JPS62154505A - Fire resistant flexible insulating covering for pipe, wire, cable and optical fiber - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fire-resistant flexible insulating coating based on mica, heat-resistant polymers and glass fibers, which maintains its insulation at temperatures of about 1000°C. The coating is comprised of one or more layers of mica, one layer of high temperature polymer particle-loaded high temperature polymer, and one layer of high temperature polymer.

In a variety of applications found in the nuclear, petroleum, aviation, space, navigation, chemical, etc. industries, energy transport circuits or control signal transmission circuits must be protected against fire protection, for example, or in the case of electronic circuits, to ensure safety. It is strongly required that the circuit be resistant to high temperature conditions caused by an abnormal increase in the strength of the current flowing through the circuit for a sufficiently long period of time to enable the evacuation of the person I4 and the removal of the equipment. In the event of a short circuit or overcurrent, it is desirable that the conductor's excessive temperature during melting does not induce a fire due to burning of the coating.

Many attempts have been made to solve this type of problem. Some of them have been patented.

The following patents feature flexible coatings.

1 U.S. Patent Application No. 2.427.183. Discloses an insulating coating for metal conductors consisting of a layer of polytetrafluoroethylene inserted between two layers of asbestos or glass fiber.

Insulation is obtained by wrapping the conductor with tape.

No. 2,459,653. Discloses a method for insulating a conductor by spirally wrapping a Volite l-lafluoroethylene tape and silicone resin-impregnated glass fiber.

1 U.S. Patent Application No. 2,606.134. Discloses an insulating coating formed by sequentially winding a polytetrafluoroethylene tape of one or more layers and a glass fiber cloth tape of -m or more in a spiral shape and, if necessary, coating the tape with a polytetrafluoroethylene dispersion. .

- U.S. Patent Application No. 2.691.694. Makki Patent No. 2
．． Insulating coating similar to No. 606.134, but polytetrafluoroethylene impregnated glass instead of the last polytetrafluoroethylene layer! Discloses a coating consisting of spirally wound IN.

French Patent Application No. 2.257.555. asbestos,
Planting of glass J1i miscellaneous impregnated with a polymer binder with the addition of alumina, silica, carbon 1 quartz or talc, consisting of layers of fire suppressants (halogenated carbon 1 arsenide, etc.) and combustion suppressants (trioxide antimony, etc.). In these compositions, the binder is polyvinyl acetate, chlorine-containing rubber, natural rubber, GR8 type rubber.

Polymethyl methacrylate, polymethyl acrylate.

It may be a polyurethane elastomer, polyvinyl chloride, polyvinylidene chloride, epoxy resin, polystyrene or acrylonitrile-butadiene-styrene terpolymer.

French Patent Application No. 2,482,769. Coro Idosilica.

A heat-resistant flexible insulating coating is disclosed consisting of a knitted fabric of glass fibers impregnated with a binder based on acrylic latex with the addition of alumina, zircon or calcium silicate.

No. 3,602,636. A coating is disclosed in which a glass fiber phase coated with fire-resistant synthetic rubber is spirally wrapped and further protected with a polyvinyl chloride sheath.

- European Patent No. 80.107,217.4. Discloses an insulating coating composed of polyimide and mica.

However, the technology described in these patents does not address the problems that arise when one or more cables are exposed to a fire condition (withstanding temperatures of approximately 1000 degrees Celsius without melting the conductors or spreading fire, withstanding shock or vibration, The problem of having to withstand spraying of water or digestive fluids, the generation of fog, gases or toxic fumes, etc.) cannot be solved to maintain the electrical connection of the circuit.

In fact, polyvinyl chloride, polyvinylidene chloride.

Cable insulation of nonflammable plastic materials, such as chlorine-containing rubber, cannot withstand moxibustion for very long. When such cables are exposed to fire, the insulation decomposes and the liberated chlorine combines with a can of air or fire extinguishing water to produce hydrochloric acid, which is highly corrosive to the conductor or nearby metal structures. form.

Vinyl or elastomeric compositions also induce fire spread and release toxic fumes when exposed to death temperatures in excess of 370°C.

For the above reasons, if it is desired to improve the fire resistance of the insulating coating, it is sufficient to limit the proportion of the organic substance in the composition so as to be advantageous for the non-combustible inorganic substance.

However, most of the inorganic materials conventionally used alone or in combination with each other have the following drawbacks. For example, glass fiber has a temperature of about 550℃, and asbestos has a temperature of about 650℃.
Loses mechanical resistance at °C. Asbestos is also now known to be a carcinogen, and its use is avoided to the greatest extent possible.

In order to solve the various problems explained above, various rigid coatings containing no or only a small amount of organic components have been developed for the following ms.
It was developed as shown in

- French Patent Application No. 2.381, 377: Covering for electric wires consisting of a conduit concentric with the conductor filled with magnesia.

French Patent Application No. 2,462,771 Specification: Similar to the above-mentioned coating, but due to the presence of moisture during connection, by adding silicone oil with a heat resistance of 600 ° C to Magnesia. A coating that solves the problems that arise.

Although these coatings exhibit very high performance at high temperatures or in the presence of fire and meet some of the requirements mentioned above, they also have some drawbacks.

i.e. the cable connection operation is time-consuming and expensive; fire-resistant connections are difficult; especially when used in relatively acidic media (e.g. H2S atmosphere in oil refineries) or when the cable is sprayed with water for extinguishing purposes; For example, the flexibility of the i-cable, whose jacket is easily oxidized, is lost.

BACKGROUND OF THE INVENTION A fire-resistant, flexible insulating coating is already known (European Patent Application No. 0106708), which falls within the preamble of claim 1 of the present specification. This known coating consists of a mica layer, a glass fiber layer and a polytetrafluoroethylene layer laminated to provide electrical insulation and heat resistance up to 1000°C, and an outer layer of polytetrafluoroethylene. Coatings containing fluorine have the disadvantage of emitting fluorine-containing vapors. If the fluorine-containing vapors are released, a chemically corrosive effect on the surrounding inorganic or scrap metal materials may occur.

The aim of the invention is to eliminate these drawbacks. The present invention has the features as described in the claims, and includes electric wires,
Cables, conduits and optical fibers are approximately 800°C to 1000°C
A flexible insulating coating capable of protecting the 1st wire, etc. from ignition or dielectric breakdown for 15 minutes or more when exposed to heat or contact with fire at a temperature of It is also an object to provide a fire-resistant flexible insulating image attachment that is easy to manufacture and use.

The coating of the present invention includes a heat resistant polymer layer disposed over one or more mica layers of polyimide, polyamide-imide, polysulfone, polyethersulfone.

It consists of polyphenylene sulfide, silicone or polytetrafluoroethylene deposited by coating, and the heat-resistant polymer impregnated into the glass membrane layer and constituting the final skin of the coating is added with a fire-resistant inorganic compound or polytetrafluoroethylene, or The refractory inorganic compounds used are titanium dioxide, zirconium dioxide, 1g1t magnesium, silicon dioxide, aluminum trioxide (At) 203), magnesium silicate, calcium silicate, aluminum silicate, silicon carbide, Zirconium carbide, alumino (Aj 20
3), zircon (Zr02) or any mixture of these compounds, and the main feature is that the heat-resistant polymer constituting the IA final layer of the coating is polytetrafluoroethylene. The mica tape and the non-tape for polytetrafluoro Ib are arranged so that the winding directions of these tapes alternate once at a time.

The advantages obtained by the invention are that the coating exhibits excellent reliability and resistance to adverse weather conditions both under normal use and under extreme conditions (such as fire), does not spread fire, does not contain shock, vibration and The object is to withstand spraying of quenching fluids and to emit no or little toxic and/or corrosive fumes.

When exposed to the heat of a fire, the organic acid components decompose and the inorganic components melt to form bubbles. This foam is vitrified to ensure sufficient airtightness and excellent electrical insulation.

The present invention will be explained in more detail below by giving two non-limiting specific examples based on the accompanying drawings.

As is clear from FIGS. 1 and 3, the covering of the first embodiment is an inner layer 11!
including. This first layer 2 may be covered with a layer 3 made of the same material. The two middle layers 4 and 5 are then placed, and then the outer layer 6 is placed.

The coating of the second embodiment includes an inner first layer 8 surrounding the conductor, conductor or conduit 7, as seen in FIGS. 2 and 4. This first layer may be coated with WI9 made of the same material. Then the two middle layers 11110 and 11 and the outer layer 1
2 are arranged sequentially.

In FIG. 5, a first embodiment of the coating consisting of an outer layer 18, two intermediate layers 16 and 17 and two inner layers 14 and 15 was coated as in FIG. 1: three media. Main conductor (
(conducteurs primaires) 1. The wire 13 in FIG. 5 constitutes a seal to fill the gap to obtain a single cylindrical assembly.

The inner layers 2 and 3 or 8 and 9 of the coating preferably consist of glass U&fibers in the form of a flexible fabric coated with a polymeric resin which acts as an adhesive and supports the mica particles5. The material used in this case is 6mm to 251I wide, consisting of a continuous layer of mica particles placed on woven glass fibers via an adhesive bond.
III1 or more, it has a tape shape with a thickness of 0.05 mm to 0.2 mm. In this type of tape, the mica may be a muscovite cape or phlogopite tomer, polyimide, polyamide-imide or any other heat resistant polymer.

The intermediate layer 4 of the coating in FIG. 1 and the intermediate layer 4 and 1G of the couple in FIG. 5 are composed of polymers, optionally with the addition of refractory inorganic compounds. It depends on the formation of this layer.

- Polyiodos: polyarylamide, polyamino-sumareimide, polyether-imide.

Polyimidine, polyimidazopyrrolone.

- Polysulfones: polyarylsulfone, polyphenylene ether sulfone, polyether sulfone bisphenol A polysulfone.

-Fluorine-containing polymers: polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinyl fluoride, polyvinylidene fluoride.

- Fluorine-containing copolymers: tetrafluoroethylene-perfluorobropene copolymers, ethylene-7tetrafluoroethylene copolymers, ethylene-chlorotrifluoroethylene l copolymers, tetrafluoroethylene-perfluoroalkoxyphrosimers, and others. Heat-resistant polymer: polyparabanic acid, polybenzoxazole, polypenzimidazole, poly-1,3
, 47 oxadiazole, polyquinoline, polyquinoxaline, polypyrone, polyphenanthroline, polycarbonane, polyphosphazene, polystyrylpyridine, polysilasdyrene, polyameryletherketone, polyphenylene oxide or modified polyphenylene oxide, polyphenylene sulfide or silicone resin .

Preferred resins for forming layers 4 and 16 of the coating are polyimides, polyamide-imides, polysulfones, polyethersulfones, polyphenylsulfides, silicone resins, and polytetrafluoroethylenes.

These resins form the inner layer 2 or 3 of the coating of FIG.
It is preferably deposited on top of the inner layers 2 or 3 and 14 or 15 of the illustrated cable by coating techniques known to those skilled in the art.

In this case the resin can be dissolved in a suitable solvent or dispersed in water.

In order to improve the heat resistance of the intermediate layer 4 or 16, a fire-resistant inorganic compound may be added to the polymer resin. These refractory materials can fuse with the glass fibers 511M5, 11 and 17 forming layers 2 or 3 and 14 or 15 when these materials are heated at a temperature of 950°C or higher. It exists in finely ground form.

These refractory materials include titanium, zirconium oxide,
Magnesium chloride, silicon oxide, aluminum oxide,
It can be calcium oxide, magnesium silicate, calcium silicate, aluminum silicate, silicon carbide, zirconium carbide, and the like.

The resin constituting the binder for adhering to the glass fiber cloth and glass fibers of the layer around the refractory material 2 must be one that decomposes at high temperatures without emitting flames. When the temperature exceeds 950°C, the refractory material melts on the surface of the glass fibers and ceases to exist at a temperature clearly higher than the melting point of the paste glass. be done.

Intermediate layers 5 and 17 of the coatings of FIGS. 1 and 5 are intermediate layers 4
Or a glass fiber set 1 coated with a resin constituting 16 or, in some cases, a resin different from the resin described above.
Consists of one tressage.

As mentioned above, the same kind of refractory inorganic substances as those added to 4 and 16 may be added to these heat-resistant resins.

The outer layers 6 and 18 of the coating of FIGS. 1 and 5 are the intermediate layer 4.
and 16.

That is, these layers are comprised of a heat resistant polymer optionally with the addition of a fire resistant bamboo paste material as described above.

The outer layer 12 of the coating of the second embodiment of the present invention shown in FIG.
consists of polytetrafluoroethylene deposited onto layer 11 by dispersion coating.

The entire manufacturing steps of the first shell case coating are as follows.

The first layer of mica tape is arranged so that the mica particle layer and the member to be protected face each other, and is spirally wound around the member to be protected using a conventional tape winding machine. For example, the tape should be 50% or 66% thick to provide sufficient heat insulation.
% can be wrapped overlapping each other.

When layering the second layer of mica tape on top of the first layer of mica tape, the surface covered with mica still faces inward, but the winding direction of the Arp is reversed from that of the 11th Mth layer.

- Then deposit on said second layer a thin layer of about 0.02 to Q, 11111 of a binder based on a heat resistant polymer resin by coating. This "-ting 1" polymer dissolves in the solvent and 1! When the polymer is soluble in any solvent, it is carried out by immersion in a polymer-containing solution, and when the polymer is soluble in any solvent, it is carried out by immersion in a water-frozen dispersion of the polymer.

Generally the solution contains 10% to 10% weighted gloss polymer and the dispersion contains 10-40% borine by weight.

This coating method, which is carried out continuously, provides
rat; co +6).

In addition, when better heat resistance and resistance are required, the above-mentioned refractory substance may be added to the crack or dispersion.

In the case of a solution, it is preferable to use the following composition.

Thickening agent: 10-45% heat-resistant polymer, 5-25% fire-resistant inorganic additive, 30-85% solvent.

In the case of a dispersion, it is preferred to use the following composition.

Thickening agent: 10-35% heat-resistant polymer, 5-25% fire-resistant inorganic additive, 40-85% water.

The dispersion used for coating may optionally contain, in addition to binders, additives and water, thickeners to adjust the viscosity to facilitate coating.

It is an aqueous dispersion containing 50% of the thickener used (usually acrylate-1-vinylpyrrolidone) polymer.

The heat-resistant or fire-resistant resin layer is then inked with the same heat-resistant or fire-resistant mixture as this layer = 1-7- inked glass U & fiber braid.
゜To do so, perform the following operations.

One glass fiber is coated in the same manner with the same mixture that was previously used to coat the tube, conduit or cable.

The coated glass fibers are conditioned on a small EA tape specially attached to the braiding machine.

- For braid-forming operations, use a spindle adapted to the diameter of the sheath, tube, conduit or couple? ! This is carried out using several assembly machines in a manner known to those skilled in the art.

The final operation consists of coating the previously described braided covering in a similar manner with a layer of heat-resistant polymer or a layer of refractory binder, such as a small one.

The entire manufacturing steps of the second shell coating of the present invention are as follows.

The first layer of my color and C are the second layer.
The layers of mica tape are arranged in the same manner as in the first specific example.

- A tape, preferably of polytetrafluoroethylene, is then spirally wound onto the one or two mica layers. The thickness of this tape is, for example, from 0.071 to 0.25.
The range of m1 is zero, and the width can be in the range of 3 to 501n111. The tape is placed by a conventional tape winding machine so that the winding direction is opposite to that of the mica tape constituting the lower layer. This PTFE tape is usually 5
Wrap with 0% or 66% overlap.

- A braid of glass fibers coated with PTFE is then placed on this PTFE layer. These glass fibers are commercially available, but can also be made by coating lightly pre-oiled glass fibers with a water dispersion containing 33% by weight PTFE. The formation of the glass fiber braid is carried out in the same manner as in the first embodiment.

One final operation consists of coating the coating with a PTFE layer. In this case, dispersion water containing 33% PTFE is used, and the treatment is carried out in the same manner as in the first example.

Coating with a heat-resistant polymer, optionally with the addition of refractory inorganic substances, allows all inorganic substances present in the coating to be encapsulated and firmly retained.

If this coating is attacked by a fire or by the highly flaming roots of a fire, the polymer coating present on the surface will decompose without burning, thus avoiding the spread of the fire. If exposure to heat and/or flame continues, two outcomes can occur depending on the type of coating used:

In the case of coatings that do not contain refractory inorganic substances, a glowing state of the protective black iso compound made of glass fibers is observed after the surface polymer has decomposed. Direct exposure to flame for at least 10 minutes or above 430°C, which corresponds to exposure to heat, glass mN begins to lose its tensile strength.Direct exposure to flame for at least 20 minutes At temperatures above 730°C, which corresponds to exposure to large flames, the glass fibers soften and melt into a paste, forming a kind of fluffy glass bubble that reduces the thermal barrier properties of the protective coating. As the temperature decreases, this highly viscous protective barrier vitrifies and together with the mica particles forms a dielectric and hermetic insulating coating.

- In the case of a coating containing a refractory inorganic substance, as in the case described above, the inorganic substance becomes white hot after the heat-resistant polymer decomposes, and when the temperature exceeds 800°C, the refractory inorganic compound partially melts together with the glass. . This melting is only partial and only a small portion of the inorganic material is mixed with the glass. In fact, most of these inorganic materials have continuous use temperatures higher than 1250℃,
It has a melting point higher than 1800°C. Most of these inorganic particles penetrate into the voids of the glass fibers, resulting in a composite structure that has excellent dielectric strength and large insulation and heat reflection capabilities, and can withstand high temperatures and thermal shock.

Also, regardless of the manufacturing method used, the protective coatings of the present invention can withstand shock and vibration when subjected to the direct action of heat or flame, and can withstand extremely large temperature changes.

Using the invention, therefore, a thermally insulating protective coating is obtained which is extremely flame resistant and suitable for insulating pipes, conduits, wires or electrical cables. More particularly in the case of electric wires or electrical cables, the coating of the invention allows electrical energy to be transmitted even under the effects of the high temperatures of a fire, with the advantage of flexibility.

[Brief explanation of drawings]

FIG. 1 is a partial perspective view of an electrical cable, tube or conduit surrounded by one embodiment of the coating of the invention; FIG. 2 is a partial perspective view of an electrical cable, tube or conduit surrounded by another embodiment of the coating of the invention; FIG. 3 is a cross-sectional view taken along line AA in FIG. 1; FIG. 4 is a cross-sectional view taken along line BB in FIG. 2; FIG. 5 shows three elements as shown in FIG. 1. FIG. 3 is a cross-sectional view of a case where the electric cable including the electric cable is surrounded by the covering of the first specific example. 2.3, 8.9... Mica tape, 4, 16.
...Middle polymer layer, 10 ... Polytetrafluoroethylene tape, 5.17 ... Braided glass fiber, 6.18 ... Outer polymer layer, 1
2...Polytetrafluoroethylene layer.

Claims (2)

[Claims] (1) A fire-resistant flexible insulation coating for pipes, electric wires, electric cables and optical fibers that is based on mica, heat-resistant polymer and glass fiber and maintains insulation properties at temperatures of about 1000°C, the above mica layer, one heat-resistant polymer layer or heat-resistant polymer/fire-resistant inorganic particle mixture layer, one heat-resistant polymer-impregnated glass fiber layer or fire-resistant inorganic particle-added heat-resistant polymer layer, and one heat-resistant polymer layer or fire-resistant and a heat-resistant polymer layer with inorganic particles added thereto, the heat-resistant polymer layer overlying one or more mica layers comprising polyimide, polyamide-imide, polysulfone, polyethersulfone, polyphenylene sulfide, silicone, or polytetrafluoroethylene. The heat-resistant polymer impregnated into the glass fiber layer and constituting the final layer of the coating is a resin with or without addition of a fire-resistant inorganic compound or polytetrafluoroethylene, and the fire-resistant inorganic compound used is Titanium dioxide, zirconium dioxide, magnesium oxide, silicon dioxide,
Aluminum trioxide (Al_2O_3), magnesium silicate, calcium silicate, aluminum silicate, silicon carbide, zirconium carbide, alumina (Al_2O_3
), zircon (ZrO_2), calcium silicate, or any mixture of these compounds, and the heat-resistant polymer constituting the final layer of the coating is polytetrafluoroethylene. (2) The insulating coating according to claim 1, characterized in that the mica tape and the polytetrafluoroethylene tape are arranged so that their winding directions alternate in sequence.