KR100536568B1 - A composition of modified flame retarding foams - Google Patents

Abstract

The present invention relates to a flame retardant foam composition which minimizes the toxic gas and smoke density in the event of a fire. More specifically, the rubber resin is used as a base, and inorganic metal hydroxide, organophosphorus compound, loess, etc. are used as a flame retardant. It is a composition made by mixing other additives (foaming agent, crosslinking agent and preparation). Especially, it has excellent environmental friendliness, stability, flame retardancy and mechanical properties. When used in a wide range of applications, such as sporting goods, other industrial products, it relates to a flame-retardant foam composition with a minimized toxic gas and smoke density of a new composition that can be very useful because the environmental friendliness, stability, flame retardancy is secured. Therefore, the present invention completely eliminated a halogen compound that emits harmful gases in the event of a fire and was designed to have a relatively high char formation.

Description

Flame retardant foam composition {A COMPOSITION OF MODIFIED FLAME RETARDING FOAMS}

The present invention relates to a flame-retardant foam composition, more specifically, using a rubber-based resin as a base, using inorganic metal hydroxides, organophosphorus compounds, loess, etc. as a flame retardant, and other additives (foaming agents, crosslinking agents and preparations, etc.) It is a composition made by mixing the material. Especially, it has excellent environmental friendliness, stability, flame retardancy and mechanical properties, and is widely applied to various construction materials, automobile parts, railway parts, sports goods, and other industrial products by extrusion, compression, or injection molding. When used in the field of the present invention relates to a flame retardant foam composition that minimizes the toxic gas and smoke density of the new composition that can be used very usefully to ensure environmental friendliness, stability, flame retardancy and the like. Therefore, the present invention completely eliminated a halogen compound that emits harmful gases in the event of a fire and was designed to have a relatively high char formation.

Existing foams are molding compositions widely used in construction, construction, automobiles, railways, sporting goods, and other fields, and they are considered to be flame retardant and harmful to humans in the event of fire due to various regulations in the world and domestic countries based on environment and stability. However, minimization of toxic gas and smoke density is required. However, in case of conventional products, the degree of flame retardancy is low, and the use of halogen-based flame retardants releases toxic gases such as hydrogen chloride (HCl), which is applicable to human health. The scope is shrinking.

Known flame retardant polyolefin foams, in the case of flame retardant foams of VO grade according to ASTM-D-2863 or class 'O' according to BS 476, the composition of which only blends nitrile rubber (NBR) and polyvinyl chloride (PVC) It has been disclosed that the case is prepared by adding a flame retardant and other additives to the resin. In the case of materials that are not foamed or whose smoke density is reduced for insulation and wire coating, polyvinyl chloride (PVC) is manufactured by adding chlorinated polyvinyl chloride, molybdemum oxide, alumina trihydrate, isodecyl dipheyl phosphate and other additives. [US Pat. No. 5,518,033, Ronald S. Lenox, Lancaster, Pa .; Kim S. Boyd, Quincy, Mass .; William S. Vought, Jr., Landisville, Pa, Feb. 16, 1993). , (US Pat. No. 4670494, Gary Chemical Corp., Leominster, Mass, Jun. 2, 1987), (US Pat. No. 4245055, Wayne E. Smith, Washington Boro, Pa, Jan. 13, 1981), (US Patent 3993607, David M. Florence, Lancaster, Pa, Nov. 23, 1976).

Although such a flame retardant composition is slightly different depending on its specification, one of the compositions is representatively exemplified by 15 to 85 parts by weight of polyvinyl chloride or 1 to 200 parts by weight, plasticizer based on 100 parts by weight of nitrile rubber. 10 to 100 parts by weight, flame retardant 100 parts by weight (5 to 75 parts by weight of iron oxide), 10 to 85 parts by weight of lubricant, 0.1 to 10 parts by weight of stabilizer, 10 to 20 parts by weight of blowing agent, 2.5 parts by weight of sulfur, zinc oxide (ZnO 5 parts by weight, 2.1 parts by weight of stearic acid, 0.8 parts by weight of benzothial disulfides (MBTS), and 0.4 parts by weight of tetramethylthinram monosulfide (Monex).

In addition, the present inventors have applied for an improved composition of a flame retardant polyolefin foam composition and a method for producing the same, by blending polyolefin and rubber-based resins and adding inorganic and chlorine-based flame retardants and other additives to improve the problems of conventional flame retardant compositions. Domestic Patent Application No. 1999-0047008]

Although the conventional flame retardant polyolefin foam composition has a certain degree of flame retardancy, other physical properties are not good, and in particular, it is difficult to consider it as an environmentally friendly material because a large amount of toxic gas and smoke density are released during a fire, and there is much room for improvement. . In the case of the composition of the flame-retardant polyolefin foam and the method for producing the same filed by the present inventors [Korean Patent Application No. 1999-0047008], the flame retardancy is improved and the toxic gas and the smoke density have been reduced.

Therefore, in the present invention, in order to greatly improve the disadvantages of the conventional flame retardant polyolefin foam composition, in particular, in order to minimize the toxic gas and the smoke density in consideration of human harmfulness in the event of a fire, and in the composition filed by the present inventors Unlike the conventional method, nitrile rubber is completely used as a resin to minimize minimization and smoke density reduction, and a series of compositions such as the composition of flame retardants and other additives are newly constructed, and in particular, environmentally friendly. And to provide a flame retardant foam composition excellent in stability and excellent flame retardancy and mechanical properties.

The present invention relates to a flame retardant foam composition comprising a nitrile rubber as a resin and comprising a flame retardant, a foaming agent and a stabilizer as an additive, wherein the flame retardant is 10 to 300 parts by weight of Al (OH) ₃ based on 100 parts by weight of the nitrile rubber. , The blowing agent is 10 to 40 parts by weight, the stabilizer is 5 to 20 parts by weight, Mg (OH) ₂ 10 to 200 parts by weight, Sb ₂ O ₃ 5 to 30 parts by weight, P-FR (phosphates) 5 to 100 parts by weight, 5 to 30 parts by weight of ocher, 1 to 5 parts by weight of vulcanizing agent, 1 to 5 parts by weight of crosslinking accelerator, 1 to 5 parts by weight of foaming aid, 1 to 5 parts by weight of heat transfer accelerator, external mold release agent 1-10 weight part, 1-10 weight part of internal mold release agents, 1-10 weight part of anti-aging agents, and 1-20 weight part of fillers are further contained, The said crosslinking promoter is 2-melcap benzothiazole ( M), dibenzothiadyl disulfide (DM) and Zn-dimethyl dithiocarbamate (PZ). Had the nitrile rubber is acrylonitrile content is characterized in that 28-34 wt denied.

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Referring to the present invention in more detail as follows.

Specific examples of the component configuration of the composition of the present invention, the resin component is 10 to 300 parts by weight of Al (OH) _3, 10 to 200 parts by weight of Mg (OH) ₂ with respect to 100 parts by weight of nitrile rubber, 5 to 30 parts by weight of Sb ₂ O _3, 5 to 100 parts by weight of P-FR (phosphates), 5 to 30 parts by weight of ocher, including 5 to 20 parts by weight of stabilizer, 1 to 5 parts by weight of vulcanizing agent, and crosslinking. 2-Melcap benzothiazole (M), di-benzothiadyl disulfide (DM) and Zn-dimethyl-dithiocarbamate (PZ) are 1 to 5 parts by weight and 10 to 40 weight of the blowing agent, respectively, as accelerators. Part, 1 to 5 parts by weight of foaming aid, 1 to 5 parts by weight of heat transfer accelerator, 1 to 10 parts by weight of external mold release agent, 1 to 10 parts by weight of internal mold release agent, 1 to 10 parts by weight of antioxidant, 1 to 20 parts by weight of filler It can be prepared.

In particular, the loess which is preferably used as a flame retardant component in the present invention is kaolin mineral (kaolin; Al ₂ O ₃ · 2 SiO ₂ · nH ₂ O), montmorillonite (monmorillonite; Al ₂ O ₃ · ₄ SiO ₂ · 6H ₂ O), pyrophyll Light _{(pyrophyllite; Al 2 O 3 ·} 4SiO 2 · H 2 O), illite _{(illite; KAl 2 (OH)} 2 [AlSi 3 (O, OH) 10]) and talc _{(talc; 3MgO · 4SiO 2 ·} H Refers to one or more mixtures selected from ₂ O). Depending on the type of loess, they can intercalate organic materials and have an extremely high specific surface area of about 800 m ² / g, which acts as an absorbent and can serve as an efficient filler due to their high surface adsorption. do.

In the present invention, in consideration of the environment and safety, that is, in the event of a fire in consideration of the harmful effects of the human body caused by the release of toxic gases such as hydrogen chloride (HCl) without using a halogen-based flame retardant, inorganic flame retardant (Al (OH) _3, etc.) and phosphorus The flame retardant was maximized by using a flame retardant. In general, halogenated compounds have a flame retardant effect by fundamentally stabilizing radicals generated in the gas phase, and the mechanism is inferred by a chemical reaction as in Scheme 1 below.

HO · + HX ---> HOH + X

X · + RH ---> HX + R · Regeneration (Stop chain reaction)

XO · + · OH ---> HX + O ₂ (flame retardant effect by reducing the concentration of active O · and · OH and stopping the chain reaction)

X + O + M ---> XO + M

X2 + O · ---> XO · + X · ( during decomposition effect to block the non-flammable gas generating O ₂₎

O + OX ---> O ₂ + X

In the chemical formula 1, activating radicals such as OH radicals generate heat through a chemical reaction, and the latent heat generated acts as an energy source required for combustion of surrounding flammable materials.

On the other hand, the flame retardant gives the flame retardant effect by reducing the concentration of the active radicals O · and · OH and stopping the chain reaction as in the above mechanism, the cleavage of CX bond during combustion has the effect of reducing the heat of combustion of the combustible material by the endothermic reaction. . It also has the effect of blocking oxygen by generating incombustible gases during decomposition. Therefore, the actual flame retardant effect is given by HX and reacts and is converted into X radical of low energy source. In addition, the halogen-containing flame retardant exhibits a flame retardant effect even in the solid phase. HX acts as an oxidation catalyst of the combustible material, and the oxidized material is ring-structured, resulting in a carbon compound char. The carbon compound thus produced serves to help prevent the combustible material from below the combustion zone by blocking oxygen and latent heat.

In the present invention, as mentioned above, as mentioned above, the halogen-based flame retardant is completely eliminated in consideration of human toxicity, and inorganic and phosphorus-based flame retardants may be used as, for example, aluminum hydroxide, antimony oxide, magnesium hydroxide, and the like. As the P-FR (phosphates) and the like can be used. Unlike organic flame retardants, inorganic flame retardants are not volatilized by heat and decompose to release non-combustible gases such as H ₂ O, CO ₂ , SO ₂ , HCl and are mostly endothermic. In the gas phase, the flammable gas is diluted and the plastic surface is coated to prevent the access of oxygen. At the same time, there is an effect of reducing the generation of plastic cooling and pyrolysis water through the endothermic reaction on the solid phase surface. For example, aluminum hydroxide and magnesium hydroxide produce water after decomposition, as shown in Scheme 1, at which time a large amount of endotherm is accompanied to impart flame retardancy.

2Al (OH) ₃ + heating ------> Al ₂ O ₃ + 3H ₂ O -298 kJ / mol

Mg (OH) ₂ + heating ------> MgO + H ₂ O -328kJ / mol

In addition, antimony trioxide and antimony pentoxide may be used as antimony oxide, and it is used as an adjuvant that exhibits a flame retardant synergistic effect of a halogen-containing flame retardant without being used as such. The mechanism is inferred as follows. That is, SbCl ₃ generated in each step reaction of Scheme 2 has an effect of lowering the temperature of the plastic through endothermic reaction, and acts as a radical interceptor like HCl and HBr. Some have suggested that both SbCl ₃ and SbOCl have a flame retardant synergistic effect by lowering the rate of halogen release in the combustion zone, increasing the time to act as a radical interceptor.

In addition, the generated heavy gas surrounds the surface of the solid phase, thereby blocking oxygen access and thus exhibiting a flame retardant effect. This reaction mechanism can be summarized as in Scheme 2 below.

Sb ₂ O ₃ + 2HCl (~ 250 ° C) ----------> 2SbOCl + H ₂ O

5SbOCl (Maintain 245 ~ 280 ℃) ----------> Sb ₄ O ₅ Cl ₂ + SbCl ₃ ↑

4Sb ₄ O ₅ Cl ₂ (Maintain 410 ~ 475 ℃) ----------> 5Sb ₃ O ₄ Cl + SbCl ₃ ↑

3Sb ₃ O ₄ Cl (Maintain 475 ~ 565 ℃) ----------> 4Sb ₂ O ₃ + SbCl ₃ ↑

Sb ₂ O ₃ (S) (Maintain at 685 ℃) ----------> Sb ₂ O ₃ (I)

In addition, the phosphorus-based flame retardant can give a particularly excellent flame retardant effect on the polymer having a large number of hydroxyl groups. This mechanism is known because the phosphorus (P) compound added as shown in Scheme 3 promotes the dehydration reaction of the base polymer and crosslinks thereby to produce a nonflammable carbonaceous char (condensed). -phase mechanism).

At this time, pyrophosphoric acid and metaphosphoric acid present on the surface play a role of enhancing char formation through dehydration effect, and metaphosphate easily reacts. And because of the generated char, it is difficult for heat to penetrate inside the material, and thus a self insulating layer is generated. In addition, the water generated by the dehydration reaction has the effect of diluting the concentration of the flammable gas to enhance the flame retardant effect, and the amount of soot generated is significantly reduced by converting the generated carbonizable intermediate into char.

In addition, in the present invention, in order to prepare an environmentally friendly composition having a stable stability in consideration of the effects on stability and environmental aspects and processability, especially considering the human hazards, to completely exclude the use of halogen-based flame retardant, preferably The use of inorganic flame retardant Al (OH) ₃ , Mg (OH) ₂ , Sb ₂ O ₃ , phosphorus flame retardant P-FR (phosphate) and ocher to minimize the toxic gas and smoke density in consideration of human toxicity It is desirable to ensure stability and environmental friendliness, and to have an effect of improving flame retardancy. The present invention also includes using all five components or selecting one or more of them as a flame retardant.

As the blowing agent, azodicarbonamides (7000MC, 5000F, 3000F) or N, N'-dinitrosopentamethylenetetramine (N, N'-Dinitrosopenta -methylenetetramine; DPT) which are azo compounds are preferably used. In order to control the foamability and temperature which will affect the processability and productivity, it is preferable to use urea foaming aid (trade name Cellex-A) as the foaming aid and ZnO as the heat transfer accelerator.

Sulfur as a vulcanizing agent used in the present invention, 2-melcap-benzothia, which is relatively scorch fast as thiazoles in consideration of the vulcanization accelerator effect, scorch resistance, aging resistance, activating temperature, dispersibility, contaminant, etc. Sol (M), di-benzothiadyl disulfide (DM) with relatively low scorch, dithioates, and scorch and vulcanized Zn-dimethyl dithiocarbamate (PZ) at an appropriate ratio as described above. It is preferable. In addition, as a stabilizer, a Ba-Zn-based stabilizer is used in consideration of the foaming rate and the effect of obtaining a uniform cell according to the use of a large amount of filler. For example, trade names BZ-806F and BZ-119 are preferably used. Can be used. Antioxidants are considered 2,2,4-trimethyl-1,2-dihydroquinone (Kumanox RD), N- (1,3-Dimethylbutyl)-N'phenyl-ρphenylene diamine (Kumanox 13) , N'-isopropyl-N-phenyl-ρ-Phenylene diamine (Kumanox 3C), Styrenated phenol (Kumanox SP, SP-N) may be preferably used, and the internal release agent is polyethylene wax (LC-102N) as a rubber processing enhancer. As the external release agent, it is preferable to use stearic acid in consideration of extrusion property and carbon black in consideration of color impartment and photooxidation prevention, reinforcing effect and cost reduction.

Method for producing a composition according to the present invention as described above will be described as an example of the present invention through each of the following examples, this embodiment of the present invention is to illustrate the case that is manufactured according to the intended use of the present invention is limited It is not intended that, in the examples, the percentage (%) indicating the content of the composition means% by weight unless otherwise indicated.

The abbreviation of the component used in the Example shall mean NBR as nitrile rubber.

Example 1.

The thermal and dynamic behaviors of the resin / additive blends with respect to composition ratio, temperature and time were observed, and these were flame retardant, limiting oxygen index, cone-calorimeter, smoke density control system (LOI), and foamability (foaming rate). , cell structure, surface condition, etc.). In particular, NBR is used as a resin in consideration of stability and environmental friendliness (ie, minimizing toxic gas and smoke density) and flame retardancy, and the resin composition ratio, resin / flame retardant composition ratio, type and content of flame retardant, and type and content of other additives are controlled. It was.

The composition ratios of the resin components were configured as shown in Tables 1 and 2, respectively, and the blend was used at a temperature of 110 to 130 ° C, RPM50 for 20 to 40 minutes without addition of a crosslinking and crosslinking accelerator in rheomixer (HAAKE), and then crosslinking. And adding a crosslinking accelerator and foaming at a temperature of 60-70 ° C., RPM 50, time 5-10 minutes, and extrusion within a temperature of 70-80 ° C., Rs 5, time 1-3 minutes in a Minimax molder (Bau 915L). In the oven (HB-503M) was carried out at a temperature of 120 ~ 200 ℃. In addition, the foaming investigation was carried out to investigate the surface state, foaming rate, cell structure, etc. after foaming, flame retardancy and toxic gas emission investigation using the LOI (Atlas) tester and cone-calorimeter, LOI test according to ASTM-D-2863 The specimen size was 6.5 +/- 0.5mm wide, 2.0 +/- 0.25mm thick and 70-150mm long, and the limiting oxygen index (LOI) was measured while arbitrarily adjusting the amount of oxygen and nitrogen injected. The cone calorimeter test was conducted in accordance with ASTM E 1354-94. The specimen size was 100mm in width, 100mm in length and 9mm in thickness, and the heat flux was 50 ㎾ / m ² and the average HRR (Heat Release Rate), COY (CO yield), C ₂ Y (CO ₂ yield) and the like were measured. In addition, the light density was measured using the Atlas smoke density control system, and the morphology survey observed the fracture surface of the specimen using the SEM (JEOL JSM-840A, Hitachi S 4700). It was.

As a result, the appropriate foaming occurred in the temperature range of 120 to 165 ℃ for all samples 1 to 10, and the time required was 30 minutes, the surface was smooth, the cell structure was uniform as a closed cell, and the foaming rate was 220 to 280%. It was confirmed that it has a. The LOI test showed that the critical oxygen index was 28-30.3. As a result of measuring the smoke density, that is, the light transmittance, it was found that 90.0 to 94.8% was much higher than 73.3% of the commercialized foam.

The cone-calorimeter was measured for samples 1-6, which are typical compositions, and as a result, the average HRR was 74, 75, 68, 67, 77, 75㎾ / m ² , and COY 0.070, 0.051 at 50 ㎾ / m ² of heat flux. , 0.077, 0.045, 0.047, 0.049kg / kg and CO ₂ Y were found to be 0.87, 0.98, 0.98, 0.97, 0.94, 1.00kg / kg, while the average commercialized foam had an average HRR of 112㎾ / m ² 35 the ~45㎾ / m ² Fair, COY is the the amount of generation of CO 0.014~0.046kg / kg plenty to 0.091kg / kg, CO ₂ Y the amount of C0 ₂ to 1.07kg / kg 0.2~0.07kg / kg Cloudy It was confirmed. Therefore, it was found that the flame retardancy is much higher than that of the conventional commercialized foam, and the human harmfulness is significantly reduced.

As a result, the foaming rate is 220-280%, the surface is smooth, the cell structure is uniform with clsed-cell, and the human harmfulness is significantly reduced (low smoke density, ie high light transmittance, and hydrogen chloride due to the complete elimination of halogen compounds ( No foaming of toxic gases such as HCl), and significantly reduced emissions of carbon monoxide and carbon dioxide, and a limiting oxygen index (LOI) of 28 to 30.3, which has excellent foaming rate and flame retardancy, and minimizes toxic gas and smoke density. In addition, it was possible to identify the processing method and conditions for this.

Thus, in the identified formulation and processing conditions, the blend was brought to a temperature of 110 to 130 ° C., RPM50 for 20 to 40 minutes without the addition of crosslinking and crosslinking accelerator in rheomixer (HAAKE), followed by the addition of crosslinking and crosslinking accelerator and 60 to 70 ° C., RPM 50, time 5 to 10 minutes, extrusion at a temperature of 70 to 80 ° C., Rs 5, time 1 to 3 minutes in a Minimax molder (Bau 915L), and foaming to an oven (HB— 503M) at a temperature of 120-200 ° C. resulted in a foam that minimizes toxic gases and smoke densities and has excellent foamability and flame retardancy.

The results of the above results are shown in the following Tables 1, 2, and 3 and the accompanying drawings of Fig. 1 (Sample 1), Fig. 2 (Sample 5), and Fig. 3 (Sample 6). The cell structure of the flame retardant polyolefin foam and the degree of dispersion of the additives are shown in Fig. 4 (A). And cone-calorimeter measurement results are shown in Figures 5, 6 and 7.

Flame retardant and other additives [Al / Mg / P / Sb / Oc] / OT in the above table means [Al (OH) ₃ / Mg (OH) ₂ / P-FR / Sb ₂ O ₃ / ocher] / other additives CF means commercial foam.

As described above, the present invention uses nitrile rubber (NBR) as a base resin unlike the conventional one, and completely eliminates halogen compounds in consideration of human hazards in the event of a fire as a flame retardant, and inorganic metal hydroxides and organophosphorus compounds. It is a composition made by mixing a proper amount of other additives (foaming agent, crosslinking agent, and preparation agent) by using ocher, ocher, etc., and has excellent flame retardancy and mechanical properties, and in particular, it has excellent environmental friendliness and stability by minimizing toxic gas and smoke density. Therefore, by extrusion, compression or injection molding, there is an effect that can be very usefully applied to a wide range of fields, such as various building materials, automobile parts, railway parts, sporting goods, and other industrial products.

1A and 1B are electron microscopy (SEM) photographs confirming the cell structure (A) and the additive dispersion degree (B) of the foam composition (sample 1) prepared in Example 1 of the present invention.

2A and 2B are electron microscope (SEM) photographs confirming the cell structure (A) and the additive dispersion degree (B) of the foam composition (sample 5) prepared in Example 1 of the present invention.

3a and 3b are electron microscope (SEM) photographs confirming the cell structure (A) and the additive dispersion degree (B) of the foam composition (sample 6) prepared in Example 1 of the present invention.

4A and 4B are electron microscope (SEM) photographs confirming the cell structure (A) and the additive dispersion degree (B) with respect to the conventional foam.

Figure 5 shows the average HRR which is the cone-calorimeter measurement results for the foam composition prepared in Example 1 of the present invention,

Figure 6 shows the CO yield which is a cone-calorimeter measurement result for the foam composition prepared in Example 1 of the present invention,

Figure 7 shows the CO2 yield of the cone-calorimeter measurement results for the foam composition prepared in Example 1 of the present invention.

Claims (4)

delete In a flame retardant foam composition using nitrile rubber as a resin and comprising a flame retardant, a foaming agent and a stabilizer as an additive, The flame retardant is 10 to 300 parts by weight of Al (OH) ₃ , the foaming agent is 10 to 40 parts by weight, the stabilizer is 5 to 20 parts by weight, and Mg (OH) ₂ based on 100 parts by weight of the nitrile rubber. 10 to 200 parts by weight, 5 to 30 parts by weight of Sb ₂ O _3, 5 to 100 parts by weight of P-FR (phosphates), 5 to 30 parts by weight of ocher, 1 to 5 parts by weight of vulcanizing agent, 1 to 5 parts by weight of crosslinking accelerator Parts, 1 to 5 parts by weight of the foaming aid, 1 to 5 parts by weight of the heat transfer accelerator, 1 to 10 parts by weight of the external mold release agent, 1 to 10 parts by weight of the internal mold release agent, 1 to 10 parts by weight of the anti-aging agent, 1 to 20 parts by weight of the filler is further included, The crosslinking accelerator is 2-melcap benzothiazole (M), di-benzothiadyl disulfide (DM) and Zn-dimethyl dithiocaramate (PZ). The method of claim 2, The nitrile rubber has a acrylonitrile content of 28 to 34 parts by weight, flame retardant foam composition. delete