JPS6137105B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a fireproof heat insulating sheet. More specifically, the inorganic core material is (A) a silanol-based hydroxyl end-blocked diorganosiloxane resin, (B) a crosslinking agent made of an alkyl silicate or a hydrolyzable silane compound, (C) a curing catalyst, and (D) titanic acid. The present invention relates to a fire-resistant heat-insulating sheet characterized by being covered with a coating layer containing an alkali as a main component. Traditionally, it has been used in manufacturing plants to protect the human body from the high temperatures and scorching iron powder that scatters during the steelmaking process, and to protect the human body and surrounding combustible materials and equipment from the slag that scatters during welding or fusing operations. For this purpose, asbestos fibers, aluminum foil, and sheets mainly made of flame-retardant plastics are used. However, all of these currently used refractory insulation materials have their own drawbacks, so they cannot be said to be satisfactory for their purposes. That is, materials mainly composed of asbestos fibers lack durability in terms of mechanical strength, fire resistance, and the like. Also, those made mainly of aluminum foil have good heat resistance against radiant heat, but because of their poor mechanical strength, slag from welding or fusing easily penetrates when collided with them, so the protective effect is small. Furthermore, those made mainly of flame-retardant plastics are not only virtually ineffective against scorching iron powder and slag, but may even decompose due to the heat of the iron powder or slag, producing toxic gases. In addition to the above-mentioned conventional sheets, composite sheets have also been proposed in which asbestos fibers or a coating layer is provided on the surface of glass fiber cloth, but the coating layer of these sheets has low heat resistance, and is also free from high-temperature iron powder. It is also impractical because it is easily perforated when the slag collides with it. In addition, a fireproof sheet has been proposed in which a silicone varnish layer in which a scale-like heat-resistant inorganic substance and an inorganic pigment are dispersed is provided on the surface of glass fiber cloth. Although it has improved fire resistance, it has poor insulation properties, and because it uses polysiloxane with a three-dimensional network structure obtained by hydrolyzing organochlorosilanes as a silicone varnish, it tends to become rigid, making it practical as a fireproof sheet. Considering the texture of the sheet, workability, etc., it is recommended to use a self-extinguishing rubber-like silicone varnish with a three-dimensional network structure. There were drawbacks, and it was difficult to adjust the texture of the fireproof sheet. As outlined above, conventional fireproof insulation materials each have their own merits and demerits, and none are satisfactory.
Improvements have been requested, but in recent years there has been a movement to ban the use of sheets made mainly of asbestos fiber, which has traditionally been the most widely used material, due to concerns about carcinogenicity, mainly in Western countries. This is a fact that deserves attention. Based on the above facts, the present inventors have endeavored to create a more excellent fire-resistant insulation material, and have developed an alkali titanate and silicone resin composition that already has excellent fire-resistant insulation properties and has solved health problems such as carcinogenicity. We have made proposals regarding fire-resistant heat-insulating coating compositions, sheets, and films, and we have made earnest efforts to improve the industrial applicability of such technologies, and have arrived at the present invention. An object of the present invention is to provide a sheet material that has excellent fire resistance and heat insulation, and particularly has a high reflective effect against radiant heat. Yet another object of the present invention is to provide a stable sheet material that will not decompose, burn or melt when in contact with hot materials such as slag. Still another object of the present invention is to provide a safe sheet material that will not be perforated even if it is hit by flying hot slag or the like. The features of the present invention will be explained in detail below. Component (A) used in the present invention is a silanol-based hydroxyl-terminated diorganosiloxane resin used in condensed polysiloxane compositions, which exhibits particularly good coating properties when applied to the surface of inorganic fabrics and forms an excellent film after curing. It provides suitability as a covering material such as formability, bending resistance, mechanical strength, and texture, and 25
Preferably, the viscosity at °C is in the range of 100 to 200,000 cst. If the viscosity is less than 100 cst, the flexibility after curing will be insufficient, and even for fireproof and heat insulating sheets that do not require much elongation, a decrease in texture and flexibility will be observed; However, it is difficult to obtain a homogeneous composition as it is; for example, even if a diluting solvent is used as an auxiliary agent, a large amount of solvent is required to achieve a viscosity suitable for coating, and it is difficult to obtain a homogeneous composition on the surface of the inorganic fabric. It becomes difficult to form a coating layer, and coating workability deteriorates. Therefore, the preferred range is from 100 to 100 in terms of harmonizing the properties of the composition before and after curing.
It is in the range of 150000cst, especially preferably 500~
If a polyorganosiloxane resin containing 50,000 cst contains at least 50% by weight of the component (A) and has a viscosity adjusted to a range of 1,000 to 100,000 cst, coating workability and bending resistance will be improved. It has excellent texture, texture, and miscibility with various inorganic compounds according to the present invention. Examples of organic groups directly bonded to silicon atoms include alkyl groups such as methyl, ethyl, propyl, butyl, and hexyl; alkenyl groups such as vinyl and allyl; aryl groups such as phenyl; Examples include aralkyl groups such as phenylethyl groups, and monovalent substituted hydrocarbon groups such as 3,3,3-trifluoropropyl groups, chloromethyl groups, and β-cyanoethyl groups, but methyl groups are preferred for ease of synthesis. , monovalent hydrocarbons such as vinyl or phenyl groups are generally preferred;
Other organic groups are recommended only to impart special properties to the cured rubber-like elastomer, such as oil resistance or paintability. Among these, methyl groups are easily obtained when the raw material intermediate has them, and the viscosity when the organosiloxane is polymerized is low, which improves the extrusion workability of the composition before curing and the physical properties of the rubber elastic body or coating composition after curing. It is preferable that 85% or more of all organic groups be methyl groups, and it is more preferable that substantially all organic groups be methyl groups, in order to maintain an advantageous balance. Component (B) used in the present invention serves as a crosslinking agent,
It cures by reacting with the silanol hydroxyl group of component (A), and is currently in practical use as an acetic acid or long-chain carboxylic acid releasing type, an organic amine, amide, or organic hydroxylamine releasing type, or an oxime, alcohol, or acetone releasing type. It can also be used in combination with a crosslinking agent. However, acetic acid and long-chain carboxylic acid releasing types, organic amine, amide, and organic hydroxylamine releasing types may cause odor, corrosion of coating equipment during the crosslinking process, pollution of the working environment, etc., and oxime and acetone releasing types may cause There are problems such as difficulty in synthesis. On the other hand, the alcohol-releasing type can be manufactured easily at a low cost, has reduced environmental pollution problems, has less corrosion of coating equipment, etc., and is advantageous in terms of industrial applicability. Although the crosslinking agent is not particularly limited in the present invention, dealcoholization type crosslinking agents, which were conventionally considered to be difficult to put into practical use due to their low cost, low toxicity, and reduced adverse effects on adherends, can also be used. : R ¹ x-Si-(OR ² ) _4-x (wherein, R ¹ and R ² are monovalent substituted or unsubstituted hydrocarbon groups such as alkyl groups and aryl groups, and x is a real number from 0 to 4) ), alkyl silicates such as tetramethyl silicate, tetraethyl silicate, tetraalkyl silicate, tetrabutyl silicate, and their condensates, methyltrimethoxysilane, ethyltrimethoxysilane, butyltrimethoxysilane, dimethyl Alkyloxyallylsilanes such as dimethoxysilane, dimethyldimethoxysilane, dimethyldibutoxysilane, methyltriphenoxysilane, dimethyldiphenoxysilane, ethyltriphenoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyl Tripropoxysilane, phenyltributoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane or phenylalkoxysilane, etc., and substantially have two or more alkoxy groups, phenoxy groups, etc. per silicon atom, preferably
Cross-linking agents with 2.5 or more bonds are economical,
Preferable in terms of labor safety and mechanical properties. However, compared to alkoxy groups, phenoxy groups have inferior reactivity with component (A).Although they are advantageous in adjusting the storage stability and pot life during the coating process of coating compositions,
Tetraethyl orthosilicate and its condensates or methylalkoxysilanes are difficult to use due to the fact that the reaction requires a long time, high temperature, and long heating time, and methoxy groups, ethoxy groups, etc. are supplied cheaply and in large quantities on the market. Use is recommended. The crosslinking agent that is component (B) of the present invention is not limited to the general formula: R ¹ xSi−(OR ² ) _4-x (wherein R ¹ , R ² , and x are the same as above). Any commonly used material can be used as long as it reacts with the silanol hydroxyl group of component (A) to cure the composition. These include the general formula: (In the formula, R ¹ and x are the same as above, and R ³ is an alkyl group) which releases acetic acid or long-chain carboxylic acid, such as methyltriacetyloxysilane, dimethyldiacetyloxysilane, methyltripropylcarbonyl Oxysilane, dimethyldipropylcarbonyloxysilane, methylacetyloxydipropylcarbonyloxysilane, methyltributylcarbonyloxysilane, dimethyldibutylcarbonyloxysilane, etc. alone or in a mixture of two or more, general formula: (In the formula, R ¹ , R ³ , x are the same as above).
Dimethyl(dimethylethylcarboximinooxy)silane, etc. alone or a mixture of two or more, general formula: R ¹ xSi(NR) ³ _4-x (wherein R ¹ , R ³ , x are the same as above) It is an amine-releasing type represented by methyltri(dimethylamino)silane, dimethyldi(dimethylamino)
Silane, methyltri(methylethylamino)silane, dimethyldi(methylethylamino)silane,
These are various crosslinking agents such as methyltri(dimethylamino)silane, dimethyldi(diethylamino)silane, etc. alone or in a mixture of two or more. Component (C) used in the present invention is a catalyst that cures the composition through the reaction of components (A) and (B), including iron octoate, zinc octoate, tin octoate, cobalt octoate, and manganese octoate. , lead octoate, iron naphthenate, titanium naphthenate, zinc naphthenate, tin naphthenate, cobalt naphthenate,
Metal carboxylates such as lead naphthenate, tin caprylate, tin oleate, zinc stearate, dibutyltin diacetate, dibutyltin dioctate, dibutyltin laurate, phenyltin diacetate, dibutyltin oxide, dibutyltin methoxide, etc. Organotin compounds, organic titanate esters such as tetrapropyl titanate, tetrabutyl titanate, and tetraoctyl titanate, diisopropoxybis(acetylacetonato)titanium, diisopropylbis(ethylacetoacetato)titanium, 1,3-propylenedioxy Titanium chelate compounds such as bis(ethylacetoacetate) titanium, N,N-dimethylaniline,
Examples include tertiary amines such as dimethyloctadecylamine and γ-(tetramethylguanidino)propyltrimethoxysilane. Component (D) of the present invention has the general formula: M ₂ O・aTiO ₂・bH ₂ O (wherein, M is an alkali metal such as Li, Na, K, etc., a is a positive real number of 8 or less, and b is 0. It is a well-known compound represented by Li ₄ TiO ₄ , Li ₂ Ti ₃ (in the formula, 0<a<1,
alkali titanate with a salt-type structure represented by b=0), Na ₂ Ti ₇ O ₁₅ , K ₂ Ti ₁₆ O ₁₃ , K ₂ Ti ₈ O ₁₇ (wherein a<6, b=0) These include alkali titanate with a tunnel structure. Among these, potassium hexatitanate and its hydrate, which is represented by the general formula: K ₂ O・6TiO ₂・bH ₂ O (in the formula, b is the same as above), greatly improve the fire resistance and insulation properties of the final target product. This is preferable in this respect. Not limited to potassium hexatitanate, alkali titanates are generally powder or fibrous microcrystals, but among these, those with a fiber length of 5 μm or more and an aspect ratio of 20
Above, especially those of 100 or more bring about favorable results in improving the strength of the fireproof heat insulating sheet of the present invention. In particular, fibrous potassium titanate has a high specific heat and excellent heat insulating performance, and is particularly preferred for realizing the performance of the fireproof heat insulating sheet of the present invention. In the present invention, ordinary heat-resistant inorganic substances can also be used, and these include micas such as phlogopite, muscovite, and sericite, montmorillonites, graphite scale-like stainless steel fluorine-containing synthetic micas, and others. . The high refractive index inorganic compound used in the present invention has a particularly excellent shielding property against radiant heat, and when the endothermic inorganic compound comes into direct contact with slag during welding or fusing, it is heated at the contact surface and absorbs heat upon contact. Since the reaction occurs and the temperature of the slag is lowered, collapse and penetration of the refractory and heat-resistant sheet of the present invention is suppressed. In the present invention, the high refractive index inorganic compound having a refractive index of 1.5 or more and a specific gravity of 2.8 or more is particularly suitable for improving heat insulation properties. (1) Dolomite (dolomite, specific gravity 2.8 to 2.9) , refractive index
1.50-1.68), magnesite (rhombite, specific gravity
3.0-3.1, refractive index 1.52-1.72), aragonite (specific gravity 2.9-3.0, refractive index 1.53-1.68), apatite (apatite, specific gravity 3.1-3.2, refractive index 1.63-
1.64), spinel (spinel, specific gravity 3.5-3.6, refractive index 1.72-1.73), corundum (specific gravity 3.9-4.0, refractive index 1.76-1.77), zircon (specific gravity 3.9-4.1, refractive index 1.79-1.81), carbonized Silicon (specific gravity 3.17~
3.19, refractive index 2.65-2.67), crushed stone powder of natural or synthetic minerals. (2) Fused phosphorus obtained as a solid solution of frit or high refractive glass or phosphate rock and serpentine;
Other examples include crushed powders or granular materials of similar solid solutions, fibrous materials, and foams. In addition, endothermic inorganic compounds include crystalline releasing type such as calcined gypsum, alum, calcium carbonate, aluminum hydroxide hydrosaltite aluminum silicate, carbon dioxide releasing type, decomposition endothermic type, and phase change type. Compounds can be exemplified. The mixing ratio of components (A), (B), and (C) of the present invention varies depending on the desired type and combination of each component, as well as the purpose of use as a fireproof heat insulating sheet.
Normally (B) for 100 parts (parts by weight, same below) of component (A)
The amount of component (B) is 1 to 30 parts, preferably 3 to 20 parts.If component (B) is less than 1 part, it is difficult to obtain sufficient strength when used as a composition, and on the other hand, if it exceeds 30 parts, the tensile strength and bending resistance are poor. Sexuality decreases. The curing catalyst, which is component (C), is
It ranges from 0.01 to 10 parts, preferably from 0.1 to 1 part. Less than 0.01 part is not sufficient as a curing catalyst;
Not only does it take a long time to cure, but it is also difficult to obtain desired physical properties. On the other hand, if it exceeds 10 parts, it may gel during mixing or significantly increase the apparent viscosity, resulting in decreased workability and storage stability. When component (C) is brought into contact with the mixture of components (A) and (B) of the present invention, the reaction between components (A) and (B) progresses due to humidity and moisture, forming a three-dimensional network structure even at room temperature. Therefore, in order to mix all of the components (A), (B), and (C) in advance, mix them in a state that excludes moisture and store them in a closed container, or (C) Ingredients, (B)
It is appropriate to store the +(C) component separately and to cure it by exposing it to air before use. Both of these reactions are accelerated by heat. Therefore, in the present invention, a homogeneous dispersion of components (A), (B), and (C), alkali titanate as component (D), and a high refractive index inorganic compound and/or an endothermic inorganic compound is prepared. Either mix all the ingredients (A), (B), (C) and (D) in their entire amounts in a state where moisture is removed, or add (D) ingredient to (A) + (B) ingredients. Immediately before coating on an inorganic fabric as a two-component system consisting of a homogeneously dispersed component and (C) component, or a homogeneously dispersed component (A) and (D) component, and (B) + (C) component. There is a method of mixing the two components. The proportions of component (D) used in the present invention are (A), (B), and (C).
Although it varies depending on the type and blending ratio of the components and the type and particle size of the (D) component, in general, if there is too much of the (D) component, the fireproof insulation properties will improve, but there will be drawbacks such as insufficient strength as a fireproof insulation sheet. On the other hand, if the amount of component (D) is too small, the heat resistance will decrease, and in severe cases, flaming combustion may occur. Therefore, in the present invention, the amount of component (D) to be blended is 1 to 200 parts, preferably 30 to 100 parts, based on 100 parts of component (A), and in addition, a high refractive index inorganic compound and (or) When blending endothermic inorganic compounds, the blending ratio of these should be the same as component (A).
400 parts or less per 100 parts, preferably 10~
300 copies. In this case, component (D) may be blended in an amount that is the same as the blended amount of these inorganic compounds but reduced by 1/4 weight. In addition, if part or all of these high refractive index inorganic compounds and endothermic inorganic compounds are used in place of commonly used inorganic pigments, inorganic fillers, inorganic powders that impart flame retardancy, etc. The amount used is not more than 400 parts per 100 parts of component (A),
Preferably it should be no more than 300 copies. The fireproof heat insulating sheet of the present invention can be obtained, for example, as follows. That is, a crosslinking agent consisting of a diorganosiloxane resin, an alkyl silicate or a hydrolyzable compound, an alkali titanate, a high refractive index inorganic compound and/or an endothermic inorganic compound, toluene, xylene,
Add an organic solvent such as trichlene and additives such as a dispersant to create a dispersion liquid with an appropriate concentration. A curing catalyst is added to this dispersion, or all of these species or the organic solvent is omitted, and the mixture is homogeneously dispersed in a state where moisture and water are removed, and the resulting dispersion is used as it is or immediately before coating with an organic solvent. In addition, it is diluted and coated with glass fiber cloth, asbestos sheet, rock wool sheet, metal foil, ceramic wool sheet by conventionally well-known coating methods such as dipping, spraying, roll coating, reverse roll coating, and knife coating. The polydiorganosiloxane is cured by applying it to one or the entire surface of an inorganic fabric such as special inorganic fiber cloth, and heat-treating it at room temperature or under heat, preferably within the range of 150 to 200°C, for 1 to 30 minutes. It is put into practical use by being integrally fixed to the material. In the present invention, in addition to components (A), (B), (C), and (D), there are dispersants and defoamers for homogeneous dispersion, colorants for adjusting color and mechanical strength, resin powder, Flame retardants and various other fillers can be freely mixed. However, metal powders such as copper powder, nickel powder, etc. to improve the surface heat reflection effect and penetration suppression effect,
Brass powder, aluminum powder, etc. should be mixed in immediately before coating on the inorganic fabric from the viewpoint of storage stability, and when using these metal powders or when the inorganic fabric is metal foil (B As the crosslinking agent for component (), an alkyl silicate or alkoxysilane type crosslinking agent should be used, and other crosslinking agents should be avoided as they generally tend to corrode metal powder or metal foil. The thickness of the fireproof insulation sheet of the present invention is preferably
0.1mm or more and 3mm or less is preferable. If the thickness is less than 0.1 mm, sufficient fireproof insulation properties cannot be obtained, and if the thickness is less than 3 mm,
If it exceeds mm, the fire resistance and insulation properties will improve, but the cost will increase and the weight will increase, making it impractical. However, the fireproof heat insulating sheet of the present invention is not only made by coating components (A), (B), (C) and (D) on the surface of a single sheet of inorganic fabric, but also by pressure bonding or coating of several layers of these. Before the layer dries, other inorganic fabrics are layered, and components (A), (B), (C), and (D) are coated on the surface of the layer, and then the layers are cured. Can be used. As described above, the fire-resistant insulation sheet of the present invention has extremely excellent fire-resistant insulation properties and can form a flexible coating layer, and when it comes into direct contact with high-temperature molten slag etc. generated during welding, etc. However, the coating layer only turns white and does not burn, decompose, or melt, making it possible to create a trowel that completely protects objects to be protected, such as the human body, combustible materials, and equipment. Moreover, it is advantageous in that it is lightweight and has excellent toughness and heat ray reflection properties.Also, when an alkyl silicate, especially tetraethyl orthosilicate and its condensate, or an alkoxysilane, especially methyltrimentoxysilane is used as a crosslinking agent, these crosslinking agents Compared to other crosslinking agents, it is easy to handle due to its low cost and low toxicity, and has extremely high chemical utilization. The present invention will be specifically explained below with reference to Examples, but these are, of course, for illustrative purposes only and are not intended to define the scope or scope of the spirit of the invention. Example 1 100 parts of silanol hydroxyl end-blocked dimethylsiloxane resin with a viscosity of 20,000 cst at 25°C,
Potassium titanate (trade name Teismo D, manufactured by Otsuka Chemical Co., Ltd.) in a mixture of 15 parts of tetraethyl orthosilicate and 0.3 parts of dibutyltin dilaurate.
Add in various proportions and stir and mix to make a uniform dispersion. This was applied to one side of 0.5 mm thick asbestos paper in various thicknesses, air-dried for 5 minutes, and then
Heat treatment was performed at 150°C for 5 minutes to produce a fireproof heat insulating sheet in which one side of the asbestos paper was covered with a silicone resin layer containing potassium titanate. This sheet was cut to a size of 100 cm in width and 180 cm in length to prepare test samples (No. 1 to No. 9). A fire resistance and insulation test was conducted according to the "Flame Retardant Test Method", and Table 1 shows the measurement results and comparative results using commercially available asbestos (Class 3A).

[Table] Example 2 Viscosity at 25°C of silanol hydroxyl end-capped dimethylpolysiloxane resin is 20000cst and 3000cst
40 parts and 60 parts respectively, 15 parts of tetraorthoethylsilicate, 50 parts of potassium titanate (as above), 30 parts of zinc oxide, and aluminum hydroxide.
A uniform dispersion consisting of 150 parts of xylene and 100 parts of xylene was obtained. A mixture of 100 parts of this dispersion and 0.1 part of dibutyltin dioctoate was applied to one side to a thickness of 0.2 mm, dried and hardened, and then coated with a silicone resin containing potassium titanate, zinc oxide and aluminum hydroxide. A coated fireproof insulation sheet was obtained. When this sheet was evaluated by the above-mentioned fire resistance and heat insulation test method, it was classified as Class A. Example 3 8 mol % diphenylsiloxane units were mixed with 100 parts of a silanol hydroxyl end-capped dimethyldiphenylsiloxane resin consisting of the remaining dimethylsiloxane units and having a viscosity of 20,000 cst at 25°C and 15 parts of methyltrimethoxysilane. A fireproof sheet was produced in the same manner as in Example 2, and evaluated by the fireproof and heat insulation test method described above, and found to be Class A. Examples 4 to 13 Fireproof heat insulating sheets were prepared in the same manner as in the previous example by changing the type and amount of the inorganic core material, the type and amount of silicone resin, the type and amount of alkali titanate, and the type and amount of other auxiliary materials. The above-mentioned fire resistance and insulation test was conducted, and the measurement results and commercially available asbestos (3A
Table 2 shows the results of a comparison using the same grade.

【table】

[Table] In Table 2, Resins 1, 2 and 3 represent the resins of Examples 1, 2 and 3, respectively. Explanation of abbreviations in Table 2 TES: Tetraethylsilicate MTMS: Methyltrimethoxysilane DMDMS: Dimethyldimethoxysilane PTMS: Finyltrimethoxysilane.

Claims (1)

[Scope of Claims] 1 The inorganic core material is (A) a silanol-based hydroxyl end-blocked diorganosiloxane resin, (B) a crosslinking agent comprising an alkyl silicate and/or a hydrolyzable silane compound, (C) a curing catalyst, and (D) a fire-resistant heat insulating sheet characterized by being covered with a coating layer mainly composed of alkali titanate. 2. The sheet according to claim 1, wherein the coating layer contains a high refractive index inorganic compound and/or an endothermic inorganic compound as an auxiliary constituent material. 3 The silanol hydroxyl end-capped diorganosiloxane resin has a viscosity (25°C) of 500 to 50,000 cst.
3. The sheet according to claim 1, wherein the sheet contains at least 50% by weight of the total amount of components (A), (B), and (C).