolymer and carbodiimide-modified MDI, with a mass ratio of 100:0.5~5.

2. The elastic polyurethane sealing coating according to claim 1, characterized in that: The reactive phosphate flame retardant is a polyol phosphate ester or a polyol phosphite ester, with a hydroxyl content of 2-8% by mass.

3. The elastic polyurethane sealing coating according to claim 1, characterized in that: The reinforcing fiber is a mineral fiber.

4. The elastic polyurethane sealing coating according to claim 1, characterized in that: The boron nitride is hexagonal boron nitride with a specific surface area of ​​7.0~9.0 m². 2 / g.

5. The elastic polyurethane sealing coating according to claim 1, characterized in that: The mass ratio of DMTDA to DETDA is 2~4:

1.

6. The elastic polyurethane sealing coating according to claim 1, characterized in that: The additives also include any one or more combinations of thickeners, defoamers, dispersants, desiccants, and antioxidants.

7. The elastic polyurethane sealing coating according to claim 6, characterized in that: The thickener accounts for 2-4% of the mass of the main agent.

8. The elastic polyurethane sealing coating according to claim 6, characterized in that: The defoamer accounts for 1-3% of the mass of the main agent.

9. The elastic polyurethane sealing coating according to claim 6, characterized in that: The dispersant accounts for 0.2-0.5% of the mass of the main agent.

10. The elastic polyurethane sealing coating according to claim 6, characterized in that: The desiccant accounts for 1-2% of the mass of the main agent.

11. The elastic polyurethane sealing coating according to claim 1, characterized in that: The anti-degradation agent accounts for 0.3-1.5% of the mass of the main agent.

12. The elastic polyurethane sealing coating according to claim 6, characterized in that: The antioxidant is selected from any one or more combinations of phenothiazine and diphenylamine sulfide, and its mass percentage in the main agent is 0.1~1.5%.

13. The elastic polyurethane sealing coating according to claim 1, characterized in that: The plasticizer is selected from any one or a combination of dioctyl phthalate and diisononyl phthalate.

14. The elastic polyurethane sealing coating according to claim 1, characterized in that: The plasticizer accounts for 15-20% of the mass of the main agent.

15. The elastic polyurethane sealing coating according to claim 1, characterized in that: The filler is selected from at least one of talc and titanium dioxide.

16. The elastic polyurethane sealing coating according to claim 1, characterized in that: The filler accounts for 10-20% of the mass of the main agent.

17. A sealing coating, characterized in that, It is formed by curing the elastic polyurethane sealant coating according to any one of claims 1-16.

18. The sealing coating according to claim 17, characterized in that: The tensile strength of the sealing coating is 27~31MPa, and the elongation at break is 550~600%.

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