FLAME RETARDANT PARTICLE, MANUFACTURING METHOD THEREFOR, AND FLAME RETARDANT STYROFOAM USING SAME

Abstract

The present invention relates to a flame retardant particle having excellent flame retardancy or moisture resistance, a manufacturing method therefor, and a flame retardant Styrofoam using the same.

Claims

1. A flame retardant particle comprising a dry gel including at least one inorganic particle selected from cenospheres, fly ash, ceramic microspheres, cleaned ash, and unburned carbon, wherein the flame retardant particle includes a peak having a chemical shift of 91 ppm to 95 ppm in a .sup.29Si NMR spectrum.

2. The flame retardant particle of claim 1, wherein the flame retardant particle has a maximum diameter of 0.01 m to 1000 m.

3. The flame retardant particle of claim 1, wherein the dry gel includes a cross-linked (co)polymer of at least two inorganic particles.

4. The flame retardant particle of claim 1, wherein the dry gel further includes 1 part by weight to 50 parts by weight of titanium oxide relative to 100 parts by weight of the inorganic particle.

5. The flame retardant particle of claim 1, wherein the dry gel further includes a siloxane-based polymer.

6. The flame retardant particle of claim 5, wherein the siloxane-based polymer has viscosity measured at 20 C. of 0.65 cps to 10000 cps.

7. The flame retardant particle of claim 5, wherein the siloxane-based polymer has a weight average molecular weight of 4000 g/mol to 10,000 g/mol.

8. A method of manufacturing a flame retardant particle, comprising: heat-treating a flame retardant composition including at least one inorganic particle selected from cenospheres, fly ash, ceramic microspheres, cleaned ash, and unburned carbon, and an inorganic binder having viscosity at 20 C. of less than 100,000 cP, at a temperature of 60 C. to 200 C.; and pulverizing the resulting material after the heat-treating.

9. The method of manufacturing a flame retardant particle of claim 8, wherein the flame retardant composition further includes 1 part by weight to 50 parts by weight of titanium oxide relative to 100 parts by weight of the inorganic particle.

10. The method of manufacturing a flame retardant particle of claim 8, wherein the heat-treating of the flame retardant composition is performed while stirring the flame retardant composition at a speed of 100 rpm to 200 rpm.

11. The method of manufacturing a flame retardant particle of claim 8, wherein the flame retardant composition further includes a siloxane-based polymer.

12. The method of manufacturing a flame retardant particle of claim 11, wherein the flame retardant composition includes 0.1 part by weight to 10 parts by weight of the siloxane-based polymer based on 100 parts by weight of the inorganic binder.

13. The method of manufacturing a flame retardant particle of claim 8, wherein the flame retardant composition includes 10 parts by weight to 100 parts by weight of the inorganic particle based on 100 parts by weight of the inorganic binder.

14. The method of manufacturing a flame retardant particle of claim 8, wherein the inorganic binder includes liquid sodium silicate.

15. The method of manufacturing a flame retardant particle of claim 14, wherein the liquid sodium silicate has a mole ratio of greater than or equal to 2.25 according to Equation 1:
mole ratio={SiO.sub.2 (wt %)/Na.sub.2O (wt %)*1.032}.[Equation 1]

16. The method of manufacturing a flame retardant particle of claim 8, wherein the inorganic particle has a diameter of 100 mesh to 1000 mesh.

17. The method of manufacturing a flame retardant particle of claim 8, wherein the method further includes, before heat-treating the flame retardant composition at a temperature of 60 C. to 200 C., heat-treating at least one inorganic particle selected from cenospheres, fly ash, ceramic microspheres, cleaned ash, and unburned carbon at a temperature of 500 C. to 1000 C.

18. A flame retardant Styrofoam comprising: a polystyrene foamed particle; and a flame retardant layer formed on the polystyrene foamed particle and including the flame retardant particle of claim 1.

19. The flame retardant Styrofoam of claim 18, wherein 10 parts by weight to 500 parts by weight of the flame retardant particle is included based on 100 parts by weight of the polystyrene foamed particle.

20. The flame retardant Styrofoam of claim 18, wherein an adhesive layer is further formed between the polystyrene foamed particle and the flame retardant layer.

Description

DESCRIPTION OF THE DRAWINGS

[0123] FIG. 1 is a surface SEM image showing flame retardant particles according to Example 1.

[0124] FIG. 2 is a camera-taken image showing the flame retardant particles according to Example 1.

[0125] FIG. 3 is a camera-taken image showing Styrofoam of Example 10 before foaming.

[0126] FIG. 4 is a camera-taken image showing Styrofoam of Example 10 after foaming.

[0127] FIG. 5 is a camera-taken image showing Styrofoam of Example 10 after molding.

[0128] FIG. 6 shows a .sup.29Si NMR spectrum of the flame retardant particles according to Example 1.

[0129] FIG. 7 is a surface SEM image showing flame retardant particles according to Example 2.

[0130] FIG. 8 shows a .sup.29Si NMR spectrum of the flame retardant particles according to Example 2.

[0131] FIG. 9 shows a .sup.29Si NMR spectrum of waterglass as a reference example.

[0132] FIG. 10 shows a .sup.29Si NMR spectrum of cenosphere as a reference example.

[0133] FIG. 11 is a surface SEM image showing flame retardant particles according to Example 5.

[0134] FIG. 12 is a surface SEM image showing flame retardant particles according to Example 6.

[0135] FIG. 13 is a surface SEM image showing flame retardant particles according to Example 7.

[0136] FIG. 14 is a surface SEM image showing flame retardant particles according to Example 8.

MODE FOR INVENTION

[0137] Hereinafter, the present invention is described in detail with reference to examples. However, the following examples are only illustrative of the present invention, and do not limit the disclosure of the present invention in any way.

Example 1 to 9: Manufacture of Flame Retardant Particle

Example 1

[0138] 100 g of cenospheres (silicon dioxide (SiO.sub.2): about 60 wt %, aluminum oxide (Al.sub.2O.sub.3): about 30 wt %, iron oxide (Fe.sub.2O.sub.3): about 4 wt %, calcium oxide (CaO): about 4 wt %, and magnesium oxide particles (200 mesh) (MgO): about 2 wt %), 400 g of waterglass (KS standard 2: Na.sub.2SiO.sub.2.nH.sub.2O), and 20 g of polydimethylsiloxane having viscosity of 100 cps at 20 C. (Element 14 PDMS 100 made by Momentive Chemicals Co.; weight average molecular weight: 6000 g/mol) were mixed, and the mixture was put in an approximately 100 C. hot-air agitator and then hot-air dried and gelated for about 1.5 hour, while being stirred at a speed of about 150 rpm. The gelated mixture was pulverized with a grinder to obtain the flame retardant particle.

Example 2

[0139] 100 g of cenospheres (silicon dioxide (SiO.sub.2): about 60 wt %, aluminum oxide (Al.sub.2O.sub.3): about 30 wt %, iron oxide (Fe.sub.2O.sub.3): about 4 wt %, calcium oxide (CaO): about 4 wt %, and magnesium oxide particles (200 mesh) (MgO): about 2 wt %), and 400 g of waterglass (KS standard 2: Na.sub.2SiO.sub.2.nH.sub.2O) were mixed, and the mixture was put in an approximately 100 C. hot-air agitator and then hot-air dried and gelated while being stirred at a speed of about 150 rpm. The gelated mixture was pulverized with a grinder to prepare the flame retardant particle.

Example 3

[0140] 100 g of cenospheres (silicon dioxide (SiO.sub.2): about 60 wt %, aluminum oxide (Al.sub.2O.sub.3): about 30 wt %, iron oxide (Fe.sub.2O.sub.3): about 4 wt %, calcium oxide (CaO): about 4 wt %, and magnesium oxide particles (200 mesh) (MgO): about 2 wt %), 400 g of waterglass (KS standard 2: Na.sub.2SiO.sub.2.nH.sub.2O), 4 g of titanium dioxide, 8 g of an aluminum sulfate aqueous solution (aluminum sulfate: 3 g), 6 g of a calcium phosphate aqueous solution (calcium phosphate: 2 g), 2 g of carbon black, and 20 g of polydimethylsiloxane having viscosity of 100 cps at 20 C. (Element 14 PDMS 100, Momentive Chemicals Co.; a weight average molecular weight: 6000 g/mol) were mixed, and the mixture was put in an approximately 100 C. hot-air agitator and then hot-air dried and gelated while being stirred at a speed of about 150 rpm. The gelated mixture was pulverized with a grinder to prepare the flame retardant particle.

Example 4

[0141] 100 g of cenospheres (silicon dioxide (SiO.sub.2): about 60 wt %, aluminum oxide (Al.sub.2O.sub.3): about 30 wt %, iron oxide (Fe.sub.2O.sub.3): about 4 wt %, calcium oxide (CaO): about 4 wt %, and magnesium oxide particles (200 mesh) (MgO): about 2 wt %), 400 g of waterglass (KS standard 2: Na.sub.2SiO.sub.2.nH.sub.2O), 4 g of titanium dioxide, 8 g of an aluminum sulfate aqueous solution (3 g of aluminum sulfate), 6 g of a calcium phosphate aqueous solution (2 g of calcium phosphate), and 2 g of carbon black were mixed, and the mixture was put in an approximately 100 C. hot-air agitator and then hot-air dried and gelated while being stirred at a speed of about 150 rpm. The gelated mixture was pulverized with a grinder to prepare the flame retardant particle.

Example 5

[0142] The flame retardant particle was prepared according to the same method as Example 3, except for using a ceramic microsphere particle instead of the cenosphere particle.

Example 6

[0143] The flame retardant particle was prepared according to the same method as Example 3, except for using an unburned carbon particle instead of the cenosphere particle.

Example 7

[0144] The flame retardant particle was prepared according to the same method as Example 3, except for using a cleaned ash particle instead of the cenosphere particle.

Example 8

[0145] The flame retardant particle was prepared according to the same method as Example 3, except for using a fly ash particle instead of the cenosphere particle.

Example 9

[0146] The flame retardant particle was prepared according to the same method as Example 3, except for using cenosphere (silicon dioxide (SiO.sub.2): about 60 wt %, aluminum oxide (Al.sub.2O.sub.3): about 30 wt %, iron oxide (Fe.sub.2O.sub.3): about 4 wt %, calcium oxide (CaO): about 4 wt %, and magnesium oxide particles (200 mesh) (MgO): about 2 wt %), and heat-treated at 800 C. for 10 minutes.

Examples 10 to 21: Manufacture of Flame Retardant Styrofoam

Example 10

[0147] 70 g of polystyrene beads (SB 2,000 made by SH Energy & Chemical Co., Ltd.; particle diameter 1.1 mm) including 94 wt % of polystyrene resin and 6 wt % of pentane was mixed with 15 g of a polyvinyl acetate resin in an agitator to form a polyvinyl acetate resin coating layer on the bead surface, 80 g of the flame retardant particles according to Example 1 was added thereto in the agitator, and the mixture was mixed and dried.

[0148] Subsequently, 20 g of an acrylic resin was added to the agitator to form an acrylic resin coating layer on the surface, 40 g of the flame retardant particle according to Example 1 was added thereto, and the obtained mixture was mixed and dried.

[0149] Then, the dried mixture was put in a steam agitator and then primarily foamed through heat-treatment for 80 seconds with vapor at 105 C. under a pressure of 0.2 kg/cm.sup.2 and dried in the air for one hour. The primarily-foamed and dried Styrofoam was put in a steam-molder and then secondarily compression-foamed through heat treatment with vapor at 120 C. under a pressure of 6.5 kg/cm.sup.2 for 80 seconds, and then dried for about 2 days to manufacture a flame retardant Styrofoam.

Example 11

[0150] 70 g of polystyrene beads (SB 2,000 made by SH Energy & Chemical Co., Ltd.: particle diameter 1.1 mm) including 94 wt % of a polystyrene resin and 6 wt % of pentane was mixed with 15 g of a polyvinyl acetate resin in an agitator to form a polyvinyl acetate resin coating layer on the bead surface, 80 g of the flame retardant particles according to Example 1 was added to the agitator, and the mixture was mixed and dried.

[0151] Subsequently, 20 g of an acrylic resin was added to the agitator to form an acrylic resin coating layer on the surface, 40 g of the flame retardant particles according to Example 1 was added thereto, and the obtained mixture was mixed and dried. Subsequently, 5 g of polydimethylsiloxane (Element 14 PDMS 100, Momentive Chemicals Co.; weight average molecular weight: 6000 g/mol) having viscosity of 100 cps at 20 C. was additionally added thereto, and the obtained mixture was dried.

[0152] The dried mixture was put in a steam agitator and primarily foamed through heat treatment with vapor at 105 C. temperature under a pressure of 0.2 kg/cm.sup.2 for 80 seconds and dried in the air for 1 hour. The primarily-foamed and dried Styrofoam was put in a steam molder and then secondarily compression-foamed with vapor at 120 C. under a pressure of 6.5 kg/cm.sup.2 for 80 seconds, and then dried for about 2 days to manufacture a flame retardant Styrofoam.

Example 12

[0153] 70 g of polystyrene beads (SB 2,000 made by SH Energy & Chemicals Co., Ltd.; particle diameter: 1.1 mm) including 94 wt % of polystyrene resin and 6 wt % of pentane was mixed with 20 g of an acrylic resin to form an acrylic resin coating layer on the bead surface, 40 g of the flame retardant particles according to Example 1 was added to the agitator, and the mixture was mixed and dried.

[0154] Subsequently, 15 g of a polyvinyl acetate resin was added to the agitator to form a polyvinyl acetate resin coating layer on the surface, 80 g of the flame retardant particles according to Example 1 was added thereto, and the mixture was mixed and dried.

[0155] The dried mixture was put in a steam agitator and then primarily foamed through heat treatment with vapor at 105 C. under a pressure of 0.2 kg/cm.sup.2 for 80 seconds and dried in the air for 1 hour. The primarily foamed and dried Styrofoam was put in a steam molder and then secondarily compression-foamed through heat treatment with vapor at 120 C. under a pressure of 6.5 kg/cm.sup.2 for 80 seconds, and dried for about 2 days to manufacture a flame retardant Styrofoam.

Example 13

[0156] 70 g of polystyrene beads (SB 2,000 made by SH Energy & Chemicals Co., Ltd.; particle diameter: 1.1 mm) including 94 wt % of polystyrene resin and 6 wt % of pentane was mixed with 20 g of an acrylic resin in an agitator to form an acrylic resin coating layer on the bead surface, 40 g of the flame retardant particle according to Example 1 was added to the agitator, and the mixture was mixed and dried.

[0157] Subsequently, 15 g of a polyvinyl acetate resin was added to the agitator to form a polyvinyl acetate resin coating layer on the surface, 80 g of the flame retardant particles according to Example 1 was added thereto, and the obtained mixture was mixed and dried. Then, 5 g of polydimethylsiloxane having viscosity of 100 cps (Element 14 PDMS 100, Momentive Chemicals Co.; weight average molecular weight: 6000 g/mol) was added thereto at 20 C., and the obtained mixture was dried.

[0158] Then, the dried mixture was put in a steam agitator and then primarily foamed through heat treatment with vapor at 105 C. under a pressure of 0.2 kg/cm.sup.2 for 80 seconds, and dried in the air for 1 hour. The primarily foamed and dried Styrofoam was put in a steam molder and then secondarily compression-foamed through heat treatment with vapor at 120 C. under a pressure of 6.5 kg/cm.sup.2 for 80 seconds, and dried for about 2 days to manufacture a flame retardant Styrofoam.

Example 14

[0159] 70 g of polystyrene beads (SB 2,000 made by SH Energy and Chemicals Co., Ltd.; particle diameter: 1.1 mm) including 94 wt % of polystyrene resin and 6 wt % of pentane was mixed with 25 g of a starch-based acrylic resin in an agitator for about 1 minute to form a starch-based acrylic resin coating layer on the bead surface, 60 g of the flame retardant particles according to Example 1 was added thereto, and the mixture was mixed for about 1 minute and dried.

[0160] Subsequently, 15 g of a phenol resin was added to the agitator and mixed for one minute to form a phenol resin coating layer on the surface, 40 g of the flame retardant particles according to Example 1 was added thereto, and the obtained mixture was mixed for 1 minute and dried with hot air of room temperature in an oven for about 1 hour.

[0161] The dried mixture was put in a steam agitator and then primarily foamed through heat treatment with vapor at 105 C. under a pressure of 0.2 kg/cm.sup.2 for 80 seconds, and dried in the air for 1 hour. The primarily foamed and dried Styrofoam was put in a steam molder and then secondarily compression-foamed through heat treatment with vapor at 120 C. under a pressure of 6.5 kg/cm.sup.2 for 80 seconds, and dried for about 2 days.

Example 15

[0162] 70 g of polystyrene beads (SB 2,000 made by SH Energy and Chemicals Co., Ltd.; particle diameter: 1.1 mm) including 94 wt % of polystyrene resin and 6 wt % of pentane was mixed with 25 g of a phenol resin in an agitator for about 1 minute to form a phenol resin coating layer on the bead surface, 60 g of the flame retardant particles according to Example 1 was added thereto, and the mixture was mixed for about 1 minute and dried.

[0163] Subsequently, 25 g of a starch-based acrylic resin was added to the agitator and mixed for one minute to form a starch-based acrylic resin coating layer on the surface, 40 g of the flame retardant particles according to Example 1 was added thereto, and the obtained mixture was mixed for 1 minute and dried with hot air of room temperature in an oven for about 1 hour.

[0164] The dried mixture was put in a steam agitator and then primarily foamed through heat treatment with vapor at 105 C. under a pressure of 0.2 kg/cm.sup.2 for 80 seconds, and dried in the air for 1 hour. The primarily foamed and dried Styrofoam was put in a steam molder and then secondarily compression-foamed through heat treatment with vapor at 120 C. under a pressure of 6.5 kg/cm.sup.2 for 80 seconds, and dried for about 2 days to form a flame retardant Styrofoam.

Example 16

[0165] 70 g of polystyrene beads (SB 2,000 made by SH Energy and Chemicals Co., Ltd.; particle diameter: 1.1 mm) including 94 wt % of polystyrene resin and 6 wt % of pentane was mixed with 15 g of a polyvinyl acetate resin in an agitator for about 1 minute to form a polyvinyl acetate resin coating layer on the bead surface, 80 g of the flame retardant particles according to Example 2 was added thereto, and the mixture was mixed for about 1 minute and dried.

[0166] Subsequently, 20 g of an acrylic resin was added to the agitator and mixed to form an acrylic resin coating layer on the surface, 40 g of the flame retardant particles according to Example 1 was added thereto, and the obtained mixture was mixed and dried.

[0167] The dried mixture was put in a steam agitator and then primarily foamed through heat treatment with vapor at 105 C. under a pressure of 0.2 kg/cm.sup.2 for 80 seconds, and dried in the air for 1 hour. The primarily foamed and dried Styrofoam was put in a steam molder and then secondarily compression-foamed through heat treatment with vapor at 120 C. under a pressure of 6.5 kg/cm.sup.2 for 80 seconds, and dried for about 2 days to manufacture a flame retardant Styrofoam.

Example 17

[0168] 70 g of polystyrene beads (SB 2,000 made by SH Energy and Chemicals Co., Ltd.; particle diameter: 1.1 mm) including 94 wt % of polystyrene resin and 6 wt % of pentane was mixed with 20 g of an acrylic resin in an agitator for about 1 minute to form an acrylic resin coating layer on the bead surface, 40 g of the flame retardant particles according to Example 2 was added thereto, and the mixture was mixed for about 1 minute and dried.

[0169] Subsequently, 15 g of a polyvinyl acetate resin was added to the agitator to form a polyvinyl acetate resin coating layer on the surface, 80 g of the flame retardant particles according to Example 2 was added thereto, and the obtained mixture was mixed and dried.

[0170] The dried mixture was put in a steam agitator and then primarily foamed through heat treatment with vapor at 105 C. under a pressure of 0.2 kg/cm.sup.2 for 80 seconds, and dried in the air for 1 hour. The primarily foamed and dried Styrofoam was put in a steam molder and then secondarily compression-foamed through heat treatment with vapor at 120 C. under a pressure of 6.5 kg/cm.sup.2 for 80 seconds, and dried for about 2 days to manufacture a flame retardant Styrofoam.

Example 18

[0171] 70 g of polystyrene beads (SB 2,000 made by SH Energy and Chemicals Co., Ltd.; particle diameter: 1.1 mm) including 94 wt % of polystyrene resin and 6 wt % of pentane was mixed with 25 g of a starch-based acrylic resin in an agitator for about 1 minute to form a starch-based acrylic resin coating layer on the bead surface, 60 g of the flame retardant particles according to Example 2 was added thereto, and the mixture was mixed for about 1 minute and dried.

[0172] Subsequently, 15 g of a phenol resin was added to the agitator and mixed for one minute to form a phenol resin coating layer on the surface, 40 g of the flame retardant particles according to Example 2 was added thereto, and the obtained mixture was mixed for 1 minute and dried with hot air of room temperature in an oven for about 1 hour.

[0173] The dried mixture was put in a steam agitator and then primarily foamed through heat treatment with vapor at 105 C. under a pressure of 0.2 kg/cm.sup.2 for 80 seconds, and dried in the air for 1 hour. The primarily foamed and dried Styrofoam was put in a steam molder and then secondarily compression-foamed through heat treatment with vapor at 120 C. under a pressure of 6.5 kg/cm.sup.2 for 80 seconds, and dried for about 2 days to manufacture a flame retardant Styrofoam.

Example 19

[0174] 70 g of polystyrene beads (SB 2,000 made by SH Energy and Chemicals Co., Ltd.; particle diameter: 1.1 mm) including 94 wt % of polystyrene resin and 6 wt % of pentane was mixed with 25 g of a phenol resin in an agitator for about 1 minute to form a phenol resin coating layer on the bead surface, 60 g of the flame retardant particles according to Example 2 was added thereto, and the mixture was mixed for about 1 minute and dried.

[0175] Subsequently, 25 g of a starch-based acrylic resin was added to the agitator and mixed for one minute to form a starch-based acrylic resin coating layer on the surface, 40 g of the flame retardant particles according to Example 2 was added thereto, and the obtained mixture was mixed for 1 minute and dried with hot air of room temperature in an oven for about 1 hour.

[0176] The dried mixture was put in a steam agitator and then primarily foamed through heat treatment with vapor at 105 C. under a pressure of 0.2 kg/cm.sup.2 for 80 seconds, and dried in the air for 1 hour. The primarily foamed and dried Styrofoam was put in a steam molder and then secondarily compression-foamed through heat treatment with vapor at 120 C. under a pressure of 6.5 kg/cm.sup.2 for 80 seconds, and dried for about 2 days to manufacture a flame retardant Styrofoam.

Example 20

[0177] 70 g of polystyrene beads (SB 2,000 made by SH Energy and Chemicals Co., Ltd.; particle diameter: 1.1 mm) including 94 wt % of polystyrene resin and 6 wt % of pentane was mixed with 15 g of a polyvinyl acetate resin in an agitator for about 1 minute to form a polyvinyl acetate resin coating layer on the bead surface, 50 g of the flame retardant particles according to Example 3 was added thereto, and the mixture was mixed and dried.

[0178] Subsequently, 20 g of an acrylic resin was added to the agitator to form an acrylic resin coating layer on the surface, 30 g of the flame retardant particles according to Example 3 was added thereto, and the obtained mixture was mixed and dried.

[0179] The dried mixture was put in a steam agitator and then primarily foamed through heat treatment with vapor at 105 C. under a pressure of 0.2 kg/cm.sup.2 for 80 seconds, and dried in the air for 1 hour. The primarily foamed and dried Styrofoam was put in a steam molder and then secondarily compression-foamed through heat treatment with vapor at 120 C. under a pressure of 6.5 kg/cm.sup.2 for 80 seconds, and dried for about 2 days to manufacture a flame retardant Styrofoam.

Example 21

[0180] 70 g of polystyrene beads (SB 2,000 made by SH Energy and Chemicals Co., Ltd.; particle diameter: 1.1 mm) including 94 wt % of polystyrene resin and 6 wt % of pentane was mixed with 15 g of a polyvinyl acetate resin in an agitator for about 1 minute to form a polyvinyl acetate resin coating layer on the bead surface, 50 g of the flame retardant particles according to Example 4 was added thereto, and the mixture was mixed and dried.

[0181] Subsequently, 20 g of an acrylic resin was added to the agitator and mixed for one minute to form an acrylic resin coating layer on the surface, 30 g of the flame retardant particles according to Example 4 was added thereto, and the obtained mixture was mixed and dried.

[0182] The dried mixture was put in a steam agitator and then primarily foamed through heat treatment with vapor at 105 C. under a pressure of 0.2 kg/cm.sup.2 for 80 seconds, and dried in the air for 1 hour. The primarily foamed and dried Styrofoam was put in a steam molder and then secondarily compression-foamed through heat treatment with vapor at 120 C. under a pressure of 6.5 kg/cm.sup.2 for 80 seconds, and dried for about 2 days to manufacture a flame retardant Styrofoam.

Comparative Examples 1 to 2: Manufacture of Flame Retardant Styrofoam

Comparative Example 1

[0183] (1) Preparation of Flame Retardant Composition

[0184] 100 g of cenospheres (silicon dioxide (SiO.sub.2): about 60 wt %, aluminum oxide (Al.sub.2O.sub.3): about 30 wt %, iron oxide (Fe.sub.2O.sub.3): about 4 wt %, calcium oxide (CaO): about 4 wt %, 100 g of magnesium oxide particles (200 mesh) (MgO): about 2 wt %), 400 g of waterglass (KS standard 2: Na.sub.2SiO.sub.2.nH.sub.2O), 4 g of titanium dioxide, 8 g of an aluminum sulfate aqueous solution (3 g of aluminum sulfate), 6 g of a calcium phosphate aqueous solution (2 g of calcium phosphate), 2 g of carbon black, and 20 g of polydimethylsiloxane having viscosity of 100 cps at 20 C. (Element 14 PDMS 100, Momentive Chemicals Co.; a weight average molecular weight: 6000 g/mol) were mixed to prepare a flame retardant composition.

[0185] (2) Manufacture of Flame Retardant Styrofoam

[0186] A flame retardant Styrofoam was manufactured according to the same method as Example 10, except for using the flame retardant composition instead of the flame retardant particle according to the example.

Comparative Example 2

[0187] (1) Preparation of Flame Retardant Composition

[0188] A flame retardant composition was prepared according to the same method as Comparative Example 1.

[0189] (2) Manufacture of Flame Retardant Styrofoam

[0190] A flame retardant Styrofoam was manufactured according to the same method as Example 16, except for using the flame retardant composition instead of the flame retardant particle according to the example.

Experimental Examples: Measurement of Properties of Flame Retardant Particle and Flame Retardant Styrofoam

[0191] Properties of the flame retardant particles and the flame retardant Styrofoam according to the examples and comparative examples were measured, and the results are shown in Table 1.

Experiment 1: Surface Characteristics

[0192] An FE-SEM image of the flame retardant particles according to Example 1 is shown in FIG. 1, and its camera-taken image is shown in FIG. 2.

[0193] In addition, a camera-taken image of the flame retardant Styrofoam before foaming according to Example 10 is shown in FIG. 3, a camera-taken image of the flame retardant Styrofoam after foaming according to Example 10 is shown in FIG. 4, and a camera-taken image of a final flame retardant Styrofoam after compression-molding is shown in FIG. 5.

[0194] As shown in FIG. 1, the flame retardant particle of Example 1 had a maximum diameter of about 50 m and showed an irregular shape. In addition, as shown in FIG. 2, the flame retardant particle of Example 1 turned out to be a black powder.

[0195] As shown in FIG. 3, since the flame retardant particle was formed on the polystyrene bead surface, the surface appeared black.

[0196] In addition, as shown in FIGS. 4 and 5, the flame retardant Styrofoam of Example 10 showed that the flame retardant particle of Example 1 was formed on the surface.

[0197] An FE-SEM image of the flame retardant particle of Example 2 is shown in FIG. 7.

[0198] As shown in FIG. 7, the flame retardant particle of Example 2 had a maximum diameter of about 50 m and showed an irregular shape.

[0199] In addition, as shown in FIGS. 11 to 14, the flame retardant particles according to Examples 5 to 8 showed a maximum diameter of about 50 m and showed an irregular shape.

Experiment 2: Component Analysis

[0200] A .sup.29Si NMR spectrum of the flame retardant particle of Example 1 was measured by using Solid 400 MHz WB NMR Spectrometer (79.51 MHz, a solvent condition of D.sub.2O), and the results are shown in FIG. 6.

[0201] As shown in FIG. 6, the flame retardant particle of Example 1 showed a chemical shift at 92.27 ppm.

[0202] A .sup.29Si NMR spectrum of the flame retardant particle of Example 2 was measured by using Solid 400 MHz WB NMR Spectrometer (79.51 MHz, a solvent condition of D.sub.2O), and the results are shown in FIG. 8.

[0203] As shown in FIG. 8, the flame retardant particle according to Example 2 showed a chemical shift at 92.27 ppm.

[0204] As a reference example, as shown in FIG. 9, waterglass showed a chemical shift at 80.41 ppm, 88.57 ppm, 90.57 ppm, 96.52 ppm, 97.41 ppm, and 106.53 ppm, and as shown in FIG. 10, cenospheres showed a chemical shift at 90.16 ppm and 108.9 ppm, which are different peaks from those of the flame retardant particles.

[0205] In other words, the flame retardant particles are not a simple mixture of the waterglass and the cenospheres, but form a gelated polymer through heat-treating the mixture.

Experimental Example 3: Flame Retardancy

[0206] The flame retardant Styrofoam according to Examples 10 to 21 and Comparative Examples 1 and 2 were used to make specimens each having a size of a width of 10 cm*a length of 10 cm*a thickness of 5 cm, and the specimens were heated with a gas torch for 5 minutes to evaluate flame retardancy.

[0207] Specifically, when a specimen was neither set on fire nor smoked during 5 minutes of firing and greater than or equal to 70% of Styrofoam particles remained, excellent was given, but when a specimen was set on fire and smoked during the 5 minutes of firing, and greater than or equal to 30% of Styrofoam particles were combusted, inferior was given.

Experimental Example 4: Moisture Resistance

[0208] The flame retardant Styrofoam according to Examples 10 to 21 and Comparative Examples 1 to 2 were used to make specimens each having a size of a width of 10 cm*a length of 10 cm*a thickness of 5 cm, and the specimens were dipped in water to evaluate moisture resistance.

[0209] Specifically, when a specimen was dipped for 24 hours in 10 cm-deep water but not dissolved therein, excellent was given, but when a specimen was dipped for 24 hours in 10 cm-deep water but dissolved therein, inferior was given.

TABLE-US-00001 TABLE 1 Experimental Example Results of Flame Retardant Styrofoam according to Examples and Comparative Examples Flame retardancy Moisture resistance Example 10 excellent excellent Example 11 excellent excellent Example 12 excellent excellent Example 13 excellent excellent Example 14 excellent excellent Example 15 excellent excellent Example 16 excellent excellent Example 17 excellent excellent Example 18 excellent excellent Example 19 excellent excellent Example 20 excellent excellent Example 21 excellent excellent Comparative Example 1 inferior inferior Comparative Example 2 inferior inferior

[0210] As shown in Table 1, Styrofoam manufactured by mixing the flame retardant particle according to Example 1 or 21 with a polystyrene bead showed excellent flame retardancy and moisture resistance.

[0211] On the other hand, Styrofoam formed by simply adding a retardant-material-including composition without using a flame retardant particle prepared through a gelation and pulverizing process as shown in the examples failed in sufficiently realizing flame retardancy and moisture resistance, since a retardant material was sufficiently adhered on Styrofoam.