Preparation method of nitrogen-containing flame retardant and flame-retardant rigid polyurethane foam
By preparing the synergistic effect of nitrogen-containing flame retardant and synergistic flame retardant, the problems of flammability of polyurethane hard bubbles and low glass transition temperature are solved, which significantly improves its flame retardant performance and compressive strength, and is suitable for industrial production.
Patent Information
- Application Number
- CN202411376946.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-30
- Publication Date
- 2025-01-07
AI Technical Summary
Existing polyurethane hard foams are prone to burn when exposed to fire. The addition of flame retardant may affect its physical properties. The low glass transition temperature leads to a decrease in compressive strength, which limits its use.
Using the preparation method of nitrogen-containing flame retardant, the intermediate product is obtained and tris(2-hydroxyethyl) isocyanurate is prepared by reacting the molecular structure containing isocyanurate. The nitrogen-containing flame retardant of uric acid ester and methacryloyloxy group, and works in concert with the synergistic flame retardant, improves the flame retardant properties and glass transition temperature of polyurethane hard bubbles.
It significantly improves the flame retardant effect and grade of polyurethane hard bubbles, improves the glass transition temperature, enhances its compressive strength and physical properties, and simplifies the preparation process, which is suitable for industrial production.
Smart Images
Figure CN119264071A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of polymer materials, and in particular to a preparation method of a nitrogen-containing flame retardant and a flame-retardant polyurethane rigid foam with a high glass transition temperature. Background Art
[0002] In recent years, with the development of economy and science and technology, polyurethane foam (PUF) has been used more and more widely, becoming an indispensable and widely used material. Among them, rigid polyurethane foam (RPUF) has excellent properties such as heat insulation, sound absorption, light weight, waterproof and fireproof, and is widely used in the fields of construction, transportation, aviation, shipbuilding, electronics, furniture, etc. Especially in the field of construction, RPUF plays an important role in heat preservation and heat insulation. However, the oxygen index of non-flame-retardant polyurethane rigid foam is only 17% to 19%. It is easy to burn when encountering open flames, and the burning speed is relatively fast. The combustible components in the polyurethane rigid foam will react with oxygen in the air and release a large amount of heat, accompanied by the release of toxic and harmful gases such as carbon monoxide and hydrogen cyanide.
[0003] The flame retardant modification of polyurethane rigid foam can be carried out through flame retardant technology to improve its performance and meet the requirements of use. The so-called flame retardant technology essentially works by intervening in the three basic elements of material combustion (combustibles, fire sources and oxygen), that is, inhibiting or reducing the effects of one or more of these elements. In the application of polyurethane materials, adding flame retardants is a widely used method to reduce or inhibit the flammability of materials. In order to delay or inhibit the combustion of polyurethane rigid foam, it plays a flame retardant role by interrupting the free radical chain growth reaction of polyurethane rigid foam during the combustion process, forming a non-flammable protective film, producing a high-density gas isolation layer, and forming a relatively stable structure. However, the commonly used flame retardants for polyurethane rigid foam often have the following problems: the addition of certain flame retardants may have an adverse effect on the physical properties of polyurethane rigid foam, such as reducing its strength, toughness, flexibility, etc. Compatibility issues: some flame retardants are not compatible with the raw materials of polyurethane rigid foam, which may lead to uneven dispersion and affect the flame retardant effect and the stability of product quality.
[0004] On the other hand, the glass transition temperature (Tg) of the prepared polyurethane rigid foam is low, which means that the interaction between molecular chains is weak, and the mechanical strength indicators such as the compressive strength of the material may decrease. It is more likely to deform when subjected to greater pressure, which limits its use. Summary of the invention
[0005] Therefore, in order to overcome the shortcomings of the above-mentioned prior art, the present invention provides a method for preparing a nitrogen-containing flame retardant and a flame-retardant polyurethane rigid foam with a high glass transition temperature, which has the characteristics of being able to effectively improve the flame retardant effect and enhance the flame retardant grade.
[0006] In order to achieve the above-mentioned object, the present invention provides a method for preparing a nitrogen-containing flame retardant, comprising: step 1, reacting hydroxyethyl methacrylate with diisocyanate at a molar ratio of 1:1 to 2 to obtain an intermediate product, wherein the intermediate product is a carbamate containing an isocyanate group at one end and a methacryloyloxy group at the other end; step 2, reacting the intermediate product with tris(2-hydroxyethyl)isocyanurate according to the amount of the remaining isocyanate group to obtain a nitrogen-containing flame retardant, wherein the nitrogen-containing flame retardant is a reaction product containing an isocyanurate structure at one end of the molecule and a methacryloyloxy group at the other end.
[0007] In one embodiment, the molar ratio of hydroxyethyl methacrylate to diisocyanate is 1:1 to 1.5.
[0008] In one embodiment, the molar ratio of tris(2-hydroxyethyl)isocyanurate to the intermediate product is 1:1-2.
[0009] In one embodiment, the reaction temperature of step 1 is 30-50°C, and the reaction temperature of step 2 is 30-50°C.
[0010] In one embodiment, the reaction temperature of step 1 is 30-40°C, and the reaction temperature of step 2 is 30-40°C.
[0011] In one embodiment, 0.01-0.1 parts of a catalyst is further added in step 2, and the catalyst is at least one of triethylenediamine, triethylamine, and dibutyltin dilaurate.
[0012] In one embodiment, in step 2, the weight portion of the intermediate product is 30-60 parts; the weight portion of tris(2-hydroxyethyl)isocyanurate is 20-40 parts; and the weight portion of the catalyst is 0.01-0.1 parts.
[0013] A flame retardant polyurethane rigid foam has a high glass transition temperature and comprises a nitrogen-containing flame retardant and a synergistic flame retardant mixed in a predetermined mass ratio, wherein the nitrogen-containing flame retardant is prepared by the above-mentioned preparation method.
[0014] In one embodiment, the synergistic flame retardant includes at least one of tris(2,3-dibromopropyl)isocyanurate, tris(2-chloropropyl)phosphate, and brominated epoxy resin.
[0015] In one embodiment, the weight ratio of the nitrogen-containing flame retardant to the synergistic flame retardant is 100:10-20.
[0016] Compared with the prior art, the advantages of the present invention are: the molecular structure of the generated nitrogen-containing flame retardant contains more N elements and flame retardant structures such as rigid rings, and has higher thermal stability and chemical stability than other small molecule nitrogen-containing compounds. At the same time, the molecular structure contains more hydroxyl groups, which can participate in the gel reaction of polyurethane rigid foam during the curing and molding process of polyurethane rigid foam, so that it can increase the glass transition temperature of polyurethane rigid foam as a foam structure.
[0017] In addition, nitrogen-containing flame retardants can significantly improve the flame retardant properties of polyurethane rigid foam by working synergistically with synergistic flame retardant components, thereby making the flame retardant polyurethane rigid foam have good flame retardant effect and grade. Ultimately, the resulting flame retardant polyurethane rigid foam with a high glass transition temperature has a high flame retardant grade while meeting the polyurethane rigid foam molding process.
[0018] Moreover, the preparation method adopted by the present invention has a short preparation route, mild reaction, no need for pressure reaction equipment, simple preparation process, convenient operation, mild reaction conditions, and is suitable for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0020] Figure 1 It is a reaction diagram of the preparation method of the nitrogen-containing flame retardant in the embodiment of the present invention. DETAILED DESCRIPTION
[0021] The embodiments of the present application are described in detail below with reference to the accompanying drawings.
[0022] The following describes the implementation methods of the present application through specific specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The present application can also be implemented or applied through other different specific implementation methods, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, in the absence of conflict, the following embodiments and the features in the embodiments can be combined with each other. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work belong to the scope of protection of the present application.
[0023] It should be noted that various aspects of the embodiments within the scope of protection of the present invention are described below. It should be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on the present application, it should be understood by those skilled in the art that an aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number and aspect described herein can be used to implement the device and / or practice the method. In addition, other structures and / or functionalities other than one or more of the aspects described herein can be used to implement this device and / or practice this method.
[0024] It should also be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present application. The drawings only show components related to the present application rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.
[0025] Additionally, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, it will be understood by those skilled in the art that the aspects described may be practiced without these specific details.
[0026] like Figure 1 As shown, the present invention provides a method for preparing a nitrogen-containing flame retardant, comprising the following steps:
[0027] Step 1: reacting hydroxyethyl methacrylate with diisocyanate at a molar ratio of 1:1 to 2 to obtain an intermediate product, which is a carbamate containing an isocyanate group at one end and a methacryloyloxy group at the other end.
[0028] The diisocyanate is first reacted with hydroxyethyl methacrylate to obtain an intermediate product. In one embodiment, the molar ratio of hydroxyethyl methacrylate to diisocyanate is 1:(1-2); preferably, the molar ratio is 1:(1-1.5); more preferably, the molar ratio is 1:(1-1.3); further preferably, the molar ratio is 1:(1-1.2). Specifically, it corresponds to the following reaction formula:
[0029]
[0030] Step 2: react the intermediate product with tris(2-hydroxyethyl)isocyanurate according to the amount of the remaining isocyanate group to obtain a nitrogen-containing flame retardant, wherein the nitrogen-containing flame retardant has an isocyanurate structure at one end of the molecule and a methacryloyloxy group at the other end.
[0031] The intermediate product is reacted with tris(2-hydroxyethyl)isocyanurate according to the amount of the remaining isocyanate groups contained to obtain a nitrogen-containing flame retardant.
[0032] In one embodiment, the molar ratio of tris(2-hydroxyethyl)isocyanurate to diisocyanate is 1:(1-2); preferably, the molar ratio is 1:(1-1.5); more preferably, the molar ratio is 1:(1-1.3); further preferably, the molar ratio is 1:(1-1.2).
[0033]
[0034] In one embodiment, the reaction temperature of step 1 is 30-50°C, and the reaction temperature of step 2 is 30-50°C.
[0035] In one embodiment, the reaction temperature of step 1 is 30-40°C, and the reaction temperature of step 2 is 30-40°C.
[0036] In one embodiment, 0.01-0.1 parts of a catalyst is further added in step 2, and the catalyst is at least one of triethylenediamine, triethylamine, and dibutyltin dilaurate.
[0037] In one embodiment, in step 2, the weight portion of the intermediate product is 30-60 parts; the weight portion of tris(2-hydroxyethyl)isocyanurate is 20-40 parts; and the weight portion of the catalyst is 0.01-0.1 parts.
[0038] A flame retardant polyurethane rigid foam with a high glass transition temperature, the flame retardant polyurethane rigid foam has a high glass transition temperature, the flame retardant polyurethane rigid foam comprises a nitrogen-containing flame retardant and a synergistic flame retardant mixed in a predetermined mass ratio, wherein the nitrogen-containing flame retardant is prepared by the above-mentioned preparation method. The flame retardant polyurethane rigid foam also comprises a common foaming polyurethane rigid foam formula.
[0039] The foamable polyurethane rigid foam formula comprises polyether polyol, crosslinking agent, flame retardant, foam leveling agent, catalyst and foaming agent. The weight ratio of the foamable polyurethane rigid foam formula to the nitrogen-containing flame retardant and the synergistic flame retardant can be 100:20:2-4.
[0040] The polyether polyol is polyether polyol 4110 provided by Shandong Dahua Chemical Technology Co., Ltd., with a weight portion of 100 parts.
[0041] The cross-linking agent is DV-125 provided by Shandong Dahua Chemical Technology Co., Ltd., with a weight portion of 10 parts.
[0042] The flame retardant is FR-TCPP provided by Zhejiang Xin'an Chemical Industry Group Co., Ltd., with a weight portion of 10 parts.
[0043] The foam leveling agent is AK8805 silicone oil foam leveling agent, and the weight proportion is 1.5 parts.
[0044] The catalyst is a mixture of N, N-dimethylcyclohexylamine, pentamethyldiethylenetriamine and N, N-dimethylbenzylamine in a mass ratio of 2:2:1, with a weight portion of 2 parts.
[0045] The foaming agent is water, with a weight portion of 3 parts.
[0046] In one embodiment, the synergistic flame retardant includes at least one of tris(2,3-dibromopropyl)isocyanurate, tris(2-chloropropyl)phosphate, and brominated epoxy resin.
[0047] In one embodiment, the weight ratio of the nitrogen-containing flame retardant to the synergistic flame retardant is 100:10-20.
[0048] The sources of the reagents and instruments used in the following examples are as follows:
[0049] Table 1 Reagents and instruments used in the examples
[0050] Reagents / Instruments Purity / Model factory Isophorone diisocyanate CP Wuhan Fuxinyuan Technology Co., Ltd. Hydroxyethyl Methacrylate CP Shanghai Titan Technology Co., Ltd. Tris(2-hydroxyethyl)isocyanurate CP Beijing Lingbao Technology Co., Ltd. Oxygen Index Tester JF-3 Jiangsu Zhengrui Taibang Electronic Technology Co., Ltd. Dynamic Mechanical Analyzer DMA242E German NETZSCH dynamic thermal analyzer
[0051] Example 1
[0052] Step 1: add 10 g of isophorone diisocyanate (IPDI) to a 500 mL four-necked flask equipped with a thermometer and a condenser, heat to 30° C. under nitrogen protection, and start the stirrer; slowly add 5.86 g of hydroxyethyl methacrylate from which water has been removed dropwise three times, and add 3 drops of triethylamine (as a catalyst); react for 1 hour to obtain an intermediate product of a carbamate containing an isocyanate group at one end and a methacryloyloxy group at the other end;
[0053] Step 2: add 11.76 g of tris(2-hydroxyethyl)isocyanurate to a flask, slowly drop the intermediate product into the flask, and add 3 drops of triethylamine (as a catalyst); after the dropwise addition is completed, slowly raise the temperature to 50° C. and continue the reaction for 2 hours to obtain a nitrogen-containing flame retardant having an isocyanurate structure at one end of the molecule and a methacryloyloxy group at the other end;
[0054] Step three, the nitrogen-containing flame retardant obtained in step two and the brominated epoxy resin as a synergistic flame retardant are mixed in a weight ratio of 100:10, so as to be subsequently reacted with the foaming polyurethane rigid foam formula to prepare a flame-retardant polyurethane rigid foam with a high glass transition temperature.
[0055] Example 2
[0056] Step 1: add 10 g of isophorone diisocyanate (IPDI) to a 500 mL four-necked flask equipped with a thermometer and a condenser, heat to 30° C. under nitrogen protection, and start the stirrer; slowly add 33.78 g of hydroxyethyl methacrylate from which water has been removed dropwise three times, and add 0.01 g of triethylenediamine (as a catalyst); react for 1 hour to obtain an intermediate product of a carbamate containing an isocyanate group at one end and a methacryloyloxy group at the other end;
[0057] Step 2: add 8.51 g of tris(2-hydroxyethyl)isocyanurate into a flask, slowly drop the reaction product I obtained in step 1 into the flask, and add 0.01 g of triethylenediamine (as a catalyst); after the dropwise addition is completed, slowly raise the temperature to 40° C. and continue the reaction for 2 h to obtain a nitrogen-containing flame retardant having an isocyanurate structure at one end of the molecule and a methacryloyloxy group at the other end;
[0058] Step three, the nitrogen-containing flame retardant obtained in step two and tris(2,3-dibromopropyl)isocyanurate (TBC) as a synergistic flame retardant are mixed in a weight ratio of 100:10, so as to be subsequently reacted with a foaming polyurethane rigid foam formula to prepare a flame-retardant polyurethane rigid foam with a high glass transition temperature.
[0059] Example 3
[0060] Step 1: add 10 g of isophorone diisocyanate (IPDI) to a 500 mL four-necked flask equipped with a thermometer and a condenser, heat to 30° C. under nitrogen protection, and start the stirrer; slowly add 33.78 g of hydroxyethyl methacrylate from which water has been removed in three times, and add 3 drops of dibutyltin dilaurate (as a catalyst); react for 1 hour to obtain an intermediate product of a carbamate containing an isocyanate group at one end and a methacryloyloxy group at the other end;
[0061] Step 2: add 8.51 g of tris(2-hydroxyethyl)isocyanurate into a flask, slowly drop the reaction product I obtained in step 1 into the flask, and add 3 drops of dibutyltin dilaurate (as a catalyst); after the dropwise addition is completed, slowly raise the temperature to 40° C. and continue the reaction for 2 hours to obtain a nitrogen-containing flame retardant having an isocyanurate structure at one end of the molecule and a methacryloyloxy group at the other end;
[0062] Step three, the nitrogen-containing flame retardant obtained in step two and the brominated epoxy resin as a synergistic flame retardant are mixed in a weight ratio of 100:10, so as to be subsequently reacted with the foaming polyurethane rigid foam formula to prepare a flame-retardant polyurethane rigid foam with a high glass transition temperature.
[0063] Examples 4 to 8 use the novel nitrogen-containing flame retardant and synergistic flame retardant prepared in Examples 1, 2, and 3 to prepare flame-retardant polyurethane rigid foams with a high glass transition temperature.
[0064] Example 4
[0065] The mixture of the nitrogen-containing flame retardant and the synergistic flame retardant prepared in Example 1 is added to the foaming polyurethane rigid foam formula to prepare a flame-retardant modified polyurethane rigid foam.
[0066] The one-step free process is adopted for foaming. First, the raw materials such as polyether polyol, crosslinking agent, flame retardant, foam leveling agent, catalyst, foaming agent, nitrogen-containing flame retardant and synergistic flame retardant prepared in Example 1 are accurately weighed according to the ratio and mixed into a cup. The mixture is stirred evenly in the cup to obtain component B. Then, isocyanate (PAPI) is weighed as component A in another cup, component A is quickly poured into component B, stirred quickly, and the milky time of polyurethane foaming is recorded. Finally, the foamed foam is placed for one week to dry to obtain flame-retardant RPUF. The prepared foam is cut according to the requirements of the required test performance, and then its performance is tested.
[0067] Example 5
[0068] The mixture of the nitrogen-containing flame retardant and the synergistic flame retardant prepared in Example 2 is added to the foaming polyurethane rigid foam formula to prepare a flame-retardant modified polyurethane rigid foam.
[0069] The one-step free process is adopted for foaming. First, the raw materials such as polyether polyol, crosslinking agent, flame retardant, foam leveling agent, catalyst, foaming agent, nitrogen-containing flame retardant and synergistic flame retardant prepared in Example 2 are accurately weighed according to the ratio and mixed into a cup. The mixture is stirred evenly in the cup to obtain component B. Then, isocyanate (PAPI) is weighed as component A in another cup, component A is quickly poured into component B, stirred quickly, and the milky time of polyurethane foaming is recorded. Finally, the foamed foam is placed for a week to dry to obtain flame-retardant RPUF. The prepared foam is cut according to the requirements of the required test performance, and then its performance is tested.
[0070] Example 6
[0071] The mixture of the nitrogen-containing flame retardant and the synergistic flame retardant prepared in Example 3 is added to the foaming polyurethane rigid foam formula to prepare a flame-retardant modified polyurethane rigid foam.
[0072] The one-step free process is adopted for foaming. First, the raw materials such as polyether polyol, crosslinking agent, flame retardant, foaming agent, catalyst, foaming agent, nitrogen-containing flame retardant and synergistic flame retardant prepared in Example 3 are accurately weighed according to the ratio and mixed into a cup. The mixture is stirred evenly in the cup to obtain component B. Then, isocyanate (PAPI) is weighed as component A in another cup, component A is quickly poured into component B, stirred quickly, and the milky time of polyurethane foaming is recorded. Finally, the foamed foam is placed for one week to dry to obtain flame-retardant RPUF. The prepared foam is cut according to the requirements of the required test performance, and then its performance is tested.
[0073] Example 7
[0074] The mixture of the nitrogen-containing flame retardant and the synergistic flame retardant prepared in Example 1 was supplemented with 10 parts of tris(2-chloropropyl) phosphate (TCPP) at a mass ratio of 40:100 and added into the foaming polyurethane rigid foam formula to prepare a flame-retardant modified polyurethane rigid foam.
[0075] The one-step free process is adopted for foaming. First, the raw materials such as polyether polyol, crosslinking agent, flame retardant, foam leveling agent, catalyst, foaming agent, nitrogen-containing flame retardant and synergistic flame retardant prepared in Example 1 are accurately weighed according to the ratio and mixed into a cup. The mixture is stirred evenly in the cup to obtain component B. Then, isocyanate (PAPI) is weighed as component A in another cup, component A is quickly poured into component B, stirred quickly, and the milky time of polyurethane foaming is recorded. Finally, the foamed foam is placed for one week to dry to obtain flame-retardant RPUF. The prepared foam is cut according to the requirements of the required test performance, and then its performance is tested.
[0076] Example 8
[0077] The mixture of the nitrogen-containing flame retardant and the synergistic flame retardant prepared in Example 1 was supplemented with 10 parts of tris(2-chloropropyl) phosphate (TCPP) at a mass ratio of 40:100 and added into the foaming polyurethane rigid foam formula to prepare a flame-retardant modified polyurethane rigid foam.
[0078] The one-step free process is adopted for foaming. First, the raw materials such as polyether polyol, crosslinking agent, flame retardant, foam leveling agent, catalyst, foaming agent, nitrogen-containing flame retardant and synergistic flame retardant prepared in Example 1 are accurately weighed according to the ratio and mixed into a cup. The mixture is stirred evenly in the cup to obtain component B. Then, isocyanate (PAPI) is weighed as component A in another cup, component A is quickly poured into component B, stirred quickly, and the milky time of polyurethane foaming is recorded. Finally, the foamed foam is placed for one week to dry to obtain flame-retardant RPUF. The prepared foam is cut according to the requirements of the required test performance, and then its performance is tested.
[0079] Comparative Example 1
[0080] The mixture of the nitrogen-containing flame retardant and the synergistic flame retardant prepared in Example 3 was added to the foaming polyurethane rigid foam formula at a mass ratio of 0:100 to prepare a flame-retardant modified polyurethane rigid foam.
[0081] The one-step free process is adopted for foaming. First, the raw materials such as polyether polyol, crosslinking agent, flame retardant, foaming agent, catalyst, foaming agent, etc. are accurately weighed according to the ratio and mixed into a cup. The mixture is stirred evenly in the cup to obtain component B. Then, isocyanate (PAPI) is weighed as component A in another cup, and component A is quickly poured into component B, stirred quickly, and the milky time of polyurethane foaming is recorded. Finally, the foamed foam is placed for a week to dry to obtain flame-retardant RPUF. The prepared foam is cut according to the requirements of the required test performance, and then its performance is tested.
[0082] Comparative Example 2
[0083] The mixture of the nitrogen-containing flame retardant and the synergistic flame retardant prepared in Example 3 was added to the foaming polyurethane rigid foam formula at a mass ratio of 5:100 to prepare a flame-retardant modified polyurethane rigid foam.
[0084] The one-step free process is adopted for foaming. First, the raw materials such as polyether polyol, crosslinking agent, flame retardant, foaming agent, catalyst, foaming agent, etc. are accurately weighed according to the ratio and mixed into a cup. The mixture is stirred evenly in the cup to obtain component B. Then, isocyanate (PAPI) is weighed as component A in another cup, and component A is quickly poured into component B, stirred quickly, and the milky time of polyurethane foaming is recorded. Finally, the foamed foam is placed for a week to dry to obtain flame-retardant RPUF. The prepared foam is cut according to the requirements of the required test performance, and then its performance is tested.
[0085] The test results of Examples 4 to 8 and Comparative Examples 1 to 2 are listed in the table below.
[0086]
[0087]
[0088] According to the above table, it can be concluded that the prepared nitrogen-containing flame retardant effectively improves the flame retardancy and heat resistance of polyurethane rigid foam, thereby widening its application range.
[0089] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed in the present application should be included in the protection scope of the present application.
Claims
1. A method for preparing a nitrogen-containing flame retardant, characterized in that: include: Step 1, reacting hydroxyethyl methacrylate with diisocyanate in a molar ratio of 1:1 to 2 to obtain an intermediate product, which is a carbamate containing an isocyanate group at one end and a methacryloyloxy group at the other end; Step 2: reacting the intermediate product with tris(2-hydroxyethyl)isocyanurate according to the amount of residual isocyanate groups contained to obtain a nitrogen-containing flame retardant, wherein one end of the nitrogen-containing flame retardant molecule contains an isocyanurate structure and the other end contains a methacryloyloxy group.
2. The preparation method according to claim 1, characterized in that: The molar ratio of the hydroxyethyl methacrylate to the diisocyanate is 1:1 to 1.
5.
3. The preparation method according to claim 1, characterized in that: The molar ratio of tris(2-hydroxyethyl)isocyanurate to the intermediate product is 1:1-2.
4. The preparation method according to claim 1, characterized in that: The reaction temperature of step 1 is 30-50°C, and the reaction temperature of step 2 is 30-50°C.
5. The preparation method according to claim 4, characterized in that: The reaction temperature of step 1 is 30-40°C, and the reaction temperature of step 2 is 30-40°C.
6. The preparation method according to claim 1, characterized in that: In step 2, 0.01-0.1 parts of a catalyst are also added, wherein the catalyst is at least one of triethylenediamine, triethylamine and dibutyltin dilaurate.
7. The preparation method according to claim 6, characterized in that: In step 2, the weight proportion of the intermediate product is 30-60 parts; the weight proportion of tris(2-hydroxyethyl)isocyanurate is 20-40 parts; and the weight proportion of the catalyst is 0.01-0.1 parts.
8. A flame retardant polyurethane rigid foam, characterized in that: The flame retardant polyurethane rigid foam has a high glass transition temperature, and the flame retardant polyurethane rigid foam comprises a nitrogen-containing flame retardant and a synergistic flame retardant mixed in a predetermined mass ratio. Wherein, the nitrogen-containing flame retardant is prepared by the preparation method according to any one of claims 1 to 7.
9. The flame retardant polyurethane rigid foam according to claim 1, characterized in that: The synergistic flame retardant includes at least one of tris(2,3-dibromopropyl)isocyanurate, tris(2-chloropropyl)phosphate, and brominated epoxy resin.
10. The flame retardant polyurethane rigid foam according to claim 1, characterized in that: The weight ratio of the nitrogen-containing flame retardant to the synergistic flame retardant is 100:10-20.