JPS63306036A - Heat-resistant refractory sheet - Google Patents

Abstract

PURPOSE:To prevent a high temperature object from piercing a sheet by quickly absorbing its retained heat even when the high temperature object such as slag developed in welding comes into contact with the sheet by a specified laminated constitution wherein a hydrous gel layer containing a highly absorptive polymeric substance is empolyed as the center layer of the specified laminated constitution. CONSTITUTION:Moist inorganic fiber layers 2 are laminated to both the sides of a hydrous gel layer 1 containing highly absorptive polymeric substance in direct contact with the hydrous gel layer 1 and further both the sides of the resultant laminate are covered by moisture-evaporation-proof films 3, and the whole assembly is enclosed by sealing its peripheral edge. When a high temperature object H such as slag developed in welding comes into contact with a sheet S, the anti-water-vaporization film 3 in the surface layer zone immediately burns away or melts, and the high temperature object H comes into contact with a heat resistant inorganic fiber layer 2, which is kept under moist state and, the rear surface of the layer 2 is in direct contact with a hydrous gel layer 2, which holds a large quantity of water, the high temperature object H is cooled down by the evaporation heat of the water supplied from the hydrous gel layer, resulting in eliminating the fear for burning or melting the inorganic fiber layer 2.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention protects combustible materials, materials, equipment, etc. existing on the floor or near the work site from spatter that is scattered during welding and fusing operations, for example. The present invention also relates to heat-resistant and fire-resistant sheets that are used as fire-proof sheets and fire-proof curtains to prevent burnout and spread of fire caused by flames during use of burners, and also as non-combustible sheets that also serve as soundproofing.

[Prior art] During welding work such as gas welding and shielding gas welding, or cutting work, a portion of molten metal (so-called slag) drips downward due to its own weight, or is spattered by gas pressure, arc force, etc. It may scatter around welding work and cause burnout and heat loss to the floor and various equipment.

In order to prevent these problems, methods are used to protect various materials and equipment placed on or around the floor of welding work sites with heat-resistant and fire-resistant sheets. Such heat-resistant and fire-resistant sheets include glass fiber cloth and carbon fiber. Heat-resistant fabrics such as cloth, asbestos boards, composite sheets in which metal foil such as aluminum foil or heat-resistant synthetic resin layers are laminated on the surface of these heat-resistant fabrics, and impregnated sheets impregnated with heat-resistant synthetic resins are known. There is.

However, these known heat-resistant and fire-resistant sheets have the following drawbacks.

■Glass fibers or carbon fibers alone may melt or decompose and penetrate if they come into direct contact with slag, which can reach temperatures exceeding 1000°C.

■Those impregnated with general organic polymers easily thermally decompose and emit smoke, sometimes emitting harmful gases, and do not function as heat-resistant and fire-resistant sheets.

■Even sheets impregnated with heat-resistant resin such as silicone resin are not completely non-combustible and cannot reliably prevent ignition and smoke generation. Moreover, it is very expensive in terms of materials and lacks versatility.

■In the case of a sheet with metal foil laminated on its surface, it can only provide a slight heat shielding effect against radiant heat, and hardly any improvement in heat resistance can be expected.For example, when used as a slag protection sheet, the retained heat of slag The metal foil easily melts and creates through holes in the sheet. In this case, in order to obtain the heat resistance and fire resistance of the metal itself, it is necessary to use a fairly thick thin metal sheet, which makes the thin metal sheet less flexible, so when used as a protective sheet for various materials and equipment. Not only is it troublesome to handle, but it is also difficult to cut at the work site.

In addition, for example, JP-A-49-39998, JP-A No. 58-
Publications such as No. 97372 and No. 58-121970 describe a fiber base material impregnated with a hydrogel (so-called water gel) containing a superabsorbent polymer substance as an initial fire extinguishing cloth used to prevent kitchen fires. is listed. This fire-fighting cloth has improved heat resistance by utilizing the heat-absorbing effect of water contained in water gel and the heat-absorbing effect of water evaporation, and is slightly different from conventional fire-resistant sheets that utilize the heat resistance of the material itself. It can be said that it belongs to

However, in these water gel-impregnated fire extinguishing cloths, the water gel is only impregnated into relatively small gaps between the stitches in the fiber base material, so the overall water retention capacity cannot necessarily be said to be sufficient. Although it can exhibit a certain degree of extinguishing effect against relatively low-temperature fire sources such as deep fryers, it is not used for insulation protection from high-temperature objects such as welding slag that can reach temperatures exceeding 1500℃. When you use
Insufficient water retention immediately manifests as a lack of endothermic action (cooling action), and the water evaporates due to the heat of the high-temperature object, and the fiber base material is further burnt out or melted, allowing the high-temperature object to penetrate and lose its insulation protection effect. .

[Problems to be Solved by the Invention] The present invention has been made with attention to these circumstances, and its purpose is to quickly dissipate retained heat even when it comes into contact with a high-temperature object such as welding slag. The object of the present invention is to provide a heat-resistant and fire-resistant sheet that absorbs heat and lowers the temperature of the object and exhibits an excellent heat-insulating protection effect without causing penetration of high-temperature objects.

[Means for Solving the Problems] The structure of the sheet of the present invention that has achieved the above object is that a wet inorganic fiber layer is formed on both sides of a hydrous gel layer containing a superabsorbent polymer substance. The gist is that the laminate is laminated so as to be in direct contact with the other layers, and both sides of the laminate are coated with a film to prevent moisture volatilization, and the periphery of the film to prevent moisture volatilization is sealed. .

[Function] The heat-resistant and fire-resistant sheet of the present invention, for example, as shown in FIG. The laminate is laminated so as to be in direct contact with the gel layer 1, and both sides of the laminate are coated with a moisture volatilization prevention film 3.3, and the periphery of the film 3.3 is sealed to form the entire sheet-like laminate. The heat-resistant and fire-resistant function is demonstrated as follows when it comes into contact with a high-temperature object.

That is, as shown in FIG. 2, for example, when a high-temperature object H such as welding slag comes into contact with the sheet S of the present invention, the moisture volatilization prevention film 3 on the surface layer immediately burns out or melts, and the high-temperature object H is made of heat-resistant inorganic material. It will come into contact with the fiber layer 2.

In this case, with conventional fire-resistant sheets made only of inorganic fibers, even if they are made of heat-resistant fibers such as glass fibers or carbon fibers, they are burned out or melted by the heat of the high-temperature object, and the high-temperature object H is exposed to the back side of the sheet. Even if a water gel-impregnated sheet is used, the cooling and cooling effect on the high-temperature object H is insufficient because it does not retain enough moisture, and a large amount of heat remains even after the retained moisture evaporates. The heat is applied directly to the fiber base material, burning it out or melting it, and the high-temperature object H also penetrates to the back side of the sheet.

On the other hand, since the inorganic fiber layer 2 in the heat-resistant and fire-resistant sheet of the present invention is kept in a moist state, the high-temperature object H
Only the moisture in the fiber layer 2 evaporates under the heat of
Since the fiber layer 2 is in direct contact with the inorganic fiber layer 2, even if the water present in the fiber layer 2 evaporates, water is immediately replenished from the hydrous gel layer 2 as shown by the arrow in FIG. 2
is kept constantly moist. Therefore, even if the high-temperature object H has a considerable amount of heat, it is reliably cooled by the heat of evaporation of the water replenished from the hydrous gel layer. As a result, there is no fear that the inorganic fiber layer 2 will burn out or melt due to an increase in temperature due to insufficient water retention.

That is, in the present invention, the high-temperature object is supported by the heat-resistant inorganic fiber layer 2 in a wet state, and a sufficient amount of water can be retained by combining the hydrogel N1 as a replenishment source for water that evaporates due to the heat of the high-temperature object H. This is to secure the high temperature object H and rapidly cool it to prevent it from penetrating.

In addition, the moisture volatilization prevention film 3 has the function of preventing moisture from evaporating during storage, and also prevents moisture from evaporating from the periphery of the laminate S. The films 3 are glued and sealed together at their peripheries.

As is clear from the above description, the material constituting the hydrogel layer 1 must be capable of retaining a large amount of water in a layered manner, and must be highly absorbent (in this specification, it must be capable of absorbing a large amount of water). It is a general term for substances that swell and give high viscosity, and those containing water-dispersible substances become a water-containing paste, which is also included in the hydrogel). Representative examples of such polymeric substances include the following.

(Natural polymers) Sodium alginate, gelatin, soy protein, vegetable protein, starch, guar gum, gum arabic, gum tragacanth, agar,
Locust Bingham, carrageenan, pectin, chitin, etc. (Synthetic polymers) Polyacrylate, polyacrylamide, polyvinyl acetate hydrolyzate, polyvinylpyrrolidone, methylcellulose, carboxymethylcellulose, hydroxypropylmethylcellulose, polyethylene oxide, or others For various super absorbent resins, such as starch-based resins, starch-
Acrylonitrile graft polymer, starch-acrylic acid graft polymer, starch-styrene sulfonic acid graft polymer, starch-vinyl sulfonic acid graft polymer, etc.: For cellulose, cellulose-acrylonitrile graft polymer, cellulose-styrene sulfonic acid graft polymer, etc. cross-linked polymers of carboxymethyl cellulose, etc.: Polyvinyl alcohol-based products include polyvinyl alcohol cross-linked polymers, acrylic-vinyl acetate saponified products, etc. Niacrylic-based products include polyacrylate cross-linked products, saponified polyacrylonitrile-based polymers, etc.: polyethylene oxide-based products Then, there are polyethylene glycol diacrylate cross-linked polymers, various copolymers and various modified polymers that use these as basic polymers, etc.

These polymeric substances can be used alone or in a mixture of 2 fi or more, and if necessary, they can be used in combination with chelating agents, crosslinking monomers, natural or synthetic water-containing granules, etc. to improve viscosity and shape retention. It is possible to further increase the Furthermore, water-swellable inorganic substances such as bentonite may be added to increase water content and shape retention, or inorganic fillers (
For example, calcium carbonate, talc, silica, alumina,
The strength of the gel is increased by adding a small amount of clay, aluminum hydroxide, etc., the evaporation of water is suppressed by adding a small amount of a high-boiling point solvent, and even small amounts of preservatives, ultraviolet absorbers, antifreeze agents, etc. are mixed in. It is also possible to prevent deterioration and putrefaction (particularly viscosity reduction) of the hydrogel layer.

The hydrogel layer composed of these polymeric substances functions as a hydrous layer for replenishing moisture to the inorganic fiber layer as described above, and in principle, the layer is composed of the hydrogel itself. However, in some cases, it is also possible to improve shape retention by impregnating a relatively thick nonwoven fabric mat with a low fiber density with a hydrogel.

Next, heat-resistant inorganic X* is laminated on both sides of the hydrogel layer.
The fibers function as a support layer for cooling water, which is the main support for high-temperature objects such as welding slag, and also serve as a support layer to support the hydrous gel layer from the back side. Specific examples of fiber materials include glass fibers, carbon fibers, rock wool fibers, asbestos fibers, metal fibers, ceramic fibers, etc. These may be blended or non-woven. I don't mind.

There are no restrictions on the type of material used for the film to prevent moisture volatilization, as long as it is moisture-impermeable, but the most common ones include polyolefins such as polyethylene and polypropylene, as well as polyvinylidene chloride, polyester, and nylon. Examples include synthetic resins, metal foils such as aluminum and stainless steel, and laminate films thereof.

When metal foil or metal foil laminate film is used, it is preferable because the outer surface of the sheet has a beautiful metallic color, which gives it a good appearance, and it also has the additional effect of further increasing the heat insulation effect by reflecting radiant heat. However, if it is used near a welding area, the radiant heat reflection effect may cause problems such as reflections on welding workers, so in such cases, the surface of the metal foil should be roughened or It is desirable to apply a treatment such as applying matte paint.

Next, a typical manufacturing method for heat-resistant and fire-resistant sheets will be explained.

First, two sheets of cloth-like material constituting the inorganic fiber cloth 2 are laminated with the film 3 for preventing moisture volatilization on one side, and a large amount of water (approximately 10 to 200 times the amount) of a super absorbent polymer material is prepared. Prepare a hydrogel by dissolving and dispersing it in Then, one sheet of the above-mentioned bonded material is spread on a flat plate with the cloth-like material facing upward, both edges of which are slightly raised, and the above-mentioned hydrogel is cast on top of this, or by roll coating or reverse coating. Apply to a predetermined thickness using a coating method or the like. In addition, in this application process, if a method is adopted in which the water-containing gel is applied after being heated to 50 to 80°C to reduce its viscosity, and then cooled and solidified into a gel-like state, uniform application can be achieved with smooth application workability. A thick hydrogel layer 1 is obtained. In addition, if a method is adopted in which a relatively low-viscosity aqueous polymer liquid is applied and then a gelling agent is applied to the top surface by a spray method or the like to gel it, a hydrogel layer can be formed in a relatively low-viscosity state. Since the hydrogel layer 1 can be coated with the same coating method, the formation workability of the hydrogel layer 1 is good and the hydrogel layer with a uniform thickness can be easily obtained.

The type of gelling agent should be selected depending on the type of polymer substance used, such as borates such as borax and potassium borate, antimony compounds, chromates, alkali metals, alkaline earth metals, copper group, iron. various metal salts and heavy metal salts such as
Examples include various organic acids and inorganic acids, metal hydroxides and carbonates, and various alkalis such as ammonia and amines, and these may be used alone or in combination of two or more as necessary.

The thickness of the hydrous gel layer 1 can be adjusted according to the required degree of heat and fire resistance, and there are no particular restrictions imposed on it, and it can be changed arbitrarily within the range of, for example, about 0.1 to 10 mm. be able to.

After forming the hydrogel layer 1 in this way, place the other bonded material prepared earlier (inorganic fiber cloth 2 + moisture volatilization prevention film 3) with the inorganic fiber cloth 2 facing down. The method of zero-periphery sealing, in which the heat-resistant and fire-resistant sheet of the present invention is obtained by laminating the above hydrogel layer 1 on the upper surface and then sealing the periphery of the bonded product, is not limited at all.
A heat-sealing method using a heat-sealable film, an adhesive sealing method using an adhesive such as an adhesive or a hot-melt adhesive, etc. are employed as appropriate. The inorganic fiber cloth 2 is naturally lubricated by the moisture transferred from the hydrous gel Fi in the above manufacturing process, but if necessary, it may be lubricated by immersion in a water tank, roll adhesion, spray adhesion, etc. prior to the above lamination process. The inorganic fiber cloth 2 can also be kept moist.

It is of course possible to commercialize the heat-resistant and fire-resistant sheet of the present invention as a plate-like product of a predetermined size, but considering the continuity of the production process and the convenience of transportation, storage, and use, it is most preferable to use a suitable sheet. It is commercialized as a rollable band with a width (for example, about 30Co1 to 150cm). In this case, for example, as shown in Fig. 3, if a dividing seal part sh that can be cut at appropriate intervals in the width direction and/or length direction of the long strip sheet is provided, the width can be adjusted according to the heat insulation protection area. It is extremely convenient because it can be cut into pieces and used.

[Example] Example 1 Glass ISL fiber cloth (plain weave sheet: thickness 0.2 +u
Prepare two laminated sheets made by laminating aluminum foil on the back side of +), spread one of the laminated sheets on a flat plate with the glass fiber cloth on top, and add 5% by weight of locust Bingham on top of this. A highly viscous polymeric aqueous solution containing 100% polyester is heated to 80'°C and coated using the knife coating method to a thickness of 2 cm.1st, it is cooled and the top surface of the hydrous gel, which has hardened into a pudding-like shape, is coated. In preparation, another laminated sheet is placed on top of the other with the glass fiber cloth facing down, and then the periphery of the upper and lower laminated sheets is sealed with a film made of aluminum foil laminated with polyethylene to form the heat-resistant and fire-resistant sheet of the present invention. Obtained.

This heat-resistant fireproof sheet was placed on the underside of the welding test stand (height 10 cm).
), carbon dioxide gas arc welding (30cm width, 3 reciprocations) was carried out, and when the falling slag was caught on the heat-resistant fire-resistant sheet, the slag was rapidly cooled as the water vapor evaporated, and there was no burning or penetration burnout of the heat-resistant fire-resistant sheet. I was not able to admit.

Example 2 Instead of the locust Bingham-containing hydrogel of Example 1,
A heat-resistant and fire-resistant sheet was obtained in the same manner as in Example 1, except that a hydrogel layer constituent material formed by impregnating a 2-mm-thick low-density glass fiber nonwoven fabric with a highly viscous polymer aqueous solution containing 3% by weight of locust Bingham was used. Ta.

When this sheet was subjected to the same fire resistance test as in Example 1, no combustion or slag penetration was observed.

Comparative Example 1 When two sheets of only the glass fiber cloth used in Example 1 were laminated and subjected to the same fire resistance test as in Example 1, the glass fibers were found not only in large particles of slag but also in areas where relatively small particles had fallen. It melted, creating a through hole, and the slag penetrated all the way to the back side.

Comparative Example 2 Locust Bingham 3 was added to the same glass fiber cloth as above.
After impregnating and adhering a viscous aqueous solution containing % by weight and removing the viscous substance adhering to both sides, the same aluminum foil as used in Example 1 was laminated on both sides to obtain a fireproof sheet.

When this sheet was subjected to a fire resistance test in the same manner as in Example 1, it was found that although it was able to prevent the penetration of extremely small particles of slag and spatter, moisture instantly evaporated in areas where medium to large particles of slag had fallen, and the glass The fibers melted, creating through-holes, and a satisfactory protective effect could not be obtained.

[Effects of the Invention] The present invention is configured as described above, and its effects are summarized as follows.

■The heat possessed by high-temperature substances such as slag and the heat caused by flames, etc.
Since the water contained in the inorganic fiber layer and the water replenished from the hydrous gel layer are taken away by the endothermic action and heat of evaporation and rapidly cooled, there is no risk of the inorganic fiber layer heating up excessively and melting. Side flooring and protected materials can be reliably protected.

■The water-containing gel layer, which serves as the water supply source to the inorganic fiber layer, is made of a polymeric material with extremely high water absorption, and since it can achieve its purpose with a very small amount of polymeric material, it can be provided at an extremely low cost. Can be done.

-Since the laminated structure is symmetrical from top to bottom, it can be used without distinction between the front and back sides, and if the film on the front side is burnt out and its appearance deteriorates, it can be turned over and reused, making it economical. It is.

■It is flexible and easy to handle, and it is safe and does not pose any health hazards like those associated with conventional asbestos boards. In addition, it has excellent shape retention and appropriate hardness as a whole, so
There is no problem with stability when walking on the sheet.

■Since it has the characteristics shown in ■～■ above,
Slag catchers in welding work can be used in a wide range of practical applications, such as protective sheets and flameproof curtains for areas where various high-temperature substances may be scattered. It can also be used as a protective sheet for exposed equipment, equipment, and the human body.

[Brief explanation of the drawing]

Fig. 1 is an enlarged cross-sectional schematic diagram showing the basic structure of the sheet of the present invention, Fig. 2 is an enlarged schematic diagram of the main part to explain the state when exposed to high-temperature substances, and Fig. 3 is a schematic enlarged cross-sectional diagram showing the basic structure of the sheet of the present invention. FIG. 2 is a partially cutaway perspective view showing an embodiment of the present invention. 1... Hydrogel layer 2... Inorganic fiber layer 3.
・・Film for preventing moisture volatilization sh ・・Seal part for separation

Claims (1)

[Claims] A wet inorganic fiber layer is laminated on both sides of a hydrogel layer containing a superabsorbent polymeric substance so as to be in direct contact with the hydrogel layer, and both sides of the laminate are further covered with a film to prevent moisture volatilization. Additionally, a heat-resistant and fire-resistant sheet characterized in that the periphery of the moisture volatilization prevention film is sealed.