JPS6360605B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a protective cover for protecting objects from fire, and particularly to a cover suitable for protecting overhead communication cables. Various efforts have been made to protect overhead communication cables from damage caused by fire. A typical example is a cylindrical body made of flame-retardant material that is loosely fitted into the cable or messenger wire.
The idea is to provide heat insulation by the cylinder and heat insulation by the air between the cylinder and the cable, and a corresponding effect has been obtained. For example, an FRP pipe is used as the cylindrical body, but even though it is made of a flame-retardant material, combustion is inevitable when exposed to temperatures above a certain level, and the cylindrical body is burnt and dissipated. However, there still remains the problem that the cables are exposed to fire due to melting and dripping, and communication becomes impossible within a short period of time, or the cables are burnt out and broken. The present invention was developed in view of the above circumstances, and it does not melt and drip even if it is ignited by a flame, and even after combustion, it maintains a heat insulating effect and protects cables and the like for a relatively long period of time. The purpose is to provide a protective cover that can be used. The present invention will be described in detail below based on drawings showing embodiments thereof. FIG. 1 is a perspective view showing a state in which a protective cover according to the present invention is applied to protect a communication cable. This cover includes a cable 11 and a messenger wire 13 supporting the cable 11 by a hanger 12.
A gutter-shaped main body 14 has a cylindrical shape with an inner diameter that can comfortably accommodate the combination of the above, and has a cross section of an arc longer than a semicircle, and the main body 14 has a slightly larger diameter than the main body 14 to cover the opening. The lid body 15 has a cross section of a shorter arc than a semicircle, and the two are integrated into a cylindrical shape by overlapping their respective ends to form a cylinder at the site of use. Now, the cover of the present invention has these main body 14 and lid body 15.
It is characterized by the material it is made of and the structure of its surface layer. This will be explained in detail below. This cover can be classified as so-called FRP, and is made of resin molded using heat-resistant fiber as a reinforcing material and using this as a skeleton. First, the heat-resistant fibers and the metal mesh will be explained. First, the material of the heat-resistant fiber may be appropriately selected from glass wool, asbestos, carbon fiber, rock wool, ceramic wool, phenolic resin fiber (for example, Kynol: trade name), etc., but glass fiber and phenolic resin fiber are preferable. It is. The form may be a woven fabric or non-woven fabric using long fibers, or a short fiber fabric with a length of 3 to 15 mm, and in the case of the former, it is a laminate consisting of multiple (2 to 6) stacked fiber layers with a thickness of 0.1 to 1.0 mm. In the case of the latter, the resin is dispersed and mixed in the molding resin described later. Next, the material of the metal mesh body is stainless steel, copper, brass, iron, aluminum, etc. Next, the material of the metal mesh body is stainless steel, copper, brass, iron, aluminum, etc., and the wire diameter is 0.05 mm to 2 mm. , 5-200
You can use one with mesh openings. Stainless steel and aluminum are good materials because of their corrosion resistance when used outdoors. In any case, any material may be used as long as it can support the cover without deforming for a certain period of time under high temperature and freezing atmosphere, and can also perform the function of supporting the foamed carbonized layer described later without dissipating.
Appropriate material, form, and amount may be determined based on the distance between a combustible object such as a building and an aerial location, expected temperature resistance, economical efficiency, compatibility with the resin used, etc. Next, the molding resin will be explained. This resin is a molding agent whose main purpose is to bond and mold reinforcing materials, that is, the original binder resin (100 parts by weight), a foamed carbon layer forming agent (100 to 500 parts by weight), a flame retardant added as necessary, and a plasticizer. It consists of additives (total less than 100 parts by weight) such as additives, fillers, anti-aging agents, and colorants. Thermoplastic plastics and rubber as the main molding material include thermoplastics such as polyethylene, polypropylene, ethylene monovinyl acetate copolymer, ethylene-ethyl acrylate copolymer, polyester, polyamide, polyvinyl chloride, chlorinated polyethylene, etc. Halogen-containing rubbers such as chloroprene rubber, chlorinated polyethylene rubber, chlorosulfonated polyethylene rubber, epichlorohydrin rubber, brominated polyethylene, ethylene-propylene rubber, ethylene-propylene-diene rubber, natural rubber, acrylonitrile rubber, urethane rubber, Halogen-free rubbers such as styrene-butadiene rubber are preferred, and halogen-containing rubbers are particularly preferred. The foaming carbonized layer forming agent used in the present invention foams the carbonized layer formed by combustion, that is, it forms many layers of carbonized shells having small cavities, and is known per se. For example, the foamable fireproof composition for molding proposed by the applicant (Japanese Patent Publication No. 53-24215) consists of (a) a hydrocarbon polyhydric alcohol, (b) a blowing agent, and (c) ) Compositions consisting of three components of a flame retardant dehydrating agent, etc. include, but are not limited to, the above-mentioned hydrocarbon polyhydric alcohol, a blowing agent that generates bubbles, and a composition that is a flame retardant dehydrating agent. Those containing a flammable dehydrating agent are preferred, and the ratio of each component (a), (b), and (c) and the amount blended in the above-mentioned thermoplastic plastic and rubber may be the same as those shown in the above-mentioned patent publication. As the hydrocarbon polyhydric alcohol used, finely powdered monopentaerythritol is particularly preferred. Of course, other polyhydric alcohols such as dipentaerythol, tripentaerystol, triethylene glycol, etc. may also be used. The foaming agent may be one that releases nitrogen gas, carbon monoxide, carbon dioxide, ammonia gas, etc. upon thermal decomposition, and it is preferable to use a foaming agent in the form of fine powder in order to produce dense and uniform foaming, such as melamine, urea formaldehyde, etc. , organic amines such as aminoacetic acid, organic amides such as dicyandiamide, butyl urea, polyamide resin, halogenated organic compounds such as chlorinated paraffin, parachloromethaxylenol, tetrachlorophthalic acid resin, etc. However, melamine, trimethylolmelamine,
Preferred are hexamethylolmelamine, dicyandiamide, and the like. The flame-retardant dehydrating agent has the function of reacting with the hydroxyl group contained in the hydrocarbon polyhydric alcohol to form a carbonized layer, and is preferably in the form of fine powder from the viewpoint of homogeneous kneading. and ammonium salts such as monoammonium phosphate, diammonium phosphate, ammonium polyphosphate, and ammonium sulfate; phosphoric acid amines such as melamine monophosphate and melamine phosphate; It may be appropriately selected from phosphoric acid amides and sulfuric acid amines such as paranitroaniline hydrogen sulfate, but ammonium polyphosphate is most preferred. Note that the foamed carbonized layer forming agent is not limited to those mentioned above, but may also contain carbohydrates such as starch instead of polyhydric alcohol, and halogen-containing polymers that contribute to improving the mechanical strength of the formed foamed carbonized layer. , may also contain other components. The foamed carbonized layer forming agent may be one that does not itself have a component that forms a carbonized layer and causes the molding base material and additives to become foamed during carbonization; Depending on the additive, even the above-mentioned foaming agent alone can produce sufficient effects. The above-mentioned molding base material may be crosslinked in a state containing a reinforcing material, a foamed carbonized layer forming agent, and other additives. Another feature of the cover of the present invention is that a water-blocking layer is formed at least on the outer peripheral surface layer. The reason for providing this impermeable layer is to prevent the elution and dissipation of the foamed carbonized layer forming agent, particularly the hydrocarbon polyhydric alcohol, due to rainwater cover, and to maintain its function over a long period of time. This water-blocking layer is formed by using a molding resin consisting of the above-mentioned reinforcing material, a molding base material, a foamed carbonized layer forming agent, and necessary additives.
4. After molding or molding cross-linking into the shape of the lid 15, apply a thermosetting resin paint such as unsaturated polyester resin, polyurethane resin, furan resin, epoxy resin, etc. to the outer peripheral surface, or It is formed by immersing it in a storage tank of this paint (in this case, it is formed on both the inside and outside surfaces). Of course, the water-blocking layer may be formed of other resins, or may be formed by winding an adhesive tape of a water-resistant organic polymer, such as polyvinyl chloride. Further, for convenience when attaching the cover to the cable, it is considered that the cover of the present invention is generally formed into a structure in which the main body 14 and the cover body 15 are divided into two as described above, rather than having a cylindrical shape. Therefore, it is necessary to integrate the main body and the lid. This can be done by bolts, nuts, adhesives, etc.; however, in the latter case, it is necessary to select the water-blocking layer adhesive so that the water-blocking layer does not interfere with adhesion. Considering the above points, it is a good choice to use epoxy resin as the main molding agent, the water-blocking layer, and the adhesive. The thickness of the molded part excluding the water-blocking layer is 0.5-8 mm, preferably about 1.0-5 mm, while the water-blocking layer is 0.1-2 mm, preferably 0.3-0.8 mm. Next, the results of a fire resistance test conducted to clarify the effects of the present invention will be explained. Table 1 shows the specifications of the test cover.

【table】

[Table] Protected cable with the above sample [conductor diameter 0.65mm
100 pairs, kraft paper, LAP tape, polyethylene-coated insulation layer (0.15mm thick), outer diameter 25mm relay
PEF-LAP cable] and mesh gear wire, and then put it into the fireproof test furnace and put it into the second
JIS A1301 outdoor grade 2 pattern shown in the figure and
It was heated in accordance with the refractory curve pattern of JIS A1304. Heat resistance was evaluated by dividing 100 pairs of strands into two groups of 100 wires each and measuring the insulation resistance between the two groups (at 500 VDC).
was measured over time, and when it bottomed out to 1MΩ, it was considered that the transmission function had been lost. Table 2 shows the average values for three samples.

[Table] As a comparative example, the above-mentioned sample with the protected cable left exposed and the conventional product [FRP (glass fiber laminated epoxy resin molded product) with approximately the same dimensions as samples 1 and 2]
A pipe] was fitted onto the protected cable. As is clear from these results, the product of the present invention exhibits extremely excellent heat-resistant protection performance. The reason for this excellent heat resistance effect is that a foamed carbonized layer is formed after kava is burned, and this is firmly held by the reinforcing agent.The bubbles act as a heat insulator, preventing thermal deterioration of the internal cable insulation layer This seems to depend on delaying the destruction. As described above, the heat-resistant cover for cables according to the present invention uses heat-resistant fibers or metal mesh as a reinforcing material, and forms a foamed carbonized layer by a heating reaction, or contains a foamed carbonized layer forming agent in a molding resin. Since the cable is made of a resin molding agent containing a water-blocking layer and has a water-blocking layer on at least the outer surface layer, the cable can be temporarily protected from high heat and fire even after the cable is burned, and the emergency contact period can be extended. There is a practical benefit in extending the heat resistance, and such heat-resistant protection performance can be maintained for a long period of time. If the structure is divided into two parts as in the above-mentioned embodiment, it can be easily attached to the existing cable, and if the main body and the lid body are arranged with their longitudinal positions shifted, multiple covers can be installed. The present invention has excellent effects, such as making it easy to protect a large area by connecting the parts.

[Brief explanation of drawings]

FIG. 1 is an external perspective view showing the state of use of the product of the present invention. FIG. 2 is a heating pattern diagram for a fire resistance test. 14...Main body, 15...Lid body.

Claims (1)

[Scope of Claims] 1. A resin molded material containing a foamed carbonized layer-forming agent in a thermoplastic or rubber, which forms or causes a foamed carbonized layer to be formed by a heating reaction, using heat-resistant fibers or a metal network as a reinforcing material. 1. A protective cover against fire, characterized in that the cover is made of a water-resistant material, and is provided with a water-blocking layer on at least the outer peripheral surface layer. 2. The heat-resistant cover for a cable according to claim 1, wherein the heat-resistant fiber is a woven fabric or a non-woven fabric made of long fibers, and is laminated in the resin molding material. 3. The heat-resistant cover for a cable according to claim 1, wherein the metal mesh has 5 to 200 meshes made of wires with an outer diameter of 0.2 to 2 mm, and is laminated in the resin molding material. 4. The heat-resistant cover for a cable according to claim 1, wherein the heat-resistant fibers are short fibers and are dispersed and mixed in the resin molding material. 5. The heat-resistant protective cover according to claim 1, wherein the foamed carbonized layer forming agent contains a hydrocarbon polyhydric alcohol, an organic foaming agent, and a flame-retardant dehydrating agent. 6. The heat-resistant cover for a cable according to claim 1, wherein the water-blocking layer is made of a component contained in a molding resin.