KR100976175B1 - Flame-retardant agent for resin composition - Google Patents

Abstract

PURPOSE: A flame retardant for a resin composition is provided to secure the swelling property during a combustion process, and to offer a polymer material with the superior fire retardant property when applied to a resin. CONSTITUTION: A flame retardant for a resin composition is a graphite oxide includes a complex structure of the graphite oxide and graphite. The graphite oxide is obtained by mixing graphite powder with strong sulfuric acid in a ratio of 1:5~1:25, mixing the graphite powder with KMnO4 in a ratio of 1:0.5~1:4, and reacting the mixture at 60~80 deg C.

Description

Flame-retardant agent for resin composition

The present invention relates to a flame retardant for a resin composition, and more particularly, to a flame retardant for a resin composition in the form of a graphite oxide having a complex structure of graphite oxide and graphite, and a flame retardant resin composition comprising the same.

As the use of polymer materials is widely extended to construction, automobiles, electrical appliances, aircraft, ships, etc., the necessity of flame retardancy considering safety in the event of a fire continues to increase. In addition, in recent years, the development of materials suitable for the environment with high flame retardancy is strongly demanded, and the development of high flame retardancy, low harmful products has emerged as an important task.

As flame retardants that impart flame retardancy to polymer materials, halogen-based flame retardants containing bromine or chlorine have excellent flame retardant effects and are widely used because of their excellent cost / performance. However, since halogen-based flame retardants have the disadvantage of generating toxic substances such as dioxins during combustion, their use is increasingly regulated worldwide.

One of the eco-friendly flame retardants that can replace halogen-based flame retardants, the swelling charcoal layer acts as a wall to block the movement of oxygen, heat and combustion products by forming the swollen char as it swells during combustion. There is a growing interest in intumescent flame retardants, which cause further combustion to proceed and cause a flame retardant effect.

 Graphite oxide (GO) as one of the swellable flame retardants has been recently introduced in the literature. Graphite is a material in which graphene sheets are stacked in a layered structure and has a peak at 2θ = 26.5 ° in XRD analysis because the interval between layers is constant at 3.35 35. Graphite oxide is a material that oxidizes graphite, and is attached to functional groups containing oxygen such as carboxylic acid and hydroxyl group in each graphene layer by oxidation. XRD peaks are observed at 15 °. When the graphite oxide is placed at a high temperature, the oxygen-containing functional groups decompose into carbon dioxide, and the layers are swollen by the pressure of the generated gas, and the swollen carbon component acts as a barrier to block the movement of materials and heat. It can express a flame retardant effect.

In the meantime, as the method for producing graphite oxide, the Stadenmair method, the Brodie method, the Hummers method, and the like are used. In these methods, sulfuric acid, fuming nitric acid, and NaClO ₃ are intercalated. Used as oxidant. However, since graphite oxide prepared by these general graphite oxide production methods has a disadvantage in that the swelling property and the barrier property are not good and the flame retardancy is not effectively exhibited, it is necessary to improve the swelling property and the barrier property.

The present invention is to produce a composite structure graphite oxide excellent in swelling and barrier properties, and to use it as a flame retardant of a polymer material. Graphite oxide itself has excellent swelling properties, but when it is dispersed in a polymeric material, the swelling properties are greatly reduced. This is because, when graphite oxide is dispersed in the polymer, it is judged that it is not strong enough to push the matrix polymer around when it is swollen at a high temperature, and contemplating a solution to solve this problem; In the case of preparing graphite oxide having a considerable amount of graphite oxide having an XRD characteristic peak at 2θ = 10-15 ° and a graphite structure having an XRD characteristic peak at 2θ = 26 ° and adding it to a polymer and using it as a flame retardant, oxidation The graphite structure contributes to the swelling property, and the graphite structure forms a strong structure capable of effectively extruding the surrounding polymer and chars having excellent barrier properties, thereby observing that the swelling property and the barrier property are effectively expressed and completed the present invention.

According to the present invention, the XRD characteristic peak height of graphite exhibited at around 2θ = 26 ° / XRD characteristic peak height ratio value of graphite oxide at 2θ = 10 to 15 ° is in the range of 1 to 20/1, and atoms of C / O A flame retardant for resin compositions of graphite oxide having a composite structure of graphite oxide and graphite having a number ratio in the range of 2 to 10/1 is provided.

In the graphite oxide having a composite structure which is a flame retardant of the present invention, the XRD characteristic peak height of graphite appearing in the vicinity of 2θ = 26 ° / the XRD characteristic peak height ratio of graphite oxide appearing at 2θ = 10-15 ° is preferably 2 ~. It is the range of 15/1, and the atomic number ratio of C / O becomes like this. Preferably it is 3-7 / 1.

In addition, the present invention provides a flame retardant resin composition comprising 100 parts by weight of a polymer material and 0.5 to 40 parts by weight, preferably 1 to 30 parts by weight, and more preferably 3 to 20 parts by weight of the flame retardant of the present invention. . When the composite structure graphite oxide which is the flame retardant of the present invention is used less, the flame retardant effect of the resin may not be sufficiently expressed, and when used excessively, the physical properties of the polymer material may be deteriorated. Moreover, the synergistic effect of resin flame retardance can also be acquired by using another kind of flame retardant with the flame retardant of this invention.

The polymer to which the flame retardant of the present invention can be used is not particularly limited, but for example, addition polymers such as polymethyl methacrylate (PMMA), polystyrene, polyacrylonitrile, condensation polymers such as polyester, polyamide, polyurethane, etc. It covers all kinds of polymers such as natural polymers, and may be used in combination with additives for improving the performance of polymers such as stabilizers and plasticizers.

The composite graphite oxide, which is a flame retardant of the present invention, is prepared using graphite powder, sulfuric acid as an intercalating agent, and KMnO ₄ as an oxidizing agent. In the composite graphite oxide, the relative amounts of the graphite structure and the graphite oxide structure may be controlled by combining interlayer intercalating agents and oxidizing agents in various ways. In order to obtain composite graphite oxide, the ratio of graphite powder (g) / concentrated sulfuric acid (mL) is in the range of 1/5 to 25, and the graphite powder (g) / KMnO ₄ (g) ratio is in the range of 1 / 0.5 to 4 It is preferable. If the amount of concentrated sulfuric acid and KMnO ₄ smaller than these ranges is used, the structure of graphite will be excessive. If the amount of concentrated sulfuric acid and KMnO ₄ is used, the structure of graphite oxide will be excessive. . In addition, the reaction temperature should be 90 ° C. or lower, and preferably 60 to 80 ° C. is appropriate. At lower temperatures, the structure of the graphite is excessively high, and at higher temperatures, the structure of the graphite oxide is excessively large.

The flame retardant resin is prepared by mechanically mixing a polymer material and a composite structure graphite oxide which is a flame retardant of the present invention. If necessary, the polymer material and the composite structure graphite oxide may be dissolved or dispersed in a solvent or a dispersion medium, and the solvent or dispersion medium may be removed or used as it is after manufacture. However, at the time of manufacture, it is necessary to minimize the swelling of the composite structure graphite oxide because it is not heated above 50 ° C, and in the case of excessively fine dispersion, the expansion force may decrease and the flame retardancy may decrease.

According to the present invention, it is possible to provide a flame retardant made of a composite graphite oxide having excellent swelling and barrier properties during combustion, and excellent flame retardancy, and by introducing the same into a resin, a polymer material having excellent flame retardancy can be prepared.

1 is a pattern of XRD of (a) graphite, (b) C-1, (c) C-2, and (d) C-3, respectively.
2 and 3 are images of the shape observed by SEM of (a) fracture cross section and (b) post-combustion cross section of Example 5 sample, respectively.

Production Example  One

C-1 a composite structure of graphite oxide to 1000 mL of concentrated sulfuric acid 110 mL and the natural graphite to the flask powder to manufacture (Modern komasa HC-598) 20 g were dissolved, and then immersed in an ice-water cooling, the KMnO ₄ 12 g of a temperature of 20 It was added slowly so as not to exceed ℃, and then stirred at 30 캜 for 30 minutes. 230 mL of water was slowly added so that the temperature of the reaction did not exceed 90 ° C., followed by stirring for 30 minutes. The reaction was terminated by further addition of 500 mL of water and 40 mL of 30% H ₂ O _{2 in} order to reduce the excess KMnO ₄ . The obtained graphite oxide powder was filtered, washed several times with 5% aqueous HCl solution, washed with distilled water until neutral and dried in a 50 ° C. vacuum oven for 24 hours. Elemental analysis showed that the atomic composition was C _1.00 O _0.18 H _0.15 .

Production Example  2

C-2 and the composite structure of graphite oxide was prepared in the same manner as in Production Example 1 except for increasing the degree of oxidation as compared to C-1 using a KMnO ₄ 24 g, atomic composition of C _{1 .00} O _{0. 25} H _{0 .} Was ₁₇ .

Production Example  3

In the case of C-3 composite structure graphite oxide was prepared as follows to further increase the degree of oxidation. That is, 460 mL of concentrated sulfuric acid and 20 g of graphite powder were added to a 3000 mL flask, and after cooling by soaking in ice water, 60 g of KMnO ₄ was slowly added so that the temperature did not exceed 20 ° C, followed by stirring at 30 ° C for 30 minutes. 920 mL of water was slowly added so that the temperature of the reaction did not exceed 90 ° C., followed by stirring for 30 minutes. The reaction was terminated by further addition of 2800 mL of water and 200 mL of 30% H ₂ O _{2 in} order to reduce excess KMnO ₄ . The obtained graphite oxide powder was filtered, washed several times with 5% aqueous HCl solution, washed with distilled water until neutral and dried in a 50 ° C. vacuum oven for 24 hours. Elemental analysis confirmed the composition atom is _{C 1 .00 O 0 .33 H 0} . ₂₆ .

Analysis of the prepared composite graphite oxide

By the elemental analysis, the ratio of C / O constituent atoms of C-1, C-2, and C-3 was 5.55, 4.00, 3.03, respectively, and the degree of oxidation increased in the order of C-1, C-2, C-3. Can be seen. The particle sizes of graphite, C-1, C-2, and C-3 used for oxidation were 6.8 μm, 7.2 μm, 5.4 μm, and 6.1 μm, respectively.

It can be seen that the graphite used for oxidation in FIG. 1 (FIG. 1 (a)) has a sharp peak at 2θ = 26.5 ° (the graph shows that the peak strength of graphite is graphite oxide as shown in the figure with the XRD pattern of graphite oxide). This figure shows that the graphite has a layered structure in which graphene layers are regularly stacked with an interlayer spacing of 3.35 mm 3. In the case of C-1 (FIG. 1 (b)), the characteristic peak of the graphite shifts slightly to the lower angle, and the peak height decreases and the sharpness of the peak decreases at 2θ = 25.6 °. These results show that the layered structure of graphite is partially disturbed by oxidation and the interlayer spacing is slightly increased. It can also be seen that a small, broad new peak appears at 2θ = 12.2 °, which is a characteristic peak of the (002) plane of graphite oxide, showing that the interlayer spacing of the resulting graphite oxide is 7.25 mm 3. This shows that the interlayer spacing increased more than 3.35 kPa of graphite because of the attachment of various oxygen-containing polar groups to graphite oxide. These XRD results show that C-1 is a composite graphite oxide having both graphite and graphite oxide.

On the other hand, looking at the XRD pattern (C) of C-2, the height of the characteristic peak of graphite appearing near 2θ = 26 ° is lower than that of C-1, and the characteristic peak of graphite oxide is lower at 2θ. It can be seen at = 12.0 °. These results show that C-2 is a composite graphite oxide that is more oxidized than C-1.

In the case of C-3 (FIG. 1 (d)), the characteristic peak of the graphite is further reduced, and the characteristic peak of the graphite oxide is shifted toward the lower angle, and it can be seen that 2θ = 11.8 °. This shows that C-3 is a composite graphite oxide that is more oxidizing than C-2. On the other hand, the XRD characteristic peak height of graphite which appears in the vicinity of 2θ = 26 ° / XRD characteristic peak height ratio of graphite oxide which appears at 2θ = 10 to 15 °, respectively, for C-1, C-2 and C-3 12.3, 3.8, and 2.0 show that all three of these materials are composite graphite oxides having both graphite and graphite oxide structures.

Comparative Examples 1 and 2 Example  1-8

After degassing the epoxy resin (Kukdo Chemical YD-128, digylcidyl ether of bisphenol-A) at 100 ° C. for 1 hour in a vacuum, the mixture was stirred and mixed with the composite graphite oxide prepared above, followed by diethylenetriamine (TETA, a curing agent). Sigma-Aldrich) was mixed and cured at 60 ° C. for 12 hours in a Teflon mold. Comparative Examples 1 and 2 are carried out in the same manner as in Examples 1 to 8 except that the composite structured graphite oxides prepared above are not used at all or the graphite is used without any treatment. The detailed composition is shown in Table 1. In Table 1, the sample name indicates the type and amount of the composite structured graphite oxide used. 1C10E indicates that 10 parts of C-1 was added per 100 parts of epoxy resin and TETA.

The flame retardance was evaluated by measuring the combustion speed in the horizontal direction of the sample having a width of 2 mm, a height of 10 mm, and a length of 70 mm. Fire at the tip of the sample for about 5 seconds to ignite, and then calculate the combustion rate by dividing the distance from the point of 10 mm (point A) to the point 60 mm (point B) from the end of the sample by the time it takes for the flame to proceed. It was. When the flame was extinguished without progressing to point B, the combustion speed was calculated by dividing the distance traveled until the flame was extinguished by the time required to proceed.

It can be seen from Table 1 that the epoxy resin itself (C00E) proceeds at 0.57 mm / sec to point B without the flame going off in the middle. On the contrary, when the amount of C-1 is added as a flame retardant, the amount of combustion and the rate of combustion decrease before the flame is extinguished as the amount increases, indicating that C-1 is an effective flame retardant. C-2 shows similar flame retardancy, but C-3 shows less flame retardancy than C-1 or C-2. In case of using C-3 as an additive in the flame retardant experiment, it was found that the degree of swelling of the sample during combustion was relatively smaller than that of adding C-1 or C-2. Due to the low content of graphite structure, the mechanical strength of C-3 is weak so that it does not swell sufficiently while pushing the epoxy resin matrix during combustion. These experimental results show that the swellable graphite oxide structure and the graphite structure with mechanical strength must be properly combined in order for the composite structure graphite oxide to effectively exhibit a flame retardant effect.

On the other hand, Fig. 2 shows the shape of the cross-section of the sample of Example 5 and Fig. 3 shows the cross-section burned after observing with a scanning electron microscope. It can be seen from FIG. 2 that the composite graphite oxide is unevenly dispersed to a size of several μm or smaller. In FIG. 3, it can be seen that the composite structure graphite oxide swells during combustion to have a honeycomb-like shape, and the size of the composite structure graphite oxide is greatly swollen compared to FIG. 2.

Comparative Examples 3 and 4 and Examples 9 to 14

The prepared composite graphite oxide was dispersed in 17 times distilled water, sonicated for 1 hour, mixed with an aqueous acrylic pressure-sensitive adhesive (CS-30 of CS Chemical, 60 wt% solids), and poured into a mold made of release paper. Then, the sample was dried at 60 ° C. for 6 hours and at 80 ° C. for 48 hours to prepare a specimen having a width of 30 mm, a height of 15 mm, and a length of 100 mm. Comparative Examples 3 and 4 are carried out in the same manner as in Examples 9 to 14, except that the composite structured graphite oxides prepared above are not used at all or graphite is used without any treatment. The detailed composition is shown in Table 2. In Table 2, the sample name indicates the type and amount of the composite structured graphite oxide used. That is, 1C05A shows that 5 parts of C-1 was added per 100 parts of adhesive solids. The flame retardancy was evaluated by measuring the combustion rate in the horizontal direction of the sample. In other words, after firing by applying a flame to the end of the sample for about 10 seconds, the distance from the point 10 mm away from the sample point (C point) to the point 90 mm away (point D) is divided by the time required for the flame to proceed. Was calculated.

In Table 2 it can be seen that the adhesive itself (C00A) proceeds to 0.18 mm / sec to the point D. On the contrary, when C-1 and C-2 were added as flame retardants, the combustion speed was decreased, which shows that C-1 and C-2 are effective flame retardants. In contrast, C-3 shows less flame retardancy than C-1 or C-2. In case of using C-3 as an additive in the flame retardant experiment, it was found that the degree of swelling of the sample during combustion was relatively smaller than that of adding C-1 or C-2. As shown in C-3, since the oxidation degree is large and the graphite content is low, the mechanical strength of C-3 is weak, so that it does not swell sufficiently while pushing the pressure-sensitive adhesive during combustion. These experimental results also show that in order for the composite graphite oxide to exhibit an effective flame retardant effect, a swellable graphite oxide structure and a mechanical strength graphite structure must be properly combined.

practice
number Sample Name Composition (weight ratio) combustibility Epoxy resin DETA Flame retardant Burning speed
(mm / sec) Combustion length (mm) Kinds amount Comparative Example 1 G00E 90 10 - - 0.57 50 Comparative Example 2 0C10E 90 10 black smoke 10 0.47 50 Example 1 1C01E 90 10 C-1 One 0.35 39 Example 2 1C03E 90 10 C-1 3 0.30 35 Example 3 1C05E 90 10 C-1 5 0.14 9 Example 4 1C10E 90 10 C-1 10 0.07 4 Example 5 2C05E 90 10 C-2 5 0.15 23 Example 6 2C10E 90 10 C-2 10 0.06 3 Example 7 3C05E 90 10 C-3 5 0.41 50 Example 8 3C10E 90 10 C-3 10 0.35 50

Conduct number Sample Name Composition (weight ratio) Burning speed (mm / sec) Acrylic adhesive
(Solid content) Flame retardant Kinds amount Comparative Example 3 C00A 100 - - 0.18 Comparative Example 4 0C10A 100 black smoke 10 0.17 Example 9 1C5A 100 C-1 5 0.14 Example 10 1C10A 100 C-1 10 0.11 Example 11 2C5A 100 C-2 5 0.13 Example 12 2C10A 100 C-2 10 0.10 Example 13 3C5A 100 C-3 5 0.15 Example 14 3C10A 100 C-3 10 0.13

Claims (5)

delete XRD characteristic peak height of graphite appearing near 2θ = 26 ° / XRD characteristic peak height ratio of graphite oxide appearing at 2θ = 10-15 ° ranges from 1 to 20/1, and C / O atomic ratio is 2 to 10 In the flame retardant for a resin composition composed of graphite oxide having a composite structure of graphite oxide and graphite in the range of / 1, the graphite oxide having a composite structure of graphite oxide and graphite is characterized in that the concentrated sulfuric acid and KMnO ₄ are added to the graphite powder. g) / concentrated sulfuric acid (mL) ratio value is 1 / 5-25, graphite powder (g) / KMnO ₄ (g) ratio value is added in 1 / 0.5-4 range, and obtained by making it react at 60-80 degreeC range. Flame Retardant For Resin Composition The XRD characteristic peak height ratio of graphite oxide exhibited at 2θ = 26 ° in the graphite oxide / 2θ = 10-15 ° in the graphite oxide is in the range of 2 to 15/1. Flame retardant for resin compositions in which the atomic number ratio of C / O is in the range of 3 to 7/1 delete delete

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