An environmentally friendly modified phenolic foam and its preparation process

Abstract

This invention relates to the field of phenolic foam technology, specifically to an environmentally friendly modified phenolic foam and its preparation process. The invention involves reacting allyl isocyanate with 1,1,3,3-tetramethyldisiloxane to prepare an organosilicon-modified diisocyanate; preparing a dihydroxyl flame retardant using phenylphosphodichloro and 10-(2,5-dihydroxyphenyl)-10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide as raw materials; reacting the organosilicon-modified diisocyanate and the dihydroxyl flame retardant to prepare a diisocyanate-containing silicon-based flame-retardant compound; mixing the diisocyanate-containing silicon-based flame-retardant compound, polyethylene glycol 1000, and toluene diisocyanate to prepare a silicon-based flame-retardant polyurethane prepolymer; reacting furfural and phenol as raw materials, and adding the silicon-based flame-retardant polyurethane prepolymer for modification to obtain a modified phenolic resin. The modified phenolic resin, surfactant, curing agent, and foaming agent are mixed and cured to obtain an environmentally friendly modified phenolic foam.

Description

Technical Field

[0001] This invention relates to the field of phenolic foam technology, specifically to an environmentally friendly modified phenolic foam and its preparation process. Background Technology

[0002] Polystyrene and polyurethane foams, as traditional insulation materials, pose significant safety hazards due to their poor flame retardancy and the release of harmful gases during combustion. Therefore, their use in high-rise buildings has been banned in some countries. Phenolic foams, with their excellent flame retardancy, heat resistance, and insulation properties, have gained increasing attention and are gradually becoming one of the preferred materials in the insulation field.

[0003] However, phenolic foam plastics suffer from low toughness and high shedding rate, which limits their development and application to some extent. Furthermore, phenolic resin raw materials contain formaldehyde, so the products inevitably release formaldehyde, posing a potential health hazard. Therefore, it is essential to toughen and modify phenolic resin to provide an environmentally friendly modified phenolic foam plastic. Summary of the Invention

[0004] The purpose of this invention is to provide an environmentally friendly modified phenolic foam and its preparation process to solve the problems mentioned in the background art.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: an environmentally friendly modified phenolic foam and its preparation process, comprising the following steps:

[0006] Step 1:

[0007] S11: Allyl isocyanate is dispersed in tetrahydrofuran, and isopropanol solution of chloroplatinic acid is added as a catalyst. Argon gas is introduced as a protective gas, and 1,1,3,3-tetramethyldisiloxane is added. The mixture is heated to 55~65℃ and reacted for 8~12h to obtain organosilicon-modified diisocyanate.

[0008] S12: Phenylphosphoryl dichloride is dispersed in tetrahydrofuran. Under nitrogen atmosphere and at -5~0℃, a mixed solution of triethylamine / tetrahydrofuran is added as an acid-binding agent. After the acid-binding agent is added, the temperature is raised to 40~45℃, and 10-(2,5-dihydroxyphenyl)-10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide is added. After the reaction is completed, tetrahydrofuran is removed, deionized water is added to the remaining material, and the reaction is refluxed to obtain a crude product. A 5% sodium hydroxide solution is dissolved and then diluted with deionized water. A 5% sulfuric acid solution is added at 0~5℃ until the pH of the reaction solution is <1. The precipitate is collected by filtration, washed with water, and dried to obtain a dihydroxy flame retardant.

[0009] S13: Take a dihydroxyl flame retardant and an organosilicon-modified diisocyanate and disperse them in tetrahydrofuran. Under nitrogen atmosphere, with dibutyltin dilaurate as catalyst, react at 50~60℃ for 1~2h to obtain a silicon-containing flame retardant compound of diisocyanate.

[0010] S14: Dehydrate polyethylene glycol 1000 under vacuum at 110~120℃; mix silicon-containing flame retardant diisocyanate compound and toluene diisocyanate at a weight ratio of 1:1 to obtain mixed diisocyanate; add the mixed diisocyanate to polyethylene glycol 1000 under nitrogen atmosphere with dibutyltin dilaurate as catalyst, and stir and react at 50~60℃ for 2~3 hours to obtain silicon-containing flame retardant polyurethane prepolymer;

[0011] Step 2:

[0012] S21: Mix furfural and molten phenol, heat to 60~65℃, maintain for 30 min, then heat to 105~110℃, stir and add 20% sodium hydroxide solution, adjust the pH of the system to 9~10, react for 3~4 h, cool and add dilute hydrochloric acid to neutralize to pH 7, then perform vacuum distillation at 85~90℃ to obtain phenolic resin;

[0013] S22: Add the silicone flame-retardant polyurethane prepolymer to the phenolic resin and stir to obtain the modified phenolic resin; mix the modified phenolic resin, surfactant, curing agent and foaming agent, and cure to obtain environmentally friendly modified phenolic foam plastic.

[0014] Furthermore, in S11, the molar ratio of allyl isocyanate to 1,1,3,3-tetramethyldisiloxane is 2:1.

[0015] Furthermore, in S12, the molar ratio of phenylphosphodichloro, triethylamine, and 10-(2,5-dihydroxyphenyl)-10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide is 2:2:1.

[0016] Furthermore, in S13, the molar ratio of dihydroxyl flame retardant to organosilicon-modified diisocyanate is 1:2.

[0017] Further, in S14, the mixed diisocyanate is added to polyethylene glycol 1000 at a ratio of n(NCO) / n(OH) = (1.2~1.8):1.

[0018] Further, in S21, furfural and molten phenol are mixed in a molar ratio of furfural to phenol of (1.6~1.7):1.

[0019] Furthermore, in S22, the weight of the silicone flame-retardant polyurethane prepolymer in the modified phenolic resin is 8-12% of the total weight of the phenolic resin.

[0020] Further, in S22, 100 parts of modified phenolic resin, 4-5 parts of surfactant, 10-13 parts of curing agent, and 8-9 parts of foaming agent are mixed by weight percentage.

[0021] Furthermore, in S22, the curing temperature is 70~80℃ and the curing time is 2~3h.

[0022] Compared with existing technologies, the beneficial effects achieved by this invention are as follows: This invention provides an environmentally friendly modified phenolic foam plastic and its preparation process. Traditional phenolic resin uses formaldehyde as a raw material, while furfural, as a product obtained from renewable biomass raw materials through acid catalysis, has lower toxicity and can replace formaldehyde in the preparation of phenolic resin, effectively reducing the harm of formaldehyde to human health and the environment.

[0023] In the preparation of phenolic foam, this invention incorporates a polyurethane prepolymer for toughening modification. The polyurethane prepolymer contains active isocyanate groups at both ends, which can bond with the hydroxymethyl groups in phenolic resin. This allows the phenolic resin and polyurethane prepolymer to form a three-dimensional interpenetrating cross-linked network structure during foaming and curing, thereby improving the toughness and pulverization of the phenolic foam. Typically, polyurethane prepolymers are obtained by reacting polyether polyols with isocyanate compounds, resulting in products that are flammable and not heat-resistant. While direct mixing with phenolic resin can improve mechanical properties, it simultaneously reduces the material's flame retardant and heat resistance properties, making it counterproductive. Therefore, this application uses allyl isocyanate to react with 1,1,3,3-tetramethyldisiloxane to prepare organosilicon-modified diisocyanate; then, it uses phenylphosphoyl dichloride and 10-(2,5-dihydroxyphenyl)-10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide as raw materials to prepare a dihydroxyl flame retardant; the organosilicon-modified diisocyanate and the dihydroxyl flame retardant are reacted to prepare a diisocyanate silicon-containing flame retardant compound; the diisocyanate silicon-containing flame retardant compound and toluene diisocyanate are mixed and reacted with polyethylene glycol 1000 to prepare a silicon-containing flame-retardant polyurethane prepolymer. The introduction of flame-retardant components into the polyurethane prepolymer, along with the presence of silicon-oxygen bonds, improves the flexibility and heat resistance of the prepolymer. After modification, the phenolic foam exhibits good heat resistance, mechanical properties, and flame retardant properties, with a significant reduction in slagging.

[0024] Furthermore, it should be noted that more silicone-containing flame-retardant polyurethane prepolymer is not necessarily better. Excessive use can reduce its compatibility with phenolic resin, leading to a decrease in the modification effect. Therefore, controlling the weight of the silicone-containing flame-retardant polyurethane prepolymer to 8-12% of the total weight of the phenolic resin yields the best modification effect. Detailed Implementation

[0025] Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] The materials and sources used in this invention are as follows: the curing agent is a mixture of toluene-4-sulfonic acid, phosphoric acid and distilled water in a mass ratio of 2:1:2; the surfactant is Tween 80; and the foaming agent is n-pentane.

[0027] Example 1: An environmentally friendly modified phenolic foam and its preparation process, comprising the following steps:

[0028] Step 1:

[0029] S11: Allyl isocyanate is dispersed in tetrahydrofuran, and an isopropanol solution of chloroplatinic acid is added as a catalyst. Argon gas is introduced as a protective gas, and 1,1,3,3-tetramethyldisiloxane is added. The mixture is heated to 55°C and reacted for 8 hours to obtain organosilicon-modified diisocyanate. The molar ratio of allyl isocyanate to 1,1,3,3-tetramethyldisiloxane is 2:1.

[0030] S12: Phenylphosphoryl dichloride was dispersed in tetrahydrofuran. Under nitrogen atmosphere and at -5°C, a triethylamine / tetrahydrofuran mixed solution was added. The temperature was raised to 40~45°C, and 10-(2,5-dihydroxyphenyl)-10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide was added. After the reaction was completed, the tetrahydrofuran was removed. Deionized water was added to the remaining material and the reaction was refluxed to obtain the crude product. The crude product was dissolved in 5% sodium hydroxide solution and then diluted with deionized water. 5% sulfuric acid solution was added at 0°C until the pH of the reaction solution was <1. The precipitate was collected by filtration, washed with water, and dried to obtain the dihydroxy flame retardant. The molar ratio of phenylphosphoryl dichloride, triethylamine, and 10-(2,5-dihydroxyphenyl)-10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide was 2:2:1.

[0031] S13: A dihydroxyl flame retardant and an organosilicon-modified diisocyanate were dispersed in tetrahydrofuran and reacted at 50°C for 1 hour under nitrogen atmosphere with dibutyltin dilaurate as a catalyst to obtain a silicon-containing diisocyanate flame retardant compound; wherein the molar ratio of the dihydroxyl flame retardant and the organosilicon-modified diisocyanate was 1:2.

[0032] S14: Polyethylene glycol 1000 was vacuum dehydrated at 110°C; a silicon-containing flame retardant diisocyanate compound and toluene diisocyanate were mixed at a weight ratio of 1:1 to obtain a mixed diisocyanate; under nitrogen atmosphere, using dibutyltin dilaurate as a catalyst, the mixed diisocyanate was added to polyethylene glycol 1000 at a ratio of n(NCO) / n(OH)=1.2:1, and the mixture was stirred and reacted at 50°C for 2 hours to obtain a silicon-containing flame retardant polyurethane prepolymer;

[0033] Step 2:

[0034] S21: Furfural and molten phenol were mixed at a molar ratio of 1.65:1, heated to 60°C, held for 30 min, then heated to 105°C, and 20% sodium hydroxide solution was added with stirring. The pH of the system was adjusted to 9. After reacting for 3 h, the mixture was cooled and neutralized to pH 7 with dilute hydrochloric acid. Then, the mixture was distilled under reduced pressure at 85°C to obtain phenolic resin.

[0035] S22: Add the silicone flame-retardant polyurethane prepolymer to the phenolic resin and stir to obtain modified phenolic resin; mix 100kg of modified phenolic resin, 5kg of surfactant, 12kg of curing agent and 8kg of foaming agent, and cure at 70℃ for 2h to obtain environmentally friendly modified phenolic foam plastic; in the modified phenolic resin, the weight of the silicone flame-retardant polyurethane prepolymer is 8% of the total weight of the phenolic resin.

[0036] Example 2: An environmentally friendly modified phenolic foam and its preparation process, comprising the following steps:

[0037] Step 1:

[0038] S11: Allyl isocyanate is dispersed in tetrahydrofuran, and an isopropanol solution of chloroplatinic acid is added as a catalyst. Argon gas is introduced as a protective gas, and 1,1,3,3-tetramethyldisiloxane is added. The mixture is heated to 60℃ and reacted for 10 h to obtain organosilicon-modified diisocyanate. The molar ratio of allyl isocyanate to 1,1,3,3-tetramethyldisiloxane is 2:1.

[0039] S12: Phenylphosphoryl dichloride was dispersed in tetrahydrofuran. Under nitrogen atmosphere and at -3°C, a triethylamine / tetrahydrofuran mixed solution was added. The temperature was raised to 40~45°C, and 10-(2,5-dihydroxyphenyl)-10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide was added. After the reaction was completed, the tetrahydrofuran was removed. Deionized water was added to the remaining material and the reaction was refluxed to obtain the crude product. The crude product was dissolved in 5% sodium hydroxide solution and then diluted with deionized water. 5% sulfuric acid solution was added at 3°C ​​until the pH of the reaction solution was <1. The precipitate was collected by filtration, washed with water, and dried to obtain the dihydroxy flame retardant. The molar ratio of phenylphosphoryl dichloride, triethylamine, and 10-(2,5-dihydroxyphenyl)-10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide was 2:2:1.

[0040] S13: A dihydroxyl flame retardant and an organosilicon-modified diisocyanate were dispersed in tetrahydrofuran and reacted at 55°C for 1.5 h under nitrogen atmosphere with dibutyltin dilaurate as a catalyst to obtain a silicon-containing diisocyanate flame retardant compound; wherein the molar ratio of the dihydroxyl flame retardant and the organosilicon-modified diisocyanate was 1:2.

[0041] S14: Polyethylene glycol 1000 was vacuum dehydrated at 115°C; a silicon-containing flame retardant diisocyanate compound and toluene diisocyanate were mixed at a weight ratio of 1:1 to obtain a mixed diisocyanate; under nitrogen atmosphere, using dibutyltin dilaurate as a catalyst, the mixed diisocyanate was added to polyethylene glycol 1000 at a ratio of n(NCO) / n(OH) = 1.2:1, and the mixture was stirred and reacted at 55°C for 2.5 h to obtain a silicon-containing flame retardant polyurethane prepolymer;

[0042] Step 2:

[0043] S21: Furfural and molten phenol were mixed at a molar ratio of 1.65:1, heated to 63°C, held for 30 min, then heated to 110°C, and 20% sodium hydroxide solution was added with stirring. The pH of the system was adjusted to 9-10. After reacting for 3.5 h, the mixture was cooled and neutralized to pH 7 with dilute hydrochloric acid. Then, the mixture was distilled under reduced pressure at 90°C to obtain phenolic resin.

[0044] S22: Add the silicone flame-retardant polyurethane prepolymer to the phenolic resin and stir to obtain modified phenolic resin; mix 100 kg of modified phenolic resin, 5 kg of surfactant, 12 kg of curing agent and 8 kg of foaming agent, and cure at 75℃ for 2.5 h to obtain environmentally friendly modified phenolic foam plastic; in the modified phenolic resin, the weight of the silicone flame-retardant polyurethane prepolymer is 10% of the total weight of the phenolic resin.

[0045] Example 3: An environmentally friendly modified phenolic foam and its preparation process, comprising the following steps:

[0046] Step 1:

[0047] S11: Allyl isocyanate is dispersed in tetrahydrofuran, and an isopropanol solution of chloroplatinic acid is added as a catalyst. Argon gas is introduced as a protective gas, and 1,1,3,3-tetramethyldisiloxane is added. The mixture is heated to 65°C and reacted for 12 hours to obtain organosilicon-modified diisocyanate. The molar ratio of allyl isocyanate to 1,1,3,3-tetramethyldisiloxane is 2:1.

[0048] S12: Phenylphosphoryl dichloride was dispersed in tetrahydrofuran. Under nitrogen atmosphere and at 0°C, a triethylamine / tetrahydrofuran mixed solution was added as an acid-binding agent. The temperature was raised to 40-45°C, and 10-(2,5-dihydroxyphenyl)-10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide was added. After the reaction was completed, the tetrahydrofuran was removed, and deionized water was added to the remaining material and the reaction was refluxed to obtain the crude product. The crude product was dissolved in a 5% sodium hydroxide solution and then diluted with deionized water. A 5% sulfuric acid solution was added at 5°C until the pH of the reaction solution was <1. The precipitate was collected by filtration, washed with water, and dried to obtain the dihydroxy flame retardant. The molar ratio of phenylphosphoryl dichloride, triethylamine, and 10-(2,5-dihydroxyphenyl)-10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide was 2:2:1.

[0049] S13: A dihydroxyl flame retardant and an organosilicon-modified diisocyanate were dispersed in tetrahydrofuran and reacted at 60°C for 2 hours under nitrogen atmosphere with dibutyltin dilaurate as a catalyst to obtain a silicon-containing diisocyanate flame retardant compound; wherein the molar ratio of the dihydroxyl flame retardant and the organosilicon-modified diisocyanate was 1:2.

[0050] S14: Polyethylene glycol 1000 was vacuum dehydrated at 120°C; a silicon-containing flame retardant diisocyanate compound and toluene diisocyanate were mixed at a weight ratio of 1:1 to obtain a mixed diisocyanate; under nitrogen atmosphere, using dibutyltin dilaurate as a catalyst, the mixed diisocyanate was added to polyethylene glycol 1000 at a ratio of n(NCO) / n(OH) = 1.2:1, and the mixture was stirred at 60°C for 3 hours to obtain a silicon-containing flame retardant polyurethane prepolymer;

[0051] Step 2:

[0052] S21: Furfural and molten phenol were mixed at a molar ratio of 1.65:1, heated to 65°C, held for 30 min, then heated to 110°C, and 20% sodium hydroxide solution was added with stirring. The pH of the system was adjusted to 10. After reacting for 4 h, the mixture was cooled and neutralized to pH 7 with dilute hydrochloric acid. Then, the mixture was distilled under reduced pressure at 90°C to obtain phenolic resin.

[0053] S22: Add the silicone flame-retardant polyurethane prepolymer to the phenolic resin and stir to obtain modified phenolic resin; mix 100kg of modified phenolic resin, 5kg of surfactant, 12kg of curing agent and 8kg of foaming agent, and cure at 80℃ for 3h to obtain environmentally friendly modified phenolic foam plastic; in the modified phenolic resin, the weight of the silicone flame-retardant polyurethane prepolymer is 12% of the total weight of the phenolic resin.

[0054] Comparative Example 1: Phenolic resin was modified without the addition of a silicone-containing flame-retardant polyurethane prepolymer, and the remaining parameters were the same as in Example 1.

[0055] Step 1:

[0056] Furfural and molten phenol were mixed in a molar ratio of 1.65:1, heated to 60°C, held for 30 min, then heated to 105°C, and a 20% sodium hydroxide solution was added with stirring. The pH of the system was adjusted to 9. After reacting for 3 h, the mixture was cooled and neutralized to pH 7 with dilute hydrochloric acid. Then, the mixture was distilled under reduced pressure at 85°C to obtain phenolic resin.

[0057] Step 2:

[0058] Mix 100 kg of phenolic resin, 5 kg of surfactant, 12 kg of curing agent and 8 kg of foaming agent, and cure at 70°C for 2 h to obtain phenolic foam plastic; in the modified phenolic resin, the weight of the silicone flame-retardant polyurethane prepolymer is 8% of the total weight of the phenolic resin.

[0059] Comparative Example 2: No diisocyanate-containing silicon flame retardant compound was added, and all other parameters were the same as in Example 2.

[0060] Step 1:

[0061] Polyethylene glycol 1000 was dehydrated under vacuum at 115°C; under nitrogen atmosphere, toluene diisocyanate was added to polyethylene glycol 1000 with dibutyltin dilaurate as catalyst at a ratio of n(NCO) / n(OH)=1.2:1, and the mixture was stirred at 55°C for 2.5 h to obtain polyurethane prepolymer.

[0062] Step 2:

[0063] S21: Furfural and molten phenol were mixed at a molar ratio of 1.65:1, heated to 63°C, held for 30 min, then heated to 110°C, and 20% sodium hydroxide solution was added with stirring. The pH of the system was adjusted to 9-10. After reacting for 3.5 h, the mixture was cooled and neutralized to pH 7 with dilute hydrochloric acid. Then, the mixture was distilled under reduced pressure at 90°C to obtain phenolic resin.

[0064] S22: Add polyurethane prepolymer to phenolic resin and stir to obtain modified phenolic resin; mix 100kg modified phenolic resin, 5kg surfactant, 12kg curing agent and 8kg foaming agent, and cure at 75℃ for 2.5h to obtain environmentally friendly modified phenolic foam plastic; in the modified phenolic resin, the weight of polyurethane prepolymer is 10% of the total weight of phenolic resin.

[0065] Comparative Example 3: The amount of silicone flame-retardant polyurethane prepolymer was increased, while the other parameters were the same as in Example 3.

[0066] Step 1:

[0067] S11: Allyl isocyanate is dispersed in tetrahydrofuran, and an isopropanol solution of chloroplatinic acid is added as a catalyst. Argon gas is introduced as a protective gas, and 1,1,3,3-tetramethyldisiloxane is added. The mixture is heated to 65°C and reacted for 12 hours to obtain organosilicon-modified diisocyanate. The molar ratio of allyl isocyanate to 1,1,3,3-tetramethyldisiloxane is 2:1.

[0068] S12: Phenylphosphoryl dichloride was dispersed in tetrahydrofuran. Under nitrogen atmosphere and at 0°C, a triethylamine / tetrahydrofuran mixed solution was added as an acid-binding agent. The temperature was raised to 40-45°C, and 10-(2,5-dihydroxyphenyl)-10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide was added. After the reaction was completed, the tetrahydrofuran was removed, and deionized water was added to the remaining material and the reaction was refluxed to obtain the crude product. The crude product was dissolved in a 5% sodium hydroxide solution and then diluted with deionized water. A 5% sulfuric acid solution was added at 5°C until the pH of the reaction solution was <1. The precipitate was collected by filtration, washed with water, and dried to obtain the dihydroxy flame retardant. The molar ratio of phenylphosphoryl dichloride, triethylamine, and 10-(2,5-dihydroxyphenyl)-10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide was 2:2:1.

[0069] S13: A dihydroxyl flame retardant and an organosilicon-modified diisocyanate were dispersed in tetrahydrofuran and reacted at 60°C for 2 hours under nitrogen atmosphere with dibutyltin dilaurate as a catalyst to obtain a silicon-containing diisocyanate flame retardant compound; wherein the molar ratio of the dihydroxyl flame retardant and the organosilicon-modified diisocyanate was 1:2.

[0070] S14: Polyethylene glycol 1000 was vacuum dehydrated at 120°C; a silicon-containing flame retardant diisocyanate compound and toluene diisocyanate were mixed at a weight ratio of 1:1 to obtain a mixed diisocyanate; under nitrogen atmosphere, using dibutyltin dilaurate as a catalyst, the mixed diisocyanate was added to polyethylene glycol 1000 at a ratio of n(NCO) / n(OH) = 1.2:1, and the mixture was stirred at 60°C for 3 hours to obtain a silicon-containing flame retardant polyurethane prepolymer;

[0071] Step 2:

[0072] S21: Furfural and molten phenol were mixed at a molar ratio of 1.65:1, heated to 65°C, held for 30 min, then heated to 110°C, and 20% sodium hydroxide solution was added with stirring. The pH of the system was adjusted to 10. After reacting for 4 h, the mixture was cooled and neutralized to pH 7 with dilute hydrochloric acid. Then, the mixture was distilled under reduced pressure at 90°C to obtain phenolic resin.

[0073] S22: Add the silicone flame-retardant polyurethane prepolymer to the phenolic resin and stir to obtain modified phenolic resin; mix 100kg of modified phenolic resin, 5kg of surfactant, 12kg of curing agent and 8kg of foaming agent, and cure at 80℃ for 3h to obtain environmentally friendly modified phenolic foam plastic; in the modified phenolic resin, the weight of the silicone flame-retardant polyurethane prepolymer is 15% of the total weight of the phenolic resin.

[0074] Experiment: Performance tests were performed on the samples prepared in Examples 1-3 and Comparative Examples 1-3. Wherein:

[0075] Flame retardant performance: Characterized by limiting oxygen index, with sample size of 100mm×10mm×10mm.

[0076] Heat resistance: The test temperature range is 30~750℃, under nitrogen atmosphere, with a heating rate of 10℃ / min, and the temperature Td at which 10% thermal weight loss is recorded. 10% .

[0077] Bending strength: Tested according to GB / T8812.1-2007 standard, with a bending rate of 10 mm / min and a sample size of 120 mm × 25 mm × 20 mm.

[0078] Slag shedding rate test: Refer to the standard GB / T12812-1991, cut out a standard sample with a size of 30mm×30mm×30mm; weigh and record the total mass M1 of the original foam sample; then fix the standard P360 grit sandpaper, add a 100g weight to the sample, and manually grind it back and forth evenly 30 times, weigh it, calculate the total mass M2 of the foam sample after the test, and then calculate the mass abrasion rate according to the formula, which is the slag shedding rate.

[0079] Wear rate = (M1 - M2) / M1 × 100%

[0080] The experimental results are shown in Table 1.

[0081] Table 1. Test results of various properties of phenolic foam

[0082] Conclusion: Data from Examples 1-3 show that the environmentally friendly phenolic foam prepared by this invention exhibits excellent performance. Data from Example 1 and Comparative Example 1 indicate that the addition of a silicon-containing flame-retardant polyurethane prepolymer improves all properties of the phenolic foam. Data from Example 2 and Comparative Example 2 show that when the polyurethane prepolymer is prepared without the addition of diisocyanate silicon-containing flame-retardant compounds, the thermal stability and flame retardancy of the modified phenolic foam are significantly reduced, and the flexural strength and flaking rate also decrease to some extent. Data from Example 3 and Comparative Example 3 show that excessive amounts of silicon-containing flame-retardant polyurethane prepolymer lead to a significant decrease in the mechanical strength of the phenolic foam.

[0083] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A preparation process for an environmentally friendly modified phenolic foam, characterized in that: Includes the following steps: Step 1: S11: Allyl isocyanate is dispersed in tetrahydrofuran, and isopropanol solution of chloroplatinic acid is added as a catalyst. Argon gas is introduced as a protective gas, and 1,1,3,3-tetramethyldisiloxane is added. The mixture is heated to 55~65℃ and reacted for 8~12h to obtain organosilicon-modified diisocyanate. S12: Phenylphosphoryl dichloride is dispersed in tetrahydrofuran. Under nitrogen atmosphere and at -5~0℃, a mixed solution of triethylamine / tetrahydrofuran is added as an acid-binding agent. After the acid-binding agent is added, the temperature is raised to 40~45℃, and 10-(2,5-dihydroxyphenyl)-10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide is added. After the reaction is completed, tetrahydrofuran is removed, deionized water is added to the remaining material, and the reaction is refluxed to obtain a crude product. A 5% sodium hydroxide solution is dissolved and then diluted with deionized water. A 5% sulfuric acid solution is added at 0~5℃ until the pH of the reaction solution is <1. The precipitate is collected by filtration, washed with water, and dried to obtain a dihydroxy flame retardant. S13: Take a dihydroxyl flame retardant and an organosilicon-modified diisocyanate and disperse them in tetrahydrofuran. Under nitrogen atmosphere, with dibutyltin dilaurate as catalyst, react at 50~60℃ for 1~2h to obtain a silicon-containing flame retardant compound of diisocyanate. S14: Dehydrate polyethylene glycol 1000 under vacuum at 110~120℃; mix silicon-containing flame retardant diisocyanate compound and toluene diisocyanate at a weight ratio of 1:1 to obtain mixed diisocyanate; add the mixed diisocyanate to polyethylene glycol 1000 under nitrogen atmosphere with dibutyltin dilaurate as catalyst, and stir and react at 50~60℃ for 2~3 hours to obtain silicon-containing flame retardant polyurethane prepolymer; Step 2: S21: Mix furfural and molten phenol, heat to 60~65℃, maintain for 30 min, then heat to 105~110℃, stir and add 20% sodium hydroxide solution, adjust the pH of the system to 9~10, react for 3~4 h, cool and add dilute hydrochloric acid to neutralize to pH 7, then perform vacuum distillation at 85~90℃ to obtain phenolic resin; S22: Add the silicone flame-retardant polyurethane prepolymer to the phenolic resin and stir to obtain the modified phenolic resin; mix the modified phenolic resin, surfactant, curing agent and foaming agent, and cure to obtain environmentally friendly modified phenolic foam plastic. In S22, the weight of the silicone flame-retardant polyurethane prepolymer in the modified phenolic resin is 8-12% of the total weight of the phenolic resin.

2. The preparation process of an environmentally friendly modified phenolic foam according to claim 1, characterized in that: In S11, the molar ratio of allyl isocyanate to 1,1,3,3-tetramethyldisiloxane is 2:

1.

3. The preparation process of an environmentally friendly modified phenolic foam according to claim 1, characterized in that: In S12, the molar ratio of phenylphosphodichloro, triethylamine, and 10-(2,5-dihydroxyphenyl)-10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide is 2:2:

1.

4. The preparation process of an environmentally friendly modified phenolic foam according to claim 1, characterized in that: In S13, the molar ratio of dihydroxyl flame retardant to organosilicon-modified diisocyanate is 1:

2.

5. The preparation process of an environmentally friendly modified phenolic foam according to claim 1, characterized in that: In S14, the mixed diisocyanate is added to polyethylene glycol 1000 at a ratio of n(NCO) / n(OH) = (1.2~1.8):

1.

6. The preparation process of an environmentally friendly modified phenolic foam according to claim 1, characterized in that: In S21, furfural and molten phenol are mixed in a molar ratio of furfural to phenol of (1.6~1.7):

1.

7. The preparation process of an environmentally friendly modified phenolic foam according to claim 1, characterized in that: In S22, 100 parts of modified phenolic resin, 4-5 parts of surfactant, 10-13 parts of curing agent, and 8-9 parts of foaming agent are mixed by weight percentage.

8. The preparation process of an environmentally friendly modified phenolic foam according to claim 1, characterized in that: In S22, the curing temperature is 70~80℃ and the curing time is 2~3h.

9. The environmentally friendly modified phenolic foam prepared by the preparation process according to any one of claims 1 to 8.

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