A polyurea coating suitable for use in waterproofing membranes

Abstract

The application discloses a polyurea coating suitable for waterproofing membrane, which comprises a first component and a second component, the first component comprises isocyanate polyurea prepolymer; the second component comprises amino-terminated polyether, amine chain extender, plasticizer and auxiliary agent; the amino-terminated polyether is primary amino-terminated polyether or secondary amino-terminated polyether; the mass ratio between the amino-terminated polyether and the amine chain extender is 1:0.5-2; the second component is prepared by the following method: mixing the amino-terminated polyether, the amine chain extender and the plasticizer, dehydrating to a moisture content of less than 300 ppm, stirring uniformly after cooling and adding the auxiliary agent, and defoaming to obtain the second component. The polyurea coating of the application preferably selects a specific structure of amine chain extender, which has better adaptability with the selected polyether amine, the product made has high crosslinking density, has excellent strength performance and self-healing ability of rubber body, and improves the low-temperature flexibility, bonding strength, weather resistance and mechanical properties of traditional polyurea coatings.

Description

[0001] This application is a divisional application of the invention patent application filed on February 4, 2021, with application number 2021101528541 and entitled "Polyurea Coating Applicable to Waterproof Membranes and its Preparation Method and Waterproof Material". Technical Field

[0002] This invention relates to the field of waterproof membrane technology, and more specifically to a polyurea coating suitable for waterproof membranes. Background Technology

[0003] In existing polyurea coatings, amine chain extenders have poor compatibility with polyetheramines, resulting in products with low crosslinking density, poor strength properties, and poor self-healing ability. Summary of the Invention

[0004] In view of this, in order to overcome the shortcomings of the prior art, the object of the present invention is to provide a polyurea coating suitable for waterproof membranes, which, when used on waterproof membranes, can improve the adhesion of the waterproof membranes and the self-healing adhesion of the coating.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A polyurea coating includes a first component and a second component. The first component comprises an isocyanate polyurea prepolymer. The second component comprises an amino-terminated polyether, an amine chain extender, a plasticizer, and additives. The weight ratio of the first component to the second component in the polyurea coating is 1:0.2-2. The mass ratio of the amino-terminated polyether to the amine chain extender is 1:0.5-2. The first and second components are stored separately and mixed only before use.

[0007] According to some preferred embodiments of the present invention, the isocyanate polyurea prepolymer is prepared from a hindered secondary amine and an isocyanate, wherein the hindered secondary amine is a compound having the following general formula:

[0008]

[0009] Where X is an alkyl group having 1-3 carbon atoms, R 1 R 2 R 3 R 4 They are straight-chain or branched alkyl groups with 2-8 carbon atoms, respectively.

[0010] Introducing a large number of urea bonds can improve the cohesive strength and tack of materials. Two-component polyurea reacts rapidly, has a high cross-linking density, and reaches its final strength in a short time, thus improving the efficiency of on-site adhesive preparation. It has strong permeability and wettability, allowing it to slowly penetrate various substrates, strengthening chemical and physical anchoring, and improving adhesion to various substrates.

[0011] In some preferred embodiments of the present invention, the isocyanate is selected from one, two or more combinations of diphenylmethane diisocyanate (MDI), toluene diisocyanate (TDI), isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), xylene diisocyanate (XDI), hydrogenated diphenylmethane diisocyanate, etc.

[0012] According to some preferred embodiments of the present invention, the amine chain extender in the second component is a compound having the same chemical formula as the sterically hindered secondary amine, that is, the amine chain extender is also a compound having the following general formula:

[0013]

[0014] Where X is an alkyl group having 1-3 carbon atoms, R 1 R 2 R 3 R 4 They are straight-chain or branched alkyl groups with 2-8 carbon atoms, respectively.

[0015] In some preferred embodiments of the present invention, the amine chain extender may be a compound that is exactly the same as the sterically hindered secondary amine, or a different compound that conforms to the above general formula may be used.

[0016] According to some preferred embodiments of the present invention, the terminal amino polyether is a primary amino polyether or a secondary amino polyether.

[0017] In some preferred embodiments of the present invention, the terminal amino polyether is a primary amino polyether such as Huntsman's D230, D400, D2000, D4000, T403, T3000, T5000, or a secondary amino polyether such as Huntsman's SD231, SD401, SD2001.

[0018] In some preferred embodiments of the present invention, the plasticizer is selected from at least one of naphthenic oil, chlorinated paraffin, DINP (diisononyl phthalate), DIDP (diisodecyl phthalate), DOTP (dioctyl terephthalate), vegetable oil, etc.

[0019] In some preferred embodiments of the present invention, the mass percentage of terminal amino polyether, amine chain extender, and plasticizer in the second component is 10%-70%.

[0020] In some preferred embodiments of the present invention, the additives include conventional reagents such as defoamers and antioxidants, which can be selected according to the actual situation.

[0021] Among them, the defoamer is a combination of two or more of the following physical defoamers: polysiloxane defoamers and / or silicone defoamers, and chemical defoamers: calcium oxide, magnesium oxide, calcium hydroxide, oxazolidine latent curing agents, and ketimine latent curing agents.

[0022] The antioxidant is selected from one, two or more of 2,6-tributyl-4-methylphenol, bis(3,5-tributyl-4-hydroxyphenyl) sulfide, and pentaerythritol tetrakis[β-(3,5-tributyl-4-hydroxyphenyl)propionic acid] ester.

[0023] The present invention also provides a method for preparing the polyurea coating as described above, comprising the following steps:

[0024] Preparation of the first component: Isocyanate is added to a sterically hindered secondary amine with a moisture content of less than 300 ppm for reaction. The reaction is terminated after the mass fraction of NCO reaches the preset value, and isocyanate polyurea prepolymer is obtained.

[0025] Preparation of the second component: The terminal amino polyether, amine chain extender and plasticizer are mixed and dehydrated to a moisture content of less than 300 ppm. After adding the additives, the mixture is stirred evenly to obtain the second component.

[0026] According to some preferred embodiments of the present invention, in the step of preparing the isocyanate polyurea prepolymer, the preset value of the mass fraction of NCO in the reaction system is 1-5%.

[0027] According to some preferred embodiments of the present invention, the dehydration temperature for preparing the isocyanate polyurea prepolymer and the second component is 115-130°C. In some preferred embodiments of the present invention, the dehydration temperature is preferably 120°C.

[0028] In some embodiments of the present invention, the method for preparing polyurea coatings includes the following steps:

[0029] 1) Preparation of the first component

[0030] The hindered secondary amine was dehydrated at 120°C to a moisture content of less than 300 ppm, and then isocyanate was added dropwise. The reaction was carried out at 70-100°C for 2-4 hours. When the mass fraction of NCO reached the preset value, the reaction was terminated to obtain isocyanate polyurea prepolymer.

[0031] 2) Preparation of the second component

[0032] The terminal amino polyether, amine chain extender, and plasticizer were dehydrated at 120°C to a moisture content below 300 ppm, then cooled to 55°C. Additives and colorant were added, stirred until homogeneous, and degassed for 30 minutes to obtain the second component. The second component was then stored in a light-proof, sealed container.

[0033] For ease of description and understanding, the steps have been distinguished and numbered. In actual preparation, the above steps, such as the preparation of the isocyanate polyurea prepolymer in the first component and the preparation of the second component, can be carried out simultaneously or in any order.

[0034] The present invention also provides a waterproof material comprising a substrate and an anti-adhesive layer, and an adhesive layer for bonding the substrate and the anti-adhesive layer, wherein the adhesive layer is prepared using a polyurea coating as described above. Using the above-described polyurea coating on waterproof membranes can improve the adhesion of the waterproof material and the self-healing tack of the coating.

[0035] According to some preferred embodiments of the present invention, the waterproof material is obtained by mixing and reacting the first component and the second component, coating the mixture onto the substrate, covering the coated polyurea coating with an anti-stick layer, and heating the entire mixture. Specifically, the first component and the second component are added to a reaction vessel and reacted at 20-60°C for 1-3 hours. After the materials have fully reacted, the temperature is raised to 180°C to reduce the viscosity of the coating. The coating is then applied to the substrate using a coater or allowed to flow naturally onto the substrate and spread evenly. An anti-stick layer is then covered on the coated polyurea coating, and the mixture is then heated in an oven. After heat setting, other structural layers are attached to form the finished roll material.

[0036] In some preferred embodiments of the present invention, the substrate can be a base material or another anti-adhesive layer. The base material can be PET polyester film, cross-laminated PE film, PVC sheet, PE sheet, TPO sheet, composite sheet, polyester nonwoven fabric base material, glass fiber base material, copper base material, etc.

[0037] In some preferred embodiments of the present invention, the anti-sticking layer may be natural sand, manufactured sand or other fine powder, silicone oil film, emulsion, etc.

[0038] In some embodiments of the present invention, when the substrate is an anti-adhesive layer, the waterproof material does not contain a base material. The simplest form is that there is a polyurea adhesive layer formed by the above-mentioned polyurea coating between two anti-adhesive layers.

[0039] In some preferred embodiments of the present invention, in addition to the adhesive layer prepared by polyurea coating, other adhesive layers may be provided between the base material and the anti-adhesive layer; the other adhesive layers may be asphalt adhesive, epoxy adhesive, butyl adhesive, hot melt pressure sensitive adhesive, polyurethane adhesive, etc.

[0040] Compared with the prior art, the advantages of the present invention are as follows: The polyurea coating of the present invention preferably uses amine chain extenders with specific structures, which have better compatibility with the selected polyetheramines. The resulting product has a high crosslinking density, excellent strength properties and self-healing ability of rubber, and improves the low-temperature flexibility, bonding strength, weather resistance and mechanical properties of traditional polyurea coatings. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0042] Figure 1 This is a cross-sectional schematic diagram of the waterproof material in preferred embodiment 1 of the present invention;

[0043] Figure 2 This is a cross-sectional schematic diagram of the waterproof material in preferred embodiment 2 of the present invention;

[0044] Figure 3 This is a cross-sectional schematic diagram of the waterproof material in preferred embodiment 3 of the present invention;

[0045] Figure 4 This is a cross-sectional schematic diagram of the waterproof material in preferred embodiment 4 of the present invention;

[0046] Figure 5 This is a cross-sectional schematic diagram of the waterproof material in preferred embodiment 5 of the present invention;

[0047] Figure 6 This is a cross-sectional schematic diagram of the waterproof material in preferred embodiment 6 of the present invention;

[0048] Figure 7 This is a cross-sectional schematic diagram of the waterproof material in preferred embodiment 7 of the present invention;

[0049] Figure 8 This is a cross-sectional schematic diagram of the waterproof material in preferred embodiment 8 of the present invention. Detailed Implementation

[0050] To enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0051] Example 1

[0052] The polyurea coating in this embodiment includes a first component and a second component, with a weight ratio of 1:2 between the first component and the second component.

[0053] The first component includes isocyanate polyurea prepolymer; the second component includes amino-terminated polyether, amine chain extender, plasticizer, colorant, antioxidant and defoamer.

[0054] The preparation method of polyurea coating in this embodiment includes the following steps:

[0055] 1) Preparation of the first component

[0056] Preparation of isocyanate polyurea prepolymer: 200g of hindered secondary amine was dehydrated at 120℃ to a moisture content of less than 300ppm, and then 200g of diphenylmethane diisocyanate was added dropwise. The reaction was carried out at 80℃ for 3h. When the mass fraction of NCO reached the preset value of 5%, the reaction was stopped to obtain isocyanate polyurea prepolymer.

[0057] The sterically hindered secondary amine in this embodiment is a compound with the following structural formula:

[0058]

[0059] Where X is -CH2-, R 1 R 2 R 3 R 4 It is -CH2CH3.

[0060] 2) Preparation of the second component

[0061] 150g of amino-terminated polyether, 150g of amine chain extender, and 198g of plasticizer were dehydrated at 120℃ to a moisture content below 300ppm. The mixture was then cooled to 55℃, and 1g of antioxidant, 0.5g of defoamer, and 0.5g of colorant were added. The mixture was stirred until homogeneous and defoamed for 30 minutes to obtain the second component. The second component was stored in a light-proof, sealed container.

[0062] In this embodiment, the terminal amino polyether in the second component is Huntsman's D230 primary amino polyether, and the amine chain extender is a compound with the same structural formula as the sterically hindered secondary amine mentioned above.

[0063] Example 2

[0064] The polyurea coating in this embodiment includes a first component and a second component, with a weight ratio of 1:0.5 between the first component and the second component.

[0065] The first component includes isocyanate polyurea prepolymer; the second component includes amino-terminated polyether, amine chain extender, plasticizer, colorant, antioxidant and defoamer.

[0066] The preparation method of polyurea coating in this embodiment includes the following steps:

[0067] 1) Preparation of the first component

[0068] Preparation of isocyanate polyurea prepolymer: 200g of hindered secondary amine was dehydrated at 120℃ to a moisture content of less than 300ppm, and then 200g of toluene diisocyanate was added dropwise. The reaction was carried out at 80℃ for 3h. When the mass fraction of NCO reached the preset value of 2%, the reaction was stopped to obtain isocyanate polyurea prepolymer.

[0069] The sterically hindered secondary amine in this embodiment is a compound with the following structural formula:

[0070]

[0071] Where X is -CH2CH2CH2-, R 1 R 2 R 3 R 4 It is CH3CH2C(CH3)CH(CH3)CH2CH3.

[0072] 2) Preparation of the second component

[0073] 200g of amino-terminated polyether, 100g of amine chain extender, and 198g of plasticizer were dehydrated at 120℃ to a moisture content below 300ppm. The mixture was then cooled to 55℃, and 1g of antioxidant, 0.5g of defoamer, and 0.5g of color paste were added. The mixture was stirred until homogeneous and defoamed for 30 minutes to obtain the second component. The second component was stored in a light-proof, sealed container.

[0074] In this embodiment, the terminal amino polyether in the second component is Huntsman's T3000 primary amino polyether, and the amine chain extender is a compound with the same structural formula as the sterically hindered secondary amine mentioned above.

[0075] Example 3

[0076] Reference Figure 1 In this embodiment, the waterproof material comprises, from top to bottom, a first anti-adhesive layer, a first polyurea adhesive layer, a base layer, a second polyurea adhesive layer, and a second anti-adhesive layer. The first and second polyurea adhesive layers are prepared from the polyurea coating described in embodiments 1-2.

[0077] When preparing waterproof membrane, the first and second components are added to the reaction vessel and reacted naturally at 40°C for 2 hours. After the materials have fully reacted, the temperature is raised to 180°C to reduce the viscosity of the coating. The coating is then applied to the substrate using a coater. An anti-stick layer is then placed on the coated polyurea coating, and the membrane is then placed in an oven for curing to form the finished membrane.

[0078] In this embodiment, the substrate is a TPO sheet, and both the first and second anti-adhesive layers are silicone oil films. In other embodiments, the substrate can be a base material or another anti-adhesive layer. The base material can be a PET polyester film, a cross-laminated PE film, a PVC sheet, a PE sheet, a TPO sheet, a composite sheet, a polyester nonwoven fabric base material, a fiberglass base material, a copper base material, a composite base material, etc.; the anti-adhesive layer can be natural sand, manufactured sand or other fine powders, silicone oil films, emulsions, etc.

[0079] In other embodiments, if the second polyurea adhesive layer and the second anti-adhesive layer are removed, a structure as shown is formed. Figure 2 Waterproof material with the structure shown.

[0080] like Figure 3 As shown, in another embodiment of this application, the waterproof material has no base material, and a polyurea adhesive layer formed by a polyurea coating is present between the two anti-adhesive layers. Figure 8 As shown, there are other adhesive layers between the polyurea adhesive layer and the anti-adhesive layer. These other adhesive layers can be asphalt adhesive, epoxy adhesive, butyl adhesive, hot melt pressure-sensitive adhesive, polyurethane adhesive, etc., and there is no base material in the entire waterproof material.

[0081] like Figure 4 and Figure 5 As shown, in another embodiment of this application, there are other adhesive layers between the base material and the polyurea adhesive layer. These other adhesive layers may be asphalt adhesive, epoxy adhesive, butyl adhesive, hot melt pressure-sensitive adhesive, polyurethane adhesive, or other adhesives.

[0082] like Figure 6 and Figure 7 In another embodiment of this application, the polyurea adhesive layer and the anti-adhesive layer are further provided with other adhesive layers, which may be asphalt adhesive, epoxy adhesive, butyl adhesive, hot melt pressure sensitive adhesive, polyurethane adhesive, etc.

[0083] Comparative Example 1

[0084] The difference between the polyurea coating in this comparative example and Example 1 is that the second component contains only terminal amino polyether and no amine chain extender. The content of amine chain extender is replaced by terminal amino polyether. The other components are the same as in Example 1.

[0085] Comparative Example 2

[0086] The difference between the polyurea coating in this comparative example and Example 1 is that the second component contains only amine chain extenders and does not contain terminal amino polyethers. The content of terminal amino polyethers is replaced by amine chain extenders. The other components are the same as in Example 1.

[0087] Comparative Example 3

[0088] This comparative example uses conventional hot melt pressure-sensitive adhesive as the coating to form the adhesive layer.

[0089] The manufacturing process involves heating and melting materials such as naphthenic oil and SIS to 180°C, which reduces the viscosity of the coating. The coating is then applied to the substrate using a coater. An anti-stick layer is then placed on top of the polyurea coating, and the coating is then placed in an oven for heating and curing to form a finished waterproof membrane.

[0090] Comparative Example 4

[0091] This comparative example uses a conventional polyurea coating as the adhesive layer. Specifically, in the preparation of the isocyanate polyurea prepolymer, the sterically hindered secondary amine is replaced with a polyether polyol, thereby obtaining a conventional polyurea coating.

[0092] Testing and Analysis

[0093] Referring to the relevant methods in GB / T 23457-2017 Pre-laid waterproof membrane and GB / T19250-2013 Polyurethane waterproof coating standards, the coatings in Examples 1-2 and Comparative Examples 1-4 were applied to waterproof membranes and their relevant performance was tested. The results are shown in Table 2.

[0094] Table 1 shows the raw material formulations (by mass parts) of the coatings used in Examples 1-2 and Comparative Examples 1-4.

[0095]

[0096] Table 2. Performance test results of waterproof membranes prepared with polyurea coatings from Examples 1-3 and Comparative Examples 1-3.

[0097]

[0098]

[0099] As shown in Table 2, the polyurea materials prepared in Examples 1 and 2 exhibit similar properties to those of waterproof membranes made with conventional hot melt adhesives in some aspects. However, hot melt adhesives are physically dispersed and melted, without reactive cross-linking. In contrast, polyurea is reactively cross-linked, resulting in a denser polymer structure, better durability, resistance to extreme low temperatures, and good resistance to high temperatures, as well as resistance to acid and alkali immersion. Amine chain extenders and amino-terminated polyethers need to be used together to achieve better results; using either alone will result in poor overall performance. Furthermore, changing the ratio of amine chain extenders to amino-terminated polyethers will affect the adhesion of the material, requiring careful control. Using conventional polyurethane (Comparative Example 4) significantly reduces adhesion and lacks self-healing properties.

[0100] Compared with the prior art, the present invention has the following advantages:

[0101] 1. The polyurea coating of this application forms a viscoelastic coating, similar to non-curing rubber asphalt coatings, and is in a state of never curing; the coating product has 100% solids content, is safe, environmentally friendly, and has no irritating odor. The resulting roll material is environmentally friendly and has no irritating odor.

[0102] 2. Compared with asphalt adhesives, the polyurea coating material of this application has better compatibility with the substrate and is less prone to oil migration.

[0103] 3. Compared with hot melt pressure-sensitive adhesives, it has superior initial tack and holding power, and strong cohesion, which can resist the effects of high temperature on tire base deformation.

[0104] 4. The polyurea coating of this application has excellent adhesion and outstanding self-healing properties.

[0105] 5. The polyurea coating of this application has excellent adhesion to damp concrete or mortar surfaces.

[0106] The above embodiments are only for illustrating the technical concept and features of the present invention. Their purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. 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 should be covered within the scope of protection of the present invention.

Claims

1. A polyurea coating suitable for waterproof membranes, characterized in that, The product comprises a first component and a second component, wherein the weight ratio of the first component to the second component is 1:0.2-2; the first component comprises an isocyanate polyurea prepolymer; the second component comprises an amino-terminated polyether, an amine chain extender, a plasticizer, and an additive; the amine chain extender in the second component is a compound having the following general formula: ； Where X is an alkyl group having 1-3 carbon atoms, R 1 R 2 R 3 R 4 They are straight-chain or branched alkyl groups with 2-8 carbon atoms, respectively; The terminal amino polyether is a primary amino polyether or a secondary amino polyether; the mass ratio of the terminal amino polyether to the amine chain extender is 1:0.5-2; The second component was prepared by the following method: amino-terminated polyether, amine chain extender and plasticizer were mixed and dehydrated to a moisture content of less than 300 ppm, cooled and additives were added and stirred evenly, and the second component was obtained by degassing. The isocyanate polyurea prepolymer is prepared from a hindered secondary amine and an isocyanate; the hindered secondary amine is a compound having the following general formula: ； Where X is an alkyl group having 1-3 carbon atoms, R 1 R 2 R 3 R 4 They are straight-chain or branched alkyl groups with 2-8 carbon atoms, respectively; The first component is prepared by the following method: isocyanate is added to a sterically hindered secondary amine with a moisture content of less than 300 ppm for reaction, and the reaction is terminated after the mass fraction of NCO reaches a preset value, to obtain isocyanate polyurea prepolymer; the mass fraction of NCO in the isocyanate polyurea prepolymer is 1-5%.

2. The polyurea coating according to claim 1, characterized in that, The dehydration temperature is 115-130℃.

3. The polyurea coating according to claim 1, characterized in that, The system needs to be cooled to 55°C before adding the additives.

4. The polyurea coating according to claim 1, characterized in that, The primary amino polyether is selected from Huntsman's D230, D400, D2000, D4000, T403, T3000, and T5000 primary amino polyethers; the secondary amino polyether is selected from Huntsman's SD231, SD401, and SD2001 secondary amino polyethers.

5. The polyurea coating according to claim 1, characterized in that, The isocyanate is selected from one or more of diphenylmethane diisocyanate, toluene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, xylene diisocyanate, and hydrogenated diphenylmethane diisocyanate.

6. The polyurea coating according to claim 1, characterized in that, The plasticizer is selected from at least one of naphthenic oil, chlorinated paraffin, DINP (diisononyl phthalate), DIDP (diisodecyl phthalate), DOTP (dioctyl terephthalate), and vegetable oil.

7. The polyurea coating according to claim 1, characterized in that, The additives include defoamers and / or antioxidants; the defoamer is selected from one or more of polysiloxane defoamers and silicone defoamers; the antioxidant is selected from one or more of 2,6-tributyl-4-methylphenol, bis(3,5-tributyl-4-hydroxyphenyl) sulfide, and pentaerythritol tetrakis[β-(3,5-tributyl-4-hydroxyphenyl)propionate].

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