A thermoplastic for foam board and a method for preparing the same

Abstract

This invention discloses a thermal insulation plastic for foam boards and its preparation method, relating to the field of polyurethane plastics technology. The invention uses aluminum nitride ceramic microspheres as the core material, with an outer layer of low thermal conductivity mullite shell formed by sintering. The mullite, combined with the spherical shell structure, produces a synergistic effect, isolating the thermal conductivity of aluminum nitride and forming a low thermal conductivity filler. This filler is then hydroxylated to further optimize its thermal insulation effect. (2R,3R)-2,3-dihydroxy-4-(hydroxyamino)-4-oxybutyl phosphate dihydrogen ester is selected as a polyhydroxy compound and polymerized with isocyanate. Simultaneously, the hydroxyl groups on the surface of the thermal insulation filler participate in chain extension, thereby forming a three-dimensional network foam plastic with the thermal insulation filler as crosslinking points. This effectively improves the mechanical properties of the plastic and enhances its flame retardant and smoke-suppressing effects.

Description

Technical Field

[0001] This invention relates to the field of polyurethane plastics technology, specifically to a heat-insulating plastic for foam boards and its preparation method. Background Technology

[0002] Polyurethane is a high-performance polymer material with excellent oil resistance, toughness, wear resistance, aging resistance, and adhesion. Its products are used in many fields such as light industry, chemical industry, textiles, medical industry, electronics, construction, automobiles, and aerospace, and it is known as the "fifth largest plastic". However, currently used rigid polyurethane foams usually rely solely on the foamed pore structure to achieve thermal insulation, resulting in poor thermal insulation performance; and the addition of thermal insulation fillers leads to poor mechanical properties such as tensile strength.

[0003] Rigid polyurethane foam contains a high proportion of combustible hydrocarbon molecular chains in its molecular chains. Moreover, the foam has a porous structure, low density, and large specific surface area, which accelerates the combustion rate. Therefore, the oxygen index of ordinary rigid foam is only about 17%, which makes it a flammable material and it cannot achieve the ideal flame retardant effect. At the same time, although rigid polyurethane foam itself is non-toxic, its combustion produces a large amount of toxic gases, which makes fire extinguishing and fire escape very difficult. Summary of the Invention

[0004] The purpose of this invention is to provide a heat-insulating plastic for foam boards and a method for preparing the same, so as to solve the problems existing in the prior art.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a method for preparing thermal insulation plastic for foam boards, comprising the following preparation steps:

[0006] (1) Mix the slurry and aluminum nitride ceramic microspheres at a ratio of 1g:15mL, stir at 40-60rpm for 4-8h, take out, dry at 100℃ and 1000Pa vacuum to constant weight, put into a sealed crucible, put the sealed crucible into a muffle furnace, heat treatment, and then cool to room temperature with the furnace to obtain core-shell type heat insulation filler.

[0007] (2) Disperse 1-3g of core-shell type heat insulation filler in 32-44mL of ethanol aqueous solution using ultrasonication, then add 2-5g of modifier, stir at 40-80rpm for 24h, filter to obtain solid, wash with ethanol and acetone 4 times respectively, and dry at 60℃ for 12h to obtain modified filler.

[0008] (3) Weigh (2R,3R)-2,3-dihydroxy-4-(hydroxyamino)-4-oxobutyl phosphate dihydrogen ester, heat to 40-50℃, add isocyanate and catalyst, then heat to 70-80℃, stir at 300-500 rpm for 1-3 hours, cool to 25-50℃, add foaming agent, foaming stabilizer and modified filler while stirring at 300-500 rpm, increase stirring speed to 2400-2600 rpm, continue stirring for 30 minutes, quickly pour into mold, then foam at 25℃ and 25-50% relative humidity. After foaming, place in an oven at 20-50℃ for 2-4 days to mature, cool and demold to obtain foam plastic.

[0009] Further, the preparation method of the slurry in step (1) is as follows: diatomaceous earth, aluminum sec-butoxide, and industrial waste gypsum slag are mixed, deionized water is added until the solid content is 40-50%, and the mixture is fed into a grinding mill and ground until the average particle size of the solid is 200-300 mesh to obtain the slurry.

[0010] Furthermore, the mass ratio of the diatomaceous earth, aluminum sec-butoxide, and industrial waste gypsum slag is 30-55:40-67:3-6.

[0011] Furthermore, the aluminum nitride ceramic microspheres described in step (1) have a particle size of 100–150 μm.

[0012] Furthermore, the specific process of the heating treatment in step (1) is as follows: in an air atmosphere, the temperature is increased to 1000℃ at 2-3℃ / min and held for 1-2 hours, then the temperature is increased to 1250-1340℃ at 3-4℃ / min and held for 1-2 hours.

[0013] Furthermore, the ethanol in the aqueous ethanol solution in step (2) has a mass fraction of 68%.

[0014] Furthermore, the modifier in step (2) is hydroxymethyltriethoxysilane.

[0015] Further, the components in step (3) are as follows by mass fraction: 40-80 parts of (2R,3R)-2,3-dihydroxy-4-(hydroxyamino)-4-oxobutyl phosphate dihydrogen ester, 50-90 parts of isocyanate, 0.2-1 parts of catalyst, 8-13 parts of foaming agent, 0.01-2.5 parts of foaming stabilizer, and 10-22 parts of modified filler.

[0016] Furthermore, the foaming agent in step (3) is a mixture of pentane and isopentane in a mass ratio of 2:1.

[0017] Further, in step (3), the isocyanate is MDI-100 and toluene diisocyanate are mixed in a mass ratio of 1-2.5:2-4; the catalyst is dibutyltin dilaurate and triethanolamine are mixed in a mass ratio of 0.5-3:0.01-2.5; and the foam stabilizer is polydimethyl silicone oil.

[0018] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0019] This invention uses aluminum nitride ceramic microspheres as raw materials, and then uses diatomaceous earth, aluminum sec-butoxide, and industrial waste gypsum slag to wet ball mill into a slurry, which is then used to wet the surface of the aluminum nitride microspheres and uniformly coat them. Through calcination, a mullite layer is formed on the surface of the aluminum nitride microspheres, forming a spherical shell structure microsphere. Since mullite and the spherical shell structure itself have low thermal conductivity, the overall heat insulation effect of the filler is very good, thereby achieving the heat insulation effect of the plastic. Then, it is modified by hydroxylation to improve the compatibility with polymers. At the same time, due to the same charge, it can more effectively shield electromagnetic waves of heat energy, thereby optimizing the heat insulation effect of the plastic.

[0020] This invention uses (2R,3R)-2,3-dihydroxy-4-(hydroxyamino)-4-oxobutyl phosphate dihydrogen ester as a polyhydroxy compound, which is polymerized with isocyanate. At the same time, the hydroxyl groups on the surface of the heat-insulating filler participate in chain extension, thereby forming a three-dimensional network foam plastic with the heat-insulating filler as the crosslinking point. This type of polyurethane foam plastic, which has its own flame-retardant elements and the heat-insulating filler grafted onto the polyurethane foam skeleton, forms an intrinsically flame-retardant polyurethane foam plastic. This avoids the migration and precipitation of traditional flame retardants, making the flame-retardant effect more durable. Moreover, the heat-insulating filler uses aluminum-based metals as the core material, which can greatly reduce the smoke generated by the combustion of the foam plastic. The core layer and shell layer have high temperature resistance, and their addition significantly improves the fire resistance and mechanical strength of the plastic. Detailed Implementation

[0021] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0022] To more clearly illustrate the method provided by the present invention, the following embodiments are provided in detail. The testing methods for various indicators of the plastics produced in the following embodiments are as follows:

[0023] Thermal insulation: Thermal conductivity was tested according to GB / T10295-2008.

[0024] Flame retardancy: Oxygen index tested according to GB / T2406-93

[0025] Mechanical properties: Tensile strength was tested according to ISO 1798-2008.

[0026] Example 1

[0027] (1) Diatomaceous earth, aluminum sec-butoxide, and industrial waste gypsum slag are mixed in a mass ratio of 30:40:3. Deionized water is added until the solid content is 40%. The mixture is fed into a grinder and ground until the average particle size of the solid is 200 mesh to obtain a slurry. Aluminum nitride ceramic microspheres with a particle size of 100μm are added in a ratio of 1g:15mL. The mixture is stirred at 40rpm for 4h. The mixture is taken out and dried at 100℃ and 1000Pa vacuum to constant weight. The mixture is then placed in a sealed crucible and placed in a muffle furnace. The furnace is heated to 1000℃ at 2℃ / min in an air atmosphere and held for 1h. Then the furnace is heated to 1250℃ at 3℃ / min and held for 1h. The mixture is then cooled to room temperature with the furnace to obtain a core-shell type heat insulation filler.

[0028] (2) 1g of core-shell heat insulation filler was ultrasonically dispersed in 32mL of 68% ethanol aqueous solution, then 2g of hydroxymethyltriethoxysilane was added, and the mixture was stirred at 40rpm for 24h. The solid was filtered and washed with ethanol and acetone 4 times respectively, and dried at 60℃ for 12h to obtain the modified filler.

[0029] (3) Weigh 40 parts of (2R,3R)-2,3-dihydroxy-4-(hydroxyamino)-4-oxobutyl phosphate dihydrogen ester, heat to 40℃, add 50 parts of isocyanate and 0.2 parts of catalyst. The mass ratio of MDI-100 to toluene diisocyanate in the isocyanate is 1:2; the mass ratio of dibutyltin dilaurate to triethanolamine in the catalyst is 0.5:0.01; then heat to 70℃, stir at 300 rpm for 1 h, and cool. At 25°C, while stirring at 300 rpm, add 8 parts of foaming agent, 0.01 parts of polydimethyl silicone oil, and 10 parts of modified filler. The mass ratio of pentane to isopentane in the foaming agent is 2:1. Increase the stirring speed to 2400 rpm and continue stirring for 30 minutes. Quickly pour the mixture into a mold and then foam it at 25°C and 25% relative humidity. After foaming, place it in a 20°C oven for 2 days to cure. Cool and demold to obtain foamed plastic.

[0030] Example 2

[0031] (1) Diatomaceous earth, aluminum sec-butoxide, and industrial waste gypsum slag are mixed in a mass ratio of 41:55:4.5. Deionized water is added until the solid content is 45%. The mixture is fed into a grinder and ground until the average particle size of the solid is 250 mesh to obtain a slurry. Aluminum nitride ceramic microspheres with a particle size of 120 μm are added in a ratio of 1 g:15 mL. The mixture is stirred at 50 rpm for 6 h. The mixture is then removed and dried at 100 °C and 1000 Pa vacuum until constant weight. The mixture is then placed in a sealed crucible and placed in a muffle furnace. The furnace is heated to 1000 °C at 2.5 °C / min in an air atmosphere and held for 1.5 h. The temperature is then increased to 1300 °C at 3.5 °C / min and held for 1.5 h. The mixture is then cooled to room temperature with the furnace to obtain a core-shell type heat insulation filler.

[0032] (2) Disperse 2g of core-shell heat insulation filler in 40mL of 68% ethanol aqueous solution by ultrasonication, then add 3.2g of hydroxymethyltriethoxysilane, stir at 60rpm for 24h, filter to obtain solid, wash with ethanol and acetone 4 times respectively, and dry at 60℃ for 12h to obtain modified filler.

[0033] (3) Weigh 60 parts of (2R,3R)-2,3-dihydroxy-4-(hydroxyamino)-4-oxobutyl phosphate dihydrogen ester, heat to 45℃, add 72 parts of isocyanate and 0.5 parts of catalyst, then heat to 75℃ again, stir at 400 rpm for 2 hours, cool to 33℃, and while stirring at 400 rpm, add 10 parts of foaming agent, 1.1 parts of foaming stabilizer, and 17 parts of modified filler, increase the stirring speed to 2500 rpm, and continue stirring for 30 minutes. The mixture is quickly poured into a mold and then foamed at 25°C and 33% relative humidity. After foaming, it is placed in a 40°C oven for 3 days to mature, cooled, and demolded to obtain foamed plastic. The foaming agent is a mixture of pentane and isopentane in a mass ratio of 2:1. The isocyanate is a mixture of MDI-100 and toluene diisocyanate in a mass ratio of 1.6:3. The catalyst is a mixture of dibutyltin dilaurate and triethanolamine in a mass ratio of 2.1:1.6. The foam stabilizer is polydimethyl silicone oil.

[0034] Example 3

[0035] (1) Diatomaceous earth, aluminum sec-butoxide, and industrial waste gypsum slag are mixed in a mass ratio of 55:67:6, deionized water is added until the solid content is 50%, and the mixture is fed into a grinder and ground until the average particle size of the solid is 300 mesh to obtain a slurry; aluminum nitride ceramic microspheres with a particle size of 150μm are added in a ratio of 1g:15mL, and the mixture is stirred at 60rpm for 8h. The mixture is then taken out and dried at 100℃ and 1000Pa vacuum to constant weight. The mixture is then placed in a sealed crucible and placed in a muffle furnace. The temperature is increased to 1000℃ at 3℃ / min in an air atmosphere and held for 2h. The temperature is then increased to 1340℃ at 4℃ / min and held for 2h. The mixture is then cooled to room temperature with the furnace to obtain a core-shell type heat insulation filler.

[0036] (2) Disperse 3g of core-shell heat insulation filler in 44mL of 68% ethanol aqueous solution by ultrasonication, then add 5g of hydroxymethyltriethoxysilane, stir at 80rpm for 24h, filter to obtain solid, wash with ethanol and acetone 4 times respectively, and dry at 60℃ for 12h to obtain modified filler.

[0037] (3) Weigh 80 parts of (2R,3R)-2,3-dihydroxy-4-(hydroxyamino)-4-oxobutyl phosphate dihydrogen ester, heat to 50℃, add 90 parts of isocyanate and 1 part of catalyst, then heat to 80℃, stir at 500 rpm for 3 hours, cool to 50℃, and while stirring at 500 rpm, add 13 parts of foaming agent, 2.5 parts of foaming stabilizer, and 22 parts of modified filler, increase the stirring speed to 2600 rpm, and continue stirring for 30 minutes. The mixture is quickly poured into a mold and then foamed at 25°C and 50% relative humidity. After foaming, it is placed in a 50°C oven for 4 days to mature, cooled, and demolded to obtain foamed plastic. The foaming agent is a mixture of pentane and isopentane in a mass ratio of 2:1. The isocyanate is a mixture of MDI-100 and toluene diisocyanate in a mass ratio of 2.5:4. The catalyst is a mixture of dibutyltin dilaurate and triethanolamine in a mass ratio of 3:2.5. The foam stabilizer is polydimethyl silicone oil.

[0038] Comparative Example 1

[0039] (1) 2g of aluminum nitride ceramic microspheres with a particle size of 120μm were ultrasonically dispersed in 40mL of 68% ethanol aqueous solution, and then 3.2g of hydroxymethyltriethoxysilane was added. The mixture was stirred at 60rpm for 24h, filtered to obtain the solid, washed 4 times with ethanol and acetone respectively, and dried at 60℃ for 12h to obtain the modified filler.

[0040] (2) Weigh 60 parts of (2R,3R)-2,3-dihydroxy-4-(hydroxyamino)-4-oxobutyl phosphate dihydrogen ester, heat to 45℃, add 72 parts of isocyanate and 0.5 parts of catalyst, then heat to 75℃ again, stir at 400 rpm for 2 hours, cool to 33℃, and while stirring at 400 rpm, add 10 parts of foaming agent, 1.1 parts of foaming stabilizer, and 17 parts of modified filler, increase the stirring speed to 2500 rpm, and continue stirring for 30 minutes. The mixture is quickly poured into a mold and then foamed at 25°C and 33% relative humidity. After foaming, it is placed in a 40°C oven for 3 days to mature, cooled, and demolded to obtain foamed plastic. The foaming agent is a mixture of pentane and isopentane in a mass ratio of 2:1. The isocyanate is a mixture of MDI-100 and toluene diisocyanate in a mass ratio of 1.6:3. The catalyst is a mixture of dibutyltin dilaurate and triethanolamine in a mass ratio of 2.1:1.6. The foam stabilizer is polydimethyl silicone oil.

[0041] Comparative Example 2

[0042] (1) Diatomaceous earth, aluminum sec-butoxide, and industrial waste gypsum slag are mixed in a mass ratio of 41:55:4.5. Deionized water is added until the solid content is 70%. The mixture is fed into a grinder and ground until the average particle size of the solid is 250 mesh. The mixture is granulated and dried at 100°C and 1000Pa vacuum until constant weight. The granulated mixture is then placed in a sealed crucible and placed in a muffle furnace. The furnace is heated to 1000°C at 2.5°C / min in an air atmosphere and held for 1.5 hours. The furnace is then heated to 1300°C at 3.5°C / min and held for 1.5 hours. The mixture is then cooled to room temperature with the furnace to obtain the heat-insulating filler.

[0043] (2) Disperse 2g of heat insulation filler in 40mL of 68% ethanol aqueous solution by ultrasonication, then add 3.2g of hydroxymethyltriethoxysilane, stir at 60rpm for 24h, filter to obtain solid, wash with ethanol and acetone 4 times respectively, and dry at 60℃ for 12h to obtain modified filler.

[0044] (3) Weigh 60 parts of (2R,3R)-2,3-dihydroxy-4-(hydroxyamino)-4-oxobutyl phosphate dihydrogen ester, heat to 45℃, add 72 parts of isocyanate and 0.5 parts of catalyst, then heat to 75℃ again, stir at 400 rpm for 2 hours, cool to 33℃, and while stirring at 400 rpm, add 10 parts of foaming agent, 1.1 parts of foaming stabilizer, and 17 parts of modified filler, increase the stirring speed to 2500 rpm, and continue stirring for 30 minutes. The mixture is quickly poured into a mold and then foamed at 25°C and 33% relative humidity. After foaming, it is placed in a 40°C oven for 3 days to mature, cooled, and demolded to obtain foamed plastic. The foaming agent is a mixture of pentane and isopentane in a mass ratio of 2:1. The isocyanate is a mixture of MDI-100 and toluene diisocyanate in a mass ratio of 1.6:3. The catalyst is a mixture of dibutyltin dilaurate and triethanolamine in a mass ratio of 2.1:1.6. The foam stabilizer is polydimethyl silicone oil.

[0045] Comparative Example 3

[0046] (1) Diatomaceous earth, aluminum sec-butoxide, and industrial waste gypsum slag are mixed in a mass ratio of 41:55:4.5. Deionized water is added until the solid content is 45%. The mixture is fed into a grinder and ground until the average particle size of the solid is 250 mesh to obtain a slurry. Aluminum nitride ceramic microspheres with a particle size of 120 μm are added in a ratio of 1 g:15 mL. The mixture is stirred at 50 rpm for 6 h. The mixture is then removed and dried at 100 °C and 1000 Pa vacuum until constant weight. The mixture is then placed in a sealed crucible and placed in a muffle furnace. The furnace is heated to 1000 °C at 2.5 °C / min in an air atmosphere and held for 1.5 h. The temperature is then increased to 1300 °C at 3.5 °C / min and held for 1.5 h. The mixture is then cooled to room temperature with the furnace to obtain a core-shell type heat insulation filler.

[0047] (2) Weigh 60 parts of (2R,3R)-2,3-dihydroxy-4-(hydroxyamino)-4-oxobutyl phosphate dihydrogen ester, heat to 45℃, add 72 parts of isocyanate and 0.5 parts of catalyst, then heat to 75℃ again, stir at 400 rpm for 2 hours, cool to 33℃, and while stirring at 400 rpm, add 10 parts of foaming agent, 1.1 parts of foaming stabilizer, and 17 parts of core-shell heat insulation filler, increase the stirring speed to 2500 rpm, and continue stirring for 30 minutes. The mixture is quickly poured into a mold and then foamed at 25°C and 33% relative humidity. After foaming, it is placed in a 40°C oven for 3 days to mature, cooled, and demolded to obtain foamed plastic. The foaming agent is a mixture of pentane and isopentane in a mass ratio of 2:1. The isocyanate is a mixture of MDI-100 and toluene diisocyanate in a mass ratio of 1.6:3. The catalyst is a mixture of dibutyltin dilaurate and triethanolamine in a mass ratio of 2.1:1.6. The foam stabilizer is polydimethyl silicone oil.

[0048] Comparative Example 4

[0049] (1) Diatomaceous earth, aluminum sec-butoxide, and industrial waste gypsum slag are mixed in a mass ratio of 41:55:4.5. Deionized water is added until the solid content is 45%. The mixture is fed into a grinder and ground until the average particle size of the solid is 250 mesh to obtain a slurry. Aluminum nitride ceramic microspheres with a particle size of 120 μm are added in a ratio of 1 g:15 mL. The mixture is stirred at 50 rpm for 6 h. The mixture is then removed and dried at 100 °C and 1000 Pa vacuum until constant weight. The mixture is then placed in a sealed crucible and placed in a muffle furnace. The furnace is heated to 1000 °C at 2.5 °C / min in an air atmosphere and held for 1.5 h. The temperature is then increased to 1300 °C at 3.5 °C / min and held for 1.5 h. The mixture is then cooled to room temperature with the furnace to obtain a core-shell type heat insulation filler.

[0050] (2) Disperse 2g of core-shell heat insulation filler in 40mL of 68% ethanol aqueous solution by ultrasonication, then add 3.2g of hydroxymethyltriethoxysilane, stir at 60rpm for 24h, filter to obtain solid, wash with ethanol and acetone 4 times respectively, and dry at 60℃ for 12h to obtain modified filler.

[0051] (3) Weigh 60 parts of polyether polyol, heat to 45°C, add 72 parts of isocyanate and 0.5 parts of catalyst, heat to 75°C again, stir at 400 rpm for 2 hours, cool to 33°C, add 10 parts of foaming agent, 1.1 parts of foaming stabilizer and 17 parts of modified filler while stirring at 400 rpm, increase the stirring speed to 2500 rpm, continue stirring for 30 minutes, quickly pour into a mold, and then foam at 25°C and 33% relative humidity. After foaming, place in a 40°C oven for 3 days to mature, cool and demold to obtain foam plastic; the foaming agent is pentane and isopentane mixed in a mass ratio of 2:1; the isocyanate is MDI-100 and toluene diisocyanate mixed in a mass ratio of 1.6:3; the catalyst is dibutyltin dilaurate and triethanolamine mixed in a mass ratio of 2.1:1.6; the foam stabilizer is polydimethyl silicone oil.

[0052] Example of effect

[0053] Table 1 below shows the performance analysis results of the foamed plastics produced by Examples 1 to 3 and Comparative Examples 1 to 4 of the present invention.

[0054] Table 1

[0055]

[0056]

[0057] A comparison of experimental data from the examples and comparative examples reveals that this invention uses aluminum nitride ceramic microspheres as the core material, with an outer layer of low thermal conductivity mullite formed by sintering. The mullite, combined with the spherical shell structure, produces a synergistic effect, isolating the thermal conductivity of aluminum nitride and forming a low thermal conductivity filler. Further hydroxylation modification allows for more effective shielding of electromagnetic waves carrying the same charge, thus optimizing the thermal insulation effect of the plastic. Finally, (2R,3R)-2,3-dihydroxy-4-(hydroxyamino)-4-oxobutyl phosphate dihydrogen ester is selected as the polyhydroxyl group. The compound polymerizes with isocyanate, and the hydroxyl groups on the surface of the heat-insulating filler participate in chain extension, thereby forming a three-dimensional network foam plastic with the heat-insulating filler as the crosslinking point. This type of polyurethane foam plastic, which has flame-retardant elements and is grafted onto the polyurethane foam skeleton, forms an intrinsically flame-retardant polyurethane foam plastic. This avoids the migration and precipitation of traditional flame retardants, making the flame-retardant effect more durable. Moreover, the heat-insulating filler uses aluminum-based metals as the core material, which can greatly reduce the smoke generated by the combustion of the foam plastic. The core layer and shell layer have high temperature resistance, and their addition significantly improves the fire resistance and mechanical strength of the plastic.

[0058] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No markings in the claims should be construed as limiting the scope of the claims.

Claims

1. A method for preparing a heat-insulating plastic for foam boards, characterized in that, The preparation steps include the following: (1) Mix the slurry and aluminum nitride ceramic microspheres at a ratio of 1g:15mL, stir at 40~60rpm for 4~8h, take out, dry at 100℃ and 1000Pa vacuum to constant weight, put into a sealed crucible, put the sealed crucible into a muffle furnace, heat treatment, and then cool to room temperature with the furnace to obtain a core-shell type heat insulation filler; The preparation method of the slurry is as follows: mix diatomaceous earth, aluminum sec-butoxide and industrial waste gypsum slag at a mass ratio of 30~55:40~67:3~6, add deionized water to the solid content to 40~50%, send to a grinder, grind to the average particle size of solid to 200~300 mesh to obtain the slurry; (2) Disperse 1~3g of core-shell type heat insulation filler in 32~44mL of ethanol aqueous solution by ultrasonication, then add 2~5g of hydroxymethyltriethoxysilane, stir at 40~80rpm for 24h, filter to obtain solid, wash with ethanol and acetone 4 times respectively, and dry at 60℃ for 12h to obtain modified filler. (3) Weigh (2R,3R)-2,3-dihydroxy-4-(hydroxyamino)-4-oxobutyl phosphate dihydrogen ester, heat to 40~50℃, add isocyanate and catalyst, then heat to 70~80℃, stir at 300~500rpm for 1~3h, cool to 25~50℃, add foaming agent, foaming stabilizer and modified filler under stirring at 300~500rpm, increase stirring speed to 2400~2600rpm, continue stirring for 30min, quickly pour into mold, then foam at 25℃ and 25~50% relative humidity. After foaming, place in an oven at 20~50℃ for 2~4d to mature, cool and demold to obtain foam plastic.

2. The method for preparing a heat-insulating plastic for foam boards according to claim 1, characterized in that, The aluminum nitride ceramic microspheres in step (1) have a particle size of 100~150μm.

3. The method for preparing a heat-insulating plastic for foam boards according to claim 1, characterized in that, The specific process of the heating treatment in step (1) is as follows: in an air atmosphere, the temperature is increased to 1000℃ at 2~3℃ / min and held for 1~2h, then increased to 1250~1340℃ at 3~4℃ / min and held for 1~2h.

4. The method for preparing a heat-insulating plastic for foam boards according to claim 1, characterized in that, The ethanol in the aqueous solution in step (2) has a mass fraction of 68%.

5. The method for preparing a heat-insulating plastic for foam boards according to claim 1, characterized in that, The components in step (3) are as follows by mass fraction: 40-80 parts of (2R,3R)-2,3-dihydroxy-4-(hydroxyamino)-4-oxybutyl phosphate dihydrogen ester, 50-90 parts of isocyanate, 0.2-1 parts of catalyst, 8-13 parts of foaming agent, 0.01-2.5 parts of foaming stabilizer, and 10-22 parts of modified filler.

6. The method for preparing a heat-insulating plastic for foam boards according to claim 1, characterized in that, The foaming agent in step (3) is a mixture of pentane and isopentane in a mass ratio of 2:

1.

7. The method for preparing a heat-insulating plastic for foam boards according to claim 1, characterized in that, In step (3), the isocyanate is MDI-100 and toluene diisocyanate are mixed in a mass ratio of 1~2.5:2~4; the catalyst is dibutyltin dilaurate and triethanolamine are mixed in a mass ratio of 0.5~3:0.01~2.5; and the foam stabilizer is polydimethyl silicone oil.

Images