DE4433590A1 - Cavity-filling polymer insulation and sealant, used e.g. for electrical insulation - Google Patents

Abstract

Polymer-based insulation and sealant, for insulating and/or sealing sections of elongated substrates or their ends or joints, has an inner layer of expandable polymer on a polymer support. Also claimed is a method for insulating and/or sealing the substrates. Pref. the blowing agent is a nitrogen cpd. based on azo cpds. or tetrazoles. The support and/or inner layer contains flame retardant and the support is shrinkable. The material is made in the form of sheet, strip, tube for cutting or moulding.

Description

The invention relates to an insulating and sealing material for Isolate and / or seal long sections stretched substrates or from their ends or from their connection junction points based on polymer plastics and a ver drive to isolate and / or seal sections of the route elongate substrates using this material.

Find insulation and sealing materials of the type mentioned their application in almost all fields of technology. she are used, for example, for electrical insulation in energy technology and cable connection technology in low voltage rich and also in household appliances and in the automobile industry. A large field of application is also the building industry, in Peculiarity of road construction, where it is used for mechanical protection and corrosion protection of pipes laid in the ground or on Masts and signs, especially in the transition area to the ground be used. Pipe penetrations and entries must sealed against the ingress of moisture and against cor rosion be protected. Flame protection is also often used for different substrates, e.g. B. cables, pipes, hoses, etc. ge calls, or different materials are ver together sticks and seals at the same time.  

Shrink sleeves or shrink caps with an in are known Hot melt adhesive or bitumen coating.

In the important area of cable connection technology electrical insulation and moisture proofing single wire connection mostly by means of a pressver binders is produced, a shrinkage over the connector hose pushed, the inside with a hot melt adhesive is layered. When shrinking the shrink tube in hot the hot melt adhesive becomes and should flow penetrate into the cavities of the press connector and isolie these Fill rend and sealing.

However, it turns out again and again that the filling of the hollow the usual hot melt adhesive is insufficient. In addition, the hot melt adhesive becomes very shrinking hot, come out at both ends of the heat shrink tubing and drip off, which makes it particularly difficult to install there is a considerable risk of injury to the fitter.

The most common hot melt in cable connection technology adhesives consist of polyamides as the base material, and polyamides have the disadvantage that they easily absorb moisture, so that there is a risk of corrosion. If a hot melt adhesive with a Flame retardant equipped, this affects the quality action of the adhesive, d. H. it adheres less well to the different which substrates, and other mechanical properties who that affects.

When used together with shrink products, the enamel often glue to the substrate before crosslinking same applied, which means that the choice of Ver type of network is restricted.  

Is z. B. the networking of the carrier material with the help of Elek causes radiation, the glue can be damaged and degrade so that the liability decreases very much.

Must do the hot melt adhesive together with maintenance or repair work Carrier material are removed, so there is a large Reini effort, because the adhesive doesn't just stick to it substrate to be protected or insulated other items, e.g. B. Tool.

As already mentioned, it is also known to use a carrier material to coat a bitumen sealing compound. This has the disadvantage that it has high stickiness even when cold, on the other hand, flows poorly when used. So the verar processing and handling very difficult. For example Hoses with bitumen inner coating under high technical Effort can be cut because it is otherwise at the interfaces to sticking, which only again with additional effort can be separated. In addition, when using sol Chen materials are taken care that no dirt stick in the hose or on the sticky bitumen surface remain, otherwise the shrink material during the shrinking process can tear.

In comparison to the well-known hot melt adhesives can also be only significantly smaller amounts of bitumen sealing compound in hoses or bring cuffs, etc., so that the actually spac Visible filling of cavities, e.g. B. with wire connections, can be realized even worse. The use of flame Protective agents also affect the mechanical properties of bitumen.  

In construction, the use of open sealing and assembly foams known to fill joints, cracks or other cavities; the application is uncomplicated, abundant after foaming Sige foam is removed and construction continues technical protection, such as plastering, boarding, cladding, etc. Oxygen serves as a blowing agent for these known construction foams connections, what their use in cases where Corrosion Ge driving exists, makes problematic.

The object of the invention is an improved insulation and Ab to provide sealing material that is simple and versatile can be used and is also straightforward to manufacture. It is said to be both of electrical insulation and thermal insulation also sealing against moisture and corrosion protection to serve.

According to the invention this is achieved in that on a Polymer carrier material is a layer of a foamable Polymer is applied as the inner layer. Will isolate that de and / or to be sealed point of a substrate with this mate rial wrapped and then foamed the foamable polymer, so this penetrates into all existing cavities and fills them up casual, so that there is an excellent insulation and sealing effect results.

Preferably serves as a blowing agent in the foamable polymer a nitrogen compound based on azo compounds or Tetrazoles. This has the advantage that during the foaming process no corrosive gases are released, whereas at other known blowing agents carbon oxides or ammonia ent stand.  

Not only the polymer carrier material but also the foamable one Polymer of the inner layer can be made with a flame retardant be prepared, because when using a suitable propellant it is equally easy to foam. Unlike other mecha The foamability does not suffer from its properties.

Especially if a protective effect against corrosion or the on penetrate from moisture or even electrical insulation To be achieved, it is advantageous if the carrier mat rial is shrinkable. The shrunk material then practices one radial force on the substrate to be protected, the existing Cavities already reduced; remaining voids by foaming the foamable material reliably and completed.

The insulating and sealing material according to the invention can be used as Sheets or strips or cutable tubular goods be made and cut to size on site, or it can be in the form of finished moldings, e.g. B. Caps, Man greasy or in the predetermined hoses use fin the. There is a risk of sticking when cutting not his material.

To seal and / or isolate according to the invention insulating and / or sealing point of a substrate the new insulation and sealing material in initially unsung foamed state of the inner layer completely enveloped; after that the insulation and sealing material except for the activation tion temperature in the foamable polymer of the inner layer contained blowing agent heated and the foaming process turned on directs. The foamable polymer increases as a result of use  the volume of the foaming process and encloses the substrate tight. The air that forms in the foamable polymer bubbles have a good additional insulation effect.

The temperature of the foamable polymer is based on the activation temperature of the blowing agent contained therein, until the blowing agent has completely decomposed and the Foaming process is complete.

The foaming process can also be done by interrupting the heat feed interrupted and at a later date by him heating again. It follows the possibility of the Iso invention during assembly work lier- and sealing material by foaming the inner layer made of foamable polymer on a specific part to be protected le of a vertical substrate, for example just to position and interrupt the foaming process in order to perform other necessary work; when the latter is completed sen, the foaming process can end by reheating be performed and the desired sealing and insulation he be enough.

On the point to be insulated and / or sealed, in a molded part from the insulating and sealing material with a heat-shrinkable outer support layer can be pushed, and the shrink and foam process can he advantageously in one operation consequences.

Starting material for the insulating and sealing according to the invention tion material can be a wide variety of polymers. Either for the carrier material as well as for the one to be applied to it  foamable material come polyethylene, polyethylene copolymers, Polypropylene, polyvinyl chloride, polyamide and the like. a. in question. Here these materials can also be combined in different ways.

It should be noted that the moisture pulling property of the polyamides in the case of the fiction moderate insulation and sealing material partially affected as in their use mentioned above the state of the art, because within the foamable material Air bubbles form during foaming, which are ideal Provide insulation and sealing especially against moisture. If moisture should penetrate into the carrier material, this occurs saturation very soon in the outside areas further penetration of moisture is made possible by the foamable Prevents material.

The production of the carrier material, cross-linked or non-cross-linked, takes place according to known methods by extrusion, injection casting or deep drawing; and also the application of the foamable Material on the carrier material is done in a known manner by coextrusion or coating in the form of laminating or Spread.

The insulating and sealing material according to the invention can in very different shape according to the later use intended purpose. The production is possible as By the meter, including in addition to web and strip goods such. B. also from to understand a rollable hose or tube which can then be cut on site as required, or as molded parts such as cuffs, caps or in size certain hoses. Of course there is Layer of the foamable polymer on the inside of the parts or goods.  

In many cases, for example when primarily a protective effect against corrosion or the ingress of moisture or electrical insulation is recommended the use of shrink materials as a carrier material, e.g. B. in the form of shrink sleeves, shrink caps, shrink cuffs, because by shrinking on one Shrink tubing on the one to be insulated and / or sealed Place a substrate, such as the press connector of a cable core connection, the shrink tube attaches itself around this point and exerts a radial force through the existing cavities already be reduced. Then in the foaming process foamable polymer penetrate into the remaining cavities and fill them out reliably and completely because the mass of the foamable polymer can be significantly larger and look better distributed than that of known hot melt adhesives or bitumen sealant.

Another advantage of the invention is that a simple modification of the foamable material the Haf tion on the substrate surface can be changed relatively easily can. When used at reopable protection points, e.g. B. Plug connections that are to be used under water is a non-sticky foam advantageous, although all hollow reliably seals rooms against moisture, but not to leads to an adhesion on the substrate surface.

The foamable materials can easily be found where it is is required to be equipped with a flame retardant, since they work equally well when using a suitable blowing agent let foam.  

The procedure for isolating and / or sealing is in use of the material according to the invention simple; z. B. in the form a tube, a cap or a sleeve with the layer made of foamable polymer inside so over the one to be insulated, preferably a point to be sealed or otherwise protected elongated substrate positioned to protect it dominated the position. After that, it becomes so through a heat source heated gently until the activation temperature of the Blowing agent is reached in the foamable material layer and the blowing agent, preferably a nitrogen compound, to decomposes and the foaming process begins.

This process can now continue until the Propellant is completely decomposed; but he can also by Remove the heat source and cool the substrate under broken and started again later. The protection to be achieved in this way serves primarily the mechanical and thermal protection of a substrate, the Isolation effect is also remarkable.

When using a shrinkable carrier material, this can Shrinking on after the hot or cold shrinking process, even after previous expansion. Is that hot shrinking process applied, so can shrink and foam process advantageously take place in one operation.

In the attached drawing, use is purely exemplary possibility of insulation and sealing according to the invention tion material shown.  

You can see a substrate 3 , e.g. B. a tube or an electric cable, over the point to be protected, a hose or an end cap 5 is pushed out of the insulating and sealing material according to the invention. It consists of a carrier material 1 and an inner layer made of foamable mate rial 2 , which is still in Fig. 1 in the unfoamed state, so that between it and the substrate 3 there is a cavity 4 be. After the foaming process; (See FIG. 2), which is initiated and maintained by careful heating, this cavity 4 is completely filled with the foamed material 2 and the area of the substrate 3 to be protected is tightly sealed and reliably insulated and sealed, because the foamable material 2 penetrates during the foaming process wherever there is only space, including very small cavities, cracks and the like.

Claims (9)

1. Insulating and sealing material for insulating and / or sealing off sections of elongated substrates or of their ends or of their junctions based on polymeric plastics, characterized in that a layer of a foamable polymer is applied as an inner layer on a polymer carrier material . 2. Insulating and sealing material according to claim 1, characterized characterized in that the blowing agent in the foamable Polymer a nitrogen compound based on azoverbin or tetrazoles. 3. Insulating and sealing material according to claim 1 or 2, characterized in that the polymer carrier material and / or the foamable polymer inner layer with a flame protective equipment is or are.   4. Insulating and sealing material according to one of claims 1 to 3, characterized in that the polymer carrier ma material is shrinkable. 5. Insulating and sealing material according to one of claims 1 to 4, characterized in that it as a web or Striped or cutable tubular goods or in the form of Molded parts can be produced. 6. Process for isolating and / or sealing sections cut elongated substrates or from their ends or from their liaison offices using the inventions material according to the invention according to one or more of claims 1 to 5, characterized in that the to be isolated and / or point to be sealed with the insulating and sealing material in initially completely unfoamed the inner layer is wrapped and then the insulating and sealing material up to the activation temperature of the in the foamable polymer the blowing agent contained in the inner layer heated and so the Foaming process is initiated. 7. The method according to claim 6, characterized in that the Temperature of the foamable polymer on the activation temperature of the blowing agent contained in it is maintained, until the blowing agent has completely decomposed and the Foaming process is complete. 8. The method according to claim 6 and 7, characterized in that the initiated foaming process by interrupting the Heat supply interrupted and at a later time reheating can be resumed.   9. The method according to one or more of claims 6 to 8, characterized in that to be isolated and / or A part to be sealed from the insulating and sealing processing material with heat-shrinkable outer carrier layer is pushed and shrinking and foaming process by heating in done in one operation.