KR20240021322A - Manufacturing method of flame retardant flexable polyurethane foam - Google Patents

Abstract

A method of producing flame-retardant flexible polyurethane foam by reacting polyether polyol (A) and polymer polyol (B) with a polyol mixture of solid flame retardant particles, dispersants, foaming agents, foam stabilizers and catalysts, and an isocyanate compound, wherein the polyether polyol (B) The polyol (A) has a hydroxyl value of 15 to 56 mgKOH/g, and the polymer polyol (B) has a hydroxyl value of 10 to 30 mgKOH/g, and contains solid flame retardant particles and has excellent flame retardant performance and elasticity. This relates to a method of manufacturing flame-retardant soft polyurethane foam suitable for use as a material for automobile interior materials.

Description

Method for manufacturing flame retardant flexible polyurethane foam. {MANUFACTURING METHOD OF FLAME RETARDANT FLEXABLE POLYURETHANE FOAM}

The present invention relates to a method of manufacturing flame-retardant soft polyurethane foam, and more specifically, to a method of manufacturing flame-retardant soft polyurethane foam that contains solid flame retardant particles and exhibits excellent mechanical properties of flexible polyurethane foam.

Flexible polyurethane foam is manufactured through a process of mixing and reacting ingredients to form polyurethane foam (e.g., foam, stabilizer, dispersant, water, auxiliary foaming agent, and isocyanate and polyol with catalyst). . In this manufacturing process, the yield and quality of the flexible polyurethane foam manufactured by mixing the ingredients to produce a mixture and measuring the ingredients into a reaction chamber that delivers the mixture into a conveyor or mold to form a foam and process variables. This is decided.

Polyurethane foam is manufactured by adding a foaming agent and foaming when polyurethane is formed through the reaction of reactants consisting of isocyanate and polyol. When a flame retardant is added to provide flame retardant performance, it must be homogeneously mixed with the reactants at ambient temperature. For this purpose, a solid flame retardant with very small particles or a liquid flame retardant with low viscosity can be used.

Recently, fires in electric vehicles have become a problem. There is concern about the possibility of casualties due to the flammability and toxic gases of the polyurethane foam that makes up the seats in the event of a fire inside the vehicle. Therefore, the development of automotive seats with excellent flame retardant performance is required. there is. In order to improve flame retardant performance, as described above, there is a method of adding a flame retardant during the manufacturing process of polyurethane foam. Additionally, flame retardant components such as phosphorus, nitrogen, or halogen can be chemically combined with polyol or isocyanate to improve flame retardant performance. It may be possible.

However, in the case of flexible polyurethane foam, a material that can be used in automobile seats, when a flame retardant is mixed to improve flame retardant performance, the physical properties such as the strength characteristics of the polyurethane foam pad deteriorate, so it is necessary to develop technology for mixing flame retardants. do.

For example, in Republic of Korea Patent Publication No. 10-1313409, a composite metal cyanide complex catalyst containing Zn and Co was polymerized to ensure flame retardancy without using a flame retardant in the process of manufacturing flexible polyurethane foam. Polyurethane foam is manufactured without purifying polyether polyol. If this method is applied, flexible polyurethane foam can be manufactured without mixing flame retardants, but sufficient flame retardant performance cannot be secured, so its application is limited, especially , there is a problem that it cannot be used in applications that require high flame retardant performance, such as automobile seats.

In addition, in Republic of Korea Patent Publication No. 10-1638255, additives showing flame retardant performance such as anhydrous silicic acid, aluminum hydroxide, liquid TEP, and polyphosphoric acid are mixed in the manufacturing process of flexible polyurethane foam. Process optimization is very difficult and product quality variations increase, so the process is limited to manufacturing soft polyurethane foam products that are difficult to use for special purposes such as automobile seats.

The present invention was developed in consideration of the prior art as described above, and manufactures a flame-retardant soft polyurethane foam that can improve the flame retardant performance of the polyurethane foam produced by highly dispersing the flame retardant mixed in the manufacturing process of the flexible polyurethane foam. The purpose is to provide a method for doing so.

In addition, the purpose is to provide a method of manufacturing a flame-retardant flexible polyurethane foam that has excellent physical properties and flame retardant performance while containing a solid flame retardant that is excellent in flame retardancy but is difficult to highly disperse because it is a solid particle.

The method for manufacturing flame-retardant flexible polyurethane foam of the present invention to solve the above problems is a method of manufacturing flame-retardant flexible polyurethane foam comprising the step of reacting a polyol mixture and an isocyanate compound, wherein the polyol mixture has a hydroxyl value of 15. Characterized by mixing a polyether polyol (A) with a hydroxyl value of 10 to 30 mgKOH/g (B), solid flame retardant particles, a dispersant, a foaming agent, a foam stabilizer, and a catalyst. do.

At this time, the polyether polyol (A) is a polyether polyol (A1) with a hydroxyl value of 25 to 30 mgKOH/g, a polyether polyol (A2) with a hydroxyl value of 15 to 25 mgKOH/g, and a hydroxyl value of 30. It may be any one selected from polyether polyol (A3) having a content of 56 mgKOH/g or a mixture thereof.

In addition, the polymer polyol (B) may contain 15 to 50% by mass of styrene-acrylonitrile copolymer (SAN) based on 100% by mass of polyether polyol.

In addition, the content of the polyether polyol (A) is 50 to 95% by mass based on the total mass of the polyether polyol (A) and the polymer polyol (B), and the content of the polymer polyol (B) is the polyether polyol (A) ) and may be 5 to 50% by mass based on the total mass of the polymer polyol (B).

Additionally, the flexible polyurethane foam manufactured according to the manufacturing method of the present invention may be mold foam or slab foam.

By applying the method for manufacturing flame-retardant flexible polyurethane foam according to the present invention, the flame retardant performance of the manufactured flexible polyurethane foam can be improved because the flame retardant mixed in the manufacturing process of the flexible polyurethane foam is dispersed by a dispersant.

In addition, it is possible to manufacture a flame-retardant flexible polyurethane foam that has excellent physical properties and flame retardant performance while containing a solid flame retardant that is excellent in flame retardancy but is difficult to highly disperse because it is a solid particle.

Figure 1 is an SEM photograph showing the state of flexible polyurethane foam manufactured with different types of flame retardants.
Figure 2 shows the vertical flame test results of a flexible polyurethane foam sample.
Figure 3 shows thermogravimetric analysis (TGA) measurement results of a flexible polyurethane foam sample.
Figure 4 shows the results of measuring the tensile strength of flexible polyurethane foam samples according to the type of flame retardant.
Figure 5 shows the results of measuring the elongation of flexible polyurethane foam samples according to the type of flame retardant.
Figure 6 is a combustion test analysis result of a flexible polyurethane foam sample.
Figure 7 shows dispersion results according to the type of dispersant used in polyol mixing.
Figure 8 shows urethane foam results according to the type of dispersant used in polyol mixing.

Hereinafter, the present invention will be described in more detail. Terms or words used in this specification and claims should not be construed as limited to their common or dictionary meanings, and the inventor may appropriately define the concept of terms in order to explain his or her invention in the best way. It must be interpreted with meaning and concept consistent with the technical idea of the present invention based on the principle that it is.

The manufacturing method of the flame-retardant flexible polyurethane foam of the present invention follows the conventional method of manufacturing flame-retardant flexible polyurethane foam in which a polyol mixture and an isocyanate compound are reacted in the presence of a blowing agent, a catalyst, a foaming agent, etc., through high dispersion of the flame retardant. In order to improve flame retardancy, the polyol mixture includes a polyether polyol (A) with a hydroxyl value of 15 to 56 mgKOH/g, a polymer polyol (B) with a hydroxyl value of 10 to 30 mgKOH/g, solid flame retardant particles, a dispersant, A technical feature is that a polyol mixture containing a foaming agent, a foaming agent, and a catalyst is used.

By applying the manufacturing method of the present invention, flexible polyurethane foam showing good physical properties, elasticity, and flame retardant performance can be obtained. Additionally, by applying the above manufacturing method, mold foam or slab foam can be manufactured.

The mold foam is a foam obtained by injecting polyurethane solution into a mold and curing it. If it is soft, it can be used for parts such as seat cushions, seatbacks, and headrests of automobiles. In addition, slab foam is obtained by freely foaming polyurethane solution in a belt-type device rather than a mold, and if it is soft, it can be used as a cushioning agent for furniture.

In addition, rim foam (reaction injection molding foam) manufactured by injecting polyurethane solution into the solution injection port while the mold is closed, spray foam that reacts by applying polyurethane solution to the surface of an object, and automobile steering wheel airbag There are integral skin foams (ISF) used for coverings, but these foams are hard or semi-rigid foams and are difficult to apply to soft polyurethane foams.

The flexible polyurethane foam of the present invention exhibits properties particularly suitable for mold foam, as it has improved flame retardancy and is therefore particularly suitable for use as a material for automobile interior materials.

Each raw material used in the manufacturing method of the present invention will be described below.

[polyether polyol (A)]

Polyether polyol (A) is a polyol with a hydroxyl value of 15 to 56 mgKOH/g. When the hydroxyl group value is set to 15 mgKOH/g or more, the obtained flexible polyurethane foam exhibits good strength, and when the hydroxyl group value is set to 56 mgKOH/g or less, the obtained flexible polyurethane foam has good elasticity, so the hydroxyl group within the above range It is preferable to use a polyether polyol (A) having a high value.

Specifically, the polyether polyol (A) is a polyether polyol (A1) with a hydroxyl value of 25 to 30 mgKOH/g, a polyether polyol (A2) with a hydroxyl value of 15 to 25 mgKOH/g, and a hydroxyl value of 30. It may be any one selected from polyether polyol (A3) having a content of 56 mgKOH/g or a mixture thereof.

The polyether polyol can be obtained by ring-opening addition polymerization of propylene oxide to an initiator using an alkali metal catalyst, and then ring-opening addition polymerization of ethylene oxide. It has an oxyethylene terminal structure, and the amount of oxyethylene groups is the polyether polyol. It is 10 to 20% by mass based on 100% by mass, and the number of functional groups is about 2 to 4.

[Polymer polyol (B)]

The polymer polyol (B) is a polyol obtained by sequentially adding an initiator, styrene, and acrylonitrile monomer to the polyether polyol (A) and polymerizing it to form styrene-acrylonitrile copolymer (SAN) particles. The content of SAN is 15 to 50% by mass based on 100% by mass of the total polymer polyol, and a polymer polyol (B) having a hydroxyl value of 10 to 30 mgKOH/g can be used. It was shown that good elasticity and hardness of the manufactured flexible polyurethane foam can be secured when the content of SAN in the polymer polyol (B) is 15 to 50% by mass based on 100% by mass of the total polymer polyol.

[polyol mixture]

In the production method of the present invention, a polyol mixture of the polyether polyol (A) and the polymer polyol (B) is used, and the content of the polyether polyol (A) is the same as the polyether polyol (A) and the polymer polyol (B). It may be 50 to 95% by weight, preferably 60 to 95% by weight, based on the total mass. By setting the content of the polyether polyol (A) to 95 mass% or less, the number of closed cells in the obtained flexible polyurethane foam decreases, thereby suppressing shrinkage of the flexible polyurethane foam, and by setting the content to 50 mass% or more, good flowability and It can be made to have moldability.

Additionally, the content of the polymer polyol (B) may be 5 to 50 mass%, preferably 5 to 30 mass%, based on the total mass of the polyether polyol (A) and polymer polyol (B). By setting the content of the polymer polyol (B) to 5% by mass or more, the closed cell rate is lowered and good soft polyurethane foam can be obtained, and by setting the content to 30% by mass or less, flowability and moldability can be improved.

[Flame retardant]

In the present invention, solid flame retardant particles are used as the flame retardant. Flame retardants can be added directly to the polyol, or flame retardant components such as phosphorus, nitrogen, or halogen can be chemically bound to the polyol or isocyanate.

Since the foam produced by foaming flexible polyurethane is manufactured by a reaction using isocyanate and polyol as reactants, the flame retardant can be a solid flame retardant with very small particles so that it can be easily and completely mixed with the reactants at ambient temperature. there is. Additionally, low viscosity liquid flame retardants can also be used.

The solid flame retardant preferably has a particle size of less than 50㎛ in terms of dispersibility. Additionally, the solid flame retardant particles may be contained in the range of 2 to 40 parts by weight, preferably 7 to 20 parts by weight, based on 100 parts by weight of the polyol mixture. The content of the solid flame retardant particles is selected in consideration of the dispersibility and flame retardant performance of the manufactured flexible polyurethane foam. If the content is outside the above range, the flame retardant performance is insufficient or the dispersibility deteriorates, leading to a decrease in the physical properties of the flexible polyurethane foam. Problems may occur.

[Cross-linking agent]

The crosslinking agent used in the production method of the present invention is preferably a compound having two or more active hydrogens such as a hydroxyl group, a primary amino group, or a secondary amino group. Such crosslinking agents include, for example, ethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, diethylene glycol, triethylene glycol, dipropylene glycol, glycerin, and trimethylolpropane. , aliphatic alcohols such as pentaerythritol, diglycerin, dextrose, sorbitol, and sucrose; Monoethanolamine, diethanolamine, triethanolamine, bisphenol A, ethylenediamine, 3,5-diethyl-2,4(or 2,6)-diaminotoluene (DETDA), 2-chloro-p-phenylene Diamine (CPA), 3,5-bis(methylthio)-2,4(or 2,6)-diaminotoluene, 1-trifluoromethyl-3,5-diaminobenzene, 1-trifluoromethyl -4-Chlor-3,5-diaminobenzene, 2,4-toluenediamine, 2,6-toluenediamine, bis(3,5-dimethyl-4-aminophenyl)methane, 4,4'-diaminodi Compounds such as phenylmethane, ethylenediamine, m-xylylenediamine, 1,4-diaminohexane, 1,3-bis(aminomethyl)cyclohexane, and isoronediamine; Examples include compounds obtained by ring-opening addition polymerization of a relatively small amount of alkylene oxide to these compounds. In addition, as the crosslinking agent, one type of compound may be used individually, or two or more types may be used in combination.

The crosslinking agent may have a number average molecular weight of less than 2000, preferably less than 1500, and more preferably less than 1000. This may be selected considering dispersibility and reactivity with polyol and isocyanate.

The crosslinking agent may be contained in the range of 0 to 10 parts by mass, preferably 1 to 8 parts by mass, based on 100 parts by mass of the polyol mixture.

[Isocyanate compound]

The isocyanate compound may be toluene diisocyanate (TDI), diphenylmethane diisocyanate, or a mixture thereof. Additionally, it is preferable to use a mixture of toluene diisocyanate and diphenylmethane diisocyanate in a mass ratio of 25:75.

The amount of the isocyanate compound used is preferably 80 to 120 and more preferably 85 to 115 in the isocyanate index. The isocyanate index is a value expressed by multiplying the number of isocyanate groups by 100 for the total of all active hydrogens such as polyol, crosslinking agent, and water.

[blowing agent]

As a blowing agent used to produce a foam, water, which is a chemical blowing agent, or a volatile substance, which is a physical blowing agent, can be used. In addition, one type of foaming agent may be used individually, or two or more types may be used together.

When using only water, the amount of the foaming agent may be 10 parts by mass or less, preferably 0.1 to 8 parts by mass, based on 100 parts by mass of the polyol mixture. When using a different type of foaming agent, it can be adjusted appropriately according to requirements such as foaming ratio.

[Food purifier]

As a foam stabilizer, a silicone-based foam stabilizer or a fluorinated compound-based foam stabilizer can be used. In order to form good foam among these foam stabilizers, a silicone-based foam stabilizer with a strong foam stabilizer can be used.

The silicone-based tablet

As the agent, a silicone-based foam stabilizer for flexible polyurethane foam is preferable, and a silicone-based foam stabilizer for cold cure is particularly preferable. Examples of the silicone-based foam stabilizer include B-8734LF2, B-8735LF2, and B-8736LF2 manufactured by Evonik Corporation; Examples include L3002, L5305, L5307, and L5309 manufactured by Momentive. These may be used individually by 1 type, or may be used in combination of 2 or more types.

The amount of the foam stabilizer used can be in the range of 0.1 to 2 parts by mass, preferably 0.2 to 1.5 parts by mass, based on 100 parts by mass of the polyol mixture. When the amount of the foam stabilizer used is 0.1 parts by mass or more, the cell diameter becomes small and cell roughness is less likely to occur, and when the amount used is less than 2 parts by mass, the foaming properties of the soft polyurethane foam obtained are reduced and the ventilation is good. This can improve the sound absorption performance in the high frequency range.

[Dispersant]

As a dispersant, a dispersant selected from fatty acid-based, phosphorus-based, or acidic group-containing polyester can be used. Among these dispersants, for good dispersibility, a liquid dispersant with good dispersing power can be used. For example, BYK's DISPERBYK-111, DISPERBYK-180, BYK-220S, ANTI-TERRA-U; PE40 manufactured by Evonik, etc. can be mentioned. These may be used individually by 1 type, or may be used in combination of 2 or more types.

The amount of the dispersant used can be in the range of 0.1 to 2 parts by mass, preferably 0.2 to 1.5 parts by mass, based on 100 parts by mass of the polyol mixture. By setting the amount of the dispersant to 0.1 parts by mass or more, the dispersibility of the solid flame retardant in the polyol becomes good, thereby obtaining a foam with uniform mechanical properties, and it is possible to prevent deterioration of the physical properties of the flexible polyurethane foam obtained by using less than 2 parts by mass. there is.

[catalyst]

As a catalyst used for urethanization, a conventionally known catalyst can be used. For example, aliphatic amines such as triethylenediamine, dipropylene glycol solution of bis-((2-dimethylamino)ethyl)ether, and morpholines; Organic tin compounds such as tin octanoate and dibutyltin dilaurate can be used. The said urethanization catalyst may be used individually by 1 type, or may be used in combination of 2 or more types.

In addition, the amount of the urethanization catalyst used is preferably 1.0 parts by mass or less, and especially preferably used in the range of 0.05 to 1.0 parts by mass, based on 100 parts by mass of the polyol mixture.

[Other ingredients]

In the production method of the present invention, desired additives may be used in addition to the solid flame retardant particles, catalyst, foaming agent, foam stabilizer, dispersant, and crosslinking agent described above. As additives, fillers such as calcium carbonate and barium sulfate; Bubble opener; emulsifier; Anti-aging agents such as antioxidants and ultraviolet absorbers, plasticizers; coloring agent; anti-fungal agent; defoaming agent; Discoloration prevention agents, etc. can be mentioned.

Flame-retardant soft polyurethane can be produced by reacting using such raw materials.

Additionally, as a method of molding the manufactured flame-retardant soft polyurethane foam, a reaction injection molding method can be used in which the reactive mixture is directly injected into the mold using a low-pressure foamer or a high-pressure foamer. Additionally, the flame-retardant flexible polyurethane foam can be manufactured by either a cold cure method or a hot cure method. Among the above manufacturing methods, the cold cure method is preferable.

The manufacturing conditions for the flame-retardant flexible polyurethane foam are not particularly limited as long as the conditions allow for manufacturing the flexible polyurethane foam. For example, after adjusting the polyol system and the isocyanate compound, which are a mixture of all raw materials except the isocyanate compound, to 15 to 40° C., a predetermined amount of the isocyanate compound is added to the polyol system and stirred for 2 to 15 seconds using a high-speed mixer, etc. After mixing, the mixture is immediately sealed in a container heated to 30 to 80°C and cured for 4 to 20 minutes to obtain flame-retardant flexible polyurethane foam.

In addition, in order to apply the manufactured flame-retardant soft polyurethane foam as a material for automobile seats, the following physical properties are required.

The thickness of the flame-retardant soft polyurethane foam is preferably 30 mm or more when used in automobile seat cushions. This is because the feeling of sinking down is less likely to occur when the thickness is 30 mm or more.

Additionally, the core density of the flexible polyurethane foam may be 30 to 80 kg/m3, preferably 40 to 70 kg/m3. By setting the core density to 80 kg/㎥ or less, the mass of the flexible polyurethane foam does not increase, and thus physical properties suitable for application to electric vehicles requiring weight reduction can be obtained. Additionally, vibration characteristics and soundproofing effects can be improved by setting the core density to 30 kg/㎥ or more.

The core density is measured by a method based on MS 200-34. To measure core density, the skin portion (end portion) is removed from the center of the flame-retardant soft polyurethane foam and cut into pieces measuring 100 mm wide and 10 mm thick.

In addition, among the flame retardant properties of flame retardant flexible polyurethane foam, combustibility is measured by a method based on MS300-08:2020. It must be extinguished within 60 seconds without burning at a combustion speed (maximum) of 80 mm/min or less or more than 50 mm from the measurement point. The toxicity index (R) can be measured in accordance with BS 6853:1999 and should be less than 3.2. Smoke density can be measured according to ASTM E662-19, and Ds (1.5 min) and Ds (4min) should be less than 100 and 200, respectively.

The flame-retardant soft polyurethane foam of the present invention can be used for cushions, backrests, seat sheets, etc., and is especially suitable for use as seat cushions and backrests for vehicle seats such as automobiles and railways. In particular, it is lightweight and has excellent flame retardancy. Suitable for use on car seats.

Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited to these. In the raw materials used described in the examples, the degree of unsaturation of the polyol, the hydroxyl value of the polyol, and the viscosity of the polyol were measured according to the wet analysis method.

[polyether polyol (A)]

The polyether polyol (A) includes polyether polyol (A1) having a hydroxyl value of 25 to 30 mgKOH/g, polyether polyol (A2) having a hydroxyl value of 15 to 25 mgKOH/g, and polyether polyol (A2) having a hydroxyl value of 30 to 56 mg. Polyether polyol (A3) with KOH/g was used.

KE-810 (hydroxyl value 26 to 30 mgKOH/g, viscosity 1,000 to 1,300 cps (25°C), molecular weight 6,000 g/mol) was used as polyether polyol (A1), and HP-810 was used as polyether polyol (A2). 3753 (hydroxyl value 21 to 24 mg KOH/g, viscosity 1,530 to 1,730 cps (25°C), molecular weight 7,500 g/mol) was used, and FA-703 (hydroxyl value 30 to 35 mg KOH) was used as polyether polyol (A3). /g, viscosity 860 to 980 cps (25°C), molecular weight 5,200 g/mol) were used.

[Polymer polyol (B)]

It is a polyol formed by polymerizing polyether polyol by sequentially adding styrene and acrylonitrile monomers to an initiator to form SAN particles. The SAN content is 15 to 50% by mass based on 100% by mass of the total polymer polyol, and the hydroxyl value is 10 to 10%. It is 30mgKOH/g. In the examples, KE-737 (hydroxyl value 18 to 22 mgKOH/g, viscosity 6,000 to 9,000 cps (25°C), molecular weight 5,000 g/mol, solid content 45%) was used.

[Cross-linking agent]

A cross-linking agent (Green Chemicals product) with a hydroxyl value of 1068.6 mgKOH/g was used.

[Isocyanate compound]

CG-82W (TDl/MDI = 25/75 (mass ratio), NCO content (%) = 37.5, manufactured by Kumho Mitsui) was used.

[Urethanization catalyst]

33LV (Evonik) was used as a gel catalyst, and A-1 (BL-11) (Momentive) was used as a blowing catalyst.

[Food purifier]

B-8734LF2, B-8736LF2 (Evonik), and L-3002 and L-5309 (Momentive), which are general-purpose cold cure silicone foam stabilizers, were used.

[blowing agent]

Water was used as a foaming agent.

[Manufacture of flame retardant soft polyurethane foam]

For comparison by type and content of flame retardants, raw materials were mixed as shown in Table 1. The numerical values of the mixing amounts of raw materials shown in Table 1 are parts by mass.

Sample name polyol mixture flame retardant MDI PU-0 100 34 PU-Me 88 12 34 PU-MC 88 12 34 PU-TCPP 88 12 34 PU-CR 88 12 34 PU-GP 88 12 34 Me: Melamine powder (particle size < 50㎛)
MC: Melamine cyanurate (MC-110, particle size < 22㎛)
TCPP: Tris(1-chloro-2-propyl)phosphate (liquid)
CR: Phosphinyl alkyl phosphate ester (CR-530, liquid)
GP: expanded graphite (GP-120, particle size 80mesh~180㎛)

A polyol system was prepared by mixing raw materials excluding the isocyanate compound. The polyol system was filled into a foaming cup (Cup A) and the temperature of the liquid was adjusted to 25 ± 2°C. Another foaming cup was filled with an isocyanate compound (Cup B), and the temperature of the liquid was adjusted to 25 ± 2°C. Next, the raw materials of (B cup) are poured into (A cup), mixed with a high-speed rotating impeller, injected into a square mold, foamed, cured, and demolded after 320 seconds to obtain a flame-retardant soft polyurethane foam sample. did.

The discharge conditions for the raw materials were that the discharge amount was 900 to 1100 g/sec. A mold with internal dimensions of 400 × 400 × 100 mm was used, and the mold temperature was set at 60℃±2℃ for the upper and lower mold temperatures.

The samples obtained according to the type and content of flame retardants according to Table 1 were evaluated as follows.

To measure the shape of flame-retardant flexible polyurethane foam according to the type of flame retardant, it was measured using an SEM (Sigma 500, Carl-Zeiss, Jena, Germany) at an acceleration voltage of 10 kV, and the results are shown in Figure 1.

Looking at the results in Figure 1, PU-Me and PU-MC foams showed an open cell structure with uniform pore size, and maintained a similar cell structure and uniform cell size compared to pure urethane foam. The cell structure and cell size of PU-TCPP and PU-CR were larger than those of other polyurethane foams.

In addition, the density and hardness of polyurethane foam according to the type of flame retardant were measured according to the KSAE KS R 1082 test standard (sample height 96.05 mm, compression load 75% 82.20 kgf, compression load 25% 15.09 kgf). The test results are shown in Table 2.

Sample name Density (kg/㎥) Hardness (kgf) PU-0 58.6 8.8 PU-Me 66.9 18.4 PU-MC 66.7 17.9 PU-TCPP 69.6 14.2 PU-CR 68.3 11.3 PU-GP 67.1 14.6

Through the results in Table 2, it was observed that the overall density and hardness increased when flame retardants were added compared to the foam without the addition, but it was judged difficult to find a consistent trend.

Next, a vertical flame test was conducted to analyze the thermal properties of flexible polyurethane foam according to the type of flame retardant.

After cutting the specimen and placing it vertically, it was exposed to a flame for 10 seconds to check the state of the flame and the combustion state and ignition state according to the type of flame retardant. The results were as shown in Figure 2, the normal flame retardant was not added. Polyurethane foam (PU-0) burned completely after maintaining the flame for 10 seconds. However, in the case of PU-GP, the combustion speed was slower than that of the existing PU-0, but it burned completely, and in the case of PU-MC, some urethane foam burned when exposed to a flame. This melting and flowing shape was confirmed.

Next, thermogravimetric analysis (TGA) of flexible polyurethane foam samples was performed to evaluate the thermal stability of flexible polyurethane foam according to the type of flame retardant. TGA was used as Pyris TGA (Perkin-Elmer), and was measured in a nitrogen atmosphere at a temperature increase rate of 10°C/min.

The results are the same as Figure 3. In the case of PU-MC to which melamine cyanurate, a phosphorus-based flame retardant, was added, the initial decomposition temperature was 256°C and 10% of the total weight was reduced at 303°C. In the case of melamine cyanurate, it is decomposed into melamine and cyanuric acid by heat, and the melamine generated at this time was evaluated to improve flame retardancy by diluting oxygen and nitrogen gases during the combustion process. In addition, PU-GP with expanded graphite also had an initial decomposition temperature of 234°C and a 10% decrease in total weight at 297°C.

In addition, as a result of checking the reaction characteristics according to the type and content of the flame retardant, the W/R (liquid ratio of isocyanate based on polyol content) was high (principle 100/29) and a large amount of flame retardant was added, so the reactivity was low and the sample collapsed ( collapse occurred. When the content of melamine powder was 15 parts by weight, the foam was in good condition, but when the content increased to 20 parts by weight, the foam collapsed. It was evaluated that the physical properties deteriorated when the content of the flame retardant was too much or too little.

Next, an experiment was conducted to produce foam with the composition shown in Table 3, depending on the content of melamine, a flame retardant. In Table 3, the unit is parts by weight, and the liquid ratio of isocyanate to the total weight of polyol was 100/34.

ingredient Composition 1 Composition 2 Composition 3 polyetherpolyol (A1) 90 90 90 Polymer polyol (B) 10 10 10 Bubble opener (FA-103) 4 4 4 Cross-linking agent (DEOA) 0.5 0.5 0.5 Blowing catalyst (A-1(BL-11)) 0.17 0.17 0.17 Gel catalyst (33LV) 0.45 0.45 0.45 Antifoam agent (L3002) 0.7 0.7 0.7 Antifoam agent (L5309) 0.3 0.3 0.3 Flame retardant (melamine) 10 15 20 water 3.1 3.1 3.1

After preparing three compositions as shown in Table 3, they were foamed and the results shown in Table 4 were obtained.

Firing conditions Composition 1 Composition 2 Composition 3 C/T (seconds) 10 9 10 H/T (seconds) 30 30 33 R/T (seconds) 117 103 102 ST(%) 7.9 10.7 foam collapse C/T: cream time
H/T: half time
R/T: rise time
ST: settling rate (ratio of the reduced height after curing for 1 day to the maximum height of the foam after foaming)

Looking at the results in Table 4, in C/T, isocyanate and polyol react, bubbles are mixed and grow with color change, and in H/T, urea is formed by the reaction of polyol, increasing molecular weight and viscosity, and R/T. It was confirmed that cell openness and hardness increased as urethane foam cells were formed and stabilized at T. ST expressed the decrease in percentage by comparing the collapsed height after curing for one day compared to the maximum height after foaming.

In addition, to confirm flame retardant performance, we requested a certificate from FITI, a public certification body, and received a report. The flame retardant was foamed using melamine, and the results received regarding combustibility, toxicity index, and smoke density are as follows. Combustibility was measured according to MS300-08:2020, and it was judged acceptable as it had self-extinguishing properties. And the toxicity index (R) was measured in accordance with BS 6853:1999, and the results are shown in Table 5. Each measurement was performed three times and the average value was expressed.

gas composition average REFERENCE VALUE (g/㎡) r (individual toxicity index of gas) R (toxicity index) CO₂ 618.3 14000 0.044 0.08 C.O. 11.4 280 0.041 HF Not detected 4.9 - HCl Not detected 15 - HBr Not detected 20 - HCN Not detected 11 - NO₂ Not detected 7.6 - SO₂ Not detected 53 -

Additionally, smoke density was measured according to ASTM E662-19, and the results are shown in Table 6. Each measurement was performed 5 times and the average value was shown.

Test Items average Maximum specific optical density 166.7 Clear ray correction factor 10.7 Calibrated maximum specific optical density 156.0 DS (1.5 min) 17.1 DS(4 min) 58.9

In addition, in order to confirm the mechanical strength of the foam according to the type of flame retardant, foam was prepared with the composition shown in Table 7, and each sample was measured according to KSAE KS R 1082: 2014. Density and tear strength of polyurethane foam. Mechanical properties such as repeated compression strain and hardness were each measured five times and the average value was obtained. In Table 7, the unit is parts by weight.

Regarding the flexible polyurethane foam containing the above flame retardant, PU-TCPP and PU-CR are halogen-containing phosphorus flame retardants that exhibit a flame retardant effect due to the halogen and phosphorus elements inside the flame retardant, and PU-MC is a non-halogenated flame retardant that has low smoke density, It can exhibit smoke toxicity and low corrosion properties, and PU-GP can exhibit a flame retardant effect by forming an intumescent layer on the surface as expanded graphite expands to multiples of its volume when heated.

PU-Me PU-MC PU-TCPP PU-CR PU-GP polyetherpolyol (A1) 630 630 630 630 630 Polymer polyol (B) 70 70 70 70 70 Bubble opener (FA-103) 21 21 21 21 21 Cross-linking agent (DEOA) 3.5 3.5 3.5 3.5 3.5 Foaming catalyst (A-1(BL-11)) 1.2 1.2 1.2 1.2 1.2 Gel catalyst (33LV) 3.5 3.5 3.5 3.5 3.5 Antifoam agent (B-8734LF2) 4.9 4.9 4.9 4.9 4.9 Antifoam agent (B-8736LF2) 2.1 2.1 2.1 2.1 2.1 Flame retardant (melamine) 105 Flame retardant (MC) 105 Flame retardant (TCPP) 105 Flame retardant (CR) 105 Flame retardant (GP) 105 Foaming agent (water) 19.6 19.6 19.6 19.6 19.6 VOCs reducing agent (HM-B2) 10.5 10.5 10.5 10.5 10.5

The results of evaluating the physical properties of polyurethane foam according to Table 7 are shown in Table 8. In Table 8, the physical properties were measured according to KSAE KS R 1082: 2014.

Density (kg/㎥) Tear strength (kgf/cm) Repeated compression change rate (%) Hardness (kgf/314㎠) PU-Me 63.9 0.53 1.3 18.44 PU-MC 60.9 0.61 1.1 16.90 PU-TCPP 66.4 0.59 1.7 15.06 PU-CR 66.6 0.57 1.4 13.96 PU-GP 63.7 0.66 1.3 17.92

Looking at the results in Table 8, the densities of PU-TCPP and PU-CR were found to be high at 66.4 and 66.6 kg/㎥, respectively. In addition, the tear strength satisfies the standard if it is 0.5 or more based on the foam pad. For all samples, the tear strength was 0.5 kgf/cm or more, satisfying the standard. Repeated compression strain rate is an important measure of the durability of a foam pad by measuring the deformed hardness and thickness by repeatedly compressing a foam pad of a certain size. It was found to meet the standard for all samples. In addition, the tensile strength, which is the force required to tear the specimen by pulling it at a constant speed, and the elongation rate, which represents the ratio of the length stretched until the specimen breaks by pulling it at a constant speed, and the minimum specimen length, were measured, and the results are shown in Figures 4 and 5. Similarly, even when a flame retardant was added to the flexible polyurethane foam exceeding the standard value of 1.0 kg/cm2 and 100% for each foam pad, the mechanical strength did not deteriorate and good physical properties were exhibited.

Additionally, in order to confirm the effect of polyol content, samples were prepared with the composition shown in Table 9, and density and hardness were measured. The content and ratio of polyol were changed, but melamine powder was used as a flame retardant. In Table 9, the unit of content of the composition is parts by weight.

PU-Me(1) PU-Me(2) PU-Me(3) PU-Me(4) polyetherpolyol (A1) 560 595 630 665 Polymer polyol (B) 140 105 70 35 Bubble opener (FA-103) 17 18.5 21 22 Cross-linking agent (DEOA) 3.5 3.4 3.5 3.4 Foaming catalyst (A-1(BL-11)) 1.17 1.19 1.2 1.22 Gel catalyst (33LV) 3.25 3.4 3.5 3.6 Antifoam agent (B-8734LF2) 4.75 4.8 4.9 5.1 Antifoam agent (B-8736LF2) 2.35 2.2 2.1 2.1 Flame retardant (melamine) 105 105 105 105 Foaming agent (water) 19.6 19.6 19.6 19.6 VOCs reducing agent (HM-B2) 10.5 10.5 10.5 10.5 Density (kg/㎥) 63.3 63.1 63.7 63.5 Hardness (kgf) 21.8 20.4 18.5 17.3

Looking at the results in Table 9, it was confirmed that when the content and ratio of polyol were changed within a certain range, the density was similar, but the hardness value decreased as the content of polyol (KE-737) decreased.

In addition, in order to determine whether there was a change in physical properties depending on the type of polyol, samples were prepared with the composition shown in Table 10 and the physical properties of each sample were measured. In Table 10, the unit of content of the composition is parts by weight.

PU-Me(5) PU-Me(6) PU-Me(7) polyetherpolyol (A1) 630 0 0 polyetherpolyol (A2) 0 189 0 Polyetherpolyol (A3) 0 441 630 Polymer polyol (B) 70 70 70 Bubble opener (FA-103) 21 21 21 Cross-linking agent (DEOA) 3.5 3.5 3.5 Foaming catalyst (A-1(BL-11)) 1.2 1.22 1.17 Gel catalyst (33LV) 3.5 3.6 3.25 Antifoam agent (B-8734LF2) 4.9 5.0 4.73 Antifoam agent (B-8736LF2) 2.1 2.0 2.37 Flame retardant (melamine) 105 105 105 Foaming agent (water) 19.6 19.6 19.6 VOCs reducing agent (HM-B2) 10.5 10.5 10.5 Density (kg/㎥) 65.7 65.3 65.6 Hardness (kgf) 18.1 17.7 20.2 tensile strength 1.18 1.12 1.21 tear 0.55 0.57 0.53 elongation 104 110 99 Repeated compression reduction rate 1.3 1.5 1.2

Looking at the results in Table 10, it was confirmed that each physical property value was similar even if the content and ratio of polyol were changed within a certain range.

In addition, the vibration characteristics of flexible polyurethane foam according to the type of flame retardant were measured according to MS 200-34. After applying an excitation (A0) of 1 to 30 Hz using a vibrator and measuring the vibration (A) transmitted to the specimen with an accelerometer, the transfer function of A/A0 was obtained to measure the maximum vibration transmission rate and resonance frequency. The results are shown in Table 11.

vibration resonance PU-Me 3.86 3.86 PU-MC 4.19 4.75 PU-TCPP 3.86 4.75 PU-CR 3.86 4.75 PU-GP 3.86 4.75

Looking at the results in Table 11, it was confirmed that for all flexible polyurethane foam samples, the maximum vibration transmission rate or resonance frequency met the standards required for foam pads even if they contained a flame retardant.

In addition, the results of measuring the LOI values of flexible polyurethane foam samples according to the type of flame retardant are shown in Figure 6. Looking at the results in Figure 6, in the case of flexible polyurethane foam without added flame retardant, the oxygen limit index (LOI) value was only about 16, but the LOI value was measured to be high in each sample containing flame retardant. Among them, PU-Me was measured to have the highest flame retardancy with the highest oxygen limit index (LOI) value of 26.

In addition, combustion test analysis according to the type of flame retardant was conducted according to MS 300-08, and the results showed that the flame retardant effect was excellent except for PU-MC, as shown in Table 12.

Combustion speed (㎜/min) PU-Me 12/0.17 PU-MC 292/6.42 PU-TCPP 12/0.18 PU-CR 12/0.18 PU-GP 28/1.61

From these results, by applying the manufacturing method of the flexible polyurethane foam of the present invention, high dispersibility can be obtained even when using solid flame retardant particles that are considered difficult to mix and disperse the flame retardant, resulting in a decrease in the physical properties of the flexible polyurethane foam. It was found that excellent flame retardant performance could be secured without the use of

In addition, in order to obtain better dispersibility, samples were prepared with the composition shown in Table 13 and changes over time were measured to confirm the effect of the type of dispersant. The type of dispersant was changed, but melamine powder was used as a flame retardant. In Table 13, the unit of content of the composition is parts by weight.

PU-0 PU-U PU-220S PU-111 PU-180 PU-PE polyetherpolyol (A1) 630 630 630 630 630 630 Polymer polyol (B) 70 70 70 70 70 70 Bubble opener (FA-103) 21 21 21 21 21 21 Cross-linking agent (DEOA) 3.5 3.5 3.5 3.5 3.5 3.5 Foaming catalyst (A-1(BL-11)) 1.2 1.2 1.2 1.2 1.2 1.2 Gel catalyst (33LV) 3.5 3.5 3.5 3.5 3.5 3.5 Antifoam agent (B-8734LF2) 4.9 4.9 4.9 4.9 4.9 4.9 Antifoam agent (B-8736LF2) 2.1 2.1 2.1 2.1 2.1 2.1 Flame retardant (melamine) 105 105 105 105 105 105 Dispersant (ANTI-TERRA-U) 7 Dispersant (BYK-220S) 7 Dispersant (DISPERBYK-111) 7 Dispersant (DISPERBYK-111) 7 Dispersant (PE40) 7 Foaming agent (water) 19.6 19.6 19.6 19.6 19.6 19.6 VOCs reducing agent (HM-B2) 10.5 10.5 10.5 10.5 10.5 10.5

As a result, as shown in Table 14, it was found to have better dispersibility for one type of dispersant. In Table 14, the height of the composition is the percentage change in scale height after precipitation compared to the initial scale height of a 250 ml mass cylinder.

Rate of change (%) after 12hr Rate of change (%) after 36hr Rate of change (%) after 60hr PU-0 Almost none 35 43 PU-U Almost none 36 60 PU-220S Almost none 27 46 PU-111 Almost none 43 56 PU-180 Almost none 33 55 PU-PE Almost none 23 30

As shown in Figure 7, this result confirms higher dispersibility for type 1 dispersant (PE).

In addition, in order to maintain excellent physical properties, a cup foaming experiment was conducted according to the type of dispersant, and the results showed that one type of dispersant had excellent foaming performance as shown in Table 15.

Viscosity(P) Rise time(s) Settling(%) PU-0 21.4 93 7.5 PU-U 25.9 113 4 PU-220S 25.3 110 16.3 PU-111 19.3 254 collapse PU-180 23.7 108 collapse PU-PE 21.9 81 8.3

In addition, as shown in Figure 8, when the manufacturing method of the flexible polyurethane foam of the present invention is applied using Evonik's PE, it was found that excellent dispersibility can be secured while having a stable settling value after foaming the cup.

The rights of the present invention are not limited to the embodiments described above but are defined by the claims, and those skilled in the art can make various changes and modifications within the scope of the claims. This is self-evident.

Claims (5)

A method for producing flame-retardant flexible polyurethane foam comprising reacting a polyol mixture and an isocyanate compound,
The polyol mixture includes a polyether polyol (A) with a hydroxyl value of 15 to 56 mgKOH/g, a polymer polyol (B) with a hydroxyl value of 10 to 30 mgKOH/g, solid flame retardant particles, a dispersant, a foaming agent, a foam stabilizer, and A method for producing flame-retardant flexible polyurethane foam, characterized by mixing a catalyst.
In claim 1,
The polyether polyol (A) is a polyether polyol (A1) having a hydroxyl value of 25 to 30 mgKOH/g, a polyether polyol (A2) having a hydroxyl value of 15 to 25 mgKOH/g, and a hydroxyl value of 30 to 56. Any one selected from mgKOH/g polyether polyol (A3) or a mixture thereof,
A method of producing a flame-retardant flexible polyurethane foam, characterized in that the polymer polyol (B) contains 15 to 50% by mass of styrene-acrylonitrile copolymer (SAN) based on 100% by mass of polyether polyol.
In claim 1,
The content of the polyether polyol (A) is 50 to 95% by mass based on the total mass of the polyether polyol (A) and the polymer polyol (B), and the content of the polymer polyol (B) is the polyether polyol (A) and A method for producing a flame-retardant flexible polyurethane foam, characterized in that 5 to 50% by mass of the polymer polyol (B) based on the total mass.
In claim 1,
The polyol mixture includes at least one crosslinking agent selected from compounds having two or more active hydrogens such as hydroxyl group, primary amino group, secondary amino group, etc.
A method for producing flame-retardant flexible polyurethane foam, characterized in that it additionally contains at least one dispersant selected from fatty acid-based, phosphorus-based, and acidic group-containing polyester.
In claim 1,
A method of manufacturing flame-retardant soft polyurethane foam, wherein the soft polyurethane foam is mold foam or slab foam.