KR101039007B1 - Aluminum hydroxide Particle Improving for Fire-retardant and Production Method Thereof - Google Patents

Abstract

The present invention relates to metal hydroxide particles having improved flame retardancy and a method of manufacturing the same, and more particularly, to aluminum flame particles and sol (flame-enhanced) coated with liquid glass to be gelled based on SiO ₂ . The present invention relates to a method for producing aluminum hydroxide particles having improved flame retardancy using a gel method. The aluminum hydroxide particles having improved flame retardancy of the present invention minimize the secondary disaster of combustion gases due to dehalogenation, improve heat resistance of aluminum hydroxide, and delay the heat transfer after dehydration at a constant temperature through surface modification of aluminum hydroxide. It can be used in various industrial sectors because it delays thermal deformation and combustion.

Fire retardant, aluminum hydroxide, surface reforming, glass coated particles

Description

Aluminum Hydroxide Particle Improving for Fire-retardant and Production Method Thereof}

The present invention relates to a method for producing aluminum hydroxide particles with improved flame retardancy.

Since polymer materials are easy to burn, flame retardant is made by adding a flame retardant or chemically reacting and introducing a flame retardant element into a molecule. This flame retardant material is used in all industries such as computer, VTR, TV, power cable, communication cable and other electronic and electronic component parts, automobiles, building materials, vehicles. In particular, in the event of a building fire, insulation materials of electric and communication cables are burned to generate toxic gases, thereby increasing the damage to humans. Therefore, in order to reduce the ignition time and suppress the emission of combustion gas by applying inorganic flame retardant to the surface of the cable, it is necessary to prevent the combustion of the combustion gas. Especially, it is environmentally friendly and human-friendly due to the synthesis of inorganic flame retardant filler by metal hydroxide without using halogen material. Harmless cable burnout is required. Inorganic flame retardant fillers are metal hydroxides that dehydrate and extinguish at a certain temperature. However, since the thermal insulation layer is not formed after fire extinguishing, it is insufficient to delay heat transfer to the subject.

Recently, due to the increasing awareness of environmental problems around the world, the EU has banned the use of halogen flame retardants for materials used in copiers, computers and printers due to problems such as bromine dioxins and furans. In Korea, non-halogen flame-retardant products are used for flame-retardant products used inside buildings in consideration of human injury caused by asphyxiation rather than fire damage. In accordance with international regulations for the use of halogen-based flame retardants, research on non-halogen-based flame retardants and inorganic flame retardants has been actively conducted. An inorganic flame retardant is a metal hydride compound such as Al (OH) ₃ and Mg (OH) ₂ . Calcium aluminate, calcium carbonate, zinc borate, dosonite, calcium hydroxide and the like also exhibit endothermic reactions peculiar to hydrated metal compounds, but are rarely used in practice.

Flame retardancy is endothermic effect by dehydration reaction, concentration dilution of flammable gas by water vapor, insulation effect by composite inorganic coating layer of char produced from dehydration product and polymer, and oxygen blocking effect, and smoke by oxide produced there may be mentioned the conversion and the low-smoke effects on CO, CO ₂ gas generated by facilitating the oxidation reaction of the fine carbon particles contained in the.

Al (OH) ₃ has a dehydration temperature near 200 ℃ and a low flame retardant effect at late combustion (400 ℃), and it cannot be used for polymers with high processing temperature due to foaming during processing. In addition, Mg (OH) ₂ has a bleaching phenomenon in which magnesium carbonate is formed by carbon dioxide and moisture in the air and the surface becomes white. The defects peculiar to Al (OH) ₂ and Mg (OH) ₂ are difficult to improve in basic characteristics, but improved research is being conducted.

Therefore, the inventors of the present invention while studying the surface modification for improving the flame retardancy of the aluminum hydroxide particles, using a sol-gel method to synthesize a borosilicate liquid glass and to adhere the borosilicate glass to the aluminum hydroxide powder surface Al (OH ₃ ) The present invention was completed by confirming that a ceramic layer was formed on the surface of the particles, and that an inorganic insulating layer was formed on the surface of the particles after the dehydration reaction by heat.

SUMMARY OF THE INVENTION An object of the present invention is to improve the flame retardancy by coating a liquid synthetic glass on aluminum hydroxide to improve the flame retardancy through the surface modification and to provide a heat insulation layer after dehydration, to provide a flame-retardant aluminum hydroxide particles and a method for producing the same that can delay the heat transfer time of the subject It is.

In order to achieve the above object, the present invention provides aluminum hydroxide particles with improved flame retardancy coated with a liquid glass to be gelatinized based on SiO ₂ .

The present invention also provides a method for producing the aluminum hydroxide particles with improved flame retardancy using the sol-gel method. That is, a modified synthetic hydroxide such as B ₂ O ₃ and Al ₂ O ₃ is added to low-cost sodium silicate to prepare a liquid synthetic glass, and the prepared solution is added to aluminum hydroxide particles and dried to provide a modified aluminum hydroxide. .

Hereinafter, the present invention will be described in detail.

The present invention provides aluminum hydroxide particles having improved flame retardancy coated with liquid glass to be gelled based on SiO ₂ .

In the aluminum hydroxide particles having improved flame retardancy of the present invention, the liquid glass is preferably SiO ₂ -B ₂ O ₃ -Na ₂ O, and the liquid glass preferably contains a blowing agent. At this time, the blowing agent is preferably urea (urea).

In addition, in the aluminum hydroxide particles having improved flame retardancy of the present invention, it is preferable to use a phosphoric acid solution as a liquid for the initial reaction of the gelation.

The present invention also provides a method for producing the aluminum hydroxide particles with improved flame retardancy using the sol-gel method.

In the method for producing the aluminum hydroxide particles having improved flame retardancy of the present invention, the production method is a primary borosilicate liquid glass solution by dissolving boric acid in water, mixed with sodium silicate (water glass) Preparing a; Ii) adding a blowing agent to the primary borosilicate liquid glass solution to prepare a final borosilicate liquid glass solution (coating solution); Iii) treating the coating solution with aluminum hydroxide; And iii) gelling the coating solution by treating the solution of step iii) with a phosphoric acid solution.

In this case, the water is preferably deionized water (DI water), the blowing agent is preferably urea (urea), the coating solution is preferably SiO ₂ -B ₂ O ₃ -Na ₂ O sol, The particle size of the aluminum hydroxide is preferably 0.5 to 10 ㎛.

The composition ratio of each component is preferably 1 to 5 parts by weight of boric acid, 10 to 70 parts by weight of deionized water, 20 to 150 parts by weight of sodium silicate, 0.5 to 6 parts by weight of urea (urea) and 30 to 200 parts by weight of aluminum hydroxide.

The present invention synthesizes a borosilicate liquid glass by using a sol-gel method and makes the borosilicate glass adhere to the aluminum hydroxide powder surface to form a ceramic layer on the Al (OH) ₃ particle surface and dehydration by heat. The inorganic insulating layer is formed on the particle surface after the reaction to provide aluminum hydroxide particles having a modified surface for improving flame retardancy.

To this end, in order to modify the surface of the aluminum hydroxide powder, which is a representative material of the metal hydroxide in the inorganic flame retardant, to synthesize the SiO ₂ -Na ₂ OB ₂ O _{3 type} liquid glass using a sol-gel process, and to the aluminum hydroxide particles By sticking to induce a gelation reaction using phosphoric acid, and dried, the solidified gel (gel) body was ground by induction to prepare a surface-modified aluminum hydroxide particles. In addition, XRD, SEM, and TG-DTA analysis showed that the gel body using phosphoric acid (H ₃ PO ₄ ) was modified with a lot of porous amorphous glass around the aluminum hydroxide particles, and the surface was modified with glass. The more porous glass was formed, the more the surface-modified aluminum hydroxide particles showed 2 ~ 3% moisture loss as a result of TG-DTA analysis.

As a result, the metal hydroxide is dehydrated at its own pyrolysis temperature by receiving a certain temperature of heat, and if further heat is applied, the metal hydroxide is rapidly fired by rapid heat transfer, but when the glass is coated on the surface to form an insulating layer, the heat transfer is hindered, resulting in relatively gentle firing. .

The aluminum hydroxide particles having improved flame retardancy of the present invention minimize the secondary disaster of combustion gases due to dehalogenation, improve heat resistance of aluminum hydroxide, and delay the heat transfer after dehydration at a constant temperature through surface modification of aluminum hydroxide. This will delay heat deformation and combustion, which can be utilized in various industrial sectors.

Hereinafter, the present invention will be described in more detail based on the following examples. However, the following examples are only for illustrating the present invention, and the present invention is not limited to the following examples and may be changed to other embodiments equivalent to substitutions and equivalents without departing from the technical spirit of the present invention. Will be apparent to those of ordinary skill in the art.

Example 1 Synthesis of Coating Solution (SiO ₂ -B ₂ O ₃ -Na ₂ O-based Sol) Using Liquid Glass

Boric acid (boric acid, purity 99.5%) 2 wt%, deionized water (DI water) 32wt%, sodium silicate (water glass, Si / Na = 3) 66wt%, respectively. The borosilicate liquid glass solution was prepared at 60 ° C. using the sol-gel method as a precursor.

Specifically, the weight percent sodium silicate was first heated to 60 ° C. Separately, a solution in which boric acid was dissolved in DI water by weight was prepared and slowly applied to the sodium silicate, followed by stirring at room temperature for 4 hours to prepare a primary borosilicate liquid glass solution. As a result, the primary borosilicate liquid glass solution has a composition of 72.4SiO ₂ -24.1Na ₂ O-3.5B ₂ O ₃ .

The final borosilicate liquid glass solution (hereinafter, coating solution) for the surface modification reaction containing a blowing agent by adding 1 to 3 parts by weight of urea (urea), which is a surfactant, in addition to 100 parts by weight of the primary borosilicate liquid glass solution. (SiO ₂ -B ₂ O ₃ -Na ₂ O system sol) was prepared. As a result, the synthesized coating solution exhibited the following characteristics. There was no partial gelling phenomenon, the sol was clear, the viscosity change was within 100 cps for 10 days, stable to the addition of other alkali hydrochloride, and maintained above pH 8. The manufacturing process is illustrated in FIG.

Example 2 Coating of Liquid Glass on the Surface of Aluminum Hydroxide

The surface of aluminum hydroxide (Al (OH) ₃ ) was treated using a SiO ₂ -B ₂ O ₃ -Na ₂ O-based sol (coating solution) prepared in Example 1 (FIG. 2). Specifically, 80 parts by weight of aluminum hydroxide (KC Co., Ltd. product, average particle diameter: 0.7 μm) powder having a size of several to several tens of micrometers based on 100 parts by weight of the coating solution was added to the upper liquid glass, and the plate was heated at 40 ° C. for 2 hours. The slurry was prepared by stirring. Phosphoric acid solution was slowly added dropwise to the slurry using a pipette and added until gelation was no longer possible to stir. At this time, the phosphoric acid solution induces a gelation reaction of the coating solution. The supernatant was poured out again, and the wet gel sieve was crushed with a mortar and dried in an oven at 60 ° C. for 8 hours. As a result, the addition of the phosphate solution was observed in a form in which the porous glass was wrapped around the aluminum hydroxide particles due to the relatively slow gelation reaction.

The manufacturing process is illustrated in FIG.

In addition, the prepared aluminum hydroxide particles were XRD (High Power X-ray Diffractometer, X'pert-PRO MPD), TG-DTA (equipment company), FE-SEM (Field Emission Scanning Electron Microscopy, Hitachi S-) 4800) using an analytical instrument.

Experimental Example Characteristics of Liquid Glass Coated Aluminum Hydroxide

Experimental Example 1 Electron Microscope SEM Observation

The aluminum hydroxide particles (FIG. 3) before the coating solution prepared in Example 1 and the aluminum hydroxide particles (FIG. 4) prepared in Example 2 after the coating solution were examined were examined by an electron microscope. As a result, in the case of the aluminum hydroxide prepared in Example 2 treated with the coating solution, it could be observed that several hundred nm SiO ₂ glass surrounding the aluminum hydroxide particles. In addition, it was confirmed that the glass formation of the porous increases as the Urea content increased (FIG. 5).

Experimental Example 2 XRD Component Analysis

The XRD component using X-ray diffraction of the aluminum hydroxide particles before and after the coating solution treatment prepared in Example 1 was analyzed (FIG. 6). At this time, based on 100 parts by weight of the first borosilicate liquid glass solution, a coating solution prepared by adding 1 to 3 parts by weight of a foaming agent urea (urea) was used (Table 1). As a result, in the modified particles coated with aluminum hydroxide, SiO ₂ , Na ₂ O peaks, etc. were observed in addition to the Al (OH) ₃ peak compared to the particles not coated. Specifically, XRD analysis showed invisible peaks in pure aluminum hydroxide at 30.1 degrees, 35.2 degrees, and 34.2 to 34.5 degrees, which were analyzed by SiO ₂ (Tetragonal) and Na ₂ O crystals. However, B ₂ O ₃ was present in the composition, but the peak was weak and was not observed.

Specimens (d) and (e) show that the weight loss is more than 2 ~ 3%, which means that the pyrolysis temperature is lowered but the water release is relatively high, so it is more effective to lower the ambient temperature by dehydration.

TABLE 1 Analytical Specimens for Surface Modification of Al (OH) ₃

Psalter Primary borosilicate liquid glass solution
(Parts by weight) Urea addition amount
(Parts by weight) (a) 100 1.0 (b) 100 1.5 (c) 100 2.0 (d) 100 2.5 (e) 100 3.0

Experimental Example 3 Data Curve and TG-DTA Analysis

The data curves of the particles of aluminum hydroxide before and after the coating solution treatment prepared in Example 1 were analyzed (FIG. 7). At this time, based on 100 parts by weight of the first borosilicate liquid glass solution, a coating solution prepared by adding 1 to 3 parts by weight of a foaming agent urea (urea) was used (Table 1). As a result, it was confirmed that the modified particles coated with aluminum hydroxide exhibited a gentle firing process after Al (OH) ₃ was dehydrated between 200 and 300 ° C. for the particles not coated (FIG. 8). In addition, TG-DTA analysis showed that the surface-modified aluminum hydroxide particles had a lot of moisture loss of about 2-3%. In addition, the surface-modified aluminum hydroxide was pyrolyzed at a temperature about 10 ° C. lower than that of the untreated particles, which is judged to be due to the effect of boric acid pyrolysis at around 100 ° C.

1 is a schematic diagram of the synthesis of a liquid glass solution (coating solution) of the present invention.

FIG. 2 is a schematic diagram of a surface modification method of aluminum hydroxide (Al (OH) ₃ ) using the coating solution prepared in FIG. 1.

3 is an enlarged photograph of an electron microscope of aluminum hydroxide particles before coating solution treatment.

4 is an enlarged photograph of an SEM electron microscope of aluminum hydroxide particles after coating solution treatment.

Figure 5 is a SEM image of the aluminum hydroxide particles after the coating solution treatment is a photograph showing a tendency with the addition of various concentrations of urea ((a) 1.0 wt% (b) 1.5 wt%; (c) 2.0 wt% (d) 2.5 wt%; (e) 3.0 wt%).

FIG. 6 is X-ray diffraction data of boro-sillicate glass with varying concentrations of urea as blowing agent (where (a) 1.0 wt% (b) 1.5 wt%; (c) 2.0 wt (d) 2.5 wt%; (e) 3.0 wt%, (ref) control).

FIG. 7 is a data curve of boro-sillicate glass with varying concentrations of urea as blowing agent (where: (a) 1.0 wt% (b) 1.5 wt%; (c) 2.0 wt%; (d) 2.5 wt%; (e) 3.0 wt%, (ref) control).

8A to 8E are TG-DTA results prepared at a temperature range of 100 to 1000 ° C.

Claims (10)

Aluminum hydroxide particles with improved flame retardancy coated with a gelled liquid glass comprising SiO ₂ -B ₂ O ₃ -Na ₂ O. delete The method of claim 1, Aluminum hydroxide particles with improved flame retardancy, characterized in that the liquid glass comprises a blowing agent. The method of claim 3, wherein The blowing agent is aluminum hydroxide particles with improved flame retardancy, characterized in that the urea (urea). The method of claim 1, Aluminum hydroxide particles with improved flame retardancy, characterized in that a phosphoric acid solution is used as a liquid for initiating the gelation reaction. Iii) dissolving boric acid in water, and mixing it with sodium silicate to prepare a primary borosilicate liquid glass solution; Ii) adding a blowing agent to the primary borosilicate liquid glass solution to prepare a final borosilicate liquid glass solution (coating solution); Iii) adding aluminum hydroxide to the coating solution and stirring to prepare a slurry; And Iv) adding a phosphoric acid solution to the slurry prepared through step iii) to gel the coating solution. The method of claim 6, The water is a method of producing aluminum hydroxide particles with improved flame retardancy, characterized in that the deionized water (deionized water; DI water). The method of claim 6, The blowing agent is urea (urea) characterized in that the method of producing aluminum hydroxide particles with improved flame retardancy. The method of claim 6, The coating solution is SiO ₂ -B ₂ O ₃ -Na ₂ O Sol The production method of the aluminum hydroxide particles with improved flame retardancy, characterized in that. The method of claim 6, The particle size of the aluminum hydroxide is a method of producing aluminum hydroxide particles with improved flame resistance, characterized in that 0.5 to 10 ㎛.

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