A flame-retardant spray polyurea waterproof coating for hard foam roof insulation and a preparation method thereof

Abstract

This invention relates to a flame-retardant sprayable polyurea waterproof coating for rigid foam roofing insulation. The coating comprises component A and component B. Component A includes a modified isocyanate prepolymer. Component B includes the following components: polyether, amino chain extender, amino POSS crosslinking agent, expanded graphite flame retardant, and additives. The modified isocyanate prepolymer is obtained by reacting amino POSS, polyether polyol, and MDI. Through the compounding of component A and component B, this invention reveals that the modified isocyanate prepolymer containing a POSS cage structure, the amino POSS crosslinking agent, and the expanded graphite flame retardant synergistically and significantly improves the flame-retardant and heat-resistant properties of the coating, while also enhancing the material's hardness and adhesion, among other physical and chemical properties.

Description

Technical Field

[0001] This invention relates to the field of sprayed polyurea materials technology, and in particular to a flame-retardant sprayed polyurea waterproof coating for rigid foam roof insulation and its preparation method. Background Technology

[0002] Sprayed rigid polyurethane foam has been used as a roofing waterproofing and insulation material for over 10 years. It has excellent thermal insulation, heat insulation, fire resistance and impermeability, making it a good material that integrates waterproofing and thermal insulation. Currently, it has great application prospects in the renovation of old civil and industrial buildings in my country.

[0003] Because sprayed rigid polyurethane foam insulation materials have poor resistance to yellowing, a protective layer is required when used outdoors. Currently, cement polymer mortar, concrete, and weather-resistant acrylic coatings are commonly used as protective layers. However, the hydration of cement polymer mortar or concrete requires the addition of a certain amount of water, which can seep into the pores of the rigid polyurethane foam before hydration, severely affecting its insulation performance. While acrylic coatings are non-toxic, odorless, and easy to clean, they have poor abrasion resistance and insufficient low-temperature toughness. When applied to the surface of rigid foam insulation, they are prone to cracking after shrinkage at low temperatures, and it is difficult to achieve a certain thickness. In contrast, sprayed polyurea elastomer protective layers are solvent-free, have high solids content, are easy to apply, are resistant to low temperatures, have excellent overall performance, adjustable spray thickness, and also have superior waterproofing, making them one of the ideal protective materials for rigid polyurethane foam. As a protective layer for rigid foam insulation on roofs, it has many advantages such as high strength and elasticity, tear resistance, resistance to low-temperature deformation, super waterproofing, convenient construction, adjustable thickness, and good adhesion to rigid polyurethane foam. Polyurea elastomer itself is a flammable polymer that is easily combustible when exposed to open flame (oxygen index below 18%). The combustion process is prone to producing molten droplets. If it is used directly in the renovation of old residential areas, there are potential safety hazards in terms of fire prevention. Therefore, enhancing its flame retardant properties and increasing its oxygen index during combustion has become an inevitable choice.

[0004] Currently, there are no flame-retardant sprayed polyurea waterproof materials specifically designed for use as protective layers in rigid foam roofing. Therefore, there is an urgent need to develop a flame-retardant polyurea waterproof coating for rigid foam roofing. Summary of the Invention

[0005] Based on this, the present invention provides a flame-retardant sprayable polyurea waterproof coating for rigid foam roof insulation, overcoming the shortcomings of existing technologies. This technical solution introduces a modified isocyanate prepolymer containing a POSS cage structure and a crosslinking agent containing a POSS cage structure into components A and B of the polyurea, respectively, enhancing the toughness, heat resistance, and flame retardancy of the polyurea system. Simultaneously, an expanded graphite flame retardant with good suspension properties is introduced into component B, solving the problems of traditional flame retardants easily agglomerating and settling over time.

[0006] One object of the present invention is to provide a flame-retardant sprayed polyurea waterproof coating for rigid foam roof insulation, the flame-retardant sprayed polyurea waterproof coating for rigid foam roof insulation comprising: component A and component B;

[0007] Component A includes a modified isocyanate prepolymer;

[0008] Component B comprises the following components in parts by mass:

[0009]

[0010] in,

[0011] The modified isocyanate prepolymer is obtained by reacting amino POSS, polyether polyol and MDI (diphenylmethane diisocyanate).

[0012] Furthermore, the NCO index ratio of component A to component B is (1.05-1.1):1.0.

[0013] Specifically, the POSS is a cage-type polysilsesquioxane.

[0014] Furthermore, the aminoPOSS is aminopropylheptaisobutyl cage-like polysilsesquioxane.

[0015] Further, the mass ratio of amino POSS, polyether polyol and MDI is (1-5):(8-13):(20-30).

[0016] Furthermore, the NCO content in the modified isocyanate prepolymer is 13.5-16.5 wt%.

[0017] Furthermore, the polyether is selected from one or more of polyether polyols and amino polyethers.

[0018] Furthermore, the polyether polyol is a polyoxypropylene-terminated polyether polyol with a molecular weight of 2000-3000 and a functionality of 2-3.

[0019] Furthermore, the amino polyether is a polyoxypropylene-terminated amino polyether, and the amino polyether has a molecular weight of 2000-5000 and a functionality of 2-3.

[0020] Preferably, the amino chain extender is selected from E100, E300, ... One or more of 4200.

[0021] Furthermore, the structural formula of the amino POSS crosslinking agent is as follows: (RSiO 3 / 2 ) n ;

[0022] Where n takes values ​​from 8 to 12;

[0023] R is selected from one or more amino groups and alkyl groups;

[0024] The number of amino groups is ≥3.

[0025] Preferably, n is 8, 10, or 12, the number of amino groups is 3, and the remaining groups are alkyl groups.

[0026] Preferably, the expanded graphite flame retardant is a PUREGL-1(A) type expanded graphite flame retardant and a PUREGL-1(B) synergistic liquid expanded graphite flame retardant;

[0027] The mass ratio of the PUREGL-1(A) type expanded graphite flame retardant to the PUREGL-1(B) synergistic liquid expanded graphite flame retardant is (20-35):10.

[0028] Furthermore, the particle size D of the PUREGL-1(A) type expanded graphite flame retardant is ≤25μm.

[0029] Specifically, this invention introduces PUREGL-1(A) expanded graphite flame retardant with good suspension properties and PUREGL-1(B) liquid synergistic expanded graphite flame retardant into component B, providing excellent flame retardant and suspension dispersion effects for the flame-retardant sprayed polyurea waterproof coating for rigid foam roof insulation. This results in better process flowability of component B, overcoming the problems of traditional solid flame retardants such as difficulty in dispersion, easy agglomeration, settling, large addition amount, high viscosity of component B, and seepage of liquid flame retardants. In addition, the tiny flame-retardant graphite particles can puncture the extremely small air bubbles in the system, making the polyurea film more compact.

[0030] Furthermore, the catalyst is selected from one or more of dibutyltin dilaurate and bismuth carboxylate.

[0031] Furthermore, the viscosity of the polyurea waterproof coating at 20-30℃ is 960-1100 mPa·s.

[0032] Furthermore, the additive is selected from one or more of wetting agents, dispersants, defoamers, leveling agents, and dust-proofing agents.

[0033] Preferably, the wetting agent is selected from one or more of BYK-P104S and BYK206.

[0034] Preferably, the dispersant is selected from one or more of BYK163, BYK110, and BYK190.

[0035] Preferably, the defoamer is selected from one or more of BYK1790, BYK085, BYK1796, and BYK1799.

[0036] Preferably, the leveling agent is selected from one or more of BYK306, BYK333, and BYK354.

[0037] Preferably, the dust suppressant is H15.

[0038] Preferably, the water-absorbing agent is a 3A molecular sieve.

[0039] The present invention also provides a method for preparing the flame-retardant sprayed polyurea waterproof coating for rigid foam roof insulation, comprising the following steps:

[0040] S1. Add amino POSS and polyether polyol to a reaction vessel, heat and dehydrate under vacuum, cool down and add MDI, then heat up and stir to react to obtain component A;

[0041] S2. Add polyether, amino chain extender, amino POSS crosslinking agent and additives to the reaction vessel and stir evenly. Then add the remaining components and stir to mix evenly to obtain component B.

[0042] S3. Mix components A and B to obtain a flame-retardant sprayed polyurea waterproof coating for rigid foam roof insulation.

[0043] Further, in step S1, the heating temperature is 100-120℃, the cooling temperature is 40-60℃, and the temperature for the heating and stirring reaction is 80-85℃.

[0044] Furthermore, in step S3, high-temperature and high-pressure spraying equipment is used to mix component A and component B.

[0045] The present invention has the following beneficial effects:

[0046] 1. Components A and B of this invention contain a modified isocyanate prepolymer with a POSS cage structure and a crosslinking agent with a POSS cage structure, respectively. The two have good compatibility. After the reaction of components A and B, the amino-POSS crosslinking agent directly introduces its cage structure into the polyurea, resulting in a stable, three-dimensional network structure. This ensures the waterproof and physicochemical properties of the polyurea while improving its flame retardant and heat resistance properties. Simultaneously, the introduction of this structure also enhances the overall toughness, strength, and hardness of the polyurea.

[0047] 2. The expanded graphite flame retardant in component B of this invention can synergistically interact with the POSS component. The introduction of the POSS structure enhances the dispersibility and support effect of the expanded graphite flame retardant, improves its suspension, and the Si-O-Si structure is stable. At high temperatures, it forms a dense silicon oxide film, which can effectively prevent the escape of small molecules produced after polyurea combustion and the dripping of molten droplets. At the same time, the modified graphite will rapidly expand and suffocate the flame under high temperature, and form a thick porous carbonized layer to adsorb molten droplets and effectively isolate heat radiation and oxygen, further preventing the escape of combustible gases, thereby reducing smoke and fire intensity. This achieves dual flame retardant function, changing the oxygen index of the polyurea coating from 18% to 30%, significantly improving the flame retardant performance of the polyurea waterproof coating. Detailed Implementation

[0048] To more clearly illustrate the technical solution of the present invention, the following embodiments are provided. Unless otherwise stated, the raw materials, reactions, and post-processing methods appearing in the embodiments are all commercially available raw materials and technical methods well known to those skilled in the art.

[0049] The terms "preferred," "more preferably," and "more suitable" used in this invention refer to embodiments of the invention that provide certain beneficial effects under certain circumstances. However, other embodiments may also be preferred under the same or other circumstances. Furthermore, the description of one or more preferred embodiments does not imply that other embodiments are unavailable, nor is it intended to exclude other embodiments from the scope of this invention.

[0050] It should be understood that, except in any operational instance or otherwise indicated, all figures representing the amounts of components used, for example, in the specification and claims, should be understood to be modified in all cases by the term "about". Therefore, unless otherwise stated, the numerical parameters set forth in the following specification and appended claims are approximations varying with the desired performance to be obtained according to the invention.

[0051] AminoPOSS is an aminopropyl heptaisobutyl cage-like polysilsesquioxane, brand name: POSS303, purchased from Guangzhou Yixin Technology Co., Ltd.

[0052] MDI was purchased from Wanhua Chemical Group Co., Ltd.

[0053] Polyether polyol 1, brand name HF-230D, molecular weight 2000, was purchased from Hebei Houfa Import and Export Trading Co., Ltd.

[0054] Polyether polyol 2, brand name HF-220D, molecular weight 2000, was purchased from Hebei Houfa Import and Export Trading Co., Ltd.

[0055] Polyether polyol 3, brand name HF-235D, molecular weight 3000, was purchased from Hebei Houfa Import and Export Trading Co., Ltd.

[0056] Amino chain extender, brand name: 6200, purchased from Wanhua Chemical Group Co., Ltd.

[0057] The amino-POSS crosslinking agent was purchased from Guangzhou Yixin Technology Co., Ltd. The structural formula of the amino-POSS crosslinking agent is as follows: (RSiO 3 / 2 ) n ;

[0058] Where n takes values ​​from 8 to 12;

[0059] R is selected from one or more amino groups and alkyl groups;

[0060] The number of amino groups is 3.

[0061] PUREGL-1(A), expanded graphite flame retardant, purchased from Weihai Yunshan Technology Co., Ltd.

[0062] PUREGL-1(B), expanded graphite synergistic flame retardant, purchased from Weihai Yunshan Technology Co., Ltd.

[0063] BYK085, BYK1790, BYK1796, and BYK1799 are defoamers purchased from BYK Chemical AG, Germany.

[0064] BYK306, BYK333, and BYK354 are leveling agents purchased from BYK Chemical AG, Germany.

[0065] Pigment, brand name PU-6826.

[0066] Molecular sieve, grade 3A.

[0067] Amino crosslinking agent, brand name T5000.

[0068] Dust suppressant, H15.

[0069] Example 1

[0070] A flame-retardant sprayed polyurea waterproof coating for rigid foam roof insulation, comprising: component A and component B;

[0071] Component A is a modified isocyanate prepolymer;

[0072] Component B comprises the following components in parts by mass:

[0073]

[0074] in,

[0075] The modified isocyanate prepolymer is obtained by reacting amino POSS, polyether polyol and MDI.

[0076] The preparation method of the flame-retardant sprayed polyurea waterproof coating for rigid foam roof insulation includes the following steps:

[0077] S1. Add 4.55 parts of amino POSS and 45.45 parts of polyether polyol 1 to a reaction vessel, stir and heat to 110°C, vacuum dehydrate for 1 hour, cool to 50°C and add 100 parts of MDI, stir for 0.5 hours, heat to 80°C and react for 2 hours to obtain component A.

[0078] S2. According to the above mass proportions, add polyether polyol 1, amino chain extender, amino POSS crosslinking agent and additives to the reaction vessel, stir evenly, then add the remaining components, stir at a stirring speed of 700 rpm for 10 min, mix evenly, and obtain component B.

[0079] S3. Using high-temperature and high-pressure spraying equipment, components A and B are mixed at 70℃ to obtain a flame-retardant sprayed polyurea waterproof coating for rigid foam roof insulation.

[0080] Example 2

[0081] A flame-retardant sprayed polyurea waterproof coating for rigid foam roof insulation, comprising: component A and component B;

[0082] Component A is a modified isocyanate prepolymer;

[0083] Component B comprises the following components in parts by mass:

[0084]

[0085] in,

[0086] The modified isocyanate prepolymer is obtained by reacting amino POSS, polyether polyol and MDI.

[0087] The preparation method of the flame-retardant sprayed polyurea waterproof coating for rigid foam roof insulation includes the following steps:

[0088] S1. Add 3.84 parts of amino POSS and 46.2 parts of polyether polyol 2 to a reaction vessel, stir and heat to 110°C, dehydrate under vacuum for 1 hour, cool to 60°C and add 100 parts of MDI, stir for 1 hour, heat to 80°C and react for 4 hours to obtain component A.

[0089] S2. According to the above mass proportions, add polyether polyol 2, amino chain extender, amino POSS crosslinking agent and additives to the reaction vessel, stir evenly, then add the remaining components, stir at a stirring speed of 900 rpm for 15 min, mix evenly, and obtain component B.

[0090] S3. Using high-temperature and high-pressure spraying equipment, components A and B are mixed at 70℃ to obtain a flame-retardant sprayed polyurea waterproof coating for rigid foam roof insulation.

[0091] Example 3

[0092] A flame-retardant sprayed polyurea waterproof coating for rigid foam roof insulation, comprising: component A and component B;

[0093] Component A is a modified isocyanate prepolymer;

[0094] Component B comprises the following components in parts by mass:

[0095]

[0096] in,

[0097] The modified isocyanate prepolymer is obtained by reacting amino POSS, polyether polyol and MDI.

[0098] The preparation method of the flame-retardant sprayed polyurea waterproof coating for rigid foam roof insulation includes the following steps:

[0099] S1. Add 16.7 parts of amino POSS and 33.3 parts of polyether polyol 3 to a reaction vessel, stir and heat to 110°C, vacuum dehydrate for 1 hour, cool to 55°C and add 100 parts of MDI, stir for 40 minutes, heat to 70°C and react for 3 hours to obtain component A.

[0100] S2. According to the above mass proportions, add polyether polyol 3, amino chain extender, amino POSS crosslinking agent and additives to the reaction vessel, stir evenly, then add the remaining components, stir at a stirring speed of 800 rpm for 12 min, mix evenly, and obtain component B;

[0101] S3. Using high-temperature and high-pressure spraying equipment, components A and B are mixed at 75°C to obtain a flame-retardant sprayed polyurea waterproof coating for rigid foam roof insulation.

[0102] Comparative Example 1

[0103] A coating, the difference between this comparative example and Example 1 is that: this comparative example removes amino POSS in step S1, while the other components and preparation methods are the same.

[0104] Comparative Example 2

[0105] A coating, the difference between this comparative example and Example 1 is that: in this comparative example, amino crosslinking agent T5000 is used to replace the amino POSS crosslinking agent in component B by mass, while other components and preparation methods are the same.

[0106] Comparative Example 3

[0107] A coating, the difference between this comparative example and Example 1 is that: in this comparative example, amino POSS is removed in step S1, and amino crosslinking agent T5000 is used to replace amino POSS crosslinking agent in component B by mass, while other components and preparation methods are the same.

[0108] Test Example 1

[0109] The coatings of Examples 1-3 and Comparative Examples 1-3 were subjected to performance tests.

[0110] The testing method is as follows:

[0111] Tensile strength: The test shall be conducted in accordance with 9.2.1 of GB / T1677-2008, with a tensile speed of 500±50 mm / min.

[0112] Tear strength: Tested according to GB / T529-2008 5.1.2 right-angled specimens, without notches, at a test speed of 500±50mm / min.

[0113] Water absorption rate: The test shall be conducted in accordance with the water absorption rate requirements in section 7.1.14 of GB / T23446-2009.

[0114] Shore hardness: The test shall be conducted in accordance with the provisions of GB / T531.1-2008. The three-layer coated specimens in 7.3 shall be stacked and flattened, and then measured with a Shore A rubber hardness tester.

[0115] Melting droplets: The combustion process observed with the naked eye.

[0116] Oxygen index: The determination was carried out in accordance with GB / T2406.2-2009 Oxygen index method for plastics - Part 2: Room temperature test.

[0117] The test results are shown in Table 1 below.

[0118] Table 1. Performance test results of the coatings in Examples 1-3 and Comparative Examples 1-3

[0119]

[0120]

[0121] The experimental results in Table 1 show that the coatings of Examples 1-3 are significantly superior to those of Comparative Examples 1-3. This demonstrates that the modified isocyanate prepolymer of this invention can produce a synergistic effect with the specific expanded graphite flame retardant and amino POSS crosslinking agent, thereby enhancing product performance. In contrast, the comparative examples, by replacing the aforementioned components, resulted in a significant decrease in coating performance. In conclusion, this invention has promising application prospects.

[0122] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0123] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A flame-retardant sprayed polyurea waterproof coating for rigid foam roof insulation, characterized in that, The flame-retardant sprayed polyurea waterproof coating for rigid foam roof insulation comprises: component A and component B; Component A includes a modified isocyanate prepolymer; Component B comprises the following components in parts by mass: 50-70 parts of polyether 24-34 parts of amino chain extender 7.5-15 parts of amino POSS crosslinking agent 8-18 parts of expanded graphite flame retardant Catalyst 0.5-0.8 parts 0.5-3 parts of auxiliary agent 3-5 parts pigment 3-8 parts absorbent; in, The modified isocyanate prepolymer is obtained by reacting amino POSS, polyether polyol and MDI. The polyether is selected from one or more of polyether polyols and amino polyethers; The modified isocyanate prepolymer contains 13.5-16.5 wt% NCO. The structural formula of the amino-POSS crosslinking agent is as follows: (RSiO 3 / 2 ) n , n is in the range of 8-12, R is selected from one or more of amino, alkyl, and the number of amino groups of the amino-POSS crosslinking agent is ≥ 3; The additives are selected from one or more of wetting agents, dispersants, defoamers, leveling agents, and dust-proofing agents.

2. The flame-retardant sprayed polyurea waterproof coating for rigid foam roof insulation according to claim 1, characterized in that, The mass ratio of amino POSS, polyether polyol and MDI is (1-5):(8-13):(20-30).

3. The flame-retardant sprayed polyurea waterproof coating for rigid foam roof insulation according to claim 1, characterized in that, The catalyst is selected from one or more of dibutyltin dilaurate and bismuth carboxylate.

4. The flame-retardant sprayed polyurea waterproof coating for rigid foam roof insulation according to claim 1, characterized in that, The viscosity of the polyurea waterproof coating at 20-30℃ is 960-1100 mPa·s.

5. The preparation method of the flame-retardant sprayed polyurea waterproof coating for rigid foam roof insulation according to any one of claims 1-4, characterized in that, Includes the following steps: S1. Add amino POSS and polyether polyol to a reaction vessel, heat and dehydrate under vacuum, cool down and add MDI, then heat up and stir to react to obtain component A; S2. Add polyether, amino chain extender, amino POSS crosslinking agent and additives to the reaction vessel and stir evenly. Then add the remaining components and stir to mix evenly to obtain component B. S3. Mix components A and B to obtain a flame-retardant sprayed polyurea waterproof coating for rigid foam roof insulation.

6. The preparation method of the flame-retardant sprayed polyurea waterproof coating for rigid foam roof insulation according to claim 5, characterized in that, In step S1, the heating temperature is 100-120℃, the cooling temperature is 40-60℃, and the heating and stirring reaction temperature is 80-85℃.

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