JPH10152633A - Release agent for fire spread preventive coating - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a release agent which swells, softens and releases fire spread preventing coating film of an electric wire or cable a short time irrespective of the shape of the applied surface and which itself is excellent in flame retardancy. SOLUTION: This agent comprises an organic solvent based on benzyl alcohol and optionally containing an aromatic hydrocarbon solvent (e.g. xylene), 40-140wt.%, based on the solvent, water and 1-5wt.%, based on the solvent, surfactant. The surfactants which can be use include glycerol fatty acid esters and polyhlycerol fatty acid esters.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a release agent for fire spread prevention coating, and more particularly to a method for efficiently peeling a cured coating of a fire spread prevention material provided on the outer periphery of an electric wire or cable without damaging a sheath. Related to the release agent.

[0002]

2. Description of the Related Art Conventionally, in a facility such as a nuclear power plant or a thermal power plant in which a large amount of non-flame-retardant cables are laid, the outer periphery of a cable group laid in horizontal and vertical trays, inside a box, or the like. In preparation for a fire accident, ethylene-acrylate copolymer (EE
A) based on an aqueous emulsion containing a thermoplastic resin such as or ethylene-vinyl acetate copolymer (EVA),
An anti-fire spread material (paint) to which an organic flame retardant, an inorganic filler, non-combustible fibers, a plasticizer and the like are added is applied. The applied fire spread material dries and hardens with the passage of time and adheres to the cable sheath, forming a coating having a high fire spread prevention effect.

In the above-mentioned facilities, recently, it is necessary to remove and replace the cable once laid from the ladder tray or the like due to a change of the system, inspection of the cable, or deterioration of the cable. There is a need.

[0004] Conventionally, as a method of peeling a fire spread prevention coating provided on a cable, a method of mechanically peeling with a peeling tool such as a cutter or a hammer, a method of foaming polyurethane or a water absorbing resin, or the like. A method in which water-impregnated material is placed on a fire-prevention coating together with a heater, heated to swell and soften, and then peeled off with a bamboo spatula or the like has been used.

[0005]

However, the former method of mechanically stripping not only requires a lot of manpower and time, but also often does not make it possible to know the thickness of the anti-fire spread coating to be stripped. There is a possibility that the surface of the cable sheath or the like may be damaged at the tip.

Further, in the latter method of swelling by heating using water, the time required for softening is extremely long, that is, two to three weeks. In addition, there is a problem that the method cannot be applied when the construction surface is a vertical surface.

Further, in the interior of a nuclear power plant or the like, it is not preferable to use a material having poor flame retardancy from the viewpoint of fire prevention. Therefore, a release agent for a fire spread prevention coating applied to prevent fire spread of a non-flame retardant cable. Even so, it is required to have sufficient flame retardancy.

The present invention has been made in order to solve such a problem, and it is possible to swell and soften a fire spread coating provided on an electric wire or a cable in a short time regardless of the form of a construction surface. Moreover, it is an object of the present invention to provide a release agent for fire spread prevention coating which itself has excellent flame retardancy.

[0009]

SUMMARY OF THE INVENTION The release agent for fire spread prevention coating of the present invention comprises benzyl alcohol, 40 to 100% by weight of water relative to the benzyl alcohol, and 1 to 5% by weight of benzyl alcohol. And a surfactant.

[0010] The release agent for fire spread prevention coating according to the second invention of the present invention is a release agent applied to an outer periphery of a fire spread prevention coating provided on an electric wire or a cable, wherein the release agent is mainly composed of benzyl alcohol and aromatic hydrocarbon. An organic solvent containing a system solvent, 40 to 100% by weight of water with respect to the organic solvent, and a surfactant of 1 to 5% by weight with respect to the organic solvent.

The anti-fire spread coating to which the release agent of the present invention is applied is an anti-fire spread material obtained by adding an organic flame retardant, a flame retardant aid, an inorganic filler, a non-combustible fiber, a plasticizer, etc. to an aqueous emulsion. Paint) is applied to the outer periphery of electric wires and cables and cured. Here, as the aqueous emulsion,
Vinyl acetate emulsions such as EVA emulsions and acrylic emulsions such as EEA emulsions; organic flame retardants such as chlorinated paraffin, chlorinated naphthalene, decabromodiphenyl oxide, and ammonium polyphosphate; Examples include antimony trioxide, zinc borate, and zinc oxide; and inorganic fillers include aluminum hydroxide (hydrated alumina), calcium carbonate, hydrous magnesium silicate, clay, titanium white, talc, and the like, and non-combustible fibers. Examples thereof include asbestos, ceramic fibers, phenol fibers, and glass fibers. Examples of the plasticizer include phosphate esters such as tris (β-chloroethyl) phosphate, chlorinated biphenyl, and dibutyl phthalate.

[0012] Commercial products of such a fire spread prevention material include:
For example, frame coat (product name of our company), frame mastic (product name of Hitachi Cable, Ltd.), F-coat B
(Trade name of Fujikura Electric Wire Co., Ltd.) and Dannecka (trade name of Furukawa Electric Co., Ltd.). In the release agent of the present invention, benzyl alcohol is used alone as an organic solvent, or a solvent in which benzyl alcohol is blended with an aromatic hydrocarbon solvent so as to account for 50% by weight or less of the entire organic solvent. Is used. Here, as the aromatic hydrocarbon-based solvent, among compounds having a benzene ring, a compound composed of only carbon and hydrogen without containing a different element and usable as a solvent in a liquid state at room temperature is used. , Xylene, toluene, ethylbenzene and the like. In the combination use of benzyl alcohol and an aromatic hydrocarbon solvent, the preferable ratio of the aromatic hydrocarbon solvent in the whole organic solvent is limited to 50% by weight or less, because the preferable ratio is more than 50% by weight of the whole organic solvent. When an aromatic hydrocarbon solvent is blended, the mechanical properties of the PVC sheath,
This is because the strength and the like are undesirably reduced.

In the present invention, 40 to 100% by weight of water is added as a flame-retardant-imparting component to an organic solvent obtained by mixing benzyl alcohol alone or a mixture of benzyl alcohol and an aromatic hydrocarbon solvent. Is done. The amount of water is limited to such a ratio for the following reason. That is, the mixing ratio of water to the organic solvent is 40
When the amount is less than 100% by weight, sufficient flame retardancy cannot be obtained. On the other hand, when the mixing ratio of water exceeds 100% by weight, the softening effect of the obtained release agent on the fire spread preventing coating becomes insufficient. In order to adjust the viscosity (hardness) to a desired value, a large amount of a fibrous substance or the like must be added, which is not preferable.

The surfactant in the present invention is a substance having a hydrophilic group and a hydrophobic group in the molecule, strongly adsorbed on the water-oil two-phase interface, and having a function of remarkably lowering the interfacial tension. For example, glycerin fatty acid esters and polyglycerin fatty acid esters can be used. The amount of these surfactants is 1 to 5% by weight based on the organic solvent obtained by mixing benzyl alcohol alone or benzyl alcohol with an aromatic hydrocarbon solvent. The amount of surfactant is 1 in the organic solvent
When the amount is less than the weight percentage, the organic solvent and water are easily separated. Conversely, if the surfactant is added in an amount exceeding 5% by weight, no further emulsifying and dispersing effect can be obtained.

In the release agent of the present invention, the following adhesives, fibrous substances, flame retardants and the like are blended with these solvents obtained by mixing an organic solvent and water, and the viscosity is adjusted to an appropriate value. At the same time, flame retardancy or low flammability is further provided.

That is, after the solvent penetrates and is absorbed by the anti-fire spread coating, the pressure-sensitive adhesive wraps the remaining components by its own adhesive force and adheres to the outer periphery of the anti-fire spread coating. It has a function of preventing the scattering of components and the like, and a resin latex having a high viscosity of 5000 cps or more, such as an acrylic resin latex (dispersion liquid) or an EVA latex, is used. In addition, in a release agent containing such a latex-based pressure-sensitive adhesive, it is desirable to add a rust inhibitor having a function of suppressing copper corrosion. Here, as the rust inhibitor, benzotriazole (BTA) or a derivative of BTA, 1-methylbenzotriazole, 5-methylbenzotriazole, 1, H-benzotriazole, toltriazole, 2-mercaptobenzothiazole Etc. are used. The amount of such a rust preventive is 1 to 10% by weight, more preferably 2 to 5% by weight, based on the solvent. If the amount of the rust inhibitor is less than 1% by weight of the solvent, the effect of inhibiting the corrosion by the addition does not appear.
No improvement in the rust-preventing effect is observed even when the value exceeds.

Further, a fibrous substance having a function of collecting and solidifying the residual components after the solvent is absorbed and absorbed by the fire spread preventing coating is blended together with the adhesive to prevent scattering of powder components and the like. Removal work or disposal work can be facilitated. Examples of such a fibrous substance include phenol resin fibers and carbon fibers, wood flour, coconut husk powder, cork powder, cellulose powder, wood pulp, paper and cloth powder, and in particular, phenol resin fibers. It is desirable to use KYNOL (trade name of KAINOL CORPORATION) or cellulose powder.

Further, a liquid flame retardant and / or a powdery inorganic flame retardant may be blended. Here, examples of the liquid flame retardant include halogen-containing phosphoric acid esters such as tris (β-chloroethyl) phosphate, tris (dichloropropyl) phosphate and tris (dibromopropyl) phosphate, and organic flame retardants such as chlorinated paraffin. is there. These organic flame retardants stop the chain reaction by trapping OH free radicals generated by high-temperature oxidation of molecules (hydrocarbons) of plastics and the like, and at the same time, promote carbonization of the plastics and the like, thereby decomposing to low molecular weight flammable substances. A mechanism for preventing the generation of substances or a mechanism for generating nonflammable gas serves to suppress the continuation of combustion.

Inorganic flame retardants in powder form include aluminum hydroxide (Al (OH) ₃ ), magnesium hydroxide (Mg (OH) ₂ ), sodium hydrogen carbonate (NaHC).
O ₃ ). These inorganic flame retardants, by the structure water that decomposes and volatilizes by heating acts as a coolant,
Alternatively, by itself performing an endothermic decomposition reaction, it functions to suppress combustion and impart self-extinguishing properties.

The compounding amount of the liquid organic flame retardant is 20 to the above-mentioned benzyl alcohol alone or an organic solvent in which benzyl alcohol is mixed with an aromatic hydrocarbon solvent.
4040% by weight. If the compounding ratio of the liquid organic flame retardant is less than 20% by weight of the organic solvent, no matter how much the powdery flame retardant is added, the flame retardant effect does not increase so much. If it exceeds 40% by weight, the release agent is used. The effect of swelling and softening the fire-prevention coating is reduced, and it takes time until the coating can be peeled off with a spatula. Further, the amount of the powdery inorganic flame retardant is also 100 to 200% by weight based on the organic solvent, and the liquid organic flame retardant is used in order to make the release agent effectively flame retardant. It is desirable that the ratio be adjusted according to the blending amount. If the compounding ratio of the powdered inorganic flame retardant is less than 100% by weight of the organic solvent, in order for the release agent to have a sufficient flame retardant effect, a large amount of the liquid organic flame retardant is added beyond the above-mentioned range. If it is added, the effect of swelling and softening the anti-spreading coating is inevitably reduced. If it exceeds 200% by weight, the release agent becomes too hard and the coating operation becomes difficult, which is not preferable.

In the present invention, depending on the form of the fire spread coating to be coated with the release agent, that is, whether it is a horizontal surface or a vertical surface, or a method of applying the release agent, that is, a spatula coating or a pump, etc. The viscosity (hardness) of the release agent can be adjusted by changing the compounding ratio of the liquid organic flame retardant, the powdery inorganic flame retardant, the fibrous substance, and the like, depending on whether or not the extruder is a mechanical coating extruded.

Further, in the release agent of the present invention, a necessary and sufficient amount of the organic solvent is adsorbed or absorbed and retained on the surface or inside thereof to increase the viscosity, so that a desired and sufficient amount of the organic solvent is applied to a desired portion of the fire spread preventing coating. A holding material having a function of stably adhering can be blended. Here, as the holding material, inorganic fillers such as calcium carbonate, silica, talc, clay, and alumina; powdered rubber; plastic powders such as acrylic resin and PVC; inorganic porous materials such as zeolite; foamed rubber; Organic porous materials such as plastics, water-soluble cellulose ethers such as sodium carboxymethylcellulose (CMC), and thickeners such as sodium acrylate, surfactant, and acrylic can be used. In the case of an inorganic porous material such as zeolite, the mixing ratio of these holding materials is set so that 10 to 30% by weight of the organic solvent is adsorbed to the inorganic porous material. When using an inorganic filler, the amount of the filler is 100 to 300% by weight based on the organic solvent.
Is desirable.

Further, in the present invention, when such a solid component as a holding material or a fibrous substance is blended,
An anti-settling agent having a function of promoting dispersion in a solvent and preventing settling can be added and mixed. As anti-settling agents, silane coupling agents, titanium coupling agents,
Coupling agents such as polymer coupling agents, and fine silica powder having a particle size of several μm. The addition ratio of these anti-settling agents is appropriately selected with respect to the total amount of solid contents such as a holding material.

The release agent of the present invention is a mixture of an organic solvent mainly composed of benzyl alcohol and water, to which a surfactant is added and uniformly mixed and dispersed. And then stirring and mixing until these components are completely dissolved, and further adding and mixing a fibrous substance or a powdery inorganic flame retardant. At this time, it is possible to add a fragrance for the purpose of covering the odor of the solvent.

The release agent of the present invention thus obtained is in the form of a paste, and is applied or adhered to the outer periphery of a fire spread coating provided on electric wires and cables. And
After leaving for 30 hours or more (usually 96 to 120 hours), the anti-spread coating swelled and softened by the penetration of the solvent is peeled off using a wooden or bamboo spatula together with a release agent coating layer.

Here, to apply the release agent, a method of applying a thickness of about 5 to 20 mm using a spatula, a doctor knife or the like is adopted. The reason for setting the coating thickness of the release agent to 5 to 20 mm is that if the coating thickness is less than 5 mm, it is not possible to secure a sufficient amount of solvent to swell and soften the anti-fire spread coating,
This is because, even when applied to a thickness of 20 mm or more, the effect of swelling the fire spread prevention coating does not further increase. Also, the leaving time after applying the release agent was set to 30 hours or more,
If the time is less than 30 hours, depending on the type of the fire spread prevention coating, there is a material that does not swell very much.
The reason for setting the time is that no significant increase in the effect is observed even if the time is left for longer.

The swelling and softening effect of the release agent of the present invention due to its application or application usually reaches a thickness of several millimeters. Therefore, where the anti-fire spread coating is thick, the above-described series of operations is repeated two to three times. Must be completely removed.

Furthermore, a sheet heater such as a band heater, an infrared heater,
By heating to 20 to 50 ° C. using a warm air blower or the like, penetration of the release agent into the fire spread prevention coating and swelling and softening can be promoted, and the release effect can be further enhanced. Heating with such a heater is effective in promoting softening especially when the outside air temperature is low.

Further, an airtight sheet which is impermeable to liquid, such as a sheet of polyethylene, polypropylene, polyethylene terephthalate or the like, or an aluminum foil sheet, is placed directly on the release agent coating layer or on the heater or the like. be able to. When the airtight sheet is covered in this way, the release agent (solvent component) is applied by the sheet.
Transpiration is suppressed and this penetrates efficiently,
Softening of the fire spread coating is further promoted.

In the release agent of the present invention, since a solvent obtained by mixing an organic solvent mainly composed of benzyl alcohol and water is used, the solvent penetrates into the anti-fire spread coating and swells at room temperature for a short time. In addition to being able to soften to the extent that peeling with a spatula etc. is easy, the release agent itself has flame retardancy, even if a fire accident etc. occurs during the peeling work of the fire spread prevention coating, The release agent is not ignited and burns, and the spread of fire is effectively prevented. In addition, since a surfactant is added and the organic solvent and water are uniformly mixed, they are not separated from each other, and have excellent storage properties and good coating workability.

[0031]

Embodiments of the present invention will be described below.

Examples 1 to 4 First, our frame coat was applied to the outer periphery of a PVC sheath cable (outer diameter 12 mm) so that the thickness after drying was 15 mm, and was dried and cured to form a fire spread prevention coating.

Next, a release agent having the composition shown in Table 1 was prepared as shown below. That is, polytron (trade name of acrylic latex of Asahi Kasei Kogyo Co., Ltd.) and Poem (trade name of Riken Vitamin Co., Ltd.) as a surfactant were added to benzyl alcohol at the ratios shown in the table, respectively. After stirring the mixture until the latex was dissolved, the mixture was mixed with water and mixed with stirring. Next, KC floc (trade name of cellulose powder of Nippon Paper Industries Co., Ltd.) as a fibrous substance and Heidilite (trade name of aluminum hydroxide of Showa Denko KK) as an inorganic flame retardant were added to the cloudy solution. In each of Examples 2 to 4, SX-6013 (trade name of Takasago International Corporation) was added and kneaded to obtain a paste-like release agent.

For comparison, water and a surfactant (no additive was added in Comparative Example 4), a pressure-sensitive adhesive, a fibrous substance, and a mixture of benzyl alcohol alone or a mixed solvent of benzyl alcohol and xylene were used. Powdered inorganic flame retardants and the like were added and mixed in the composition shown in the same table to prepare release agents.

Next, the release agent obtained in each of the examples and the comparative examples was applied to the outer periphery of the above-mentioned fire spread coating of the cable to a thickness of 15 mm, and left for 120 hours. The hardness was measured in accordance with JIS K6301 A, and the thickness of the fire spread prevention coating that can be peeled off with a single application of the release agent was measured. In addition, a peeling test using a spatula was performed to evaluate the peelability. Further, a burning test of the release agent was performed according to JIS K7201 to evaluate the flame retardancy and measure the oxygen index. Further, the release agents obtained in Examples and Comparative Examples were left for 5 days, and the presence or absence of separation between the organic solvent and water was examined. The results of these measurements are shown in the lower column of Table 1.

[0036]

[Table 1] As is clear from the table, benzyl alcohol has 40-
100% by weight of water and 1 to 5% by weight of a surfactant were added and mixed, and a latex-based pressure-sensitive adhesive, a fibrous substance, and a powdery inorganic flame retardant were mixed. The agent can swell and soften the anti-spread coating of the cable over a thickness of 4 to 5 mm to the extent that it can be peeled off with a spatula, etc., for a specified standing time (96 to 120 hours). The oxygen index in the test is large and extinguishes immediately after ignition. Further, even if left for a long time, benzyl alcohol as a solvent and water hardly separate from each other, so that storage is easy and coating workability is good.

On the other hand, water is added to benzyl alcohol.
In the release agent of Comparative Example 1 in which more than 100% by weight was blended and further 1 to 5% by weight of a surfactant, an adhesive, a fibrous substance, and the like, benzyl alcohol and water were easily separated. In addition, the swelling and softening effect on the fire spread prevention coating is not sufficient, and the thickness of the fire spread prevention coating that can be peeled off by one application is thin. Further, in the stripping agent of Comparative Example 2 in which a solvent obtained by mixing 40 to 100% by weight of water and less than 1% by weight of a surfactant with an organic solvent obtained by mixing benzyl alcohol and xylene, the organic solvent was used. And water are easily separated, and a release agent uniformly mixed and dispersed cannot be obtained. Furthermore, in the organic solvent obtained by mixing benzyl alcohol and xylene, water is not mixed at all, or even if it is mixed, the compounding amount is less than 40% by weight of the organic solvent. It has a low oxygen index and does not have sufficient flame retardancy such as continued combustion after ignition. In particular, since the powdery inorganic flame retardant was not blended in the release agent of Comparative Example 4,
It does not have flame retardancy and burns very well.

[0038]

As is clear from the above description, according to the release agent of the present invention, the release agent is applied only to the desired portion of the fire spread prevention coating, and swells and softens in a short time to easily release. And there is no risk of damaging the cable sheath. In addition, the release agent itself has flame retardancy, and even if a fire accident occurs during the work of peeling the fire prevention coating, the release agent does not ignite and burn, and the fire spread effectively. Is prevented. Further, since the surfactant is added, the organic solvent and water are not uniformly mixed and dispersed, and are not separated, so that the storage property is excellent and the coating workability is good.

[0039]

Claims (3)

[Claims] 1. A release agent applied to an outer periphery of an anti-fire spread coating provided on an electric wire or a cable, comprising: benzyl alcohol;
A release agent for fire spread prevention coating, comprising 40 to 100% by weight of water and 1 to 5% by weight of a surfactant based on benzyl alcohol. 2. A release agent applied to an outer periphery of a fire spread prevention coating provided on an electric wire or a cable, comprising: an organic solvent mainly containing benzyl alcohol and containing an aromatic hydrocarbon solvent; A flame-retardant coating release agent comprising 100 to 100% by weight of water and 1 to 5% by weight of a surfactant based on an organic solvent. 3. The release agent according to claim 1, wherein the surfactant is a glycerin fatty acid ester or a polyglycerin fatty acid ester.