JPH0250143B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a heat-insulating paint with excellent high-temperature heat insulation properties. Insulating materials are important materials from the viewpoint of resource and energy conservation, and in particular, the walls of heaters, heating equipment, heating heat sources, high-temperature reaction towers, and even heat storage devices and piping used for heat transport are exposed to high-temperature atmospheres. Preventing heat dissipation from the walls of these vessels and preventing overheating accidents are important issues in terms of energy conservation, occupational safety and health, and disaster prevention. development was desired. Such heat insulating materials must have heat resistance that can withstand an atmosphere of 200 to 400°C, so it is considered difficult to use organic materials, and various inorganic heat insulating materials have been developed. From the viewpoint of heat insulating materials, various types of organic heat insulating materials with closed cell structures such as polyurethane foam, polystyrene foam, and polyethylene foam have been developed, and are considered suitable as heat insulating materials. However, the heat resistance temperature during long-term use is 150℃ or less. On the other hand, inorganic heat insulating materials include inorganic binders such as calcium silicate and alkali silicate filled with fibers such as asbestos, insulating molded products with a partially foamed structure, or simply inorganic fibers such as glass fiber, asbestos, and rock wool. An insulation method has been adopted in which these materials are used and coated on the vessel wall, but it is difficult to apply to complex shapes, and insulation work tends to be carried out on-site, and construction is not completely carried out as designed. This makes it difficult to confirm. Furthermore, these insulation methods utilize the insulation effect of the presence of air between the vessel wall and the insulation material, and utilize this micro air layer, which has the effect of lowering the temperature of the outside surface of the insulation material that is not in contact with the high-temperature heat source. However, the insulation material absorbs excess heat from the high-temperature heat source, resulting in a large amount of energy loss. A major drawback of these conventional inorganic insulation materials is that they can only be applied to the outer surface of the vessel wall of the high-temperature heat source to be protected, and cannot prevent heat loss due to heat conduction through the vessel wall material. However, there was a desire to develop a heat insulating paint that would reduce heat loss due to heat conduction through the wall material. However, the development of paints with excellent high-temperature resistance, especially binders, is a major challenge in the paint industry. However, the adhesion to metals, bending resistance, water resistance, and chemical resistance are insufficient, while organic binders have the problem that their normal insulation temperature is often below 150℃ as mentioned above. Ta. As an organic binder, organopolysiloxane binders are known to have excellent heat insulation properties at temperatures above 200°C, and although they are widely used as heat-resistant paints, there are various limitations in the application conditions. However, it has only been used as a high-temperature heat-resistant paint, and it has not been possible to develop a heat-insulating paint that has both excellent high-temperature heat resistance and heat insulation properties. The present inventor has previously completed an invention relating to a solar heat shielding coating composition and a fireproof heat insulating coating as a heat insulating coating material utilizing alkali metal titanate, particularly potassium titanate, and the invention is pending for patent application, but from the viewpoint of resource saving and energy saving. When developing a heat-insulating paint that has excellent high-temperature resistance and can be applied to the inner surface of the vessel wall if necessary,
After learning that there were improvements that could be made in the composition of the paint, heat insulation properties, heat resistance, adhesiveness, etc. that only those who were actually involved in the development could understand, they conducted extensive research and were able to complete the present invention. . The present invention comprises potassium titanate, a silicone resin binder, and if necessary, a high density filler, a high refractive index filler,
The present invention relates to a high-temperature insulation paint containing one or more inorganic fillers selected from platy mineral fillers and other ordinary fillers, a colorant, and an organic solvent. The potassium titanate of the present invention is a compound represented by K ₂ O.nTiO ₂ (where n is a positive real number), and is a fibrous crystal, a crystal powder, a crushed product of a melt, or a powder thereof. Potassium titanate is generally K ₂ O.
Crystals represented by the compositional formula of 4TiO ₂ or K ₂ O.6TiO ₂ are easily produced, and the refractive index of crystals made of these is around 2.4. In the present invention, fibrous crystalline potassium titanate having a high refractive index was particularly suitable. In addition, by treating potassium titanate crystals with an inorganic acid such as hydrochloric acid, washing with water, and drying, potassium titanate crystals with some potassium atoms extracted can be obtained. Potassium titanate crystals from which potassium atoms have been extracted by this method have a composition formula of K ₂ O.
Potassium titanate crystals (abbreviated as LKT) that do not exhibit 4TiO ₂ or K ₂ O/6TiO ₂ (abbreviated as 4TK and 6TK, respectively) and have a low potassium component are obtained. When potassium titanate is dispersed in a commonly used organic binder, any form may be used, but when potassium titanate is dispersed in an organopolysiloxane binder and used as a paint,
Insulating paints can be obtained using any of 4TK, 6TK, and LKT, but LKT is more effective when it comes to heat-resistant paints that require heat resistance of 350°C or higher that use an organopolysiloxane binder. A film with excellent physical properties was obtained. As mentioned above, the potassium titanate of the present invention may be fibrous crystals and crystal powders, crushed melt products or powders as they are, those obtained by acid treatment to partially extract potassium atoms, or those obtained by annealing and oxidation. However, in order to make it even more suitable, the thermal strain within the crystal disappears by reheating the crystal to near its melting point (approximately 1300°C) and then slowly cooling it to room temperature at a cooling rate of 100°C/hr or less. As a result, it was particularly suitable when used in the heat insulating coating of the present invention. The silicone resin binder of the present invention includes an organopolysiloxane binder, a polyacryloxyalkylalkoxysilane binder, a polyvinylsilane binder, and the like. , polydimethylsiloxane, polydiphenylsiloxane, polymethylphenylsiloxane containing at least one substituent such as an allyl group, a hydroxyl group, an alkoxy group having 1 to 4 carbon atoms, an amino group, a mercapto group, and the like. Straight silicone resin such as a copolymer, epoxy-modified silicone resin made by reacting straight silicone resin with epoxy resin, polyester-modified silicone resin made of straight silicone resin, polybasic acid and polyhydric alcohol condensate, straight silicone resin and fatty acid. , a condensate of a polybasic acid and a polyhydric alcohol, or a thick modified silicone resin made by reacting a straight silicone resin with a thick resin, a straight silicone resin and a melamine formaldehyde resin, a urea formaldehyde resin, a benzoguanamine, acetoguanamine, etc., and formaldehyde reacted. A silicone resin binder made of one or a mixture of two or more straight silicone resins and modified silicone resins, such as amino resin-modified silicone resins made by reacting guanamine resins and amino resins such as phenol formaldehyde resins, and polydimethyl For siloxane binders, the CH ₃ /Si ratio is 1.2 or more;
1.8 or less, particularly 1.3 to 1.7 is preferred, and polydiphenylsiloxane, polymethylphenylsiloxane, and copolymers of these polydimethylsiloxane and polydiphenylsiloxane or/and polymethylphenylsiloxane are preferred. Phenyl group-containing polysiloxane compounds such as those of combinations can be used alone as the binder of the present invention, but modified silicone resins such as epoxy-modified silicone resins, polyester-modified silicone resins, alkyd-modified silicone resins, and amino resin-modified silicone resins When one or a mixture of two or more of the above was used as a binder, excellent heat-resistant adhesive strength, especially heat-resistant adhesive strength at 200 to 300°C, was improved. In addition, when using modified silicone resin or a mixture of modified silicone resin and straight silicone resin as a binder, the polysiloxane component
It is preferable that the binder component contains 20% by weight or more, preferably 30% by weight or more, and if the polysiloxane component is 20% by weight or more, the heat resistance is extremely excellent even at 200° C. or higher. For the organopolysiloxane binder of the present invention, epoxy resins, polyester resins, alkyd resins, amino resins, acrylic resins, and even ethylene-vinyl acetate copolymers, which are commonly used as paint binders, are used as binders. Inside, polysiloxane component is 20% by weight
It can be used in combination with the organopolysiloxane binder of the present invention as long as it does not fall below. The polyacryloxyalkylalkoxysilane binder used in the present invention has the general formula (R is a monovalent hydrocarbon group having 1 to 10 carbon atoms, R' is hydrogen or a monovalent hydrocarbon group having 1 to 12 carbon atoms, R'' is a divalent hydrocarbon group having 2 to 10 carbon atoms, and n is 1-3
an acryloxyalkylalkoxysilane compound represented by (an integer of

[Formula] [X is H, CH ₃ or Cl, Y is hydrogen, Cl, carbon number 1
~10 monovalent hydrocarbon groups, vinyl phenyl groups, pyridyl groups, 2-oxo-1-pyrrolidinyl groups, nitrile groups,

【formula】 【formula】

A group selected from [Formula], (where R' is the same as above, Z is OCH ₂ CH ₂ OH,
OCH ₂

Free radical initiation with one or a mixture of two or more of α, β-unsaturated compounds or derivatives thereof represented by [Formula] NH ₂ , N-methylol group, N-alkoxymethylol group) Mention may be made of polymers obtained from reactions in the presence of agents and organic solvents. Examples of monovalent hydrocarbons suitable as R and R' in the acryloxyalkylalkoxysilane compound include alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl, and decyl, phenyl, naphthyl, tolyl, Aryl groups such as xylyl, cumenyl, and ethyl phenyl, aralkyl groups such as benzyl, α-phenylethyl, β-phenylethyl, and α-phenylbutyl, and examples of divalent hydrocarbon groups suitable as R″ include ethylene, trimethylene, and tetramethylene. , hexamethylene, octamethylene, etc. General formula used in the present invention

Examples of suitable α,β-unsaturated compounds or derivatives thereof represented by the formula (where X and Y are the same as above) include vinyl chloride, vinylidene chloride, vinyl acetate, vinyl propionate, vinyl acetate, styrene, Vinyl compounds such as vinyltoluene, divinylbenzene, vinylpyridine, vinylpyrrolidone, acrylonitrile, methacrylonitrile, methyl acrylate, ethyl acrylate, butyl acrylate,
Acrylic acid esters such as 2-ethylhexyl acrylate and lauryl acrylate, methacrylic acid esters such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate and lauryl methacrylate, acrylic acid, acrylamide, N- Methyloracrylamide, N-methoxymethylacrylamide, N-butoxymethylacrylamide, glycidyl acrylate, 2-hydroxyethyl acrylate, methacrylic acid,
These include acrylic and methacrylic compounds having reactive groups such as methacrylic acid amide, N-methylol methacrylamide, N-methoxymethyl methacrylamide, N-butoxymethyl methacrylamide, glycidyl methacrylate, and 2-hydroxyethyl methacrylate. In the polyacrylooxyalkylalkoxysilane binder of the present invention, it is necessary that the binder contains at least 20% by weight, preferably 30% by weight or more of the acrylooxyalkylalkoxysilane compound. Oxyalkylalkoxysilane compounds have particularly excellent heat resistance within this range. In addition, the polyacrylooxyalkylalkoxysilane binder of the present invention may include acrylic and methacrylic compounds having reactive groups, particularly acrylamide and its derivatives such as N-methylolacrylamide, N-methoxymethylacrylamide, N-butoxymethylacrylamide, etc. It is preferable that glycidyl methacrylate, 2-hydroxyethyl methacrylate, etc. be contained in the binder in an amount of 5 to 20% by weight, and it is particularly preferable that acrylonitrile be contained as another compound in an amount of 5 to 30% by weight. Ta. The characteristics of using the polyacrylooxyalkylalkoxysilane binder of the present invention are that it gives favorable results in adhesion to metal, flexibility of coating film, water resistance, boiling water resistance, and weather resistance. Oxyalkylalkoxysilane
20-50% by weight Acrylonitrile 5-30 〃 Reactive acrylic compound 5-20 〃 Acrylic acid or methacrylic acid ester
The polyacrylooxyalkyl alkoxysilane binder has a copolymer composition of 5 to 60 〃 and exhibits an intrinsic viscosity [η] of 0.5 to 2.0 in dimethylformamide solution at 30°C, which has excellent adhesive properties, water resistance, weather resistance, and heat resistance. It was suitable for In the binder of the present invention, the general formula [B is OR' or OR''-OR'(R' and R'' are the same as before)
Similar to acryloxyalkylalkoxysilane compounds, vinylsilane compounds represented by

[Formula] (X, Y are the same as above) A polymer is produced by reaction with one or a mixture of two or more of its derivatives (X, Y are the same as above) in the presence of a free radical initiator and an organic solvent. are obtained, and the binder of the present invention can also be obtained by using these vinylsilane compounds in equivalent substitution with an acryloxyalkylalkoxysilane compound or in combination. Suitable examples of the vinyl silane compound of the present invention include R' being a methyl, ethyl, propyl or butyl group,
R'' is a compound having an ethylene, trimethylene, or tetramethylene group.The high temperature heat-resistant heat insulating coating of the present invention includes the potassium titanate and silicone resin binder according to the present invention, and if necessary, commonly used colorants and inorganic It can be obtained by using a filler, an organic solvent, etc. in combination, but it was particularly suitable to use a high density filler, a high refractive index filler, and a plate-like mineral filler as an inorganic filler.Applicable to the present invention. High-density filler is especially
2.8 or higher, such as dolomite, aragonite, abatite,
Powders of spinel, corundum, zircon minerals or synthetic minerals, fused phosphorous fertilizers as solid solvents or similar compositions produced by the same method, frits, as well as powder granules, fibers and foams of high-density glass. be. Further, the high refractive index filler is preferably one having a refractive index of 1.50 or more, and the high-density fillers exemplified above all have a refractive index of 1.50 or more and are suitable inorganic fillers for the present invention. Such high density, high refractive index fillers include dolomite (SG2.8~2.9 n1.50~1.68) magnesite (SG3.0~3.1 n1.51~1.72) aragonite (SG2.9~3.0 n1.53~ 1.68) Apatite (SG3.1~3.2 n1.63~1.64) Spinel (SG3.5~3.6 n1.72~1.73) Corundum (SG3.9~4.0 n1.76~1.77) Zircon (SG3.9~4.1 n1. Powders of crushed natural and synthetic minerals such as silicon carbide (SG3.17 n2.65-2.69) were suitable, and molten phosphorus fertilizer was suitable as a solid melt. As the platy mineral filler, there are clay minerals, mica minerals, etc., and natural and synthetic mica powders are particularly suitable. The inorganic fillers of the present invention can be used alone or mixed in any proportion, but in particular apatite, zirconside, zircon flour, synthetic spinel, corundum, etc. can be supplied at relatively low cost and can be used as a solid melt. Frits are readily available, and fused phosphorus or its analogues are inexpensive materials that can be processed into granules, fibers, and foams, making them suitable for improving thermal insulation and reinforcing coatings. It was hot. In addition, it is possible to use ordinary fillers such as colored pigments and extender pigments that are commonly used as the inorganic filler of the present invention, but it is also possible to use inorganic minute hollow bodies with a high refractive index such as shirasu balloons and alumina balloons. It was effective. The heat insulating paint of the present invention is characterized by using potassium titanate, a silicone resin binder, and if necessary, a coloring agent, an inorganic filler, an organic solvent, etc., and special attention must be paid to the mixing ratio thereof. be. In the present invention, the ratio of potassium titanate and silicone resin binder (expressed by weight unless otherwise specified) is 25 to 2000 parts, particularly 50 to 1000 parts of silicone resin binder to 100 parts of potassium titanate. department, and even
It was suitable to use 100 to 500 parts. The mixing ratio of these cannot be strictly specified depending on the type of silicone resin binder used, but in general, the silicone resin binder is mixed in the above 25 to 100 parts of potassium titanate.
A content in the range of 2000 parts is preferable because the binding force of the binder is high, the coating function is fully exhibited, and the heat insulating effect is also excellent. In addition, in the case of using an inorganic filler in the present invention, 10 to 90 parts of potassium titanate, the inorganic filler
In the range of 90 to 10 parts, the binder is 25 to 2000 parts, especially 50 to 1000 parts, and even 100 to 100 parts.
500 copies was suitable. There was an interaction between the mixing ratios of potassium titanate and the inorganic filler, and especially excellent heat insulation properties were exhibited when 20 to 70 parts of potassium titanate and 80 to 30 parts of the inorganic filler were mixed. The insulating paint of the present invention contains potassium titanate, a silicone resin binder, and if necessary, a coloring agent and an inorganic filler.
It consists of a mixed dispersion of organic solvents, and its manufacturing method includes, for example, an organic solvent solution of a silicone resin binder, potassium titanate, a coloring agent, an inorganic filler, and a curing aid for a commonly used silicone resin binder. ,
It can be manufactured by mixing and dispersing a dispersant, a viscosity modifier, etc. using a high-speed rotating mixer, roll mill, ball mill, sand mill, etc. In addition, as a method for forming a coating film made of the heat insulating paint of the present invention, coating methods commonly used for the paint of the present invention, such as brush coating, air spray coating, airless press coating, and furthermore, dip coating, etc. can be applied. At this time, a diluting solvent may be added if necessary. Painted items using this method can be kept at room temperature or if necessary, at 150°C.
By heating and drying at ~200°C for about 20 to 120 minutes, a coating film of the heat insulating paint of the present invention can be obtained. The present invention will be explained below with reference to Examples. Example 1 Potassium titanate (manufactured by Otsuka Chemical Co., Ltd.) 20 parts, straight silicone resin binder (Toshiba Silicone Co., Ltd.)
solid content of methoxy group-containing phenylmethylsiloxane and dimethylsiloxane copolymer) 60
% xylene solution was stirred at high speed for 5 minutes using a TK Lab mixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) to obtain a white heat insulating paint with a non-volatile content of 68%. Example 2 A 60% xylene solution of 15 parts of potassium titanate, 10 parts of zircon flour, and an epoxy-modified silicone resin binder (manufactured by Toshiba Silicone Corporation, trade name: TSR194) 75%
Using the same method as in Example 1 below, the mixture was made into a paint.
A white heat-insulating paint with a non-volatile content of 70% was obtained. Example 3 A four-neck separable glass flask (capacity 500 ml) equipped with a stirrer, cooling tube, nitrogen introduction tube, and dropping funnel was placed on a hot water bath, and after purging with nitrogen, 40 parts of acetone and 60 parts of toluene were added. γ-methacrylopropyltrimethoxysilane
35 parts acrylonitrile 15 parts glycidyl methacrylate 10 parts 40 parts butyl methacrylate were sequentially charged and after stirring, 10 parts of a 10% azobisisobutyronitrile (AIBN) acetone solution was added.
After reaction for 16 hours with stirring while maintaining the liquid temperature at 80°C, the mixture was cooled to room temperature to obtain a resin liquid with a nonvolatile content of 45%. A portion of the above resin solution was taken, petroleum benzine was added to precipitate the resin, this precipitate was redissolved with acetone, and the resin was further precipitated with petroleum benzine, and then heated at room temperature for 48 hours.
Using a purified resin sample that had been vacuum dried for an hour,
When measuring the intrinsic viscosity [η] of DMF solution,
[η] A result of 1.5 dl/g was obtained. A coating was prepared in the same manner as in Example 1 using 80 parts of the resin liquid obtained by the above method, 10 parts of potassium titanate, and 10 parts of aluminum oxide powder.
A 56% white paint was obtained. Example 4 Vinyltri(β-methoxyethoxy)silane 30 parts Acrylonitrile 20 parts N-butoxymethylacrylamide 10 parts Methyl methacrylate 10 parts Butyl methacrylate A reaction was carried out in the same manner as in Example 3 except that 30 parts were used. A resin liquid of 44% and [η] 1.8 ^r /g was obtained. A white paint with a non-volatile content of 55% was obtained in the same manner as in Example 3 using the resin liquid obtained as described above. Comparative Example 1 A white pigment was obtained in the same manner as in Example 1 except that a titanium oxide pigment (manufactured by Ishihara Sangyo Co., Ltd.) was used instead of potassium titanate in Example 1. Comparative Examples 2 and 3 White pigments were obtained in the same manner as in Examples 2 and 3, except that a titanium oxide pigment was used instead of potassium titanate in Examples 2 and 3. Test Example 1 The paints of Examples 1 to 4 and Comparative Examples 1 to 3 were applied to the surface of a steel pipe with an inner diameter of 10 cm, a steel pipe wall thickness of 0.8 mm, and a length of 50 cm, and then baked and dried to obtain a specimen for insulation testing. Ta. The above test specimen was connected to the exhaust port of a hot air drying oven with an exhaust temperature of 200°C, and changes in the surface temperature of the coating film were measured. Table 1 shows the results.

[Table] Examples 5 to 12 Insulating paints were obtained in the same manner as in Example 1 or Example 3 using the components and proportions listed in Table 2. The resulting paint was subjected to a heat insulation test using the same method as in Test Example 1, and the results are also shown in Table 2. In addition, in Example 7, potassium titanate from which the potassium component was removed by acid treatment was used,
Further, in Example 12, potassium titanate obtained by annealing and oxidizing the acid-treated material and then slowly cooling was used.

【table】

Claims (1)

[Claims] 1. A high-temperature heat-insulating paint comprising potassium titanate and a silicone resin binder. 2 Claim 1 further contains one or more inorganic fillers selected from high-density fillers, high refractive index fillers, platy mineral fillers, and other ordinary fillers. high temperature insulation paint. 3. The high-temperature insulation paint according to claim 1 or 2, which further contains a colorant and an organic solvent. 4. The high-temperature insulation paint according to any one of claims 1 to 3, wherein 25 to 2000 parts by weight of a silicone resin binder is used per 100 parts by weight of potassium titanate. 5. The high-temperature heat insulating paint according to any one of claims 2 to 3, wherein the inorganic filler is in the form of granules, micro hollow bodies, or foamed granules. 6 Potassium titanate 10-90 parts by weight, inorganic filler 90
10 parts by weight of a silicone resin binder and 25 to 2000 parts by weight of a silicone resin binder.