JP2002309126A - Release agent for flame spread prevention coating - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a release agent for a flame spread prevention coating, which is possible easily to swell and to soften in a short time, provided on a wire and a cable regardless of a shape or the like of an applied face thereof, further does not badly influence the wire and a cable sheath, and it itself has excellent flame retardancy. SOLUTION: The release agent for the flame spread prevention coating provided on the wire and the cable comprises a mixed solvent comprising benzaldehyde or acetylacetone of 10-30 wt.% and a benzyl alcohol of 70-90 wt.%, an aqueous emulsion, a liquid organic flame retardant, and an inorganic flame retardant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stripping agent for efficiently stripping a cured coating of a fire spreader provided on the outer periphery of an electric wire or cable.

[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-flammable electric wires and cables are laid, in order to prepare for a possible fire accident, the use of electric wires and cables is required. Application of a fire spread inhibitor to the outer periphery is performed. The applied fire retardant hardens with the passage of time and adheres to the electric wire / cable sheath, forming a coating having a high fire spread prevention effect.

[0003] Recently, in such facilities, due to system changes and deterioration of electric wires and cables, etc.,
Opportunities to remove laid wires and cables from ladder trays and the like have increased, and the following problems have arisen accordingly.

[0004] That is, a flame retardant such as an inorganic hydrate is conventionally added to an aqueous emulsion of an ethylene-acrylic acid ester polymer (EEA) or an ethylene-vinyl acetate copolymer (EVA) as the fire spread inhibitor. A large amount is added, but they form an extremely hard cured body and are in close contact with the wires and cables, making it difficult to peel them off. There is a possibility that the wires, cables, ladder trays and the like may be damaged.

[0005] For this reason, there is a demand for a technique capable of easily peeling off such an applied fire spread preventing agent without damaging the surroundings. For example, water is contained in urethane foam or the like, and this is mixed with a heating element. Place it on the cured fire retardant, soften it by heating, then peel it off with a bamboo spatula, or after swelling and softening the anti-fire spread coating with a stripping solution containing an organic solvent such as dichloromethane, likewise a bamboo spatula There has been proposed a method of stripping the film.

[0006]

However, in the method of heating and softening using water, the time required for softening is long, and depending on the type of fire spread preventing agent, there are some which do not soften sufficiently. There is a problem that it cannot be applied in the case of vertical.

The method using a stripping solution containing an organic solvent such as dichloromethane has a problem that not only does the fire spread coating swell, but also the wire and cable sheaths swell.

Further, in a facility such as a nuclear power plant, it is not preferable to use a material having poor flame retardancy from the viewpoint of fire prevention.

[0009] The present invention has been made in view of such a point, it is possible to swell and soften the fire prevention coating provided on the wires and cables in a short time irrespective of the form of the construction surface. An object of the present invention is to provide a release agent for fire spread prevention coating which does not adversely affect electric wire / cable sheaths and has excellent flame retardancy itself.

[0010]

Means for Solving the Problems In order to achieve the above object, a release agent for fire spread prevention coating of the present invention is a release agent used for a fire spread prevention coating provided on electric wires and cables,
10-30% by weight of benzaldehyde or acetylacetone
And a benzyl alcohol of 70 to 90% by weight, an aqueous emulsion, a liquid organic flame retardant and an inorganic flame retardant.

In the release agent having the above constitution, a mixed solvent of benzaldehyde or acetylacetone and benzyl alcohol mixed at a specific ratio is used as a solvent, and an aqueous emulsion, a liquid organic flame retardant and an inorganic flame retardant are added to these solvents. I decided to mix
It can swell and soften in a short time regardless of the type of construction surface, etc., the fire-prevention coating provided on the wires and cables, and it does not adversely affect the wires and cable sheaths, and is itself excellent flame retardant It has nature.

In the present invention, as described in claim 2, 100 parts by weight of the mixed solvent is added to the aqueous emulsion 1
It is preferable to contain 30 parts by weight, 20 to 60 parts by weight of a liquid organic flame retardant, and 20 to 80 parts by weight of an inorganic flame retardant. With this configuration, the above-described effects are further improved and stabilized.

As described in claim 3, the release agent for fire spread prevention coating of the present invention can obtain a particularly remarkable effect when the fire spread prevention coating is a cured coating made of an acrylic fire prevention agent. it can.

[0014]

Embodiments of the present invention will be described below.

In the release agent for preventing fire spread according to the present invention, benzaldehyde or acetylacetone and benzyl alcohol are used as solvents in a weight ratio of 10:90 to 3: 3.
Use a mixed solvent that is mixed to be 0:70. If the proportion of benzaldehyde or acetylacetone is less than the above range, the swelling / softening effect on the fire spread prevention coating becomes insufficient, and it becomes difficult to swell and soften the fire spread prevention coating in a short time. On the other hand, if the ratio of benzaldehyde or acetylacetone is more than the above range, the sheath (especially, PVC sheath) of the electric wire / cable swells, and the mechanical strength and the like are reduced, and it cannot be put to practical use. A more preferred mixing ratio of benzaldehyde or acetylacetone to benzyl alcohol is in the range of 15:85 to 25:75.

FIG. 1 is a graph showing the results of a test conducted to examine the swelling / softening effect of a fire retardant (FB seal) on a cured product when benzaldehyde, acetylacetone, benzyl alcohol and triethyl phosphate are used alone. The horizontal axis is the immersion time,
The vertical axis represents the weight change rate which is an index of the swelling / softening effect of the solvent. As is clear from FIG. 1, benzaldehyde and acetylacetone have an excellent swelling / softening effect on the cured product of the fire spread inhibitor as compared with solvents such as benzyl alcohol and triethyl phosphate.

In the present invention, an aqueous emulsion, a liquid organic flame retardant and an inorganic flame retardant are blended together with such a mixed solvent of benzaldehyde or acetylacetone and benzyl alcohol.

The aqueous emulsion mainly adjusts the viscosity of the release agent according to the form of the construction surface, the construction method, and the like, and forms a coating film after the solvent has penetrated and absorbed into the anti-fire spread coating. It is blended in order to make the remaining components adhere to the outer periphery of the fire spread prevention coating. Examples of such an aqueous emulsion include an acrylic aqueous emulsion such as EEA and a vinyl acetate aqueous emulsion such as EVA. The amount of the aqueous emulsion is usually 1 part by weight to 100 parts by weight of the mixed solvent. It is in the range of 30 parts by weight.

The liquid organic flame retardant and the inorganic flame retardant are compounded in order to impart flame retardancy to the release agent in consideration of safety at the time of the release operation. By stopping the chain reaction by capturing the OH free radicals generated by high temperature oxidation of the molecules (hydrocarbons), it promotes the carbonization of plastics and the like to prevent the generation of low molecular weight combustible substances by decomposition.
Alternatively, the mechanism that suppresses the continuation of combustion is provided by a mechanism that generates nonflammable gas. In the present invention, a halogen-containing phosphoric acid ester such as tris (chloroethyl) phosphate, tris (dichloropropyl) phosphate and tris (dibromopropyl) phosphate, which is liquid at ordinary temperature, and chlorinated paraffin are used. The use of (chloroethyl) phosphate is preferred.

The inorganic flame retardant functions to suppress combustion and impart self-extinguishing property by the structure water which decomposes and volatilizes by heating as a cooling agent or by its own endothermic decomposition reaction. In the present invention, aluminum hydroxide, magnesium hydroxide, sodium hydrogen carbonate and the like are used, and among them, the use of aluminum hydroxide is preferred.

The amount of these flame retardants is based on the mixed solvent
20 parts by weight to 60 parts by weight of liquid organic flame retardant per 100 parts by weight
It is preferable that the inorganic flame retardant be in the range of 20 to 80 parts by weight. If any one of the amounts of the liquid organic flame retardant and the inorganic flame retardant is less than the above range, the flame retardant effect becomes insufficient. On the other hand, when the amount of the organic flame retardant exceeds 60 parts by weight, the effect of the release agent to swell and soften the anti-fire spread coating is reduced, and it takes a long time before the release can be performed with a spatula. On the other hand, when the amount of the inorganic flame retardant exceeds 80 parts by weight, the viscosity of the release agent becomes too high, and the application becomes difficult.

In the present invention, the amounts of the aqueous emulsion, the organic flame retardant, and the inorganic flame retardant are varied depending on the form (for example, a horizontal plane or a vertical plane) of the construction surface of the release agent and the construction method. Can be adjusted.

The release agent of the present invention may further include a filler, if necessary, in addition to the above components, as long as the effects of the present invention are not impaired.
Pigments, fragrances and other additives may be blended. For example, examples of the filler include phenol resin fibers, carbon fibers, and cellulose powder.

The release agent of the present invention is obtained by adding and mixing a liquid organic flame retardant to a mixed solvent of benzaldehyde or acetylacetone and benzyl alcohol, further adding an aqueous emulsion, and sufficiently stirring and mixing. Can be obtained by adding and mixing each component blended as required.

In order to remove the anti-fire spread coating provided on the electric wire / cable using the release agent of the present invention thus obtained, the release agent is applied to the anti-fire spread coating provided on the electric wire / cable. After the solvent in the release agent has penetrated and the fire-prevention coating has swelled and softened, peel off the softened fire-prevention coating together with the release agent coating layer using a wooden spatula. You should take it.

The release agent is applied to one surface of a plastic film such as polyethylene or polypropylene in advance, instead of being directly applied to the surface of the fire spread prevention coating, and the release agent layer side is attached to the fire spread prevention side. You may do so. In this method, since the plastic film has an effect of suppressing volatilization of the mixed solvent in the release agent, swelling and softening are further promoted. Therefore, even when the release agent is directly applied, it is desirable to cover the release agent with a plastic film or the like.

Further, a surface heater such as a band heater, an infrared heater, a hot air blower, or the like is used to cover the release agent coating layer or the plastic film.
May be heated. By heating in this manner, penetration of the release agent into the fire spread prevention coating and swelling and softening are promoted, and the release efficiency can be further increased.

When the fire-prevention coating is thick, the above-mentioned series of operations may be repeated. However, as in the case of a fire-prevention coating applied to a cable penetration portion such as a floor or a wall, the application area is limited. In addition, when the coating is very thick, as shown in FIG. 2, a plurality of holes 13 are provided around the cable 12 in the fire spread prevention coating 11 applied to the cable penetration portion 10, and these holes 13 are formed. The release agent 14 may be filled. The fire spread prevention coating 11 can be efficiently removed and removed in one operation. This method
It can be applied not only to the fire spread prevention coating of the cable penetration part but also to the fire spread prevention coating applied to the ordinary cable line. Becomes possible. In this method, taking into account the filling properties, 100 parts by weight of the above mixed solvent, 1 part by weight to 5 parts by weight of the aqueous emulsion, 20 parts by weight to 50 parts by weight of the liquid organic flame retardant, and the inorganic flame retardant 20 parts by weight
A release agent containing 50 parts by weight is preferably used.

The anti-fire spread coating to which the release agent of the present invention is applied may be an acrylic or EV such as an EEA emulsion.
Based on a vinyl acetate-based aqueous emulsion such as emulsion A, an organic fire retardant, a flame retardant aid, an inorganic filler, a non-flammable fiber, a plasticizer, etc., and a fire retardant added to the wire and cable and cured. It is a thing. As organic flame retardants, chlorinated paraffin, chlorinated naphthalene, decabromodiphenyl oxide, ammonium polyphosphate, etc., as flame retardant aids, antimony trioxide, zinc borate, zinc oxide, etc., as inorganic fillers , Aluminum hydroxide, calcium carbonate, hydrous magnesium silicate, titanium dioxide, clay, talc, etc., as non-combustible fibers, asbestos, ceramic fibers, glass fibers, phenol resin fibers, etc., and as a plasticizer, tris (chloroethyl) Phosphate such as phosphate, chlorinated biphenyl, dibutyl phthalate and the like can be mentioned.

In the present invention, chlorinated paraffin is used as an organic flame retardant, aluminum hydroxide and zinc borate are used as flame retardants, aluminum hydroxide, titanium dioxide and clay are used as inorganic fillers. A remarkable effect can be obtained when applied to the cured coating of a fire retardant mixed with phenol resin fibers as non-combustible fibers and tris (chloroethyl) phosphate as a plasticizer. An example of a commercially available product of such a fire spread agent is FB seal (trade name) manufactured by Kanegafuchi Chemical Co., Ltd.

[0031]

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. In the following description, “parts” means “parts by weight”.
Means

Example 1 To a mixed solvent in which 80 parts of benzyl alcohol and 20 parts of benzaldehyde were mixed, 40 parts of trischloroethyl phosphate, which is a liquid organic flame retardant, was added, and 25 parts of an aqueous acrylic emulsion was added. Stirred. Then
While stirring, 40 parts of aluminum hydroxide and 5 parts of cellulose powder were added and mixed to prepare a release agent.

Examples 2 to 4 and Comparative Examples 1 to 4 Release agents were prepared in the same manner as in Example 1 except that the composition was changed as shown in Table 1.

In order to examine the properties of the release agents obtained in the above Examples and Comparative Examples, the following property evaluation tests were performed.

[Softening test] An annular mold having an inner diameter of 30 mm was filled with an FB seal (fire spreader) manufactured by Kanegabuchi Chemical Co., Ltd. to a thickness of 6 mm, dried and cured, and then a release agent was applied to the surface of the cured product. about
It was applied to a thickness of 20 mm, and the change in hardness (JIS A) on the back surface of the cured product was measured.

[Tensile test] PVC for CV cable sheath
Was immersed in a mixed solvent separately from the release agent at room temperature for 1 week, and changes in strength and elongation were examined. The strength and elongation are based on JIS K 6723
It measured according to. The results of these measurements are shown in the lower column of Table 1.

[0037]

[Table 1]

Example 5 To a mixed solvent obtained by mixing 80 parts of benzyl alcohol and 20 parts of benzaldehyde, 40 parts of trischloroethyl phosphate was added, and 3 parts of an acrylic aqueous emulsion was further added, followed by sufficient stirring. Next, 40 parts of aluminum hydroxide and 5 parts of cellulose powder were added and mixed with stirring to prepare a release agent.

The obtained release agent was applied to a cured block (25 cm × 20 cm × 20 cm, approximately 10 mm in outer diameter of a cable 20) at the center of an FB seal prepared by simulating a fire spread prevention coating at the cable penetration portion.
5) are installed at approximately equal intervals around the cable group
Filled into circular holes (diameter 1cm, depth 15cm)
It was left at room temperature. After 7 days, an attempt was made to peel and remove the fire spread prevention coating. As a result, the whole was sufficiently softened and could be almost completely removed from the cable.

[0040]

As described above, according to the release agent of the present invention, the fire spread prevention coating applied to the outer periphery of the electric wire / cable can be applied in a short time without being restricted by the construction place or construction form. Swelling and softening, and can be peeled off efficiently, and without deteriorating the characteristics of the electric wire / cable sheath. Further, since it has sufficient flame retardancy, even if a fire accident or the like occurs during the peeling operation of the fire spread prevention coating, it does not catch fire and burn.

[Brief description of the drawings]

FIG. 1 is a graph showing swelling and softening characteristics of various organic solvents with respect to a fire spread prevention coating.

FIG. 2 is a cross-sectional view for explaining an example of a method for removing a fire spread prevention coating using a release agent of the present invention.

[Explanation of symbols]

 10 Cable penetration part 11 Fire spread prevention coating 12 Cable 13 Hole 14 Release agent

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Akira Moriya 3-3-22 Nakanoshima, Kita-ku, Osaka City, Osaka Prefecture Inside Kansai Electric Power Company (72) Inventor Hitoshi Shintate 2-1-1 Sakae Oda, Kawasaki-ku, Kawasaki-ku, Kanagawa Prefecture No. 1 Inside Showa Electric Wire & Cable Co., Ltd. (72) Inventor Minoru Okashita 2-1-1 Oda Sakae, Kawasaki-ku, Kawasaki City, Kanagawa Prefecture Inside of Showa Electric Wire & Cable Co., Ltd. (72) Inventor Susumu Hirai Oda, Kawasaki-ku, Kawasaki City, Kanagawa Prefecture 2-1-1 Sakae Showa Electric Wire & Cable Co., Ltd. F-term (reference) 4J038 RA02 RA05 RA06 RA09 RA15

Claims (3)

[Claims] 1. A release agent used for a fire spread prevention coating provided on an electric wire or cable, comprising a mixed solvent of 10% to 30% by weight of benzaldehyde or acetylacetone and 70% to 90% by weight of benzyl alcohol. A release agent for anti-fire spread coating, comprising an aqueous emulsion, a liquid organic flame retardant and an inorganic flame retardant. 2. 100 parts by weight of a mixed solvent, 1 to 30 parts by weight of an aqueous emulsion, 20 to 60 parts by weight of a liquid organic flame retardant, and 20 to 80 parts by weight of an inorganic flame retardant. The release agent for fire spread prevention coating according to claim 1, characterized in that: 3. The release agent for fire spread prevention coating according to claim 1, wherein the fire spread prevention coating is a cured coating comprising an acrylic fire spread prevention agent.