Foam-stabilizing flame-retardant silicone oil for flame-retardant rigid polyurethane foam plastic and preparation method of foam-stabilizing flame-retardant silicone oil

Abstract

The invention relates to foam-stabilizing flame-retardant silicone oil for flame-retardant rigid polyurethane foam plastic and a preparation method of the foam-stabilizing flame-retardant silicone oil, and belongs to the field of flame-retardant polyurethane materials. The foam-uniform flame-retardant silicone oil prepared by the method is dark brown liquid with flowability, the temperature of the maximum decomposition rate is 274.39-292.42 DEG C, and the carbon residue amount at 800 DEG C is 2.78-9.57%. According to the invention, through a reaction between a primary amine group on a thiadiazole ring and an epoxy group on silicone oil, flame-retardant elements sulfur and nitrogen are introduced into a molecular chain of silicone oil, so that the silicone oil has foam-stabilizing and flame-retardant effects in the foaming process. The foam-uniform flame-retardant silicone oil is used for preparing flame-retardant rigid polyurethane foam plastic, so that the flame-retardant property of the rigid polyurethane foam plastic is improved, and meanwhile, the overall mechanical property and the percentage of closed area of the rigid polyurethane foam plastic are enhanced by utilizing the particularity of a chemical molecular structure.

Description

Technical Field

[0001] The invention belongs to the field of flame-retardant polyurethane materials, and particularly relates to a uniform-bubble flame-retardant silicone oil for flame-retardant polyurethane rigid foam plastics and a preparation method thereof. Background Art

[0002] Rigid polyurethane foam (RPUF) is a polymer-based foam containing urethane groups in its backbone. It features low density, high specific strength, low thermal conductivity, good solvent resistance, high bonding strength, and excellent sound insulation. It is widely used in industrial and civilian applications, such as insulation for buildings, pipelines, refrigerators, and cold storage, as well as in oil pipelines and transportation. However, RPUF has a low limiting oxygen index (LOI), typically between 17% and 18%, making it highly flammable. In the event of a fire, RPUF burns violently, with flames spreading rapidly and generating significant heat. Furthermore, the combustion process releases toxic gases such as HCN and CO, which pose a health hazard. Therefore, the development of flame-retardant RPUF has become a hot topic of research.

[0003] Foam stabilizers are essential components in the rigid polyurethane foam foaming process. Also known as foam stabilizers, they reduce the surface tension of liquids, creating a uniform and stable foam and preventing it from breaking during formation. While the dosage of foam stabilizers is generally small, they significantly impact foam synthesis and product properties. They can be categorized as silicone or non-silicone, with silicone foam stabilizers being preferred due to their excellent stabilization properties. The foaming process of rigid polyurethane foam is extremely rapid. When the various components of the white material are mixed with the black material, a rapid reaction occurs immediately. During this process, the molecular weight of the rigid polyurethane foam increases significantly, along with its viscosity. The mixture of white and black materials gradually transforms from a liquid to a solid state. The heat released during this reaction vaporizes the foaming agent, further promoting the foaming and molding of the rigid polyurethane foam.

[0004] The foaming agent plays a key role in this process. It can coordinate the gas growth rate and gelation rate of rigid polyurethane foam plastics, so that the two reach a dynamic balance, thereby ensuring that the prepared rigid polyurethane foam plastics have a uniform cell structure. Specifically, the foaming agent has three main functions: first, it can promote the full fusion of the various components in the white material, improve the mixing uniformity, and thus optimize the reaction effect; second, in the initial stage of rigid polyurethane foam foaming, the foaming agent can play a "nucleation" role, providing a core for bubble formation and helping to generate uniform cells; third, by effectively reducing the surface tension of the liquid mixture, it enhances the stability of the foaming process and improves the final foaming quality.

[0005] It is worth noting that there is relatively little research in the academic community on the effects of foam leveling agents on the flame retardant properties of rigid polyurethane foam plastics, and relevant literature is relatively scarce. Summary of the Invention

[0006] In order to improve the flame retardant function, the present invention provides a uniform foam flame retardant silicone oil for flame retardant polyurethane rigid foam plastics, and at the same time, provides a preparation method of the uniform foam flame retardant silicone oil for flame retardant polyurethane rigid foam plastics.

[0007] The structural formula of a flame-retardant silicone oil for flame-retardant polyurethane rigid foam plastics is as follows:

[0008]

[0009] The uniformly foamed flame-retardant silicone oil is a dark brown fluid liquid, the temperature of the maximum decomposition rate is 274.39-292.42° C., and the residual carbon content at 800° C. is 2.78-9.57%.

[0010] The preparation steps of flame retardant silicone oil for flame retardant polyurethane rigid foam are as follows:

[0011] (1) Dissolving the epoxy-terminated silicone oil and 2-amino-5-mercapto-1, 3, 4-thiadiazole in a solvent, adding a catalyst, and heating the mixture for reaction to obtain a reactant;

[0012] The molar ratio of the epoxy group in the epoxy-terminated silicone oil to the primary amino group in the 2-amino-5-mercapto-1, 3, 4-thiadiazole is 1:0.4-1:1.2;

[0013] The epoxy value of the epoxy-terminated silicone oil is 0.490 mol / 100 g-0.530 mol / 100 g;

[0014] The solvent is N,N-dimethylformamide, and the amount used is 2-3 times the mass of the reactants;

[0015] The catalyst is an aminophenol substance, and the catalyst selected is 2, 4, 6-tris (dimethylaminomethyl) phenol;

[0016] The amount of catalyst added is 0.1% of the sum of the mass of the epoxy-terminated silicone oil and 2-amino-5-mercapto-1,3,4-thiadiazole;

[0017] (2) The reactants are subjected to reduced pressure distillation, washing, and centrifugation, and the precipitate is dried to obtain uniform foam flame retardant silicone oil.

[0018] Further preparation technology scheme is as follows:

[0019] In step (1), the reaction synthesis conditions are: heating temperature is 100-130°C, and the reaction is kept warm for 4-8 hours under nitrogen atmosphere.

[0020] In step (2), the washing conditions are: washing the product obtained by vacuum distillation three times with deionized water at 60-80°C.

[0021] In step (2), the vacuum drying conditions are: drying temperature is 100°C, and drying time is 24h.

[0022] The beneficial technical effects of the present invention are embodied in the following aspects:

[0023] (1) Silicone oil itself is a surfactant that plays the role of a foaming agent in polyurethane foaming. In the existing technology, it is generally only considered as a foam stabilizer. The present invention introduces flame retardant elements sulfur and nitrogen into the molecular chain of silicone oil through the reaction between the primary amine group on the thiadiazole ring and the epoxy group on the silicone oil, so that it can simultaneously play a foaming and flame retardant effect during the foaming process.

[0024] The total smoke release and total heat release of the uniform foam flame retardant silicone oil prepared by the present invention are both less than those of the epoxy-terminated silicone oil when the temperature is 30°C to 800°C. The total smoke release of the unmodified epoxy-terminated silicone oil is 1561.09 (m 2 / m 2 ), the total heat release is 71.75 (MJ / m 2 The total smoke emission of the modified flame-retardant silicone oil is only 314.17 (m 2 / m 2 ), the total heat release is 65.08 (MJ / m 2 ). Moreover, the ignition time of the modified uniform foam flame retardant silicone oil of the present invention is extended by 52 s compared with that of the epoxy silicone oil.

[0025] (2) The present invention not only improves the flame retardancy of rigid polyurethane foam plastics, but also utilizes the uniqueness of its chemical molecular structure to enhance the overall mechanical properties of the rigid polyurethane foam material. During the foaming process, when the mass fraction of expandable graphite (EG) is too high, although the flame retardancy level can reach V-0, the mechanical properties and closed cell ratio are reduced. When an appropriate amount of the present invention's uniformly foamed flame retardant silicone oil is added, the mechanical properties and closed cell ratio are improved while the flame retardancy level remains unchanged.

[0026] Because the hydroxyl groups in the uniformly foamed flame-retardant silicone oil molecules react with isocyanate groups to form urethane bonds, which form part of the rigid chain segment, this increases the compressive strength of the polyurethane foam. Simultaneously, the introduction of Si-O-Si bonds also improves structural stability. At the very beginning of the reaction, the uniformly foamed flame-retardant silicone oil reduces the surface tension of the foaming reaction system, allowing the air mixed in during stirring to form a certain number of bubble nuclei. These bubble nuclei act like "seed crystals" during the foaming process, enabling the foam to form smoothly and gradually expand. This nucleation effect of the uniformly foamed flame-retardant silicone oil helps form a uniform foam, thereby increasing the closed-cell ratio.

[0027] The flame retardant polyurethane rigid foam prepared by using the uniformly foamed flame retardant silicone oil of the present invention has a flame retardant grade of V-0, a closed cell rate of 97.21%, and a compressive strength of 0.33 MPa.

[0028] (3) The present invention introduces flame retardant elements sulfur and nitrogen into the molecular structure of silicone oil to prepare uniform flame retardant silicone oil with good flame retardant effect, thereby enhancing the flame retardant properties of polyurethane materials and improving the mechanical properties of polyurethane foam to a certain extent. Due to the addition of sulfur, the flame retardant process mainly occurs in the condensed phase, and acidic substances are produced during the combustion process, promoting dehydration and carbonization; the nitrogen flame retardant process occurs in the gas phase, and non-flammable gas ammonia is produced during the combustion process, which can dilute the concentration of combustible gases around the material and play a role in gas phase flame retardancy; and sulfur- and nitrogen-containing flame retardants are much less toxic than halogen flame retardants and phosphorus-containing flame retardants, and the former have better smoke suppression effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is the NMR spectrum of epoxy-terminated silicone oil;

[0030] Figure 2 This is the NMR spectrum of the uniformly foamed flame-retardant silicone oil of Example 1;

[0031] Figure 3 This is the infrared spectrum of the uniformly foamed flame-retardant silicone oil, the epoxy-terminated silicone oil, and 2-amino-5-mercapto-1, 3, 4-thiadiazole in Example 1;

[0032] Figure 4 This is a cone calorimetric total smoke emission curve of the uniform foam flame retardant silicone oil prepared in Example 1 and the epoxy-terminated silicone oil in the prior art;

[0033] Figure 5 The cone calorimetric total heat release curves of the uniform foam flame retardant silicone oil prepared in Example 1 and the epoxy-terminated silicone oil in the prior art are shown;

[0034] Figure 6The thermogravimetric curves of the uniform foam flame retardant silicone oil prepared in Examples 1-4 and the epoxy-terminated silicone oil in the prior art are shown;

[0035] Figure 7 Schematic diagram of combustion of terminated epoxy silicone oil;

[0036] Figure 8 This is a combustion schematic diagram of Example 1;

[0037] Figure 9 This is a combustion schematic diagram of Example 2;

[0038] Figure 10 This is a combustion schematic diagram of Example 3;

[0039] Figure 11 This is a combustion schematic diagram of Example 4;

[0040] Figure 12 Schematic diagram of vertical combustion in Application Example 2;

[0041] Figure 13 Schematic diagram of vertical combustion in Application Example 3;

[0042] Figure 14 Schematic diagram of vertical combustion in Application Example 4. DETAILED DESCRIPTION

[0043] The present invention will be further described below with reference to the accompanying drawings through embodiments.

[0044] Example 1

[0045] The preparation steps of a uniform foam flame retardant silicone oil are as follows:

[0046] (1) Add 50 g of epoxy-terminated silicone oil, 43.255 g of 2-amino-5-mercapto-1, 3, 4-thiadiazole and 0.093 g of 2, 4, 6-tris(dimethylaminomethyl)phenol to 250 mL of N, N-dimethylformamide, stir to dissolve, and heat to 130 °C. Keep the mixture warm under nitrogen for 6 h to obtain the reactant.

[0047] The structural formula of epoxy-terminated silicone oil is shown in Figure 1 The epoxy value is 0.490 mol / 100 g. The molar ratio of the epoxy group in the epoxy-terminated silicone oil to the primary amino group in the 2-amino-5-mercapto-1, 3, 4-thiadiazole is 1:1.2.

[0048] The amount of solvent N, N-dimethylformamide used is 2.5 times the total mass of the epoxy-terminated silicone oil and 2-amino-5-mercapto-1, 3, 4-thiadiazole.

[0049] The amount of catalyst 2, 4, 6-tris(dimethylaminomethyl)phenol added is 0.1% of the total mass of the epoxy-terminated silicone oil and 2-amino-5-mercapto-1, 3, 4-thiadiazole.

[0050] (2) The reactants were distilled under reduced pressure at 90°C for 3 h in a vacuum oven to remove N, N-dimethylformamide. The product after reduced pressure distillation was washed with 3000 mL of deionized water at 80°C three times to remove 2-amino-5-mercapto-1, 3, 4-thiadiazole and 2, 4, 6-tris(dimethylaminomethyl)phenol. The washed product was dried in a vacuum drying oven at 100°C for 24 h to obtain a uniformly foamed flame-retardant silicone oil.

[0051] See also Figure 1 The peaks at 2.71 ppm and 3.07 ppm (corresponding to position a) are attributed to the characteristic peaks of the methylene group on the epoxy group, and the peak at 3.21 ppm (corresponding to position b) is attributed to the characteristic peak of the methine group on the epoxy group. The characteristic peaks of the methylene group connected to carbon and oxygen appear at 3.37 ppm and 3.65 ppm (corresponding to position c), the characteristic peak at 2.50 ppm is attributed to the solvent peak, and the characteristic peak at 3.32 ppm is attributed to the water peak.

[0052] See also Figure 2 The peaks at 3.04 ppm and 3.23 ppm (corresponding to a') are attributed to the characteristic peaks of the methylene group on the epoxy group, and the peak at 3.83 ppm (corresponding to b') is attributed to the characteristic peak of the methine group on the epoxy group. The characteristic peaks of the methylene group connected to carbon and oxygen appear at 3.43 ppm and 3.64 ppm (corresponding to c'), the characteristic peak at 5.21 ppm (corresponding to d) is attributed to the characteristic peak of the hydroxyl group, the characteristic peak at 7.23 ppm corresponds to the characteristic peak of the imino group at e, the characteristic peak at 11.49 ppm (corresponding to f) is attributed to the characteristic peak of the thiol group on the thiadiazole ring, the characteristic peak at 2.50 ppm corresponds to the solvent peak, and the characteristic peak at 3.32 ppm corresponds to the water peak.

[0053] The structural formula of the uniform foam flame retardant silicone oil prepared in Example 1 is as follows:

[0054]

[0055] See also Figure 3 , Infrared spectra of the flame retardant silicone oil, epoxy-terminated silicone oil, and 2-amino-5-mercapto-1, 3, 4-thiadiazole of Example 1; 3295 cm -1 , 3172 cm -1 The absorption peak at 1621 cm is attributed to the characteristic absorption peak of -NH- and -OH on the flame retardant silicone oil.-1 The absorption peak at 1253 cm is the characteristic absorption peak of C=N stretching vibration on the thiadiazole group of the uniform foam flame retardant silicone oil. -1 The absorption peak at 910 cm is attributed to the characteristic absorption peak of Si-CH3 on the epoxy-terminated silicone oil. -1 It is the characteristic absorption peak of the epoxy group on the epoxy-terminated silicone oil, 3330 cm -1 , 3245 cm -1 It is the characteristic absorption peak of -NH2 on 2-amino-5-mercapto-1, 3, 4-thiadiazole, 1605 cm -1 The absorption peak at is the characteristic absorption peak of C=N stretching vibration on the thiadiazole group.

[0056] See also Figure 4 The total smoke release of the uniform foam flame retardant silicone oil prepared in Example 1 is 314.17 m 2 / m 2 The total smoke release of the epoxy silicone oil is 1561.09 m 2 / m 2 Compared with end-epoxy silicone oil, the total smoke emission of uniform foam flame retardant silicone oil is reduced by 79.87%.

[0057] See also Figure 5 The total heat release of the uniform foam flame retardant silicone oil prepared in Example 1 is 65.08 MJ / m 2 The total heat release of epoxy-terminated silicone oil is 71.75 MJ / m 2 Compared with the epoxy-terminated silicone oil, the total heat release of the uniform foam flame retardant silicone oil was reduced by 9.30%.

[0058] See also Figure 6 The temperature at which the maximum decomposition rate of the uniformly foamed flame-retardant silicone oil prepared in Example 1 is 290.96° C., and the residual carbon content at 800° C. is 9.57%.

[0059] See also Figure 8 The uniform foam flame retardant silicone oil prepared in Example 1 could not be ignited by open flame and no black smoke was generated.

[0060] Example 2

[0061] The preparation steps of a uniform foam flame retardant silicone oil are as follows:

[0062] (1) Take 50 g of epoxy-terminated silicone oil, 43.255 g of 2-amino-5-mercapto-1, 3, 4-thiadiazole and 0.093 g of 2,4, 6-tris(dimethylaminomethyl)phenol, add them into 250 mL of N, N-dimethylformamide, stir and dissolve, and heat the mixed solution to 110 °C. Keep the mixture warm under nitrogen protection for 6 h to obtain the reactant.

[0063] The molar ratio of the epoxy group in the epoxy-terminated silicone oil to the primary amino group in the 2-amino-5-mercapto-1, 3, 4-thiadiazole is 1:1.2.

[0064] The amount of solvent N, N-dimethylformamide used is 2.5 times the total mass of the epoxy-terminated silicone oil and 2-amino-5-mercapto-1, 3, 4-thiadiazole.

[0065] The amount of catalyst 2, 4, 6-tris(dimethylaminomethyl)phenol added is 0.1% of the total mass of the epoxy-terminated silicone oil and 2-amino-5-mercapto-1, 3, 4-thiadiazole.

[0066] (2) The reactants were placed in a vacuum oven at 90°C for 3 h to remove N,N-dimethylformamide from the reactants. The product after vacuum distillation was then washed with 3000 mL of deionized water at 80°C for three times to remove 2-amino-5-mercapto-1, 3, 4-thiadiazole and 2, 4, 6-tris(dimethylaminomethyl)phenol from the product. The washed product was placed in a vacuum drying oven at 100°C for 24 h to obtain a uniformly foamed flame-retardant silicone oil.

[0067] See also Figure 6 The temperature at which the maximum decomposition rate of the uniformly foamed flame-retardant silicone oil prepared in Example 2 is 279.84° C., and the residual carbon content at 800° C. is 3.71%.

[0068] See also Figure 9 When the uniform foam flame retardant silicone oil prepared in Example 2 was ignited with an open flame, no black smoke was generated and the flame height was 10.5 cm.

[0069] Example 3

[0070] The preparation steps of a uniform foam flame retardant silicone oil are as follows:

[0071] (1) Take 50 g of epoxy-terminated silicone oil, 43.255 g of 2-amino-5-mercapto-1, 3, 4-thiadiazole and 0.093 g of 2,4, 6-tris(dimethylaminomethyl)phenol, add them into 250 mL of N, N-dimethylformamide, stir and dissolve, and heat the mixed solution to 130 °C. Keep the mixture warm for 4 h under nitrogen protection to obtain the reactant.

[0072] The molar ratio of the epoxy group in the epoxy-terminated silicone oil to the primary amino group in the 2-amino-5-mercapto-1, 3, 4-thiadiazole is 1:1.2.

[0073] The amount of solvent N, N-dimethylformamide used is 2.5 times the total mass of the epoxy-terminated silicone oil and 2-amino-5-mercapto-1, 3, 4-thiadiazole.

[0074] The amount of catalyst 2, 4, 6-tris(dimethylaminomethyl)phenol added is 0.1% of the total mass of the epoxy-terminated silicone oil and 2-amino-5-mercapto-1, 3, 4-thiadiazole.

[0075] (2) The reactants were placed in a vacuum oven at 90°C for 3 h to remove N,N-dimethylformamide from the reactants. The product after vacuum distillation was then washed with 3000 mL of deionized water at 80°C for three times to remove 2-amino-5-mercapto-1, 3, 4-thiadiazole and 2, 4, 6-tris(dimethylaminomethyl)phenol from the product. The washed product was placed in a vacuum drying oven at 100°C for 24 h to obtain a uniformly foamed flame-retardant silicone oil.

[0076] See also Figure 6 The temperature at which the maximum decomposition rate of the uniformly foamed flame-retardant silicone oil prepared in Example 3 is 274.39° C., and the residual carbon content at 800° C. is 2.78%.

[0077] See also Figure 10 When the uniform foam flame retardant silicone oil prepared in Example 3 was ignited with an open flame, substantially no black smoke was generated, and the flame height was 12 cm.

[0078] Example 4

[0079] The preparation steps of a uniform foam flame retardant silicone oil are as follows:

[0080] (1) Take 50 g of epoxy-terminated silicone oil, 28.842 g of 2-amino-5-mercapto-1, 3, 4-thiadiazole and 0.079 g of 2,4, 6-tris(dimethylaminomethyl)phenol, add them to 250 mL of N, N-dimethylformamide, stir and dissolve, and heat the mixed solution to 130°C. Keep the mixture warm under nitrogen protection for 6 hours to obtain the reactant.

[0081] The molar ratio of the epoxy group in the epoxy-terminated silicone oil to the primary amino group in the 2-amino-5-mercapto-1, 3, 4-thiadiazole is 1:0.8.

[0082] The amount of solvent N, N-dimethylformamide used is 2.5 times the total mass of the epoxy-terminated silicone oil and 2-amino-5-mercapto-1, 3, 4-thiadiazole.

[0083] The amount of catalyst 2, 4, 6-tris(dimethylaminomethyl)phenol added is 0.1% of the total mass of the epoxy-terminated silicone oil and 2-amino-5-mercapto-1, 3, 4-thiadiazole.

[0084] (2) The reactants were placed in a vacuum oven at 90°C for 3 h to remove N,N-dimethylformamide from the reactants. The product after vacuum distillation was then washed with 3000 mL of deionized water at 80°C for three times to remove 2-amino-5-mercapto-1, 3, 4-thiadiazole and 2, 4, 6-tris(dimethylaminomethyl)phenol from the product. The washed product was placed in a vacuum drying oven at 100°C for 24 h to obtain a uniformly foamed flame-retardant silicone oil.

[0085] See also Figure 6 The temperature at which the maximum decomposition rate of the uniformly foamed flame-retardant silicone oil prepared in Example 4 is 292.42° C., and the residual carbon content at 800° C. is 9.15%.

[0086] See also Figure 11 The uniform foam flame retardant silicone oil prepared in Example 4 could not be ignited by open flame and no black smoke was generated.

[0087] The flame-retardant rigid polyurethane foam prepared with uniformly foamed flame-retardant silicone oil is prepared by the following method: the polyol and various additives in component A are weighed according to the formula, mixed uniformly under high-speed stirring, and then component B is added and stirred at 1000 rpm for 10 seconds. The foam is then poured into a mold for foaming. The foam is then aged in a forced air drying oven at 80°C for 8 hours to obtain the flame-retardant rigid polyurethane foam.

[0088] Application Example 1

[0089] A flame-retardant polyurethane rigid foam made from uniformly foamed flame-retardant silicone oil comprises two components, A and B, and is composed of the following raw materials in parts by mass: component A comprises 100 parts of polyether polyol, 1 part of triethylenediamine, 3 parts of triethanolamine, 0.5 parts of dibutyltin dilaurate, and 2 parts of water; and component B comprises 135 parts of polymethylene polyphenyl polyisocyanate.

[0090] Table 1 shows the performance test results of flame retardant polyurethane rigid foam prepared in Application Examples 1-4

[0091]

[0092] As shown in Table 1, the combustion grade of the polyurethane rigid foam prepared in this application example 1 cannot be determined, and the density is 45.9 kg / m 3 , the closed porosity is 97.12% and the compressive strength is 0.22 MPa.

[0093] Application Example 2

[0094] A flame-retardant polyurethane rigid foam made from uniformly foamed flame-retardant silicone oil comprises two components, A and B, and is composed of the following raw materials in parts by mass: component A comprises 100 parts of polyether polyol, 10 parts of expandable graphite, 1 part of triethylenediamine, 3 parts of triethanolamine, 0.5 part of dibutyltin dilaurate, and 2 parts of water; and component B comprises 135 parts of polymethylene polyphenyl polyisocyanate.

[0095] As shown in Table 1, the flame retardant polyurethane rigid foam prepared in this application example 2 has a combustion grade of V-1. The density is 56.7 kg / m 3 , the closed porosity is 96.39% and the compressive strength is 0.32 MPa.

[0096] See also Figure 12 a in the figure is a picture of the flame retardant polyurethane rigid foam prepared in Application Example 2, see Figure 12 b in the figure is the picture of the first ignition 10 seconds later, see Figure 12 c in the figure is the afterflame time after the first ignition is extinguished, which is 14 s. Figure 12 The d in the figure is the picture of the second ignition for 10 seconds, see Figure 12 The e in the figure is the afterflame time after the second ignition is extinguished, which is 12 s, and the afterflame does not spread to the fixture.

[0097] Application Example 3

[0098] A flame-retardant polyurethane rigid foam made from uniformly foamed flame-retardant silicone oil comprises two components, A and B, and is composed of the following raw materials in parts by mass: component A comprises 100 parts of polyether polyol, 15 parts of expandable graphite, 1 part of triethylenediamine, 3 parts of triethanolamine, 0.5 part of dibutyltin dilaurate, and 2 parts of water; and component B comprises 135 parts of polymethylene polyphenyl polyisocyanate.

[0099] As shown in Table 1, the flame retardant polyurethane rigid foam prepared in this application example 3 has a combustion grade of V-0. The density is 63.2 kg / m 3 , the closed porosity is 95.21% and the compressive strength is 0.30 MPa.

[0100] See also Figure 13 a in the figure is a picture of the flame retardant polyurethane rigid foam prepared in Application Example 3, see Figure 13 b in the figure is the picture of the first ignition 10 seconds later, see Figure 13 c in the figure is the afterflame time after the first ignition is extinguished, which is 1 s. Figure 13 The d in the figure is the picture of the second ignition for 10 seconds, see Figure 13 The e in the figure is the afterflame time after the second ignition is extinguished, which is 6 s, and the afterflame does not spread to the fixture.

[0101] Application Example 4

[0102] A flame-retardant polyurethane rigid foam made from uniform-bubble flame-retardant silicone oil comprises two components, A and B, and is composed of the following raw materials in parts by mass: component A comprises 100 parts of polyether polyol, 13.5 parts of expandable graphite, 1.5 parts of uniform-bubble flame-retardant silicone oil, 1 part of triethylenediamine, 3 parts of triethanolamine, 0.5 part of dibutyltin dilaurate, and 2 parts of water; and component B comprises 135 parts of polymethylene polyphenyl polyisocyanate.

[0103] As shown in Table 1, the flame retardant polyurethane rigid foam prepared in this application example 4 has a combustion grade of V-0. The density is 61.5 kg / m 3 , the closed porosity is 97.21% and the compressive strength is 0.33 MPa.

[0104] See also Figure 14 a in the figure is a picture of the flame retardant polyurethane rigid foam prepared in Application Example 4, see Figure 14 b in the figure is the picture of the first ignition 10 seconds later, see Figure 14 c in the figure is the afterflame time after the first ignition is extinguished, which is 5 s. Figure 14 The d in the figure is the picture of the second ignition for 10 seconds, see Figure 14 The e in the figure is the afterflame time after the second ignition is extinguished, which is 1 s, and the afterflame does not spread to the fixture.

[0105] As shown in Table 1, after adding uniform foam flame retardant silicone oil, while reducing the amount of expandable graphite added, the combustion grade did not change, the density decreased, and the closed porosity and compressive strength increased. The results show that adding uniform foam flame retardant silicone oil can enhance the synergistic effect of flame retardants, reduce the amount of flame retardants and maintain flame retardant properties, and can improve the flame retardant effect and mechanical properties at the same dosage.

[0106] Depend on Figure 6 It can be seen that the epoxy-terminated silicone oil completely burns at 500°C with virtually no residue, leaving only 2.23% residual carbon. The uniformly foamed flame-retardant silicone oils prepared in Examples 1 to 4 of the present invention exhibited less thermal weight loss than the epoxy-terminated silicone oil at temperatures between 250°C and 800°C. The uniformly foamed flame-retardant silicone oil prepared in Example 1 exhibited a carbon residue of 9.57% at 800°C.

[0107] Depend on Figure 7 It can be seen that the combustion of the epoxy-terminated silicone oil is very intense and is accompanied by the generation of a large amount of black smoke. Figure 8-11 It can be seen that the uniform foam flame retardant silicone oil prepared by the present invention has better flame retardant and smoke suppression effects than the epoxy-terminated silicone oil.

[0108] It will be easily understood by those skilled in the art that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A flame-retardant silicone oil for flame-retardant polyurethane rigid foam plastics, characterized by: The structural formula of the uniform foam flame retardant silicone oil is as follows:

2. The uniformly foamed flame-retardant silicone oil is a dark brown fluid liquid, the temperature of the maximum decomposition rate is 274.39-292.42°C, and the residual carbon content at 800°C is 2.78-9.57%.

3. The method for preparing the uniform foam flame retardant silicone oil for flame retardant polyurethane rigid foam according to claim 1, characterized in that: The steps are as follows: (1) Dissolving the epoxy-terminated silicone oil and 2-amino-5-mercapto-1, 3, 4-thiadiazole in a solvent, adding a catalyst, and heating the mixture for reaction to obtain a reactant; The molar ratio of the epoxy group in the epoxy-terminated silicone oil to the primary amino group in the 2-amino-5-mercapto-1, 3, 4-thiadiazole is 1:0.4-1:1.2; The epoxy value of the epoxy-terminated silicone oil is 0.490 mol / 100 g-0.530 mol / 100 g; The solvent is N,N-dimethylformamide, and the amount used is 2-3 times the mass of the reactants; The catalyst is an aminophenol substance, and the catalyst selected is 2, 4, 6-tris (dimethylaminomethyl) phenol; The amount of catalyst added is 0.1% of the sum of the mass of the epoxy-terminated silicone oil and 2-amino-5-mercapto-1, 3, 4-thiadiazole; (2) The reactants are subjected to reduced pressure distillation, washing, and centrifugation, and the precipitate is dried to obtain uniform foam flame retardant silicone oil.

4. The preparation method according to claim 2, wherein: In step (1), the reaction synthesis conditions are: heating temperature is 100-130°C, and the reaction is kept warm for 4-8 hours under nitrogen atmosphere.

5. The preparation method according to claim 2, wherein: In step (2), the washing conditions are: washing the product obtained by vacuum distillation three times with deionized water at 60-80°C.

6. The preparation method according to claim 2, wherein: In step (2), the vacuum drying conditions are: drying temperature is 100°C, and drying time is 24h.

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