KR101152158B1 - Preparation of magnesium hydroxide and magnesium hydroxide colloid, flame retardant compositions, flame retardant coatings, and flame retardant fibers including the same - Google Patents

Abstract

Method for producing magnesium hydroxide particles of the present invention (a) mixing the magnesium chloride and the alkaline solution in a 1: 2 molar ratio (magnesium chloride: alkali solution) (b) performing the precipitation method (c) the mixture Hydrothermally reacting (d) filtering and washing the mixture and (e) vacuum drying the mixture.

The magnesium hydroxide is excellent in terms of particle size, shape and dispersibility different from existing products, and shows high flame retardancy when prepared as a coating liquid.

Description

Magnesium hydroxide particles, preparation method thereof, and magnesium hydroxide colloid and flame retardant resin composition comprising the same, flame retardant coating liquid and flame retardant coating liquid coated with flame retardant coatings RETARDANT FIBERS INCLUDING THE SAME}

The present invention relates to magnesium hydroxide particles and a method for producing the same. More particularly, the present invention relates to magnesium hydroxide particles, a method for preparing the same, and a magnesium hydroxide colloid and flame retardant resin composition including the same, and a flame retardant fiber coated with a flame retardant coating solution and a flame retardant coating solution.

Magnesium hydroxide particles have been known for a long time, and are used in a wide range of fields for medical and industrial purposes. For example, medicaments include antacids, hypothalamic agents, and veterinary agents. Industrial applications include flame retardants which are blended with thermoplastic resins to impart flame retardancy to these resins, adsorbents for containing wastewater, flue gas desulfurization agents, waste neutralizers, and soil improvers.

Conventional methods for producing magnesium hydroxide particles are also various, using ion-intermitted water, seawater or roadmite as magnesium (Mg) source, lime or caustic soda as alkali source, method by hydration reaction of magnesium oxide, And a method of crystallizing magnesium hydroxide crystals by reacting a magnesium (Mg) salt with ammonia.

In the case of conventional magnesium hydroxide, since the size and shape, cohesiveness, and yield of magnesium hydroxide particles are limited depending on the manufacturing method, it is excellent in dispersibility of fine particles, excellent flame retardant properties in the flame retardant composition, or In order to be excellent in applicability and to increase the yield, it is necessary to closely examine the production method.

The size of magnesium hydroxide was also different, which made it difficult to obtain magnesium of a certain size. Magnesium hydroxide produced was inconvenient in terms of time and cost because it could not control its size and had to go through the process of making it into fine particles again.

On the other hand, as a flame retardant of synthetic resins, organic halogen compounds or antimony trioxide are widely used. So-called halogen-based flame retardants, composed of organic halogen compounds or antimony trioxide or a combination of both, have caused social problems because they generate a large amount of smoke and organic gas in a fire. Therefore, research has been carried out to avoid the use of halogen-based flame retardants as much as possible.

As a result, evaluation was obtained that magnesium hydroxide particles were an effective flame retardant. When the magnesium hydroxide particles are blended with the resin, the amount of smoke during combustion is of course nontoxic. Magnesium hydroxide particles have a wide range of resins to be adapted because some of the particles are not dehydrolyzed at the processing temperature of the resin as can be seen from the aluminum hydroxide particles to foam the resin molded product.

Synthetic resins filled with magnesium hydroxide particles at high concentrations as flame retardants have become widely used in electric power plants, ships, automobiles, subways, tunnels, etc., and building materials for home appliances and electronic devices.

In order to solve the above problems, an object of the present invention is to provide magnesium hydroxide particles and a method for preparing the same, and a magnesium hydroxide colloid and flame retardant resin composition including the same, and a flame retardant fiber coated with a flame retardant coating solution and a flame retardant coating solution.

Method for producing magnesium hydroxide particles of the present invention, (a) mixing the magnesium chloride and the alkaline solution in a 1: 2 molar ratio (magnesium chloride: alkaline solution); (b) subjecting the mixture to precipitation; (c) hydrothermally reacting the mixture; (d) filtering and washing the mixture and (e) vacuum drying the mixture.

Magnesium hydroxide particles prepared by the above production method may be used in the flame-retardant fibers coated with magnesium hydroxide colloid, flame retardant resin composition, flame retardant coating liquid and flame retardant coating liquid.

 According to the manufacturing method of the present invention can obtain excellent magnesium hydroxide in terms of particle size, shape and dispersibility different from the existing product, magnesium hydroxide colloid has an excellent dispersibility effect. When it is prepared as a coating solution and applied to the fiber has a high flame retardancy.

Figure 1 (a) is a process chart showing a manufacturing process according to an embodiment of the present invention.

Referring to Figure 1 (a), the manufacturing process according to an embodiment of the present invention is a mixing step of magnesium chloride and alkaline solution (S100), hydrothermal reaction step (S200), precipitation washing step (S210), vacuum drying step ( S300), magnesium hydroxide colloid synthesis step (S400), flame retardant coating solution synthesis step (S500), coating step with a coating solution (S700), flame retardant fiber production completion step (S1000).

The mixing step (S100) of the magnesium chloride and the alkaline solution is the first step of the magnesium hydroxide manufacturing process. Magnesium chloride and alkaline solution are mixed for 3 hours. When mixing, the molar ratio of magnesium chloride and alkaline solution may be 1: 2 or 1: 1.5 (magnesium chloride: alkaline solution).

The hydrothermal reaction step (S200) is subjected to the hydrothermal reaction at 120 ℃, 150 ℃, 180 ℃ the mixed solution made in the mixing step and subjected to filtering. Magnesium chloride (MgCl ₂ ) solution is prepared and filtered once (0.22 μm, Durapore, Millipore) to purify insoluble precipitate. Alkali is added to the aqueous solution of magnesium chloride (MgCl ₂ ) at a rate of 20 ml / min, and when all the alkaline solution is added, the solution is aged for 3 hours, and then 1/3 is subjected to hydrothermal reaction. Hereinafter, the hydrothermally treated sample will be referred to as HT (hydrothermal).

The precipitation washing step (S210) is to perform the precipitation method for the mixed solution made in the mixing step at 25 ℃. After washing with water and ethanol again proceeds to the second mixing step for 6 hours at room temperature. Wash with a pressure filter three times with water. At this time, the pH (<12.5) and the ionic conductivity (<13mS) are set to a similar level regardless of the alkali concentration of the manufacturing conditions. After washing with water, it is washed three times with alcohol. After performing the precipitation method below, the non-hydrothermal sample will be named PT (precipitation).

In the vacuum drying step (S300) to perform a second filtering the magnesium hydroxide undergoing hydrothermal reaction or precipitation washing and vacuum drying at room temperature for 24 hours to dry without shrinkage of the powder.

The magnesium hydroxide colloid synthesis step (S400) may be prepared by preparing magnesium hydroxide as described above and mixing (Mixing) for about 10 minutes using water or ethylene glycol as a solvent using a vortex.

The flame-retardant coating solution synthesis step (S500) is prepared by forming a colloid with water and ethylene glycol as a solvent in the magnesium hydroxide and then adding a phosphorus-based flame retardant or a binder. Water may be used as the diluent. After the mixing for 30 minutes with a homogenizer, the coating solution is completed. After confirming the miscibility of the phosphorus flame retardant with magnesium hydroxide, the phosphorus flame retardant and the diluent ratio is 1: 9 according to the content of the magnesium hydroxide particles, it is possible to prepare a uniform flame retardant coating solution.

Melamine composite flame retardant coating solution can be prepared as one of the preferred embodiments of the present invention. 5 g of melamine oligomer (cymel 303) and 35 g of ethanol were prepared, and Solution B was prepared by preparing 160 g of water and magnesium hydroxide to have a particle content of 10%. After mixing the solution A and B by using a vortex (Mixing) for about 10 minutes, it can be left for 20 minutes in the ultrasonic wave to confirm the dispersibility to complete the flame-retardant coating solution.

In the coating step (S700), the flame-retardant coating solution is put in a tray, soaked with PET nonwoven fabric, soaked for 24 hours or more, and then coated with a padding mangle after 24 hours.

The flame retardant fiber production completion step (S1000) is to dry the coated fiber for 30 minutes in an oven at 60 ℃. Curing in a 100 ° C. oven for 3 minutes completes the flame retardant fibers. The fiber may be a PET resin.

Figure 1 (b) is a process chart showing a manufacturing process according to another embodiment of the present invention.

Referring to Figure 1 (b), the manufacturing process according to another embodiment of the present invention is a mixing step of magnesium chloride and alkaline solution (S100), hydrothermal reaction step (S200), precipitation washing step (S210), vacuum drying step (S300), magnesium hydroxide colloid synthesis step (S400), polymerization input step (S600), flame retardant resin synthesis step (S800), flame retardant resin spinning step (S900), flame retardant fiber production completion step (S1000).

Comparing the difference with FIG. 1 (a) described above, the polymerization input step (S600), flame retardant resin synthesis step (S800), flame retardant resin spinning step (S900) will be described.

In the polymerization step (S600), LDPE / EVA resin or PET resin is polymerized into magnesium hydroxide colloid. Magnesium hydroxide is added when the LDPE / EVA resin or PET resin is synthesized from a single molecule into a polymer. In order to increase dispersibility, it is added in the form of colloid rather than powder.

The flame-retardant resin synthesis step (S800) and flame-retardant resin spinning step (S900) is a flame-retardant resin after the polymerization step is produced by flame-retardant fiber while extrusion and molding to go through the spinning step.

Figure 1 (c) is a process chart showing a manufacturing process according to another embodiment of the present invention.

Referring to Figure 1 (c), the manufacturing process according to another embodiment of the present invention mixing magnesium chloride and alkaline solution step (S100), hydrothermal reaction step (S200), precipitation washing step (S210), vacuum drying step (S300), melt mixing step (S601), flame retardant resin synthesis step (S800), flame retardant resin spinning step (S900), flame retardant fiber manufacturing completion step (S1000).

Comparing the difference with FIG. 1 (b) described above, the melt mixing step (S601) is included, which will be described.

The melt mixing step (S601) is vacuum-dried, characterized in that the melt mixed by putting the magnesium hydroxide in the powder state and LDPE / EVA resin or PET resin. LDPE / EVA resin or PET resin synthesized as a polymer is melted again and mixed with powdered magnesium hydroxide.

The experimental method of the magnesium hydroxide particles production process as described above will be described in detail below.

In order to observe the effect of the synthetic variables in the experiment of the present invention, the concentration of magnesium chloride (MgCl ₂ ) and the ratio of the alkaline solution / magnesium (Mg) salt, hydrothermal reaction temperature experiment range was determined, Design of experiment (DOE) The experiments were carried out by designing the experimental conditions by introducing and the effects of the factors were analyzed by observing the characteristics of the produced magnesium hydroxide particles.

Design of experiments (DOE) provides a method for investigating the effects of multiple variables on a reaction at the same time.The process conditions and products affecting the results by collecting data by changing input variables or factors with specific conditions. This is how you identify the ingredients and then determine the factors that maximize your results.

In this experiment, the characteristics of magnesium chloride (MgCl ₂ ) salt, the type and concentration of alkali, the presence / absence of hydrothermal treatment, and the hydrothermal synthesis temperature were observed.

TABLE 1 Experimental design by DOE.

NO. Magnesium chloride Molar ratio of alkali / magnesium chloride Alkaline solution Hydrothermal reaction temperature (℃) One One 1.5 1.5 120 2 One 1.5 1.5 180 3 One 2.5 2.5 120 4 One 2.5 2.5 180 5 1.5 2 3 150 6 2 1.5 3 120 7 2 1.5 3 180 8 2 2.5 5 180 9 2 2.5 5 120 10 2 2 4 180

As shown in Table 1, magnesium hydroxide was prepared by designing an experimental configuration based on the molar ratio of magnesium chloride (MgCl ₂ ) and an alkaline solution and the hydrothermal reaction temperature.

When prepared by the above method it can be obtained excellent magnesium hydroxide particles different from the existing products in particle size and shape.

Looking at the particle shape of magnesium hydroxide, the SEM shape of the particles produced according to the starting material concentration and the hydrothermal treatment temperature can be seen that the effect of the concentration and hydrothermal treatment on the particle size.

Although the particle size produced by the precipitation method does not seem to be significantly affected by the concentration of the starting material, it can be observed that the size of the particles produced varies depending on the molar ratio and the hydrothermal temperature during the hydrothermal treatment. The particles prepared by the precipitation method were composed of fine particles of about 100 nm, whereas the particles grew due to hydrothermal treatment, and increased to 440 ~ 720 nm level with temperature.

Referring to FIG. 2, in the case of FIG. 2 (a), the particles are not subjected to hydrothermal reaction, and thus are observed in the form of hexagonal plate. In FIG. 2 (b), the particle size increases as the temperature increases due to the hydrothermal reaction. At this time, it can be observed that it gradually turns into a round shape.

Next, we will look at the particle size of magnesium hydroxide.

3, the average particle size of magnesium hydroxide according to the manufacturing method of the present invention was observed by dynamic light scattering method and SEM. The difference between the dynamic light scattering method and the SEM is the change in the alkali / magnesium (Mg) molar ratio.

This indicates that, in the precipitation method, when the alkali / magnesium (Mg) molar ratio is low, highly cohesive particles can be produced. In hydrothermal treatment, the cohesiveness is greatly reduced and the effect on the alkali / magnesium (Mg) molar ratio is similar to the tendency on the size of primary particles observed by SEM.

TABLE 2 Average size of magnesium hydroxide particles observed by dynamic light scattering method.

NO
Precipitation Method (PT-7 (NaOH)) Hydrothermal reaction (HT-7 (NaOH)) ASP (nm) ASP-S (nm) Cohesion ASP (nm) ASP-S (nm) Cohesion One 1653 67 24.7 439 90 4.9 2 2697 67 40.3 567 72 7.9 3 386 57 6.8 391 109 3.6 4 1073 63 17.0 482 248 1.9 5 319 65 4.9 488 205 2.4 6 379 75 5.1 684 200 3.4 7 364 115 3.2 721 406 1.8 8 627 48 13.1 482 173 2.8 9 315 94 3.4 507 131 3.9

As observed in Table 2, the average particle size observed by the dynamic light scattering method shows a significant increase in the average particle diameter after hydrothermal treatment under low magnesium (Mg) molar ratios of samples 1 and 2, and almost similar in high concentration conditions. Or tends to increase slightly.

The average particle size observed by SEM tends to increase the average particle size by hydrothermal treatment, regardless of magnesium chloride (MgCl ₂ ) concentration and molar ratio. In particular, it can be seen that the particle size of the sample is largest when the molar ratio of alkali / magnesium (Mg) is 2.5 and the hydrothermal treatment temperature is 180 ° C.

ASP shown in [Table 2] is observed the particle size by the laser scattering method (Laser scattering method), ASP-S is observed the particle size by SEM. Cohesion is the calculated ASP / ASP-S.

Hereinafter, the results will be analyzed.

Referring to Figure 4 shows the main effect diagram according to the experiment. This is the average particle diameter of primary particles obtained by SEM image analysis for magnesium hydroxide particles prepared by precipitation and hydrothermal reaction. The higher the magnesium chloride (MgCl ₂ ) concentration, the larger the particle size, but the higher the alkali / magnesium (Mg) molar ratio, the smaller the particle size.

It is difficult to clearly identify the grain growth by hydrothermal treatment, and within the experimental range, the effect of magnesium chloride (MgCl ₂ ) concentration on the precipitation method is small, but in the case of hydrothermally treated samples, magnesium chloride (MgCl ₂ ) concentration and temperature were affected by the particle size. It can be seen that the effect is greater than the effect of the alkali / magnesium (Mg) molar ratio on the particle size.

Referring to FIG. 5, the main effect diagram shows the average particle diameter measured by the dynamic light scattering method, showing the secondary particle diameter reflecting the aggregation state of the primary particles. Unlike the SEM observation, the sample prepared by the precipitation method decreases the particle size with increasing magnesium chloride (MgCl ₂ ) concentration, and the higher the alkali / magnesium (Mg) molar ratio, the smaller the particle size.

In the hydrothermally treated samples, the effect of the average particle size on the same tendency was observed. The larger the slope of the straight line, the greater the effect of magnesium chloride (MgCl ₂ ) concentration, alkali / magnesium (Mg) molar ratio, and temperature on the average particle diameter.

When magnesium hydroxide is prepared by the precipitation method, the average particle size of the secondary particles measured by the dynamic light scattering method varies greatly depending on the alkali / magnesium (Mg) molar ratio, and when hydrothermally treated, the primary particle size is magnesium (Mg) It is influenced by salt concentration and hydrothermal temperature but its width is relatively small.

In the magnesium hydroxide particle production method may be prepared by changing the type of alkali.

TABLE 3 Average particle size of magnesium hydroxide prepared from magnesium chloride (MgCl ₂ ) and ammonium hydroxide (NH ₄ OH)

NO
Precipitation Method (PT-7 (NaOH)) Hydrothermal reaction (HT-7 (NaOH)) ASP (nm) ASP-S (nm) Cohesion ASP (nm) ASP-S (nm) Cohesion One 469 173 2.7 605 228 2.7 2 588 186 3.2 768 575 1.3 3 473 215 2.2 719 244 3.0 4 549 255 2.2 717 670 1.1 5 639 252 2.5 577 381 1.5 6 598 314 1.9 622 351 1.8 7 565 155 3.6 477 391 1.2 8 406 283 1.4 620 522 1.2 9 533 504 1.2 717 429 1.7

In order to compare the characteristics according to the alkali type, the average particle diameters of magnesium hydroxide prepared from magnesium chloride (MgCl ₂ ) and ammonium hydroxide (NH ₄ OH) as starting materials are summarized in [Table 3]. Magnesium hydroxide prepared with ammonium hydroxide (NH ₄ OH) had a lower cohesiveness and better dispersibility than that made with sodium hydroxide (NaOH).

Aggregation fator was defined as the value obtained by dividing the PSA (Particle size analyzer) result, which is the average particle size measured by dynamic light scattering, by the average particle size measured by SEM.

By considering the particle size observed by SEM as the primary particle size and the PSA as the secondary particle size, the degree of cohesion can observe the cohesiveness of the particles. The degree of cohesion of 1 means that the size of the primary particles and the size of the secondary particles are the same and there is no cohesiveness.

Looking at [Table 3], it can be seen that the coagulation degree of condition 7 is lower after the hydrothermal treatment irrespective of alkali type, but the coagulation degree is lowered when ammonium hydroxide (NH ₄ OH) is used. The decrease in the cohesiveness after hydrothermal treatment is estimated to be due to the growth and stabilization of particles due to the dissolution and crystallization process on the surface of high active particles after hydrothermal treatment.

Referring to Figure 6, it can be seen the main effect on the average particle diameter of the particles according to the alkali type and alkali / magnesium (Mg) molar ratio. The average particle diameter was observed to be slightly larger when prepared with ammonium hydroxide (NH ₄ OH). In particular, as the alkali / magnesium (Mg) molar ratio increases, the particle size tends to grow.

Referring to Figure 7 or 8, it can be seen the particle shape of magnesium hydroxide made of ammonium hydroxide. In comparison to the magnesium hydroxide prepared with sodium hydroxide (NaOH), the particle size decreased as the alkali concentration increased, but the magnesium hydroxide prepared with ammonium hydroxide (NH ₄ OH) showed a tendency to increase the particle size. When prepared with ammonium hydroxide, the alkalinity is lower than that of sodium hydroxide (NaOH), so the initial particle formation rate is slow, the number of seeds generated is limited, and the particle growth rate is faster than the seed generation rate. The size is relatively large and dispersibility seems to be improved due to the NH ₄ remaining on the surface.

For the dispersibility of magnesium hydroxide colloid, magnesium hydroxide was identified by adding a dispersant and a precipitation inhibitor using three solvents (water, ethanol, ethylene glycol). At this time, the particle content was 10%.

10% dispersant compared to magnesium hydroxide particles was added with polyester dispersant (BYK 190) and methoxy dispersant (180), and 5% methyl precipitate was added. An inhibitor (BYK 420) was added to compare dispersibility.

In addition, methyl (Methyl) precipitation inhibitor (BYK 420) alone was put into the change was observed. Magnesium hydroxide was added to water or ethylene glycol, mixed for 10 minutes using a vortex, and then allowed to stand for 20 minutes in an ultrasonic wave to confirm dispersibility.

According to the particle content (10-20wt%), a sample added with about 10% of the dispersant and a sample without the dispersant were prepared, and the dispersion state over time was compared for two weeks, and magnesium hydroxide was mixed in a solvent to vortex. ) And sand milling (0.3 μm, using ₁ kg of ZrO ₂ ) with a dispersion of 200 g (10% of particles) or ball milling (0.3 μm, ZrO ₂ 200g with a dispersion of 150 g (10% of particles)). Dispersibility was compared for 3 hours each).

Magnesium hydroxide was dispersed in three solvents to observe dispersibility for various dispersants. When the solvent is water, the methyl precipitation inhibitor (BYK 420) is added alone, and the polyester (BYK 190) and the methoxy (Methoxy) dispersant (180) is mixed immediately gelling ( gel). When the polyester-based dispersant (BYK 190) was added alone, it was observed that the dispersibility was maintained for three solvents (water, ethanol, and ethylene glycol).

In addition, polyester dispersant and methyl precipitate inhibitor (BYK 190 + precipitation inhibitor), methoxy dispersant and methyl precipitate inhibitor (BYK 180 + precipitation inhibitor) When the solvent is ethanol, it seems to maintain dispersibility with the naked eye, but after 5 hours, the gel progresses.

Another method was to disperse the commercial product M3, NB-10 and particles HT-10 (NH ₄ OH), PT-10 (NH ₄ OH), HT-7 (NaOH), PT-7 (NaOH) prepared by the experimental design. When the dispersion stability is maintained for about 1 hour. Sand milling was performed to maintain dispersibility for a longer period of time. For the natural grinding product M3, the initial particle size was 3 nm and the particle size was reduced to 180 nm after sandal milling. The acid was kept.

PT-7 (NaOH), a synthetic product prepared by the precipitation method, maintained the dispersibility of about 1 hour before milling, but maintained the dispersibility of about 6 days after milling, and the particle size was reduced to about 200 nm from 6 μm.

In particular, in the case of magnesium chloride (MgCl ₂₎ and ammonium hydroxide _{(NH 4 OH) PT-10} (NH 4 OH) prepared in had dispersibility can be seen that maintain at least 7 days, the size particles in 15 ㎛ to 190nm Decreased. There was no change in crystallinity due to milling, and in the case of PT-10 (NH ₄ OH), the crystallinity was better.

The dispersibility was confirmed by changing the kind of solvent to ethylene glycol. When dispersed in ethylene glycol it was confirmed that dispersibility is maintained for about 4 days regardless of milling. The particle size of PT-10 (NH ₄ OH) was found to decrease the initial particle size from 13 ㎛ to 130nm, it was confirmed that the natural crushed product M3 also reduced from 4 ㎛ to 210nm level.

Of the colloids as described above, the aqueous colloid is used in the process of imparting flame retardancy by mixing a binder and coating the PET fiber, and the ethylene glycol dispersed colloid is added to the PET synthesis process to prepare a Mg (OH) ₂ -PET composite. PET flame retardant fiber can be produced by spinning.

Referring to Figure 9, it can be observed that the change according to the presence or absence of the dispersant, Figure 9a is not added to the dispersant, Figure 9b is added to the dispersant. It can be seen that the addition of the dispersant is easily gelled, but the dispersibility is maintained when the dispersant is added.

[Table 4] Particle size change according to milling

① Aqueous dispersion

division PT-10 (NH ₄ OH) PT-7 (NaOH) M3 NB10 milling - ○ - ○ - ○ - ○ Particle size (㎛) 15.59 0.19 6.01 0.20 3.22 0.18 5.65 - Time (h) One 168 One 144 One 72 - -

② Ethylene Glycol Dispersion

division PT-10 (NH ₄ OH) PT-7 (NaOH) M3 NB10 milling - ○ - ○ - ○ - ○ Particle size (㎛) 13.07 0.13 6.01 0.21 4.41 0.21 4.04 0.68 Time (h) 120 120 120 120 96 96 96 96

In Table 4, the solvent was divided into water and ethylene glycol, and experimented and observed. In the case of the milled particles, the density was extremely low, and thus the particles were dispersed without being agglomerated. It is said that milling is effective in increasing dispersibility.

Referring to Figure 10, it can be observed that the change according to the presence or absence of the milling, before and after the milling can be compared and confirmed that the particle size is reduced after milling.

[Table 5] Application Conditions of Phosphorus Flame Retardant According to Magnesium Hydroxide Particle Content

Sample name Particle Content (%) Phosphorus-based flame retardant content (%) * PL1
20 8 40 6 PL2
20 8 40 6 PL3



20 8 25 7.5 30 7 35 6.5 40 6 PL4
20 8 40 6

[Table 5] is to prepare a flame-retardant coating solution by the ratio of the phosphorus-based flame retardant and diluent 1: 9 according to the content of the magnesium hydroxide particles. At this time, the phosphorus flame retardant and magnesium hydroxide mixed coating solution was divided into PL1 (HEXA NON ABC), PL2 (HEXA NON CPRF), PL3 (HEXA NON NF2000), PL4 (HEXA NON NF3000) according to the type of phosphorus flame retardant.

Looking at [Table 6] it can be observed the change of dispersibility according to the type of dispersant and solvent. The solvent was compared using water, ethanol and ethylene glycol.

Table 6 Observation of Dispersibility According to Dispersant and Solvent Type

① Aqueous dispersion

Dispersant - BYK 180 BYK 190 BYK 420 BYK 420
+ BYK 180 BYK 420
+ BYK 190 Dispersion time (h) One 5 120 G G G

G: gelation

② Ethanol dispersion

Dispersant - BYK 180 BYK 190 BYK 420 BYK 420
+ BYK 180 BYK 420
+ BYK 190 Dispersion time (h) 24 5 One One 5 5

③ Ethylene Glycol Dispersion

Dispersant - BYK 180 BYK 190 BYK 420 BYK 420
+ BYK 180 BYK 420
+ BYK 190 Dispersion time (h) 48 One 120 One One One

According to the type of magnesium hydroxide, the amount of particles in the total coating solution was increased to 10%, 20%, and 30% to confirm the amount of the coating on the PET nonwoven fabric. As the particle content of the coating solution increases, the total coating content coated on the PET nonwoven fabric increases.

Magnesium hydroxide prepared according to the above-described manufacturing method was prepared under a condition of 30% particle content, which is the highest total coating content, and coated on a PET nonwoven fabric. The adhesion rate to the particle content can be confirmed through the following [Table 7].

[Table 7] Adhesion Rate of Coating Liquid Particle Content

Sample Particle Content (%) Adhesion Rate (%)
A
10 98.74 20 98.45 30 98.37
B
10 98.67 20 98.55 30 98.44 C 30 98.55 D 30 98.65 E
20 98.68 30 98.42
F

20 98.25 25 92.23 30 90.10 35 86.79 B-M 30 98.50 C-M 30 98.75 D-M 30 98.81

* A: KISUMA-5B, B: M3, C: PT-7 (NaOH), D: PT-10 (NH ₄ OH), E: HT-7 (NaOH), F: PL (Magnesium (Mg (OH)) ₂ ) + Phosphorus Flame Retardant)

As shown in [Table 7], even when the coating content was increased, the adhesion of the coating side attached to the PET nonwoven fabric was excellent as 98% or more.

Flame retardancy according to the coating content was evaluated by the limit oxygen index. As the coating content increases, the limiting oxygen index (LOI) value tends to increase. In particular, in the case of M3, the rising width is small, but the limiting oxygen index (LOI) value keeps increasing. According to the type of binder, the value of limiting oxygen index (LOI) is different from that of the coating solution prepared by EVA and the coating solution produced by EVA rather than the coating solution produced by water-based acrylic binder. Higher. The particle content in the coating solution was fixed at 30% and the number of coatings was increased to determine the total coating content and the limiting oxygen index (LOI) value on the PET nonwoven fabric.

Even if the number of coatings is increased, there is no change in appearance and it does not affect the properties of the fiber itself and the total coating content can be seen to increase. Also, the adhesion was excellent at 98% or more. It can be seen that the limiting oxygen index (LOI) value continues to increase with the total coating content.

Referring to Figure 11 it can be confirmed the shape of the non-woven fabric coated three times. In the SEM shape according to the number of coating, as the number of coating increases, the amount of particles immersed in the PET nonwoven fabric increases and adheres evenly, so that the surface becomes uniform after three coatings than once coating.

In addition, when preparing a coating solution, the phosphorus-based flame retardant was added instead of the binder to increase the particle content and to coat the PET nonwoven fabric. As the particle content increased from 20% to 40%, it was found that the total coating content coated on the PET nonwoven fabric increased. The limiting oxygen index (LOI) value also increased with the coating content. The particle content was about 26 at 20%, but increased to 30 or more as the particle content increased.

The coating of RPET nonwovens with phosphorus alone was higher than that with magnesium hydroxide alone, resulting in higher LOI. However, when the phosphorus-based flame retardant was added in small amounts instead of the binder and mixed with magnesium hydroxide and coated on PET nonwoven fabric (PL3), the limiting oxygen index (LOI) value was relatively higher than that of other samples. . However, the adhesion was relatively low (85 ~ 90%).

Figure 1a is a process diagram showing a manufacturing process according to an embodiment of the present invention.

Figure 1b is a process diagram showing a manufacturing process according to another embodiment of the present invention.

Figure 1c is a process diagram showing a manufacturing process according to another embodiment of the present invention.

Figure 2a is a SEM photograph of magnesium hydroxide rough hydrothermally reacted 7.

Figure 2b is a SEM photograph of the magnesium hydroxide after 7 precipitated.

Figure 3a is a graph measuring the secondary particle diameter of the magnesium hydroxide without hydrothermal reaction by the dynamic light scattering method.

Figure 3b is a graph measuring the secondary particle diameter of the magnesium hydroxide without undergoing the hydrothermal reaction by SEM.

Figure 4 is a graph showing the main effect on the primary particle diameter in the magnesium hydroxide of the present invention.

Figure 5 is a graph showing the main effect on the secondary particle diameter in the magnesium hydroxide of the present invention.

Figure 6 is a graph showing the main effect of the alkaline solvent on the particle size of the magnesium hydroxide particles.

Figure 7 is a photograph of the shape of the magnesium hydroxide particles during the reaction with ammonium hydroxide as a solvent under hydrothermal reaction.

Figure 8 is a photograph of the shape of the magnesium hydroxide particles upon reaction with ammonium hydroxide as a solvent under the precipitation method.

Figure 9a is a photograph of the colloids without addition of a dispersant in magnesium hydroxide colloid.

Figure 9b is a photograph of a colloid added with a dispersant in magnesium hydroxide colloid.

10A is a SEM taken before milling the NB.

10B is a SEM photograph of the state after milling the NB.

11 is taken with SEM after three coatings.

Claims (13)

delete delete delete delete Magnesium hydroxide particles; Solvent selected from ethylene glycol and water; And Polyester-based dispersant Magnesium Hydroxide Colloid. delete delete Flame-retardant resin composition comprising the Mg (OH) ₂ -PET composite obtained by injecting the magnesium hydroxide colloid of claim 5 in the polymerization step of PET resin. delete A flame retardant coating liquid comprising the magnesium hydroxide colloid of claim 5 and a binder or a phosphorus flame retardant. Flame retardant fiber coated with a flame retardant coating solution of claim 10. The method of claim 11, The fiber is flame retardant fiber comprising a PET resin. A flame retardant fiber obtained by extruding and molding the flame retardant resin composition of claim 8.

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