HK1254539A1 - Foaming refractory coating composition - Google Patents

Abstract

The present invention relates to a foaming refractory coating composition comprising an epoxy resin, a cured resin, a flame retardant, a foaming agent, an acid catalyst and a fiber, especially the use of a flame retardant with a content of triphenyl phosphate being lower than 20 wt.-% and a thermal decomposition temperature being higher than 250℃, such that gas harmfulness is reduced. An intumescent layer is endowed with flexibility to prevent the occurrence of cracks in the carbonizing layer, thus improving fire resistance performance in the long term.

Description

Foamable fire-resistant coating composition

Technical Field

The present invention relates to a foamable fire-resistant coating composition.

Background

Oil fires occurring in marine structures, workshops, etc. have the characteristic that the temperature rises sharply to about 945 ℃ within 5 minutes during the fire. As a fire-resistant coating material in a field where oil fire may occur, a curable epoxy fire-resistant coating material is mainly used, but the conventional fire-resistant coating material has a disadvantage that a large amount of harmful gas is released when a coating film swells.

The following three U.S. patents are recent technologies that have become epoxy based fire resistant coatings.

The solventless epoxy fire-resistant coating material proposed in U.S. Pat. No. 4,529,467 suggests that in case of fire, when the coating material expands, zinc (Zn) forms a foamed layer having small pores during scorching, and the formed foamed layer can improve heat-insulating properties and adhesion to a substrate. However, if zinc is used excessively, the coating film cannot swell, and the heat insulating performance may be deteriorated.

In U.S. Pat. No. 5,108,832, an epoxy resin having excellent flexibility is synthesized, and an epoxy fire-resistant coating having excellent flexibility is proposed. In the U.S. patent, an epoxy resin is synthesized using an epoxy monomer having a chain structure, and a fire-resistant coating is prepared using the same, and the bending property is predicted by a low-temperature cycle test.

In U.S. Pat. No. 6,096,812, it is proposed that the density of a coating film to be coated is reduced by using hydrophobic fumed silica (fumeidisica), whereby the amount of the coating material used can be reduced while ensuring the fire resistance.

These U.S. patents all disclose the foaming mechanism of fire resistant coatings using boric acid and ammonium polyphosphate. Boric acid undergoes a dehydration reaction at around 170 c and releases a gas which can cause the coating film to swell. However, these foaming mechanisms have a problem that harmful gas is released during foaming.

On the other hand, in U.S. Pat. No. 1997-999536, there is disclosed a fire-resistant coating paint which can reduce the amount of paint used and exert fire-resistant properties by using hydrophobic fumed silica based on an epoxy resin, and thus can reduce the density of the coated film. However, the phosphorus-based flame retardant used in the above invention has a TPP (Triphenylphosphate) content of 21 wt% or more and a thermal decomposition temperature of less than 250 ℃, and TPP vaporizes at a lower temperature than an epoxy resin cured with a low-molecular substance, and thus, although initial foaming is improved, when the TPP content is large, gas harmfulness increases, and the long-term flame resistance is lowered.

Therefore, there is still a demand for a foamable fire resistant coating composition capable of saving the TPP content of the phosphorus-based flame retardant to reduce the gas harmfulness and improve the long-term fire resistance.

Disclosure of Invention

Technical problem

The present invention has been made in an effort to provide a foamable fire-resistant coating composition including an epoxy resin, a cured resin, a flame retardant, a foaming agent, an acid catalyst, and fibers, and particularly, a flame retardant having a triphenyl phosphate content of 20 wt% or less and a thermal decomposition temperature of 250 ℃ or more is used to reduce gas harm, impart Flexibility (flexibilitity) to a foamed layer, and prevent cracks from occurring in a carbonized layer, thereby improving long-term fire resistance.

Technical scheme

The foamable fire-resistant coating composition comprises 10-25 wt% of epoxy resin, 10-15 wt% of cured resin, 10-20 wt% of flame retardant, 3-10 wt% of foaming agent, 20-40 wt% of acid catalyst and 3-10 wt% of fiber, wherein the flame retardant is a flame retardant with triphenyl phosphate content of less than 20 wt% and thermal decomposition temperature of more than 250 ℃, based on the total 100 wt%.

Effects of the invention

The foamable fire-resistant coating composition of the present invention has a low TPP content, so that the gas harmfulness is reduced, and the thermal decomposition temperature is 250 ℃ or higher, so that flexibility is imparted to the foamed layer, and cracks are prevented from occurring in the carbonized layer, so that the long-term fire resistance can be improved. The gas harmfulness is 12 minutes or more as measured by the gas harmfulness test method (KSF 2271), and the fire resistance is 3 hours or more as measured by the fire resistance test method (UL1709) even without using a separate reinforcing material (mesh).

Detailed Description

The present invention is described in more detail below.

The foamable fire-resistant coating composition comprises 10-25 wt% of epoxy resin, 10-15 wt% of cured resin, 10-20 wt% of flame retardant, 3-10 wt% of foaming agent, 20-40 wt% of acid catalyst and 3-10 wt% of fiber, wherein the content of triphenyl phosphate in the flame retardant is less than 20 wt%, and the thermal decomposition temperature is more than 250 ℃, based on the total 100 wt%.

The epoxy resin used in the composition of the present invention allows the coating film to adhere to an object to be coated, and the cured coating film exhibits durability at room temperature. In addition, in case of fire, when the coating film is changed into a fluid state by exposure to high-temperature heat and gas is generated, the coating film can be appropriately expanded to exhibit a skeleton function of the foamed carbonized layer.

As such an epoxy resin, a bisphenol a type epoxy resin, a bisphenol F type epoxy resin, a flame retardant epoxy resin, a novolac type (novolak) epoxy resin, a polyfunctional amine epoxy resin, and an alicyclic epoxy resin can be used, and preferably, at least one selected from the bisphenol a type epoxy resin and the bisphenol F type epoxy resin can be used.

The epoxy resin has a weight average molecular weight of 150 to 900, preferably, may be 200 to 800, and an equivalent weight of 75 to 450g/eq, preferably, may be 100 to 400 g/eq.

The foamable fire-resistant coating composition of the present invention may contain the epoxy resin in an amount of 10 to 25% by weight, for example, 15 to 23% by weight. If the amount is less than 10% by weight, the adhesion of the coating film is lowered due to the insufficient resin content, and if the amount is more than 25% by weight, the foaming ratio of the coating film is hindered during a fire, and sufficient fire resistance performance cannot be exhibited.

The curing resin used in the composition of the present invention is used for curing an epoxy resin. Although not particularly limited, as the curing resin, an amide or an aminoamine resin having a viscosity of 200cps to 800cps, an amine value of 300KOH/g to 600mgKOH/g, an active hydrogen equivalent of 50g/eq to 200g/eq, and obtained by polymerizing polyvinylamine, a fatty acid dimer, and a fatty acid monomer, may be used.

The synthesis of the corresponding resin is as follows. Firstly, heating a mixture of polyvinylamine, fatty acid dimer and fatty acid monomer to 200 ℃ to carry out polycondensation reaction until the acid value of the corresponding reactant reaches 1-5. Preferably, in this step, the reaction is carried out so that the molar ratio of amine/acid is 1.2 to 2.0, but when the molar ratio is less than 1.2, the viscosity is high and the application of the coating is difficult, and when it is 2.0 or more, unreacted amine is present and it is difficult to exhibit desired physical properties when the coating is applied.

More specifically, one or a mixture of ethylenediamine, diethylenetriamine, triethylenetetramine and tetraethylenepentamine can be used as the polyvinylamine, and one or a mixture of two or more selected from among fatty acid dimer and monomer prepared from the group consisting of soybean oil fatty acid, tall oil fatty acid, castor oil fatty acid, rice bran oil fatty acid, linseed oil, coconut oil fatty acid, lauric acid and linoleic acid can be used as the fatty acid dimer and monomer, and preferably, tall oil fatty acid monomer and dimer can be used.

If the acid value of the corresponding reactant is 1 to 5 or less, the heating is terminated, and the resulting amide or amidoamine resin (amidoamine resin) can be obtained, preferably, the obtained resin has a viscosity of 200cps to 800cps, an amine value of 300KOH/g to 600mgKOH/g, an active hydrogen equivalent of 50g/eq to 200g/eq, and the curability can be maximized within the physical property range.

The foamable fire resistant coating composition of the present invention comprises the cured resin 10 to 15% by weight, for example, may comprise 11 to 14% by weight. When the content is less than 10% by weight, the content of the cured resin is small and the adhesion of the coating film is deteriorated, and when the content exceeds 15% by weight, the content of the cured resin is large and a coating film defect such as amine blushing occurs.

The phosphorus-based flame retardant used in the composition of the present invention plays a role in adjusting the thermal decomposition rate of the cured coating film to impart flexibility to the early foamed carbonized layer. The phosphorus flame retardant used in the conventional foamable fire-resistant coating composition had a TPP (Triphenyl phosphate) content of 21 wt% and a thermal decomposition temperature of less than 250 ℃. When such a phosphorus flame retardant is used, TPP is gasified at a lower temperature than an epoxy resin cured with a low molecular weight substance to improve early foaming, but when the content of TPP is large, there is a problem that gas harmfulness increases and long-term flame resistance is reduced. Therefore, in the present invention, the amount of the phosphorus flame retardant is reduced to half of the amount used in the conventional case, and the TPP content is reduced, whereby the gas harmful effect can be reduced. In addition, the use of an additional phosphorus-based flame retardant having a thermal decomposition temperature of 250 ℃ or higher (i.e., a heating loss of less than 5% at 250 ℃) slows down the thermal decomposition rate of the cured coating film, imparts flexibility to the foamed layer, prevents cracking (crack) in the carbonized layer, and ensures long-term flame resistance without using a reinforcing material (Mesh).

The phosphorus-based flame retardant contained in the foamable flame-retardant coating composition of the present invention may be a flame retardant having a triphenyl phosphate (TPP) content of 20 wt% or less and a thermal decomposition temperature of 250 ℃ or higher (i.e., a heating loss at 250 ℃ of less than 5%).

More specifically, the phosphorus-based flame retardant used in the present invention may be at least one selected from triphenyl phosphate (TPP), isopropylated triphenyl phosphate (isopropylated triphenyl phosphate), tricresyl phosphate (tricresyl phosphate), butylated triphenyl phosphate (butylated triphenyl phosphate), cresyldiphenyl phosphate (cresyldiphenyl phosphate), isopropylphenyl diphenyl phosphate (isopropylphenyl diphenylphosphate), and other aryl phosphates, and diphosphates such as resorcinol bis (diphenyl phosphate) (RDP), bisphenol a bis (diphenyl phosphate) (bisphenol-abis (diphenoxyphosphate)) (BDP).

In one specific example, as the aryl phosphate, isopropylated triphenyl phosphate having a TPP content of 5% to 10% may be used, and as the diphosphate, RDP (Resorcinol bis (diphenyl phosphate)) or BDP (Bisphenol-a bis (diphenyl phosphate)) having a TPP content of less than 5% may be used.

Preferably, the aromatic phosphate and the diphosphate may be mixed in a weight ratio of 1:0.5 to 1:3, preferably 1:0.5 to 1:1.5, but not limited thereto.

The foamable fire resistant coating composition of the present invention comprises 10 to 20% by weight of flame retardant, for example, may comprise 13 to 18% by weight. When the amount is less than 10% by weight, the flame retardancy of the coating film is insufficient and the coating film burns satisfactorily, so that the flame retardancy cannot be sufficiently exhibited. When the content exceeds 20% by weight, the melt viscosity of the coating film decreases, and the excessively foamed carbonized layer is easily broken, whereby the heat insulating property cannot be exhibited, and the TPP content increases, so that the gas harmful effect and the flame resistance cannot be secured at desired levels.

The foaming agent used in the composition of the present invention is decomposed to generate a large amount of gas at a time point when the cured coating film is softened/liquefied by being exposed to heat of high temperature and a carbonized layer is generated, and thus the carbonized layer has a fine cell layer to be expanded (foamed), thereby performing an effect of having heat insulating properties. Although not particularly limited, as the foaming agent, a foaming agent selected from the group consisting of melamine, urea, glycine, and a combination thereof may be used.

The foamable fire resistant coating composition of the present invention includes 3 to 10% by weight of a foaming agent, and may include 5 to 10% by weight, for example. When the content is less than 3% by weight, the coating material cannot be expanded to deteriorate the heat insulating property, and when the content exceeds 10% by weight, the coating material is excessively expanded to cause cracks in the carbonized layer, resulting in a decrease in strength and a deterioration in the heat insulating property.

The acid catalyst used in the composition of the present invention is decomposed at the time point when the cured coating film is softened by exposure to high-temperature heat to promote the formation of a carbonized layer, and the gas generated by the decomposition acts to expand (foam) the carbonized layer. Although not particularly limited, as the acid catalyst, an acid catalyst selected from the group consisting of ammonium phosphate, melamine polyphosphate, melamine monophosphate, melamine diphosphate, and a combination thereof may be used.

The foamable fire resistant coating composition of the present invention may include 20 to 40% by weight of the acid catalyst, for example, may include 27 to 35% by weight. If the amount is less than 20 wt%, the formation of a carbonized layer is insufficient and the flame resistance cannot be ensured, and if the amount exceeds 40 wt%, the carbonized layer is easily broken due to excessive foaming and the heat insulation performance is deteriorated.

The fibers used in the composition of the present invention perform the functions of (1) having a high specific surface area to impart thixotropic (thixo) properties to the coating material and preventing drooling during coating, (2) uniformly distributing fine and long fibers in the cured coating film to serve as a reinforcing material to prevent cracks from occurring at ordinary times, and (3) adjusting a foaming ratio to react with an acid catalyst to reinforce the strength of a foamed carbonized layer and prevent cracks from occurring when the cured coating film is softened by heat and foamed during a fire, thereby performing the function of maintaining heat-insulating properties at high temperatures.

Although not particularly limited, as the fiber, a fiber selected from the group consisting of ceramic fiber, mineral wool, carbon fiber, Kevlar (Kevlar), and a combination thereof may be used. For example, aluminum silicate fiber (alumina silicate fiber) or magnesium silicate fiber (magnesium silicate fiber) may be used as the ceramic fiber, Synthetic glass (silicate) fiber (silicate) may be used as the mineral wool, PAN-based carbon fiber (PAN-based) carbon fiber may be used as the carbon fiber, para-aramid Synthetic fiber (para-aramid Synthetic fiber) may be used as the kevlar fiber, and the like.

The foamable fire resistant coating composition of the present invention may comprise fibers in an amount of 3 to 10% by weight, for example, may comprise 3 to 8% by weight. If the amount is less than 3 wt%, the fiber content is low and the crack preventing effect of the carbonized layer cannot be exhibited, and if the amount exceeds 10 wt%, the fiber content is too high and the coating workability is lowered due to the increase in viscosity of the coating material, so that the coating material is less swollen and the heat insulating performance is lowered.

The foamable fire-resistant coating composition of the present invention may further include one or more additives selected from the group consisting of a dispersant, a defoamer, a toner, a thickener, a pigment and a curing catalyst in order to exert optimal coating and film performances.

The foamable fire resistant coating composition of the present invention may include an additive in an amount of 5 to 15% by weight. When the amount is less than 5% by weight, the dispersion of the coating material is not smooth and bubbles are generated in the coating film, and when the amount is more than 15% by weight, the adhesion property of the coating film is lowered.

The foamable fire-resistant coating composition of the present invention has a gas hazard of 12 minutes or more as measured by the gas hazard test method (KSF 2271), and exhibits a fire resistance of 3 hours or more as measured by the fire resistance test method (UL1709) without using a separate reinforcing material (mesh), and releases harmful gas when the coating film expands in the event of fire, so that the risk of choking in the event of fire can be reduced, and thus, the composition is effective not only as a fire-resistant coating material for handling oil or gas in marine structures or workshops, but also in closed spaces such as tunnels and underground.

The present invention will be described more specifically with reference to examples. However, these examples are only for the purpose of aiding the understanding of the present invention, and the scope of the present invention is not limited by these examples in any sense.

[ examples ]

After the foamable flame-retardant coating compositions of examples 1 to 3 and comparative examples 1 to 3 were prepared in the compositions shown in table 1 below, the flame-retardant performance and the gas harmfulness were evaluated.

[ Table 1]

(wt%)

Epoxy resin: bisphenol A type resin, equivalent weight 182-192 g/eq, viscosity 11,000-14,000 cps, maximum color 25APHA, maximum hydrolysable chlorine content 300ppm, weight average molecular weight 100-400

Curing the resin: amide resin (amide resin) having a viscosity of 300 to 600cps, a color (# G) of 11 at maximum, an amine value of 400 to 500mgKOH/G, and an active hydrogen equivalent of 50 to 150G/eq

Foaming agent: melamine

Acid catalyst: ammonium polyphosphate

Phosphorus flame retardant #1 (liquid): isopropylated triphenyl phosphate (TPP content >21 wt%, thermal decomposition temperature less than 250 ℃ (TGA heating loss 5% or less))

Phosphorus flame retardant #2 (liquid): isopropylated triphenyl phosphate (TPP content below 10 wt%, thermal decomposition temperature above 250 ℃ (TGA heating loss below 5%), viscosity 60-80 cps)

Phosphorus flame retardant #3 (liquid): RDP (TPP content less than 5 wt%, thermal decomposition temperature of 250 ℃ or higher (TGA heating loss less than 5%), viscosity of 600cps)

Fiber # 1: aluminosilicate fiber (diameter 1-2.5 μm, length about 5,000 μm, melting point 1,760 ℃ C.)

Fiber # 2: magnesium silicate fiber (diameter 2 to 3 μm, melting point 1,500 to 1,550 ℃ C.)

Fiber # 3: mineral wool (diameter 6 μm (number average), length 650. + -.150. mu.m, melting point 1,000 ℃ C.)

Fiber # 4: carbon fiber (diameter 7 μm, length 3mm, specific gravity 1.8)

Curing catalyst: tris (dimethylaminomethyl) phenol (tris- (dimethylaminomethyl) phenol)

Pigment: titanium dioxide

Thickening agent: alkyl quaternary ammonium clay (Alkyl quaternary ammonium clay)

Dispersing agent: unsaturated polyamine amide salt and acid polyester solution

Defoaming agent: polymethylalkylsiloxanes

Evaluation of the fire resistance (UL1709)

The Fire resistance test uses a Rapid heating oil Fire test specification (UL1709, Rapid Fire test for Structural Steel protective material) for simulating the oil Fire heating temperature of a Steel structure. The heating curve is characterized by a temperature rise to 1,093 ℃ within 5 minutes, and is a heating temperature chart that is internationally regarded as a standard in an oil fire test for steel structures. The evaluation method can ensure the performance as a refractory structure if the average temperature of each cross section at the end of the test is less than 538 ℃ and the maximum temperature of each sensor is less than 649 ℃ based on the temperature of the test body. The results of comparing the fire resistance performance with the coated test piece (W10 × 49, ANSI Designation (ANSI Designation)) without using the reinforcing material (Mesh free) are shown in table 1 above.

Evaluation of gas hazards (time to stop mouse Activity, minutes)

The gas hazard test was conducted according to the KSF 2271 test method. The main test contents are that the test piece coated with fire-resistant paint is heated to burn the test piece, at the moment, the generated smoke is collected and sent into a room where a live mouse is located, and the average activity stop time of the live mouse is measured. If the harmfulness of the gas is improved, the average time to stop the activity of the living rat becomes longer accordingly. The evaluation criterion was 9 minutes or more.

As can be seen from table 1 above, examples 1 to 3 of the foamable flame retardant coating composition of the present invention, which use a liquid phosphorus-based flame retardant having a TPP content of 20 wt% or less and a thermal decomposition temperature of 250 ℃ or higher, can demonstrate excellent gas hazardous properties while satisfying the fire resistance standards without using a reinforcing material (mesh). On the other hand, in comparative examples 1 and 2 in which a phosphorus flame retardant having a TPP content of 21% or more was used, it was confirmed that the flame retardancy was poor or the gas harmfulness was less than 9 minutes. Further, as shown in comparative example 3, it was confirmed that the flame retardant exhibited inferior fire resistance and gas harm to examples 1 and 2 when the content of TPP was 20 wt% or less and the content of the liquid phosphorus flame retardant having a thermal decomposition temperature of 250 ℃ or higher was more than 20 wt%.

Claims (5)

1. A foamable fire-resistant coating composition comprising, based on 100% by weight in total, 10 to 25% by weight of an epoxy resin, 10 to 15% by weight of a cured resin, 10 to 20% by weight of a flame retardant, 3 to 10% by weight of a foaming agent, 20 to 40% by weight of an acid catalyst, and 3 to 10% by weight of a fiber,

the flame retardant is a flame retardant having a triphenyl phosphate content of 20 wt% or less and a thermal decomposition temperature of 250 ℃ or higher.

2. The foamable fire resistant coating composition according to claim 1,

the epoxy resin has a weight average molecular weight of 150 to 900 and an equivalent weight of 75 to 450g/eq, and is selected from the group consisting of bisphenol a type epoxy resin, bisphenol F type epoxy resin, flame retardant epoxy resin, novolac type epoxy resin, polyfunctional amine epoxy resin, alicyclic epoxy resin, and combinations thereof.

3. The foamable fire resistant coating composition according to claim 1,

the curing resin is an amide or amidoamine resin having a viscosity of 200cps to 800cps, an amine value of 300mgKOH/g to 600mgKOH/g, an active hydrogen equivalent of 50g/eq to 200g/eq, and obtained by polymerizing polyvinylamine, a fatty acid dimer and a fatty acid monomer.

4. The foamable fire resistant coating composition according to claim 1,

the flame retardant is selected from the group consisting of triphenyl phosphate, isopropylated triphenyl phosphate, tricresyl phosphate, butylated triphenyl phosphate, cresyldiphenyl phosphate, isopropylphenyldiphenylphosphate, resorcinol bis (diphenylphosphate), bisphenol a bis (diphenylphosphate), and combinations thereof.

5. The foamable fire resistant coating composition according to claim 1,

the flame retardant is a flame retardant in which the mixing ratio of the aryl phosphate and the diphosphate is 1:0.5 to 1:3 by weight.