WO2020101171A1 - Heat resistant paint composition - Google Patents

Abstract

The present invention relates to a heat resistant paint composition comprising a silicone resin and a frit, wherein the frit comprises, on the basis of the total weight of the frit, 10-35 wt% of phosphorus oxide, 5-15 wt% of aluminum oxide, 5-75 wt% of alkali metal oxide, 1-15 wt% of oxygen fluoride, 0.1-10 wt% of silicon oxide, 0.1-10 wt% of calcium oxide, and 0.1-10 wt% of titanium oxide.

Description

Heat-resistant paint composition

The present invention relates to a heat-resistant coating composition with improved heat resistance and corrosion resistance.

The heat-resistant paint serves to protect the object from high-temperature environments and improve the appearance, and it is required that there is no damage such as discoloration, cracking, softening, peeling and thermal deformation even when exposed to high temperatures.

In the conventional heat-resistant paint, a technique for securing heat resistance by reacting an inorganic binder such as colloidal silica or colloidal alumina with a silane coupling agent has been used, but when such an inorganic resin is used, adhesion and bending properties with a substrate are inferior. There is this. As a method for solving such a drawback, research on heat-resistant coatings using silicone-based resins having excellent heat resistance as a binder component has been continued, but the compatibility with solvents is not excellent, and the peeling phenomenon of the coating film in an environment where temperature change is rapid There is a problem that occurs easily.

Particularly, as underground resources are gradually depleted in recent years and demand for natural resources such as liquefied natural gas (LNG) increases, the demand for heat-resistant paint compositions that ensure durability over a wide temperature range is gradually increased to mine them. Is becoming. Japanese Patent No. 4,871,951 discloses a heat-resistant coating composition capable of securing heat resistance in a range of 200 ° C to 600 ° C, including a silicone resin and / or an epoxy resin and a black pigment. However, in order to implement a heat-resistant coating system that satisfies long-term durability against extremely low and high temperatures required by the industry, it is necessary to further improve the durability against large temperature changes.

The present invention provides a heat-resistant coating composition with improved heat resistance and corrosion resistance. In particular, the present invention provides a heat-resistant coating composition excellent in durability against a large temperature change.

The present invention provides a heat-resistant coating composition comprising a silicone resin and a frit.

The heat-resistant coating composition according to the present invention has excellent heat resistance and corrosion resistance, and particularly exhibits excellent durability in a wide temperature range between -200 ° C and 700 ° C.

Hereinafter, the present invention will be described in detail. However, it is not limited only by the following contents, and each component may be variously modified or selectively mixed as necessary. Therefore, it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

The heat-resistant coating composition according to the present invention includes a silicone resin and a frit. If necessary, pigments, extender pigments, catalysts, and heat-resistant coatings may further include additives commonly used in the field. Looking at the composition of the heat-resistant coating composition of the present invention as follows.

Silicone resin

The heat-resistant coating composition according to the present invention contains a silicone resin as a main resin. The silicone resin has a siloxane bond (Si-O bond) as a main chain, and is included in the coating composition to serve to secure heat resistance. The silicone resin has excellent heat and light stability to prevent yellowing, choking, and loss of luster of the coating film, and has characteristics of exhibiting stable performance over a long period of time.

As the silicone resin, a phenyl group, a vinyl group, and / or an alkyl group substituted on the silicone resin main chain may be used. For example, methyl silicone resin, methylphenyl silicone resin, phenyl silicone resin, etc. are mentioned. For example, one or more selected from polymethylsiloxane, polyphenylsiloxane, polymethylphenylsiloxane, polyvinylmethylsiloxane and polyvinylphenylsiloxane may be used, but is not limited thereto.

In addition, a modified silicone resin can also be used as the silicone resin. The modified silicone resin is one or more organic compounds introduced into a silicone resin, and examples thereof include alkyd-modified silicone resins, epoxy-modified silicone resins, polyester-modified silicone resins, acrylic-modified silicone resins, and urethane-modified silicone resins. have.

There is no particular limitation on the position at which the organic compound is introduced, for example, part of the side chain of the main skeleton of the polysiloxane bond, both ends of the main skeleton of the polysiloxane bond, one end of the main skeleton of the polysiloxane bond, and a part of the side chain of the main skeleton of the polysiloxane bond. And an organic compound may be introduced at one end or both ends.

The number average molecular weight of the silicone resin may be 300 to 10,000 g / mol, for example, 400 to 5,000 g / mol. When the number average molecular weight of the silicone resin is less than 300 g / mol, the dryness and curability of the paint decreases, and when it exceeds 10,000 g / mol, paintability and impact resistance may deteriorate.

The silicone resin may be used in an amount of 10 to 40% by weight, for example, 15 to 30% by weight based on the total amount of the heat-resistant coating composition. When the content of the silicone resin exceeds 40% by weight, the curability of the heat-resistant coating may be lowered, and when it is less than 10% by weight, adhesion may be deteriorated.

Frit

The heat-resistant coating composition according to the present invention includes a frit. When the coating film is formed by using the silicone resin as the main resin of the coating composition, cracks can be prevented while maintaining flexibility and adhesion at low temperatures, but in a high temperature environment of 400 ° C. or higher, the organic material contained in the silicone resin As this decomposition and evaporation, a fine gap may be generated inside the coating film, thereby deteriorating the physical properties of the coating film. The frit melts in a high-temperature environment, and fills the gap generated by the evaporation of the organic matter inside the silicone resin, and as a result, serves to secure the heat resistance of the coating film even in a harsh environment at a very high temperature (for example, 700 ° C).

The frits include P (phosphorus), Al (aluminum), alkali metals (e.g. Na (sodium), K (potassium)), F (fluorine), Si (silicon), Ca (calcium) and Ti (titanium). It may be. Each of the above components is included in the form of an oxide, for example, P ₂ O ₅ , Al ₂ O ₃ , Na ₂ O, K ₂ O, OF ₂ , O ₂ F ₂ , O ₃ F ₂ , SiO ₂ , CaO, TiO ₂ days You can.

The frit may include 10 to 35% by weight of phosphorus oxide based on the total amount of frit, for example, 15 to 30% by weight. When the content of phosphorus oxide is less than 10% by weight, fouling resistance may be reduced, and when it exceeds 35% by weight, stability of the frit may be reduced. In one example, the frit may include 10 to 35% by weight of P ₂ O ₅ based on the total amount of frit, for example, 15 to 30% by weight.

The frit may include 5 to 15% by weight of aluminum oxide, for example 5 to 12% by weight, based on the total amount of frit. When the content of aluminum oxide is less than 5% by weight, the stability of the frit may be lowered, and when it exceeds 15% by weight, the frit may be difficult to melt and heat resistance of the coating may be lowered. For example, the frit may include 5 to 15% by weight of Al ₂ O ₃ based on the total amount of frit, for example, 5 to 12% by weight.

The frit may include 5 to 75% by weight of alkali metal oxide, for example, 25 to 75% by weight, based on the total amount of frits. When the content of the alkali metal oxide is less than 5% by weight, the flowability and meltability of the frit may be lowered, and when it exceeds 75% by weight, the stability of the frit may be lowered. In one example, the frit may include 5 to 15% by weight of Na ₂ O based on the total amount of frit, for example, 5 to 10% by weight. As another example, the frit may include 35 to 60% by weight of K ₂ O, for example, 40 to 55% by weight based on the total amount of frits.

The frit may contain 1 to 15% by weight of fluorine oxide, for example 1 to 10% by weight, based on the total amount of frit. When the content of the fluorine oxide is less than 1% by weight, the heat resistance of the paint may decrease, and when it exceeds 15% by weight, the transparency of the frit may decrease. In one example, the frit may include 1 to 15% by weight, for example, 1 to 10% by weight of one or more compounds selected from OF ₂ , O ₂ F ₂ and O ₃ F ₂ based on the total amount of frits.

The frit may contain 0.1 to 10% by weight of silicon oxide, for example, 0.1 to 5% by weight, based on the total amount of frit. When the content of silicon oxide is less than 0.1% by weight, the thermal stability of the frit may be lowered, and when it exceeds 10% by weight, the heat resistance of the coating may be lowered. In one example, the frit may include 0.1 to 10% by weight of SiO ₂ based on the total amount of frit, for example, 0.1 to 5% by weight.

The frit may contain 0.1 to 10% by weight of calcium oxide, for example, 0.1 to 5% by weight, based on the total amount of frit. When the content of calcium oxide is less than 0.1% by weight, the crystallinity of the frit may be lowered, and when it exceeds 10% by weight, the thermal stability of the frit may be lowered. In one example, the frit may contain 0.1 to 10% by weight of CaO based on the total amount of frit, for example, 0.1 to 5% by weight.

The frit may contain 0.1 to 10% by weight of titanium oxide, for example, 0.1 to 5% by weight, based on the total amount of frit. When the content of titanium oxide is less than 0.1% by weight, the stability of the frit may be lowered, and when it exceeds 10% by weight, the fluidity of the coating material may be lowered. In one example, the frit may include 0.1 to 10% by weight of TiO ₂ based on the total amount of frit, for example, 0.1 to 5% by weight.

The frit is based on the total amount of frit, phosphorus oxide 10 to 35% by weight, aluminum oxide 5 to 15% by weight, alkali metal oxide 5 to 75% by weight, fluorine oxide 1 to 15% by weight, silicon oxide 0.1 to 10% by weight, It may include 0.1 to 10% by weight of calcium oxide and 0.1 to 10% by weight of titanium oxide.

For example, the frit is based on the total amount of frit, P ₂ O ₅ 10 to 35% by weight, Al ₂ O ₃ 5 to 15% by weight, alkali metal oxide 5 to 75% by weight, OF ₂ , O ₂ F ₂ and It may include 1 to 15% by weight of one or more compounds selected from O ₃ F ₂ , 0.1 to 10% by weight of SiO _2, 0.1 to 10% by weight of CaO, and 0.1 to 10% by weight of TiO ₂ .

In another example, the frit is based on the total amount of frit, P ₂ O ₅ 10 to 35 wt%, Al ₂ O ₃ 5 to 15 wt%, Na ₂ O 5 to 15 wt%, K ₂ O 35 to 60 wt%, Of ₂ , O ₂ F ₂ And O ₃ F ₂ One or more compounds selected from 1 to 15% by weight, SiO ₂ 0.1 to 10% by weight, CaO 0.1 to 10% by weight and TiO ₂ 0.1 to 10% by weight to include You can.

When the components constituting the frit are blended in the above-described content range, the frit composition in which the melting temperature of the frit is formed lower than the decomposition temperature of the silicone resin to more effectively melt the gap generated by evaporation of organic substances inside the silicone resin. It can be filled.

The coefficient of thermal expansion of the frit is 1.0 x 10 ^-6 mm ³ / mm ³ ° C to 2.0 x 10 ^-5 mm ³ / mm ³ ° C, the softening point may be 350 ° C to 400 ° C, and the particle size may be 30 to 50 μm. have. The form of the frit is not particularly limited, but may be, for example, a powder form.

The frit may be used in an amount of 3 to 20% by weight based on the total amount of the heat-resistant coating composition. When the content of the frit exceeds 20% by weight, the adhesion of the heat-resistant paint may be lowered, and when the content of the frit is less than 3% by weight, a problem that the heat-resistant performance is lowered may occur.

Pigment

The heat-resistant coating composition of the present invention may further include a pigment commonly used in the heat-resistant coating field, within a range that does not impair the inherent properties of the composition.

Pigments can be used to express the desired color (colour) in the heat-resistant paint or to increase the strength of the coating film. As such a pigment, organic pigments, inorganic pigments, metallic pigments, aluminum-paste, pearl, etc., which are commonly used in heat-resistant coatings, can be used without limitation, and these can be used alone or in combination of two or more. Can be. Non-limiting examples of pigments that can be used include azo-based, phthalocyanine-based, iron oxide-based, cobalt-based, carbonate-based, sulfate-based, silicate-based, and chromate-based pigments, such as titanium dioxide, zinc oxide, and bismuth vanadate. , Cyanine green, carbon black, iron oxide, iron oxide, navy blue, cyanine blue, and mixtures of two or more thereof.

In the present invention, the content of the pigment is not particularly limited, for example, may be 1 to 30% by weight based on the total amount of the heat-resistant coating composition. When the content of the pigment is in the above-described range, the color expression of the coating film is excellent, and the hiding property and mechanical properties of the coating film can be improved.

Extender pigment

The heat-resistant coating composition of the present invention may further include an extender pigment commonly used in the heat-resistant coating field, within a range that does not impair the inherent properties of the composition.

Non-limiting examples of extender pigments that can be used include calcium carbonate, feldspar, barium sulfate, silica, mica, alumina hydroxide, magnesium hydroxide, titanium dioxide, magnesium carbonate, alumina, mica, montmorillonite, olestonite, talc, aluminum nitride, Silicon nitride, boron nitride, aluminum oxide, barium sulfate, and the like. These may be used alone or in combination of two or more.

The average particle diameter of the extender pigment is not particularly limited, and may be, for example, 1 to 20 μm. In addition, the shape of the extender pigment may be spherical or amorphous, and is not particularly limited thereto.

In the present invention, the content of the extender pigment may be, for example, 10 to 50% by weight based on the total amount of the heat-resistant coating composition. When the content of the extender pigment is within the above-described range, mechanical properties, impact resistance, and adhesion of the coating film may be improved.

additive

The heat-resistant coating composition according to the present invention may optionally further include conventional additives known in the art, in addition to the aforementioned components, if necessary. Non-limiting examples of additives usable in the present invention include catalysts, thixotropic agents, antifoaming agents, leveling agents, surface conditioners, ultraviolet absorbers, ultraviolet stabilizers, drying agents, hygroscopic agents, waxes, and the like.

The content of the additive is not particularly limited, and may be 0.1 to 5% by weight based on the total amount of the heat-resistant coating composition.

solvent

The heat-resistant coating composition according to the present invention may further include a solvent if necessary. The solvent facilitates the painting operation by adjusting the viscosity of the coating composition, and serves to improve the smoothness and coating workability of the coating film (coating layer) by controlling the volatilization rate of the solvent.

The solvent usable in the present invention is not particularly limited as long as it is a conventional solvent known in the art. For example, there are ketone-based solvents, ester-based solvents, ether-based solvents, hydrocarbon-based solvents, alcohol-based solvents, or mixtures thereof. Non-limiting examples of the solvent include butyl acetate, propylene glycol methyl ether, toluene, xylene, methyl ethyl ketone, methyl propyl ketone, methyl butyl ketone, ethyl propyl ketone, methyl isobutyl ketone, methyl acetate, ethyl acetate, normal propyl Acetate, isopropyl acetate, methyl cellosolve acetate, cellosolve acetate, butyl cellosolve acetate, carbitol acetate, normal propanol, isopropanol, normal butanol, isobutanol, tertiary butanol, benzene, acetone, tetrahydrofuran, dimethyl Formaldehyde, dimethylphthalate, cyclohexanone, methanol, and ethanol. These may be used alone or in combination of two or more.

In the present invention, the content of the solvent is not particularly limited, and may be a residual amount that is adjusted so that the total amount of the heat-resistant coating composition is 100% by weight, for example, 10 to 50% by weight. When the content of the solvent is within the above-described range, workability and appearance characteristics of the coating film may be improved.

Hereinafter, the present invention will be described in more detail through examples. However, the following examples are only to aid the understanding of the present invention, and the scope of the present invention is not limited to the examples in any sense.

[Example 1-5 and Comparative Example 1-4]

Each component was blended according to the composition shown in Table 1 below to prepare heat-resistant coating compositions of Examples 1-5 and Comparative Examples 1-4, respectively.

Silicone resin 1: Silikophen AC 1000 resins (methyl silicone resin, methoxy-functional, Evonilk industries)

Silicone resin 2: SILIKOPHEN P 80 / X 1000 (methylphenyl polysiloxane resin, Evonilk industries)

Frit 1: P ₂ O ₅ 25.4 wt%, Al ₂ O ₃ 11.7 wt%, Na ₂ O 8.5 wt%, K ₂ O 47.6 wt%, OF ₂ , O ₂ F ₂ and O ₃ F ₂ 5.0 or more Wt%, SiO ₂ 0.8 wt%, CaO 0.5 wt%, TiO ₂ 0.5 wt%

Frit 2: P ₂ O ₅ 28.65% by weight, Al ₂ O ₃ 5.55% by weight, Na ₂ O 5.55% by weight, K ₂ O 43.15% by weight, OF ₂ , O ₂ F ₂ and O ₃ F ₂ or more 6.84 Wt%, SiO ₂ 3.42 wt%, CaO 3.42 wt% and TiO ₂ 3.42 wt%

Frit 3: P ₂ O ₅ 38 wt%, Al ₂ O ₃ 20 wt%, Na ₂ O 16 wt%, B ₂ O ₃ 5 wt%, ZrO ₂ 5 wt%, SiO ₂ 5 wt% and TiO ₂ 11 wt %

Pigment 1: Aluminum pigment (STAPA 8n.1, Ekcart)

Pigment 2: Black pigment (Bayferrox 303T, Lanxess)

Body pigment 1: Non-asbestos talc powder (Youngwoo Resources Co., Ltd.)

Body pigment 2: Mica (Plastorit naintsch super, Imery talc Austria Gmbh)

Catalyst: Tetra (N-butyl) titanate (Super urecoat industries)

Solvent: Xylene (GS Caltex)

[Physical property evaluation]

After preparing a steel specimen subjected to sandblasting (blasting) surface treatment (SIS Sa2½ or SSPC SP10 or higher), spraying the heat-resistant coating compositions of Examples 1-5 and Comparative Examples 1-4 onto the specimens (W-61, Iwata Co., 4.0 bar), to form a coating film having a thickness of 100 to 150 ㎛. The physical properties of each coating film were evaluated according to the following measurement method, and the results are shown in Table 2 below.

Heat resistance test

The steel specimens were placed in furnaces at 600 ° C and 700 ° C and observed whether peeling or cracking of the coating film occurred after 3 hours.

○: no peeling and cracking, ×: peeling or cracking

Cryogenic test (-196 ℃)

After putting liquid nitrogen in the insulation container and soaking the specimen for 30 minutes, it was observed whether peeling or cracking of the coating film occurred.

○: no peeling and cracking, ×: peeling or cracking

Adhesion

After cross-cutting at 2 mm intervals using a cross-cut guide, whether or not peeling occurred by a tape peeling test was observed.

○: no peeling, ×: peeling occurred

Salt spray resistance

After cooling the specimen after 1 hour at 600 ° C, X-cut, and sprayed with 5% NaCl brine in a 35 ° C chamber. Peeling was observed after 120 hours.

○: peeling within 3 mm on one side, ×: peeling exceeding 3 mm on one side

From the results of Table 2, the coating composition of Examples 1-5 comprising the silicone resin and frit according to the present invention was not only secured heat resistance at a temperature of -196 ° C and a high temperature of 700 ° C, but also adhesion and It was confirmed that the salt water spray resistance was also excellent. On the other hand, the coating composition of Comparative Examples 1-3 using only silicone resin without frit did not cause peeling of the coating film at 600 ° C, but peeling occurred at a high temperature of 700 ° C and an extremely low temperature of -196 ° C, and also spray resistance to salt water. It turned out to be poor. In addition, the coating composition of Comparative Example 4 using a frit other than the frit according to the present invention was peeled off at a high temperature of 700 ° C., and the salt spray resistance was also poor.

The heat-resistant coating composition according to the present invention has excellent heat resistance and corrosion resistance, and particularly exhibits excellent durability in a wide temperature range between -200 ° C and 700 ° C.

Claims (4)

1. It comprises a silicone resin and a frit, the frit based on the total amount of the frit, 10 to 35% by weight of phosphorus oxide, 5 to 15% by weight of aluminum oxide, 5 to 75% by weight of alkali metal oxide, 1 to 15% by weight of fluorine oxide, Heat resistant coating composition comprising 0.1 to 10% by weight of silicon oxide, 0.1 to 10% by weight of calcium oxide and 0.1 to 10% by weight of titanium oxide.
2. According to claim 1, Based on the total amount of the frit, P ₂ O ₅ 10 to 35% by weight, Al ₂ O ₃ 5 to 15% by weight, Na ₂ O 5 to 15% by weight, K ₂ O 35 to 60% by weight , OF ₂ , O ₂ F ₂ And O ₃ F ₂ One or more compounds selected from 1 to 15 wt%, SiO ₂ 0.1 to 10 wt%, CaO 0.1 to 10 wt% and TiO ₂ 0.1 to 10 wt% Heat-resistant paint composition.
3. The frit has a coefficient of thermal expansion of 1.0 x 10 ^-6 mm ³ / mm ³ ° C to 2.0 x 10 ^-5 mm ³ / mm ³ ° C, and a softening point of 350 ° C to 400 ° C, particles. Heat-resistant coating composition having a size of 30 to 50 ㎛.
4. According to claim 1, Heat-resistant coating composition comprising 10 to 40% by weight of silicone resin and 3 to 20% by weight of frit based on the total amount of the heat-resistant coating composition.