KR20040052177A - Manufacturing method of the non -flammable polyurethane foam - Google Patents

Abstract

PURPOSE: A method for preparing a polyurethane foam for a non-flammable(KSF 2271) panel is provided, to improve adhesive strength to metal and productivity. CONSTITUTION: The method comprises the steps of reacting a resin premix comprising 55-78 wt% of a mixed polyol which comprises 25-75 wt% of a polyester polyol and 25-75 wt% of a polyether polyol having a OH value of 200-300 mg KOH/g and has a OH value of 250-350 mg KOH/g; 0.5-3.0 wt% of a urethane reactive catalyst; 5-10 wt% of a flame retardant; 0.5-2.0 wt% of a silicone surfactant; 1.0-3.0 wt% of a trimerization catalyst; 15-25 wt% of a foaming agent; and 0-2 wt% of water, with polyisocyanate within an isocyanate index of 2.5-3.5. Preferably the polyisocyanate is polymethylene diphenyl diisocyanate or an isocyanate obtained by modifying polymethylene diphenyl diisocyanate with an aliphatic or aromatic polyalkylene oxide, and the content of isocyanate groups is 30-32 wt%.

Description

Manufacturing method of polyurethane foam for flame retardant grade 3 panel {Manufacturing method of the non -flammable polyurethane foam}

The present invention relates to a method for producing a flame retardant polyurethane foam used as a heat insulating material of a building urethane panel.

Building panels with synthetic resin foam insulation are widely used in prefabricated factories, warehouses, and office buildings. The foam of the panel which uses a synthetic resin foam as a heat insulating material includes polystyrene foam (aka: Styropol), polyurethane foam and the like depending on the composition of the raw material. Polyurethane panels are manufactured by injecting and foaming foamed urethane resin into the inner wall and foaming urethane resin inside. In case of a fire, the internal polyurethane foam is burned and toxic gas is generated. It is becoming.

The standards for flame retardant materials in the Building Act are as follows. In Article 2 (1) 9 of the Enforcement Decree of the Building Act, the term "flame retardant material" refers to a material that is incombustible to fire and conforms to a material prescribed by Ordinance of the Ministry of Construction and Transportation. In Article 5 of the Regulation on the Standards of the Ministry of Construction and Transportation, Article 5 of the Construction and Transportation Decree, "materials conforming to the standards set by the Construction and Transportation Decree in Article 2 of the Building Act" were tested in accordance with the Korean Industrial Standards under the Industrial Standardization Act. The result corresponds to Class 3 flame retardant. 'And KSF 2271 (Test method for flame retardancy of interior materials and structures of building) specifies the test method for class 3 flame retardant.

The present invention relates to a process for producing rigid polyurethane foams used to produce panels exhibiting flame retardant class 3 performance as defined in KSF 2271. In general, polyurethane foams having flame retardant properties are prepared by mixing polyether and ester polyols and reacting resin premixes using flame retardants, foam stabilizers, tertiary amine catalysts, water and blowing agents with polyisocyanates. Polyurethane is a high molecular material obtained by reacting a polyol and an isocyanate compound using a tertiary amine catalyst. Polyurethane is a urethane bond ( The tertiary amine catalyst used here is called a urethane catalyst or a resination catalyst.

Isocyanate in the raw material for polyurethane production is a dimer and a monomer in combination with each other.

Two isocyanate groups bonded in the molecular structure ) Is called a dimer and isocyanate groups are bonded together to form a trimerization structure ( ) Is called a trimer. Isomerization bond structure means an isocyanurate group.

The catalyst used when preparing the trimer is called a trimerization catalyst.

In order to improve the flame retardancy in the production of polyurethane foam in the prior art, the use of aromatic polyester polyols within about 20% and the introduction of thermally stable isocyanurate bonds in the polyurethane bond structure have been continuously developed. No specific study has been made on the isocyanate index range for forming cyanurate bonds, and no polyurethane foams have been produced for the production of flame retardant grade 3 panels. Isocyanate index is an index that represents the ratio of the input amount of isocyanate and resin polymix when the polyol and isocyanate is reacted to make polyurethane. When the isocyanate is added in the same amount as stoichiometry, this index is 1 The polyisocyanate index is said to be greater than 1 when overinjected beyond the stoichiometric input. It is known that the more the bond structure in which the hexagonal ring shape such as the benzene bond structure or the isocyanurate bond structure is formed in the polyurethane bond structure, the higher the stability against heat and the generation of harmful gases during combustion are also suppressed. In addition, in order to form isocyanurate, it is necessary to use a catalyst suitable for this. Conventionally, a urethane catalyst such as a tertiary amine catalyst is used. In this case, the curing time of the polyurethane foam is late, there is a problem that the productivity is lowered and the adhesive strength with the iron plate is lowered. The less isocyanurate group in Intex 2.5 or less in the polyurethane structure is excellent in adhesion to the iron plate, but inferior in the flame retardant grade, the core of the problem. In addition, when the index is 3.5 or more, the isocyanurate group becomes high, resulting in a decrease in adhesive strength with the metal shell, dimensional stability, and unfilling due to a decrease in flowability of the stock solution.

Accordingly, in order to develop a polyurethane foam having excellent adhesion to a metal shell and excellent productivity while maintaining excellent flame retardancy, it is desired to contain isocyanurate at an index of 2.5 to 3.5.

Metal and polyurethane foam and adhesive strength is aimed at the flame retardancy that is carried out outside the urethane foam, not inside the urethane foam, and when the index is increased, the unreacted isocyanate remains on the surface and the surface becomes sticky. You cannot maintain productivity. In order to solve this problem, an index range with flame retardancy and no influence on adhesion and physical properties was set, and an appropriate trimerization catalyst was selected.

The object of the present invention is KSF. It is to provide a method for producing a polyurethane foam having a flame retardant class 3 flame retardancy specified in 2271 and can be applied to the existing production process of the panel as it is. In order to apply the invention to the field, if additional equipment is required, the economic burden is applied, so the invention was carried out from the user's standpoint. In the method for producing a polyurethane foam for flame-retardant grade 3 panel, the inventors use more than 30wt% of polyester polyol, the isocyanate index (Isocyanato Indes) ranges from 2.5 to 3.5, and uses tertiary amine catalyst and trimerization catalyst. The present invention was completed by confirming that the polyurethane foam for flame retardant grade 3 panel having excellent flame retardancy and productivity without using a flame retardant was added by preparing a polyurethane foam.

The present invention relates to a method for producing a polyurethane foam having excellent flame retardancy of the flame retardant class 3 as defined in KSF 2271 and excellent in adhesiveness and productivity with a foam panel steel sheet.

In the production of polyurethane foam used as a heat insulating material for building urethane panels, the more the polyester polyol and the trimerization catalyst is used, the more heat resistance is increased. By selecting the appropriate resin premix composition and adjusting the isocyanate index range appropriately to prepare a polyurethane foam, to provide a method for producing a urethane foam that does not degrade physical properties such as adhesion or deforming with the iron plate while maintaining sufficient heat resistance. It is.

The resin premixes used in the present invention are from 25 to 70% by weight of a polyester polyol having a hydroxyl value of 200 to 300 mgKOH / g obtained from ester compounds such as phthalic ester and terephthalic acid, and polyhydric alcohols such as ethylene glycol, glycerin, sorbitol, and sugar. 25 to 75% by weight of the polyether polyol thus prepared is mixed to form a mixed polyol, and the mixed polyol is characterized in that the number of functional groups is 2 to 5, and the average hydroxyl value is 250 to 350 mgKOH / g. 55-78 weight% of this mixed polyol, 5-10 weight% of flame retardants, 0.5-3.0 weight% of tertiary amine catalysts, 0.5-2.0 weight% of silicone foaming agents, 1.0-3.0 weight% of trimerization catalysts, 15-25 weight% of foaming agents The present invention relates to a method for preparing a rigid polyurethane foam in which a resin premix of 0 to 2.0 wt% of water is prepared and the resin premix is adjusted to a polyisocyanate by adjusting the polyisocyanate index to 2.5 to 3.5.

In the present invention, in order to increase the stability to heat, the polyester polyol used an aromatic polyester polyol having phthalic ester and terephthalic acid having a relatively stable binding force as a starting material. In addition, a trimerization catalyst was used to introduce an isocyanurate group which is very resistant to heat resistance in the bonding structure of the urethane foam, and the isocyanate index was adjusted to 2.5 to 3.5, which is 2-3 times higher than a conventional hard urethane.

In the present invention, two or more kinds of hard polyether polyols having 2 to 5 functional groups, which are generally used as raw materials for hard urethane foam for panels, are used by mixing two or more kinds thereof. Here, terephthalic acid and phthalic acid are used as initiators. The flame retardance was improved by introducing a benzene ring structure using a polyester polyol obtained by dehydrating and condensing butanediol or ethylene glycol, and using a certain amount of metal trimerization catalyst to improve the flame retardancy of the foam. This is because the metal trimerization catalyst forms a hexagonal ring shape in the bonding structure of the foam to form isocyanurate which has a strong bonding force. Such a shape has excellent thermal stability and greatly affects the generation of harmful gases during combustion. .

The polyol constituting such a resin premix has a problem in that the flame retardancy of the manufactured polyurethane foam is very poor when the mixing ratio of the polyester polyol is less than 25%, and the viscosity of the mixed polyol when the polyester polyol is 70% or more. The increase in flow rate worsens and the bonding structure is changed, which causes problems of deterioration in the numerical stability, hardness and moldability, deforming and mechanical strength of the polyurethane foam.

Catalysts used in the production of urethane foam in the present invention was applied in two types. First, an amine catalyst commonly used as a resination catalyst was used when preparing a rigid polyurethane foam. For example triethylamine (TEA), triethylenediamine (TEDA), pentamethylenediethylene triamine (PMDETA, Pentametylenediethylene triamine), dimethylcyclohexyl amine (DMCHA), tetramethylene-hexyl One or more selected from catalysts such as diamine (TMHDA, TetraMethhyl-n-HexylDiAmine) may be used in combination. It is preferable that such a catalyst is contained in the total resin premix at 0.5 to 3% by weight. If the content is less than 0.5% by weight, the reaction is delayed, resulting in poor curing and poor productivity and quality, and the weight of the amine catalyst is 3.0. If the weight percentage is exceeded, the reaction is rapid, resulting in unfilled and cracked foam, resulting in product defects.

Second is to use an organometallic trimerization catalyst which allows isocyanurate functional groups to be formed rather than urethane functional groups within the rigid polyurethane foam, and potassium otoate may be representatively used. The catalyst is preferably contained in 1.0% to 3.0% by weight of the total resin premix. If the content is less than 1.0% by weight, the isocyanurate formation is insufficient to strengthen the bonding strength, resulting in poor deforming of the foam and 3.0% by weight. If exceeded, the internal reaction heat of the foam may increase, and a phenomenon may occur, and an excessive isocyanurate group may be formed to deteriorate the foam mechanical properties, appearance, and feel.

Silicone foam stabilizers can be used for the production of rigid polyurethane foam for panels in general, it is preferable to contain 0.5 to 2.0% by weight in the total resin premix.

In order to enhance the flame retardancy in the present invention, the organophosphorus flame retardant generally used in the rigid urethane foam composition was used in an amount of 5 to 10% by weight based on the total resin premix. This not only improves flame retardancy, but also lowers the viscosity of the resin premix to induce a smooth flow of the liquid and prevents the phenomenon of mixing that normally occurs when reacting excess isocyanate. The organophosphorus flame retardant used at this time is trischloro-isopropyl phosphate [Tris (chloro-isopropyl) phoshate] is typical. As the blowing agent, it is preferable to use dichlorofluoroethane and water which are commonly used in this field at the same time, and the blowing agent may contain 15 to 25% by weight of water and 0 to 2% by weight of the total resin premix.

In the present invention, the polyisocyanate having a content of 30 to 32 wt% of the resin premix and the isocyanate group as described above may be adjusted to an isocyanate index of 2.5 to 3.5 to prepare a rigid polyurethane foam for a panel. However, the isocyanate index is best from 2.7 to 3.1. The isocyanate index plays a very important role here. If the isocyanate index is 2.5 or less, the flame retardancy tends to be poor, and when the index is 3.5 or more, the curing of the foam is slowed down, the productivity is lowered, and the friability of the foam is increased.

The present invention will be described in detail with reference to the following Examples. However, the present invention is not limited only to the examples.

Examples 1-4

As the polyisocyanate, an isocyanate group content of 31.2 wt% and a viscosity of 195 cps / 25 ° C were used. And resin premix was prepared by mixing to the composition shown in Table 1. Then calculate the weight ratio so that the index of resin premix and polyisocyanate adjusted to 20 ± 1 ℃ is 3.0g, mix to make a total of 400g and stir vigorously for 7 seconds, and then inject into a 200 × 200 × 200mm wooden box The appearance and feel of the foam were confirmed, and the mixed stock solution was injected into a 900 × 210 × 50 mm aluminum mold to form a polyurethane foam, and the strength, thermal conductivity, and dimensional stability were measured on the following day, and the results are shown in Table 1 below.

The flame retardance was evaluated by measuring the flame retardant performance after filling the foam by filling the foam material on one side of the box by manufacturing a box with a 0.5 mm thick iron plate to produce a specimen of 220 × 220 × 40 mm, the size prescribed by KSF 2271. As a result of measuring the physical properties while changing the compounding amount of the polyol in the resin premix composition, it was found that increasing the amount of the polyester polyol increased flame retardancy and thermal conductivity while decreasing the dimensional change rate and the strength.

Landscape and water castle Example One 2 3 4 Resin premix prescription ¹⁾ (by weight) Polyol A 75 60 45 30 Polyol B 25 40 55 70 Flame retardant 10 10 10 10 Defoamer 1.5 1.5 1.5 1.5 Catalyst-1 0.2 0.2 0.2 0.2 Catalyst-2 1.5 1.4 1.3 1.2 Catalyst-3 2.2 2.2 2.2 2.2 water 0.5 0.5 0.5 0.5 Physical blowing agent 28 28 28 28 Isocyanate (parts by weight) M-200 236 236 236 236 Strength ²⁾ (Bending kgf / ㎠) (Compression kgf / ㎠) 4.81.6 4.81.6 4.71.5 4.61.5 Thermal Conductivity ³⁾ (Kcal / mhr ℃) 164 165 165 166 Flame retardant ⁴⁾ pass pass pass pass Dimensional stability ⁵⁾ (Vol%) High temperature (70 ℃) Low temperature (-20 ℃) High humidity (70 ℃, 95Rh) 0.16-0.532.88 0.18-0.583.21 0.26-0.613.43 0.45-0.653.71 1) Resin premix prescription-Polyol A: Mixed polyol-polyol B: terephthalic, adjusted to an average hydroxyl value of 300 mgKOH / g by mixing three kinds of polyether polyols prepared by addition polymerization of propylene oxide to sugar, glycerin and sorbitol Polyester polyol obtained by condensation of acid, OHv 250 mg KOH / g-flame retardant: Tris (chloroisopropyl) phosphate-catalyst-1: mixed amine catalyst (Toyocat TMF, Tosoh) -catalyst-2: dimethylcyclohexylamine (DMCHA)- Catalyst-3: trimerization catalyst, potassium octoate-foaming agent: dichloro-1-fluoroethane (HCFC-141b) 2) Compressive strength: ASTM D-1621, JIS A-9514, KS M- 3809 Flexural Strength: ASTM D-490, JIS A-9514, KS M-38093) Thermal Conductivity Evaluation Method: ASTMD-1621, A-9514, KS M-38094) Flame Retardancy Evaluation Method: KSF 2271 Surface Test, Gas Hazard test 5) Evaluation method for dimensional stability: ASTM D-2126, Unit:% Dimensional stability Method * Low temperature stability: -30 ℃, volume change measurement after 24 hours * High temperature stability: 70 ℃, volume change measurement after 24 hours * High temperature and high humidity stability: Relative humidity 95%, 70 ℃, volume change rate after 24 hours = (V2-V1) / V1 V1 = volume before change, V2 = volume after change

Examples 5-8

As the isocyanate, an isocyanate group content of 31.2 wt% and a viscosity of 205 cps / 25 ° C were used. And resin premix was prepared by mixing to the composition shown in Table 2. The experiment was conducted under the same conditions as in Examples 1 to 4, and the results are shown in Table 2 below.

As a result of measuring the physical properties by changing the amount of the trimerization catalyst in the resin premix composition, the strength, flame retardancy, thermal conductivity, and dimensional stability are all improved as the trimerization catalyst is increased, but the reactivity is faster. It can be seen that there is a problem that a product defect occurs.

Landscape and water castle Example 5 6 7 8 Resin premix prescription ¹⁾ (by weight) Polyol A 60 60 60 60 Polyol B 40 40 40 40 Flame retardant 10 10 10 10 Defoamer 1.5 1.5 1.5 1.5 Catalyst-1 0.2 0.2 0.2 0.2 Catalyst-2 1.5 1.4 1.3 1.2 Catalyst-3 2.2 2.4 2.6 2.8 water 0.5 0.5 0.5 0.5 Physical blowing agent 28 28 28 28 Isocyanate (parts by weight) M-200 237 237 237 237 Strength ²⁾ (Bending kgf / ㎠) (Compression kgf / ㎠) 4.81.6 4.81.6 4.91.7 4.91.7 Thermal Conductivity ³⁾ (Kcal / mhr ℃) 164 165 165 166 Flame retardant ⁴⁾ pass pass pass pass Dimensional stability ⁵⁾ (Vol%) High temperature (70 ℃) Low temperature (-20 ℃) High humidity (70 ℃, 95Rh) 0.46-0.532.88 0.38-0.432.76 0.32-0.412.56 0.28-0.392.43 1), 2), 3), 4), 5) Resin premix raw materials and physical property measurement methods are the same as in Examples 1-4.

Examples 9-12

Resin premix was prepared by mixing the mixed polyol, monool, water, catalyst, and silicon foam stabilizer in the composition shown in Table 3 below. By adjusting the isocyanate index from 2.5 to 3.5, the rigid polyurethane foam was molded in the same manner as in Examples 1 to 4, and the thermal conductivity, dimensional stability, compression, bending strength, and density were measured on the following day, and the results are shown in Table 3 below. It was. Increasing the isocyanate index slowed the reaction slightly and resulted in molding with increasing catalyst. Experimental results show that increasing the isocyanate index increases flame retardancy, and improves the strength, dimensional stability, and thermal conductivity, but the color of the foam becomes darker and becomes more brittle.

Landscape and water castle Example 9 10 11 12 Resin premix prescription (part by weight) Polyol A 60 60 60 60 Polyol B 40 40 40 40 Flame retardant 10 10 10 10 Defoamer 1.5 1.5 1.5 1.5 Catalyst-1 0.2 0.2 0.2 0.2 Catalyst-2 1.5 1.5 1.5 1.5 Catalyst-3 2.2 2.2 2.2 2.2 water 0.5 0.5 0.5 0.5 Physical blowing agent 28 28 28 28 Isocyanate (parts by weight) M-200 158 198 237 277 Strength ¹⁾ (Bending kgf / ㎠) (Compression kgf / ㎠) 4.61.4 4.71.5 4.81.6 4.91.6 Thermal Conductivity ²⁾ (Kcal / mhr ℃) 164 164 164 164 Flame retardant ³⁾ pass pass pass pass Dimensional stability ⁴⁾ (Vol%) High temperature (70 ℃) Low temperature (-20 ℃) High humidity (70 ℃, 95Rh) 0.85-0.933.21 0.32-0.753.15 0.28-0.452.78 0.23-0.432.45 1), 2), 3), 4), 5) Resin premix raw materials and physical property measurement methods are the same as in Examples 1-4.

The flame-retardant rigid polyurethane foam produced by the method of the present invention has the effect of satisfying the flame retardancy of the flame retardant class 3 specified in KSF 2271 while excellent in adhesion and productivity with the metal shell.

Claims (2)

In the method for producing a flame retardant polyurethane foam, 55 to 78 weight percent of a mixed polyol having a hydroxyl value of 250 to 350 mg KOH / g, by mixing 25 to 75 weight percent of a polyester polyol having a hydroxyl value of 200 to 300 mg KOH / g and 75 to 25 weight percent of a polyether polyol. -0.5 to 3.0 wt% urethane reaction catalyst -5 to 10% by weight of flame retardant -0.5 to 2.0 wt% of silicone foam stabilizer 1.0-3.0 wt% of trimerization catalyst 15-25 wt% of blowing agent 0 to 2% by weight of water A method for producing a flame retardant polyurethane foam in which a resin premix and a polyisocyanate prepared in an isocyanate index range from 2.5 to 3.5. The polyisocyanate according to claim 1, wherein the polyisocyanate is an isocyanate obtained by modifying a polymethylenediphenyl diisocyanate or a polymethylenediphenyl diisocyanate with an aliphatic or aromatic polyalkylene oxide, and the content of these isocyanate groups is 30 to 32% by weight. Process for the preparation of polyurethane foams.