Environment-friendly modified phenolic foam plastic and preparation process thereof

Abstract

The invention relates to the technical field of phenolic foam plastic, in particular to environment-friendly modified phenolic foam plastic and a preparation process thereof. The preparation method comprises the following steps: reacting allyl isocyanate with 1, 1, 3, 3-tetramethyldisiloxane to prepare organic silicon modified diisocyanate; the preparation method comprises the following steps: preparing a dihydroxy flame retardant by taking phenyl phosphorus dichloride and 10-(2, 5-dihydroxy phenyl)-10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide as raw materials; reacting the organic silicon modified diisocyanate with a dihydroxyl flame retardant to prepare a diisocyanate silicon-containing flame-retardant compound; the preparation method comprises the following steps: mixing a diisocyanate silicon-containing flame-retardant compound, polyethylene glycol 1000 and toluene diisocynate to prepare a silicon-containing flame-retardant polyurethane prepolymer; the preparation method comprises the following steps: taking furfural and phenol as raw materials for reaction, and adding a silicon-containing flame-retardant polyurethane prepolymer for modification to obtain the modified phenolic resin. Mixing and curing the modified phenolic resin, a surfactant, a curing agent and a foaming agent to obtain the environment-friendly modified phenolic foam plastic.

Description

Technical Field

[0001] The invention relates to the technical field of phenolic foam plastics, in particular to an environmentally friendly modified phenolic foam plastics and a preparation process thereof. Background Art

[0002] Polystyrene, polyurethane foam and other traditional insulation materials have poor flame retardancy and produce harmful gases when burned, which poses a huge safety hazard. Therefore, they have been banned from use in high-rise buildings in some countries. Phenolic foam has excellent flame retardancy, heat resistance and thermal insulation properties, which has received more and more attention and has gradually become one of the preferred materials in the field of thermal insulation.

[0003] However, the low toughness and high slag rate of phenolic foam plastics have limited their development and application to a certain extent. On the other hand, the phenolic resin raw materials contain formaldehyde, so the product will inevitably release formaldehyde, which is potentially harmful to human health. Therefore, it is very necessary to toughen and modify the phenolic resin to provide an environmentally friendly modified phenolic foam plastic. Summary of the invention

[0004] The purpose of the present invention is to provide an environmentally friendly modified phenolic foam plastic and a preparation process thereof to solve the problems raised in the above background technology.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions: an environmentally friendly modified phenolic foam plastic and a preparation process thereof, comprising the following steps: Step 1: S11: Allyl isocyanate is dispersed in tetrahydrofuran, an isopropanol solution of chloroplatinic acid is added as a catalyst, argon is introduced as a protective gas, 1,1,3,3-tetramethyldisiloxane is added, the temperature is raised to 55-65°C and the reaction is carried out for 8-12 hours to obtain organosilicon-modified diisocyanate; S12: Disperse phenylphosphoryl dichloride in tetrahydrofuran, add an acid-binding agent triethylamine / tetrahydrofuran mixed solution at -5~0°C under a nitrogen environment, raise the temperature to 40~45°C after the acid-binding agent is added, add 10-(2,5-dihydroxyphenyl)-10-hydrogen-9-oxa-10-phosphaphenanthrene-10-oxide, remove tetrahydrofuran after the reaction is completed, add deionized water to the remaining material and reflux the reaction to obtain a crude product, dissolve it in a 5% sodium hydroxide solution and then dilute it with deionized water, add a 5% sulfuric acid solution at 0~5°C until the pH of the reaction solution is less than 1, filter and collect the precipitate, wash with water, and dry it to obtain a dihydroxy flame retardant; S13: dispersing a dihydroxy flame retardant and a silicone-modified diisocyanate in tetrahydrofuran, reacting the mixture at 50-60° C. for 1-2 hours with dibutyltin dilaurate as a catalyst under a nitrogen environment to obtain a diisocyanate silicon-containing flame retardant compound; S14: dehydrating polyethylene glycol 1000 under vacuum at 110-120° C.; mixing a diisocyanate silicon-containing flame retardant compound and toluene diisocyanate in a weight ratio of 1:1 to obtain a mixed diisocyanate; adding the mixed diisocyanate to polyethylene glycol 1000 under a nitrogen environment with dibutyltin dilaurate as a catalyst, stirring and reacting at 50-60° C. for 2-3 hours to obtain a silicon-containing flame retardant polyurethane prepolymer; Step 2: S21: mixing furfural and molten phenol, heating to 60-65°C, maintaining for 30 minutes, then heating to 105-110°C, adding a 20% mass concentration of sodium hydroxide solution with stirring, adjusting the pH value of the system to 9-10, reacting for 3-4 hours, cooling and adding dilute hydrochloric acid to neutralize to pH 7, and then performing reduced pressure distillation at 85-90°C to obtain phenolic resin; S22: adding a silicon-containing flame-retardant polyurethane prepolymer to a phenolic resin and stirring and mixing to obtain a modified phenolic resin; mixing the modified phenolic resin, a surfactant, a curing agent, and a foaming agent, and curing to obtain an environmentally friendly modified phenolic foam plastic.

[0006] Furthermore, in S11, the molar ratio of allyl isocyanate to 1,1,3,3-tetramethyldisiloxane is 2:1.

[0007] Furthermore, in S12, the molar ratio of phenylphosphoryl dichloride, triethylamine, and 10-(2,5-dihydroxyphenyl)-10-hydrogen-9-oxa-10-phosphaphenanthrene-10-oxide is 2:2:1.

[0008] Furthermore, in S13, the molar ratio of the dihydroxy flame retardant to the silicone-modified diisocyanate is 1:2.

[0009] Furthermore, in S14, the mixed diisocyanate is added to polyethylene glycol 1000 at n(NCO) / n(OH)=(1.2~1.8):1.

[0010] Furthermore, in S21, furfural and molten phenol are mixed according to a molar ratio of furfural to phenol (1.6-1.7):1.

[0011] Furthermore, in S22, in the modified phenolic resin, the weight amount of the silicon-containing flame-retardant polyurethane prepolymer is 8-12% of the total weight of the phenolic resin.

[0012] Further, in S22, 100 parts of modified phenolic resin, 4 to 5 parts of surfactant, 10 to 13 parts of curing agent, and 8 to 9 parts of foaming agent are mixed by weight percentage.

[0013] Furthermore, in S22, the curing temperature is 70-80°C, and the curing time is 2-3h.

[0014] Compared with the prior art, the beneficial effects achieved by the present invention are: an environmentally friendly modified phenolic foam plastic and a preparation process thereof. Traditional phenolic resin uses formaldehyde as a raw material, while furfural, as a product obtained by acid catalysis from renewable biomass raw materials, has lower toxicity and can replace formaldehyde to prepare phenolic resin, effectively reducing the harm of formaldehyde to human body and environment.

[0015] When preparing phenolic foam, the present invention adds polyurethane prepolymer to toughen and modify it. The two ends of the polyurethane prepolymer contain active isocyanate groups, which can be bonded with the hydroxymethyl in phenolic, so that the phenolic resin and the polyurethane prepolymer form a three-dimensional interpenetrating cross-linked network structure during the foaming and curing process, thereby improving the toughness and powdering phenomenon of the phenolic foam. Generally, the polyurethane prepolymer is obtained by reacting polyether polyol with isocyanate compound, so the product has defects such as flammability and heat resistance. If it is directly mixed with phenolic resin, although the mechanical properties can be improved, at the same time, the flame retardant and heat resistance of the material will decrease, which is not worth the loss. Therefore, the present application adopts the reaction of allyl isocyanate and 1,1,3,3-tetramethyldisiloxane to prepare organosilicon-modified diisocyanate; then phenylphosphoryl dichloride and 10-(2,5-dihydroxyphenyl)-10-hydrogen-9-oxa-10-phosphaphenanthrene-10-oxide are used as raw materials to prepare dihydroxy flame retardant; organosilicon-modified diisocyanate and dihydroxy flame retardant are reacted to prepare diisocyanate silicon-containing flame retardant compound, and diisocyanate silicon-containing flame retardant compound and toluene diisocyanate are mixed and reacted with polyethylene glycol 1000 to prepare silicon-containing flame retardant polyurethane prepolymer. Components with flame retardant properties are introduced into the polyurethane prepolymer, and the presence of silicon-oxygen bonds improves the flexibility and heat resistance of the prepolymer. After modification, the phenolic foam plastic exhibits good heat resistance, mechanical properties, flame retardant properties, and the slag drop is significantly reduced.

[0016] In addition, it should be noted that the amount of silicon-containing flame-retardant polyurethane prepolymer is not the more the better. Excessive use will also reduce its compatibility with phenolic resin and reduce the modification effect. Therefore, the weight amount of silicon-containing flame-retardant polyurethane prepolymer is controlled to 8-12% of the total weight of phenolic resin, and the modification effect is the best. DETAILED DESCRIPTION

[0017] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without making any creative work shall fall within the scope of protection of the present invention.

[0018] The materials and sources used in the present invention are as follows: the curing agent is toluene-4-sulfonic acid, phosphoric acid and distilled water mixed in a mass ratio of 2:1:2; the surfactant is Tween 80; and the foaming agent is n-pentane.

[0019] Embodiment 1: An environmentally friendly modified phenolic foam plastic and a preparation process thereof, comprising the following steps: Step 1: S11: Allyl isocyanate is dispersed in tetrahydrofuran, an isopropanol solution of chloroplatinic acid is added as a catalyst, argon is introduced as a protective gas, 1,1,3,3-tetramethyldisiloxane is added, the temperature is raised to 55° C. and reacted for 8 hours to obtain an organosilicon-modified diisocyanate; wherein the molar ratio of allyl isocyanate to 1,1,3,3-tetramethyldisiloxane is 2:1; S12: Disperse phenylphosphoryl dichloride in tetrahydrofuran, add an acid-binding agent triethylamine / tetrahydrofuran mixed solution at -5°C under a nitrogen environment, heat to 40-45°C, add 10-(2,5-dihydroxyphenyl)-10-hydrogen-9-oxa-10-phosphaphenanthrene-10-oxide, remove tetrahydrofuran after the reaction, add deionized water to the remaining material and reflux the reaction to obtain a crude product, dissolve it in a 5% sodium hydroxide solution and then dilute it with deionized water, add a 5% sulfuric acid solution at 0°C until the pH of the reaction solution is less than 1, filter and collect the precipitate, wash it with water, and dry it to obtain a dihydroxy flame retardant; wherein the molar ratio of phenylphosphoryl dichloride, triethylamine, and 10-(2,5-dihydroxyphenyl)-10-hydrogen-9-oxa-10-phosphaphenanthrene-10-oxide is 2:2:1; S13: dispersing a dihydroxy flame retardant and a silicone-modified diisocyanate in tetrahydrofuran, reacting the mixture at 50° C. for 1 h under a nitrogen environment with dibutyltin dilaurate as a catalyst to obtain a diisocyanate silicon-containing flame retardant compound; wherein the molar ratio of the dihydroxy flame retardant and the silicone-modified diisocyanate is 1:2; S14: dehydrating polyethylene glycol 1000 under vacuum at 110° C.; mixing a diisocyanate silicon-containing flame retardant compound and toluene diisocyanate at a weight ratio of 1:1 to obtain a mixed diisocyanate; adding the mixed diisocyanate to polyethylene glycol 1000 at a ratio of n(NCO) / n(OH)=1.2:1 under a nitrogen environment using dibutyltin dilaurate as a catalyst, and reacting the mixture at 50° C. for 2 hours with stirring to obtain a silicon-containing flame retardant polyurethane prepolymer; Step 2: S21: mixing furfural and molten phenol in a molar ratio of furfural to phenol of 1.65:1, heating to 60°C, maintaining for 30 minutes and then heating to 105°C, adding a sodium hydroxide solution having a mass concentration of 20% with stirring, adjusting the pH value of the system to 9, reacting for 3 hours, cooling and adding dilute hydrochloric acid to neutralize to a pH of 7, and then performing reduced pressure distillation at 85°C to obtain a phenolic resin; S22: Add the silicon-containing flame-retardant polyurethane prepolymer to the phenolic resin and stir to obtain a modified phenolic resin; mix 100 kg of the modified phenolic resin, 5 kg of a surfactant, 12 kg of a curing agent and 8 kg of a foaming agent, and cure at 70°C for 2 hours to obtain an environmentally friendly modified phenolic foam plastic; in the modified phenolic resin, the weight amount of the silicon-containing flame-retardant polyurethane prepolymer is 8% of the total weight of the phenolic resin.

[0020] Embodiment 2: An environmentally friendly modified phenolic foam plastic and a preparation process thereof, comprising the following steps: Step 1: S11: Allyl isocyanate is dispersed in tetrahydrofuran, an isopropanol solution of chloroplatinic acid is added as a catalyst, argon is introduced as a protective gas, 1,1,3,3-tetramethyldisiloxane is added, the temperature is raised to 60° C. and the reaction is carried out for 10 hours to obtain an organosilicon-modified diisocyanate; wherein the molar ratio of allyl isocyanate to 1,1,3,3-tetramethyldisiloxane is 2:1; S12: Disperse phenylphosphoryl dichloride in tetrahydrofuran, add an acid-binding agent triethylamine / tetrahydrofuran mixed solution at -3°C under a nitrogen environment, heat to 40-45°C, add 10-(2,5-dihydroxyphenyl)-10-hydrogen-9-oxa-10-phosphaphenanthrene-10-oxide, remove tetrahydrofuran after the reaction, add deionized water to the remaining material and reflux the reaction to obtain a crude product, dissolve it in a 5% sodium hydroxide solution and then dilute it with deionized water, add a 5% sulfuric acid solution at 3°C ​​until the pH of the reaction solution is less than 1, filter and collect the precipitate, wash with water, and dry to obtain a dihydroxy flame retardant; wherein the molar ratio of phenylphosphoryl dichloride, triethylamine, and 10-(2,5-dihydroxyphenyl)-10-hydrogen-9-oxa-10-phosphaphenanthrene-10-oxide is 2:2:1; S13: dispersing a dihydroxy flame retardant and a silicone-modified diisocyanate in tetrahydrofuran, reacting the mixture at 55° C. for 1.5 h under a nitrogen environment with dibutyltin dilaurate as a catalyst to obtain a diisocyanate silicon-containing flame retardant compound; wherein the molar ratio of the dihydroxy flame retardant and the silicone-modified diisocyanate is 1:2; S14: dehydrating polyethylene glycol 1000 under vacuum at 115° C.; mixing a diisocyanate silicon-containing flame retardant compound and toluene diisocyanate at a weight ratio of 1:1 to obtain a mixed diisocyanate; adding the mixed diisocyanate to polyethylene glycol 1000 at a ratio of n(NCO) / n(OH)=1.2:1 under a nitrogen environment using dibutyltin dilaurate as a catalyst, and reacting the mixture at 55° C. for 2.5 hours with stirring to obtain a silicon-containing flame retardant polyurethane prepolymer; Step 2: S21: mixing furfural and molten phenol in a molar ratio of furfural to phenol of 1.65:1, heating to 63°C, maintaining for 30 minutes, then heating to 110°C, adding a 20% mass concentration sodium hydroxide solution with stirring, adjusting the pH value of the system to 9-10, reacting for 3.5 hours, cooling, adding dilute hydrochloric acid to neutralize to pH 7, and then performing reduced pressure distillation at 90°C to obtain a phenolic resin; S22: Add the silicon-containing flame-retardant polyurethane prepolymer to the phenolic resin and stir to obtain a modified phenolic resin; mix 100 kg of the modified phenolic resin, 5 kg of a surfactant, 12 kg of a curing agent and 8 kg of a foaming agent, and cure at 75°C for 2.5 hours to obtain an environmentally friendly modified phenolic foam plastic; in the modified phenolic resin, the weight amount of the silicon-containing flame-retardant polyurethane prepolymer is 10% of the total weight of the phenolic resin.

[0021] Embodiment 3: An environmentally friendly modified phenolic foam plastic and a preparation process thereof, comprising the following steps: Step 1: S11: Allyl isocyanate is dispersed in tetrahydrofuran, an isopropanol solution of chloroplatinic acid is added as a catalyst, argon is introduced as a protective gas, 1,1,3,3-tetramethyldisiloxane is added, the temperature is raised to 65° C. and the reaction is carried out for 12 hours to obtain an organosilicon-modified diisocyanate; wherein the molar ratio of allyl isocyanate to 1,1,3,3-tetramethyldisiloxane is 2:1; S12: Disperse phenylphosphoryl dichloride in tetrahydrofuran, add an acid-binding agent triethylamine / tetrahydrofuran mixed solution at 0°C under a nitrogen environment, heat to 40-45°C, add 10-(2,5-dihydroxyphenyl)-10-hydrogen-9-oxa-10-phosphaphenanthrene-10-oxide, remove tetrahydrofuran after the reaction, add deionized water to the remaining material and reflux the reaction to obtain a crude product, dissolve it in a 5% sodium hydroxide solution and then dilute it with deionized water, add a 5% sulfuric acid solution at 5°C until the pH of the reaction solution is less than 1, filter and collect the precipitate, wash it with water, and dry it to obtain a dihydroxy flame retardant; wherein the molar ratio of phenylphosphoryl dichloride, triethylamine, and 10-(2,5-dihydroxyphenyl)-10-hydrogen-9-oxa-10-phosphaphenanthrene-10-oxide is 2:2:1; S13: dispersing a dihydroxy flame retardant and a silicone-modified diisocyanate in tetrahydrofuran, reacting the mixture at 60° C. for 2 h under a nitrogen environment with dibutyltin dilaurate as a catalyst to obtain a diisocyanate silicon-containing flame retardant compound; wherein the molar ratio of the dihydroxy flame retardant and the silicone-modified diisocyanate is 1:2; S14: dehydrating polyethylene glycol 1000 under vacuum at 120° C.; mixing a diisocyanate silicon-containing flame retardant compound and toluene diisocyanate at a weight ratio of 1:1 to obtain a mixed diisocyanate; adding the mixed diisocyanate to polyethylene glycol 1000 at a ratio of n(NCO) / n(OH)=1.2:1 under a nitrogen environment using dibutyltin dilaurate as a catalyst, and reacting the mixture at 60° C. for 3 hours with stirring to obtain a silicon-containing flame retardant polyurethane prepolymer; Step 2: S21: mixing furfural and molten phenol in a molar ratio of furfural to phenol of 1.65:1, heating to 65°C, maintaining for 30 minutes and then heating to 110°C, adding a sodium hydroxide solution having a mass concentration of 20% with stirring, adjusting the pH value of the system to 10, reacting for 4 hours, cooling and adding dilute hydrochloric acid to neutralize to a pH of 7, and then performing reduced pressure distillation at 90°C to obtain a phenolic resin; S22: Add the silicon-containing flame-retardant polyurethane prepolymer to the phenolic resin and stir to obtain a modified phenolic resin; mix 100 kg of the modified phenolic resin, 5 kg of a surfactant, 12 kg of a curing agent and 8 kg of a foaming agent, and cure at 80°C for 3 hours to obtain an environmentally friendly modified phenolic foam plastic; in the modified phenolic resin, the weight amount of the silicon-containing flame-retardant polyurethane prepolymer is 12% of the total weight of the phenolic resin.

[0022] Comparative Example 1: No silicon-containing flame-retardant polyurethane prepolymer is added to modify the phenolic resin, and the other parameters are the same as those in Example 1.

[0023] Step 1: The furfural and molten phenol were mixed in a molar ratio of furfural to phenol of 1.65:1, the temperature was raised to 60°C, maintained for 30 minutes, and then raised to 105°C, and a sodium hydroxide solution with a mass concentration of 20% was added under stirring, and the pH value of the system was adjusted to 9. After reacting for 3 hours, the mixture was cooled and neutralized to pH 7 by adding dilute hydrochloric acid, and then vacuum distilled at 85°C to obtain a phenolic resin; Step 2: 100 kg of phenolic resin, 5 kg of surfactant, 12 kg of curing agent and 8 kg of foaming agent were mixed and cured at 70° C. for 2 hours to obtain phenolic foam plastic; in the modified phenolic resin, the weight amount of the silicon-containing flame-retardant polyurethane prepolymer was 8% of the total weight of the phenolic resin.

[0024] Comparative Example 2: No diisocyanate silicon-containing flame retardant compound was added, and other parameters were the same as those in Example 2.

[0025] Step 1: The polyethylene glycol 1000 was vacuum dehydrated at 115°C; under a nitrogen environment, dibutyltin dilaurate was used as a catalyst, toluene diisocyanate was added to the 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 2.5h to obtain a polyurethane prepolymer; Step 2: S21: mixing furfural and molten phenol in a molar ratio of furfural to phenol of 1.65:1, heating to 63°C, maintaining for 30 minutes, then heating to 110°C, adding a 20% mass concentration sodium hydroxide solution with stirring, adjusting the pH value of the system to 9-10, reacting for 3.5 hours, cooling, adding dilute hydrochloric acid to neutralize to pH 7, and then performing reduced pressure distillation at 90°C to obtain a phenolic resin; S22: Add the polyurethane prepolymer to the phenolic resin and stir to obtain a modified phenolic resin; mix 100 kg of the modified phenolic resin, 5 kg of a surfactant, 12 kg of a curing agent and 8 kg of a foaming agent, and cure at 75°C for 2.5 hours to obtain an environmentally friendly modified phenolic foam plastic; in the modified phenolic resin, the weight amount of the polyurethane prepolymer is 10% of the total weight of the phenolic resin.

[0026] Comparative Example 3: The amount of silicon-containing flame-retardant polyurethane prepolymer was increased, and the other parameters were the same as those in Example 3.

[0027] Step 1: S11: Allyl isocyanate is dispersed in tetrahydrofuran, an isopropanol solution of chloroplatinic acid is added as a catalyst, argon is introduced as a protective gas, 1,1,3,3-tetramethyldisiloxane is added, the temperature is raised to 65° C. and the reaction is carried out for 12 hours to obtain an organosilicon-modified diisocyanate; wherein the molar ratio of allyl isocyanate to 1,1,3,3-tetramethyldisiloxane is 2:1; S12: Disperse phenylphosphoryl dichloride in tetrahydrofuran, add an acid-binding agent triethylamine / tetrahydrofuran mixed solution at 0°C under a nitrogen environment, heat to 40-45°C, add 10-(2,5-dihydroxyphenyl)-10-hydrogen-9-oxa-10-phosphaphenanthrene-10-oxide, remove tetrahydrofuran after the reaction, add deionized water to the remaining material and reflux the reaction to obtain a crude product, dissolve it in a 5% sodium hydroxide solution and then dilute it with deionized water, add a 5% sulfuric acid solution at 5°C until the pH of the reaction solution is less than 1, filter and collect the precipitate, wash it with water, and dry it to obtain a dihydroxy flame retardant; wherein the molar ratio of phenylphosphoryl dichloride, triethylamine, and 10-(2,5-dihydroxyphenyl)-10-hydrogen-9-oxa-10-phosphaphenanthrene-10-oxide is 2:2:1; S13: dispersing a dihydroxy flame retardant and a silicone-modified diisocyanate in tetrahydrofuran, reacting the mixture at 60° C. for 2 h under a nitrogen environment with dibutyltin dilaurate as a catalyst to obtain a diisocyanate silicon-containing flame retardant compound; wherein the molar ratio of the dihydroxy flame retardant and the silicone-modified diisocyanate is 1:2; S14: dehydrating polyethylene glycol 1000 under vacuum at 120° C.; mixing a diisocyanate silicon-containing flame retardant compound and toluene diisocyanate at a weight ratio of 1:1 to obtain a mixed diisocyanate; adding the mixed diisocyanate to polyethylene glycol 1000 at a ratio of n(NCO) / n(OH)=1.2:1 under a nitrogen environment using dibutyltin dilaurate as a catalyst, and reacting the mixture at 60° C. for 3 hours with stirring to obtain a silicon-containing flame retardant polyurethane prepolymer; Step 2: S21: mixing furfural and molten phenol in a molar ratio of furfural to phenol of 1.65:1, heating to 65°C, maintaining for 30 minutes and then heating to 110°C, adding a sodium hydroxide solution having a mass concentration of 20% with stirring, adjusting the pH value of the system to 10, reacting for 4 hours, cooling and adding dilute hydrochloric acid to neutralize to a pH of 7, and then performing reduced pressure distillation at 90°C to obtain a phenolic resin; S22: Add the silicon-containing flame-retardant polyurethane prepolymer to the phenolic resin and stir to obtain a modified phenolic resin; mix 100 kg of the modified phenolic resin, 5 kg of a surfactant, 12 kg of a curing agent and 8 kg of a foaming agent, and cure at 80°C for 3 hours to obtain an environmentally friendly modified phenolic foam plastic; in the modified phenolic resin, the weight amount of the silicon-containing flame-retardant polyurethane prepolymer is 15% of the total weight of the phenolic resin.

[0028] Experiment: The performance tests were performed on the samples prepared in Examples 1 to 3 and Comparative Examples 1 to 3. Flame retardant performance: The limiting oxygen index was used for characterization, and the sample size was 100mm×10mm×10mm.

[0029] Heat resistance: The test temperature range is 30~750℃, nitrogen atmosphere, heating rate is 10℃ / min, and the temperature Td when the thermal weight loss is 10% is recorded 10% .

[0030] Bending strength: Tested according to GB / T8812.1-2007 standard, the bending rate is 10mm / min, and the sample size is 120mm×25mm×20mm.

[0031] Debris rate test: refer to GB / T12812-1991, cut out standard samples with the size of 30mm×30mm×30mm; weigh, record the total mass M1 of the original foam sample, then fix the standard P360 grit sandpaper, add a 100g weight on the sample, use manpower to grind back and forth evenly 30 times, weigh, calculate the total mass M2 of the foam sample after the test, and then calculate the mass wear rate according to the formula, which is the debris rate.

[0032] Wear rate = (M1-M2) / M1×100% The experimental results are shown in Table 1.

[0033] Table 1. Test results of various properties of phenolic foam plastics

[0034] Conclusion: The data of Examples 1 to 3 show that the environmentally friendly phenolic foam plastic prepared by the present invention has good properties. The data of Example 1 and Comparative Example 1 show that after adding silicon-containing flame-retardant polyurethane prepolymer to phenolic resin, the various properties of phenolic foam plastic are improved; the data of Example 2 and Comparative Example 2 show that without adding diisocyanate silicon-containing flame-retardant compound to prepare polyurethane prepolymer, the thermal stability and flame retardancy of the modified phenolic foam plastic are significantly reduced, and the bending strength and slag drop rate are also reduced to a certain extent; the data of Example 3 and Comparative Example 3 show that excessive use of silicon-containing flame-retardant polyurethane prepolymer will lead to a significant decrease in the mechanical strength of phenolic foam plastic.

[0035] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A process for preparing an environmentally friendly modified phenolic foam plastic, characterized in that: The following steps are involved: Step 1: S11: Allyl isocyanate is dispersed in tetrahydrofuran, an isopropanol solution of chloroplatinic acid is added as a catalyst, argon is introduced as a protective gas, 1,1,3,3-tetramethyldisiloxane is added, the temperature is raised to 55-65°C and the reaction is carried out for 8-12 hours to obtain organosilicon-modified diisocyanate; S12: Disperse phenylphosphoryl dichloride in tetrahydrofuran, add an acid-binding agent triethylamine / tetrahydrofuran mixed solution at -5~0°C under a nitrogen environment, raise the temperature to 40~45°C after the acid-binding agent is added, add 10-(2,5-dihydroxyphenyl)-10-hydrogen-9-oxa-10-phosphaphenanthrene-10-oxide, remove tetrahydrofuran after the reaction is completed, add deionized water to the remaining material and reflux the reaction to obtain a crude product, dissolve it in a 5% sodium hydroxide solution and then dilute it with deionized water, add a 5% sulfuric acid solution at 0~5°C until the pH of the reaction solution is less than 1, filter and collect the precipitate, wash with water, and dry it to obtain a dihydroxy flame retardant; S13: dispersing a dihydroxy flame retardant and a silicone-modified diisocyanate in tetrahydrofuran, reacting the mixture at 50-60° C. for 1-2 hours with dibutyltin dilaurate as a catalyst under a nitrogen environment to obtain a diisocyanate silicon-containing flame retardant compound; S14: dehydrating polyethylene glycol 1000 under vacuum at 110-120° C.; mixing a diisocyanate silicon-containing flame retardant compound and toluene diisocyanate in a weight ratio of 1:1 to obtain a mixed diisocyanate; adding the mixed diisocyanate to polyethylene glycol 1000 under a nitrogen environment with dibutyltin dilaurate as a catalyst, stirring and reacting at 50-60° C. for 2-3 hours to obtain a silicon-containing flame retardant polyurethane prepolymer; Step 2: S21: mixing furfural and molten phenol, heating to 60-65°C, maintaining for 30 minutes, then heating to 105-110°C, adding a 20% mass concentration of sodium hydroxide solution with stirring, adjusting the pH value of the system to 9-10, reacting for 3-4 hours, cooling and adding dilute hydrochloric acid to neutralize to pH 7, and then performing reduced pressure distillation at 85-90°C to obtain phenolic resin; S22: adding the silicon-containing flame-retardant polyurethane prepolymer to the phenolic resin and stirring and mixing to obtain a modified phenolic resin; The modified phenolic resin, surfactant, curing agent and foaming agent are mixed and cured to obtain the environmentally friendly modified phenolic foam plastic.

2. The process for preparing an environmentally friendly modified phenolic foam plastic 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 process for preparing an environmentally friendly modified phenolic foam plastic according to claim 1, characterized in that: In S12, the molar ratio of phenylphosphoryl dichloride, triethylamine, and 10-(2,5-dihydroxyphenyl)-10-hydrogen-9-oxa-10-phosphaphenanthrene-10-oxide is 2:2:

1.

4. The process for preparing an environmentally friendly modified phenolic foam plastic according to claim 1, characterized in that: In S13, the molar ratio of the dihydroxy flame retardant to the silicone-modified diisocyanate is 1:

2.

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

1.

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

1.

7. The process for preparing an environmentally friendly modified phenolic foam plastic according to claim 1, characterized in that: In S22, in the modified phenolic resin, the weight amount of the silicon-containing flame-retardant polyurethane prepolymer is 8-12% of the total weight of the phenolic resin.

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

9. The process for preparing an environmentally friendly modified phenolic foam plastic according to claim 1, characterized in that: In S22, the curing temperature is 70-80°C and the curing time is 2-3h.

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

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