KR20190066360A - Fire resistant coating composition - Google Patents

Abstract

The present invention relates to a water-based foamable refractory coating composition, which is capable of exhibiting refractory performance for two hours and exhibiting environment friendliness. The refractory coating composition comprises: a vinyl acetate copolymer; a cross-linked acrylic emulsion copolymer; a blowing agent; a catalyst; a carbonating agent; a pigment; a reinforcing agent; and a residual water-based solvent.

Description

FIRE RESISTANT COATING COMPOSITION [0001]

The present invention relates to a water-based foamable refractory coating composition.

Refractory paints protect buildings and other buildings from fire, and forcibly block or delay the approach of high temperature heat in the event of a fire, thereby providing time for suppressing fire and rescuing life.

Among the above-mentioned refractory paints, the foamable refractory paint is a paint which forms a carbonized layer by foaming the dry paint film layer when exposed to heat. The formed carbonized layer finally burns, but it takes time to burn, so that it protects the conductor (e.g., steel frame) from flame and heat of combustion for a certain period of time and functions to reduce the influence thereof. The foaming fire-resisting paint is generally oil-based type, but oil-based type fire-resisting paint has a disadvantage in that the working environment is poor due to the smell caused by the organic solvent during the operation and the drying is slower than the water-based type due to the back coating.

Korean Patent No. 10-0368169 discloses a water-based foamable fire-resistant paint for exhibiting fire resistance performance. The refractory coating composition of the prior art is applicable as a refractory coating material for one hour and has a relatively high water resistance. However, it has a problem in that the stability against cracking or peeling is low when foamed. Another prior art waterborne foamed firepower of Korean Patent Laid-Open Publication No. 2015-0131694 has a fire resistance performance of only one hour. Therefore, there is a need to improve the limit to an aqueous refractory coating in which the refractory performance does not exceed 1 hour.

In addition, in the conventional water-based foamable refractory coating, a phenomenon that the foamed coating film is dropped or flowed in the fire resistance test for 2 hours at high temperature is hard to ensure the fire resistance performance. Specifically, it is possible to secure good performance in the fire resistance performance test up to a thickness of the dry hard coating film (DFT) of about 1.0 mm. However, when the thickness of the dry hard coating film is 2.0 mm or more, It was impossible to secure fire resistance performance itself.

The present invention provides a waterborne foamable refractory coating composition which is excellent in not only the refractory performance for 2 hours but also the physical properties as a refractory coating.

The present invention provides a water-based foamable refractory coating composition comprising a vinyl acetate copolymer, a crosslinked acrylic emulsion copolymer, a foaming agent, a catalyst, a carbonating agent, a pigment, a reinforcing agent and a residual water-based solvent.

The water-based foamable refractory coating composition according to the present invention improves the dropout and flow phenomenon of the foamed coating film during the refractory performance test, and can exhibit the refractory performance and eco-friendliness for 2 hours. Accordingly, the water-based foamable refractory coating composition of the present invention can be usefully applied as a coating material for a fireproof coating material for a factory building and a hazardous material storage and treatment facility by a fire resistance test method of a building structure part specified in Korean Industrial Standard KSF 2257 have.

Hereinafter, the present invention will be described in detail. However, it should be understood that the present invention is not limited to the following embodiments, and various elements may be modified or selectively mixed according to need. Accordingly, it is to be understood that the invention includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

≪ Refractory coating composition >

The refractory coating composition of the present invention includes a vinyl acetate copolymer, a crosslinked acrylic emulsion copolymer, a foaming agent, a catalyst, a carbonating agent, a pigment, a reinforcing agent and an aqueous solvent. Hereinafter, the composition of the refractory coating composition will be described in detail.

Vinyl acetate copolymer

In the refractory coating composition of the present invention, the resin as a main component exhibits durability at a room temperature of the dry cured coating film, and when exposed to high temperature heat, changes the coating film into a fluidized state so that the coating film is appropriately foamed when gas is generated.

In the present invention, a vinyl acetate copolymer is used as the resin serving as the above-mentioned resin. The vinyl acetate copolymer is a water-based resin having good durability such as chemical resistance, weather resistance, flexibility and the like, a coating film forming temperature in the range of 0 to 30 ° C, and particularly excellent foamability.

The vinyl acetate copolymer may be an emulsion resin having a glass transition temperature (Tg) of 25 to 45 ° C. If the glass transition temperature of the vinyl acetate copolymer is less than 25 ° C, the viscosity of the resin tends to be lowered by the heat too fast to obtain a sufficient foaming ratio. If the glass transition temperature is more than 45 ° C, Can not be obtained.

The vinyl acetate copolymer may be an emulsion resin having a weight average molecular weight (Mw) of 100,000 to 300,000 and a solid content (NV) of 40 to 60%. When the weight average molecular weight of the vinyl acetate copolymer is less than 100,000, the abrasion resistance and water resistance of the coating film become poor and a uniform foamed film can not be obtained. When the weight average molecular weight exceeds 300,000, workability and smoothness of the paint become poor, The foaming rate of the coating film is lowered.

The vinyl acetate copolymer may be prepared by polymerizing vinyl acetate monomer and at least one comonomer according to a conventional method known in the art.

As the comonomer, a conventional monomer in the art capable of forming a copolymer by polymerization with a vinyl acetate monomer may be used without limitation. Non-limiting examples of comonomers that can be used include vinyl versatate, iso-butyl acrylate, n-butyl acrylate, ethyl acrylate, 2-Ethylhexyl acrylate, Lauryl acrylate, Ethylene, and the like. The above-mentioned components may be used alone or in combination of two or more. The ratio of the vinyl acetate monomer to the comonomer is not particularly limited and can be suitably adjusted in consideration of the physical properties of the copolymer to be finally produced.

In addition, the vinyl acetate copolymer may be one in which a part of the compound is modified with an alkyl. When modified with an alkyl group, the hydrolysis reaction between the acetate group (-C-C = O) and water is difficult, and the water resistance of the coating film can be improved. The coating film of the refractory paint with improved water resistance can prevent cracking and early dropping of the foamed coating film due to vaporization of water vapor during foaming, thereby continuously improving the fire resistance performance. The rate of alkyl modification is not particularly limited and may be appropriately adjusted within the range known in the art.

The content of the vinyl acetate copolymer may be 15 to 30% by weight, for example, 15 to 25% by weight based on the total weight of the refractory coating composition. If the content of the vinyl acetate copolymer is less than 15% by weight, the formation of the coating film is incomplete and cracks are generated in the dried coating film. If the content of the vinyl acetate copolymer is more than 30% by weight, the properties of the dried coating film are good, while the flame retardant (foaming agent, And the foaming ratio is lowered, so that normal fire resistance performance can not be exhibited.

Bridging Combined  acryl emulsion  Copolymer

In the refractory coating composition of the present invention, the cross-linked acrylic emulsion copolymer serves as a flow inhibitor during the painting operation and prevents the prevention of hot flow and the desorption of the hot flow during the fire resistance test.

The acrylic emulsion copolymer may be an aqueous emulsion of a cured copolymer (e.g., polyacrylate) crosslinked with an acrylic resin. These acrylic emulsion copolymers are added to refractory coatings to act as thickeners to increase viscosity, thereby preventing flow during painting and further strengthening the bonding of the cured coatings through crosslinking to enhance stability. Accordingly, it is possible to prevent the hot flow of the dried cured coating film during the fire resistance test and to prevent the desiccation, thereby improving the fire resistance performance.

The crosslinked acrylic emulsion copolymer may be prepared, for example, by copolymerizing with one or more linear or branched alkyl esters of (meth) acrylic acid according to conventional methods known in the art. Non-limiting examples of one or more linear or branched alkyl esters of (meth) acrylic acid that can be used include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, (Meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl have. For example, 2-alkyl-2-propionic acid polymers crosslinked with alkyl-2-propionates such as 2-methyl-2-propionic acid polymers crosslinked with ethyl-2-propionate can be used.

The acrylic emulsion copolymer may have a solids (NV) content of 25 to 35% and a pH of 2 to 4. The acrylic emulsion copolymer may exhibit anionic properties.

The content of the crosslinked acrylic emulsion copolymer may be 0.1 to 7% by weight, for example, 0.5 to 5% by weight, based on the total weight of the refractory coating composition. If the content of the cross-linked acrylic emulsion copolymer is less than 0.1% by weight, hot flow of the foamed coating film can not be prevented and desorption of the foamed coating film occurs. When the content of the crosslinked acrylic emulsion copolymer is more than 7% by weight, And the workability is poor due to a decrease in fluidity due to an increase in viscosity at the time of producing the paint.

blowing agent

In the refractory coating composition of the present invention, the foaming agent is decomposed at a high temperature to react with the carbonizing agent and the catalyst to form a carbonized layer, and gas is generated during the reaction so that the carbonized layer can be foamed appropriately.

As the foaming agent, any conventional components known in the art may be used without limitation. For example, a nitrogen-containing foaming agent may be used. The nitrogen-containing blowing agent can sustain the adiabatic effect by foaming the carbonized layer formed by the carbonizing agent and the catalyst while releasing nitrogen-containing gas generated by thermal decomposition of the compound at a high temperature, for example, ammonia gas. At this time, a suitable decomposition temperature is required so that foaming of the nitrogen-containing foaming agent can be performed after the carbonized layer is formed from the dried coating film of the refractory paint.

Non-limiting examples of nitrogen-containing blowing agents that can be used include melamine, dicyandiamide, Ammeline, Melam, urea, Ureido Melamine, glycine and glycine. The above-mentioned components may be used alone or in combination of two or more.

The content of the foaming agent may be 5 to 15% by weight, for example, 5 to 10% by weight based on the total weight of the refractory coating composition. If the content of the foaming agent is less than 5% by weight, the amount of the produced gas is small and the carbonization layer is insufficient to foam, resulting in a low foaming ratio. If the content of the foaming agent is more than 15% by weight, It is difficult to form a carbonized layer and the strength of the foamed coating film due to foaming is lowered and the fire resistance performance is lowered together.

Catalyst

In the refractory coating composition of the present invention, the catalyst is thermally decomposed at a high temperature to release gas, thereby accelerating the reaction of the carbonizing agent and the foaming agent, and participating in the reaction to form a carbonized layer.

As the catalyst, any conventional catalyst may be used without limitation. For example, an acid catalyst may be used. The acid catalyst acts as a hydrogen ion (H ⁺ ) donor of a carbonating agent to produce a foaming gas, ammonia, and a carbonized layer during thermal decomposition.

Non-limiting examples of catalysts that can be used include primary ammonium phosphate, secondary ammonium phosphate, ammonium phosphite, melamine phosphate, dimelamine phosphate, phosphate, melamine pyrophosphate, melaminepoly phosphate, tricrecyl phosphate, trichloroalkylphosphate, ammonium polyphosphate, monoammonium phosphate, Mono ammonium phosphate, Nitropolyphosphate, and the like. The above-mentioned components may be used alone or in combination of two or more.

The content of the catalyst may be 15 to 35% by weight, for example 20 to 30% by weight, based on the total weight of the refractory coating composition. When the content of the catalyst is less than 15% by weight, the reaction with the carbonizing agent and the foaming agent is not smooth and the formation of the carbonized layer is reduced. When the content exceeds 35% by weight, the foaming effect of the carbonized layer is inhibited, .

Carbonating agent

In the refractory coating composition of the present invention, the carbonizing agent functions to react with the foaming agent at a high temperature to form a carbonized layer exhibiting the refractory performance.

As the above-mentioned carbonizer, there can be used any of ordinary components known in the art without limitation. Non-limiting examples of usable carbonating agents include pentaerythritol, dipentaerythritol, tripentaerythritol, starch, phenolformaldehyde resin, for example, sugar, polyurethane, sorbitol, trimethylolpropane, trimethylolethane, trimethylolpropane, and the like. The above-mentioned components may be used alone or in combination of two or more.

The content of the carbonizing agent may be 5 to 15% by weight, for example, 5 to 10% by weight based on the total weight of the refractory coating composition. When the content of the carbonizing agent is less than 5% by weight, formation of a foamed coating film is insignificant. When the content of the carbonating agent is more than 15% by weight, a proper foamed coating film is not formed and a foaming flow phenomenon occurs. none.

Pigment

In the refractory coating composition of the present invention, the pigment also imparts color to the refractory paint and improves the refractory performance.

Examples of the pigment include organic pigments, inorganic pigments, metallic pigments, aluminum-paste (Al-paste), pearl pigments, extender pigments and the like which are commonly used in refractory paints. Non-limiting examples of usable pigments include azo pigments, phthalocyanine pigments, iron oxide pigments, cobalt pigments, carbonate pigments, sulfate pigments, silicate pigments, chromate pigment pigments and the like. Examples of the pigments include titanium dioxide (TiO ₂ ) , Bismuth vanadate, cyanine green, carbon black, iron oxide red, iron oxide yellow, navy blue and cyanine blue can be used.

The content of the pigment may be 5 to 20% by weight, for example 8 to 15% by weight, based on the total weight of the refractory coating composition. When the content of the pigment is less than 5% by weight, coloration and concealment of the coating film is not only lowered, but also the density and foaming ratio of the foamed coating film are lowered because it is difficult to form a uniform pore layer in the foamed coating film at high temperature. On the other hand, if it exceeds 20% by weight, the content of the flame retardant (foaming agent, carbonizing agent, catalyst) for forming a carbonized layer is relatively decreased and the foaming ratio is lowered and the fire resistance performance becomes poor.

Reinforcing agent

In the refractory coating composition of the present invention, when the dry cured coating film is formed into a foamed coating film having a carbonized layer formed by foaming at a high temperature, the strength of the carbonized layer is increased to prevent the foamed coating film from being peeled or partially blown from the flame, It improves performance.

As the reinforcing agent, there can be used conventional components known in the art without limitation, and examples thereof include inorganic substances such as metal oxides, metal hydroxides, metal compounds, glass, and silicon pigments. Non-limiting examples of usable reinforcing agents include silicates (talc), molybdenum trioxide, zirconium dioxide, aluminum hydroxide, zinc borate, glass powder, glass fibers and the like. The above-mentioned components may be used alone or in combination of two or more.

The content of the reinforcing agent may be 2 to 15% by weight, for example, 2 to 10% by weight based on the total weight of the refractory coating composition. When the content of the reinforcing agent is less than 2% by weight, the effect of reinforcing the strength of the foamed coating is insignificant. When the content of the reinforcing agent is more than 15% by weight, the strength of the carbonized layer is too hard, So that the fire resistance performance becomes very poor.

additive

The refractory coating composition of the present invention may contain additives conventionally used in refractory coatings to the extent that the inherent characteristics of the composition are not impaired.

Non-limiting examples of usable additives include a mixture of at least one selected from the group consisting of antifoaming agents, dispersants, preservatives, film formers, plasticizers, cryoprotectants, thickeners and pH regulators.

Antifoaming agents are used to remove air bubbles during coating or painting. As the antifoaming agent, a solution of polydimethylsiloxane and a solvent (Solution of polydimethyl siloxane and solvent) can be used.

Since the refractory coating material has many powder components unlike the general paint, a dispersant having excellent wetting and dispersing property is used as an additive. As the dispersing agent, a solution of an alkylammonium salt of polycarboxylic acid or the like may be used.

Water-based coatings provide an environment in which fungi or bacteria can habitat due to the influence of emulsions or thickeners, which causes odor or decay. To prevent this, preservatives are used.

The film-forming agent is used to smooth the fusion between the pigment and the resin and the formation of the film when the film is formed.

Cryoprotectants are added to prevent waterborne refractory coatings that use water as a solvent from freezing at temperatures below 0 ° C. For example, a glycol-based cryoprotectant may be used.

Thickening agents are used to impart adequate viscosity and flowability to allow for backcoating. As the thickening agent, for example, amide wax may be used.

The pH adjusting agent is used not only to control the pH of the aqueous coating material but also to smooth the thickening action of the thickening agent.

The additive is added in an appropriate amount depending on its function, to the extent known in the art. For example, the content of the additive may be 3 to 10% by weight based on the total weight of the refractory coating composition.

Aqueous solvent

The refractory coating composition of the present invention uses water as a solvent. Water functions to adjust the viscosity of the paint and to provide fluidity. It replaces the organic solvent and improves the working environment and the air quality, thereby providing environment friendliness.

The water content may be a balance satisfying 100 wt% of the refractory coating composition. For example, it may be 5 to 30% by weight based on the total weight of the refractory coating composition, and may be 10 to 20% by weight as another example. If the content of water is less than 5 wt%, the coating material is difficult to produce. If the content of water is more than 30 wt%, the workability is deteriorated due to an excessive amount of solvent and the content of flame retardant (carbonating agent, foaming agent, catalyst) The foaming ratio is lowered and the refractory performance becomes poor.

In the case of conventional foamed fireproof coatings, the dry cured coating film is exposed to high temperature heat by fire or the like to form a carbonized layer, which shrinks and cracks due to non-uniform foaming during the foaming reaction, thereby deteriorating the heat insulating property of the foamed coating film . On the contrary, the water-based foamable refractory coating composition according to the present invention is characterized in that the cross-linked acrylic emulsion copolymer is mixed in a proper proportion in the paint to prevent the desorption and flow phenomenon of the foamed coating film and maintain excellent fire resistance performance for a long time . Further, by having excellent foam ratio and uniformity of the coating film, it is possible to exhibit an effective heat insulating effect with a low dry film thickness.

The water-based foamable refractory coating composition according to the present invention may have fire resistance for 2 hours according to the fire resistance test method prescribed in KS F2257. Specifically, when the dry film is heated for 2 hours (120 minutes), the average temperature of each cross section is 538 ° C or less, and the maximum total temperature can be kept constantly below 649 ° C.

The water-based foamable refractory coating composition may have a KU viscosity of 95 to 115 KU, a flow resistance (SAG) of 60 to 80 mils, a specific gravity of 1.3 to 1.5, and a solid content (NV) of 65 to 75%. It is preferable from the viewpoint of workability as a water-based refractory coating, flowability, and general coating film properties such as abrasion resistance after formation of a dry coating film.

The KU viscosity is measured using a STORMER viscometer, and the flow resistance (SAG) is measured by the following method.

1. Prepare test paint uniformly and adjust the temperature to 23 ± 2 ℃.

2. Place the ANTI SAGMETER in the proper position on the glass plate.

3. Straighten the prepared sample at a constant speed (usually 150 ㎜ / s).

4. Immediately dry the support vertically with the thinnest part of the support facing up.

5. Test in a test room at a temperature of 23 ± 2 ° C and a relative humidity of 65 ± 10%.

6. Evaluate the center section and select the thickest stripes that you want to fit between the stripes below.

The foaming process using the water-based foamable refractory coating composition of the present invention constituted as described above can be explained as follows. However, the present invention is not particularly limited to the following contents.

(First stage of foaming)

When heat is applied to the dry film surface due to a fire or the like, and the organic component (in particular, resin, etc.) has a softening point or more, the coating film is converted into a fluid state. This state means that the coating film is prepared in a state suitable for starting foaming.

(Second stage of foaming)

As the temperature of the coating increases, the catalyst, foaming agent, carbonizing agent and other organic components are decomposed to release various components of the gas. At this time, the emitted gas differs depending on the components generated by decomposition in the coating film, but generally, it is water vapor, ammonia, carbon dioxide, and the like. Such gas pushes out components such as resin in a flowing state, so that the coating film starts to foam while naturally forming a foam layer inside the coating film.

(Third stage of foaming)

The foaming of the coating film continues and the surface layer of the foam coating film begins to be carbonized. Initially, expansion and carbonization proceed at the same time, but as the time elapses, the carbonized portion increases, and the expansion of the coating gradually slows down. As time elapses, the foaming progresses only and carbonization proceeds. The thickness of the foam layer thus formed is 20 to 150 times the initial dry film thickness, and the density of the carbonized layer becomes significantly lower than that of the original coating film as a result of foaming.

(Fourth stage of foaming)

The foamed layer is continuously carbonized until the entire body is whitened, preventing external heat from being transferred to the conductor. Through the above-described foaming process, the foaming rate is 20 to 150 times, and the foaming coating film having almost no damage due to shrinkage is formed. The expanded foaming coating film is free from falling off or flaking of the foaming coating film by the flame, Is a major factor that effectively blocks heat transfer from the surrounding high temperature heat to the conductor (e.g., iron structure).

The refractory coating composition of the present invention combines excellent fire resistance and environment friendliness, so that it can be applied to various applications requiring fire resistance performance. For example, it can be used for general buildings, factories, commercial buildings, ships and marine structures, automobiles, aircraft, mobile houses, and the like. In addition, it can be applied to the surfaces of mineral board, cable, tray, concrete, steel, wood, etc. to impart fire resistance.

At this time, the thickness of the dried film is not particularly limited and can be appropriately adjusted within a range known in the art. For example, 0.5 to 3.0 mm in thickness. For example, brush coating, air spray coating, airless spray coating, roller coating, and the like can be used as a coating method.

Hereinafter, the present invention will be described more specifically by way of examples. However, the following examples are provided to aid understanding of the present invention and are not intended to limit the scope of the present invention in any sense.

[ Example  1-5]

The specifications of the raw materials constituting the refractory coating composition of the present invention are shown in Table 1 below.

The refractory coating compositions of Examples 1-5 were prepared using resins, crosslinking agents, blowing agents, catalysts, carbonating agents, pigments, reinforcing agents, additives and water according to the compositions shown in Table 2 below. In Table 2, the usage unit of each composition is% by weight. The solids content in the final composition was about 70 wt.%, Specific gravity was about 1.4, KU viscosity was about 105 KU, and flow resistance was about 70 mil.

[ Comparative Example  1-4]

Resin, crosslinking agent, foaming agent, catalyst, carbonating agent, pigment, reinforcing agent, additive and water were used according to the composition shown in Table 3 below to prepare refractory coating compositions of Comparative Examples 1-4, respectively.

[ Experimental Example . Property Evaluation of Refractory Coating Composition]

The physical properties of each of the foamable refractory coating compositions prepared in Examples 1-5 and Comparative Examples 1-4 were measured and the results are shown in Table 4 below.

≪ Method for measuring physical properties &

(1) Fire resistance performance

Fire resistance performance test was performed based on KS F2257.

(2) Expansion ratio

After completion of the above fire resistance test, the degree of foaming of the foamed coating film (foamed carbonized layer) was checked, and the foaming ratio was measured according to the following equation (1).

[Equation 1]

Foaming ratio (times) = Foam thickness / Dry film thickness before test

(3) Foamed film appearance

After completion of the above fire resistance test, the occurrence of cracks in the foamed coating film (carbonized layer) was visually determined.

(4) Foam film strength

After completing the above fire resistance test, the strength of the foamed coating film (carbonized layer) was measured by pressing with the finger and judged (touched).

As shown in Table 4, when the essential components constituting the refractory coating composition according to the present invention are not included (Comparative Examples 1, 3 and 4), and the content ranges of the constituent components are outside the scope of the present invention 2), it did not show the fire resistance performance for 2 hours, and the physical properties of the foam coating film were poor overall. Particularly, Comparative Example 2 showed that although the crosslinked acrylic emulsion copolymer was contained, excessive use of the crosslinked acrylic emulsion copolymer resulted in poor foamability and fire resistance.

In contrast, the refractory coating composition of the present invention showed not only excellent fire resistance for 2 hours but also excellent foamability, foam appearance and foam strength.

Claims (5)

Vinyl acetate copolymer resin, cross-linked acrylic emulsion copolymer, blowing agent, catalyst, carbonating agent, pigment, reinforcing agent and residual water based solvent. The vinyl acetate copolymer according to claim 1, wherein the vinyl acetate copolymer has a glass transition temperature (Tg) of 25 to 45 占 폚, a weight average molecular weight (Mw) of 100,000 to 300,000, and a solid content (NV) / RTI > The refractory coating composition according to claim 1, wherein the cross-linked acrylic emulsion copolymer has a solid content (NV) content of 25 to 35% and a pH of 2 to 4. The composition according to claim 1, which comprises 15 to 30 wt% of a vinyl acetate copolymer, 0.1 to 7 wt% of a crosslinked acrylic emulsion copolymer, 5 to 15 wt% of a foaming agent, 15 to 35 wt% of a catalyst, 5 to 15 wt% 5 to 20% by weight of a pigment, 2 to 15% by weight of a reinforcing agent, and a residual amount of an aqueous solvent. A KU viscosity of 95 to 115 KU, a flow resistance (SAG) of 60 to 80 mil, a specific gravity of 1.3 to 1.5, and a solid content (NV) of 65 to 75%.