SEALING STRIP BETWEEN TWO CONSTRUCTIONAL PARTS
The present invention concerns a sealing strip for filling, isolating and sealing an air space between two constructional parts, e.g. a frame and a wall between two walls, etc. and which includes a compressible, elastic material, which is retained in its compressed state by a cover and a method for producing the same.
THE BACKGROUND OF THE INVENTION
When applying window frames and door frames in a wall opening they are adjusted with the aid of wedges, whereafter the side parts of the frames are screwed or nailed on the wall.
Between these constructional parts is formed a gap, which is needed to allow the adjustment of the window or the door. The gap must be filled and the sealing must fulfil the demands on heat isolation. The sealing also serves as a barrier for moisture and steam, and for sound isolation.
Sealing of the gap is nowdays mainly done with strips of mineral wool covered in plastic which mineral wool is pressed into the gap against a bottom list with the aid of a tool. It still happens that hemp or jute is used as sealing material. A drawback with this known method is that it demands a lot of work, that it can be done so hard that, the frame is bending and gives an unsatisfactory result, as a guaranteed complete and even, filling cannot be achieved. Some of these problems can be solved by using a joining foam, which is sprayed into the gap and which expands during the setting. The joining foam is however during the spraying dangerous for the health , is not diffusion impermeable against the inside, the frame is fixated so that it cannot be adjusted later. Measures must be taken so that the side parts of the frames do not bend inwards during the foaming. The joining foam has unwanted features for the environment and is much more expensive than the sealing material and the sealing work together. In order to achieve a steam barrier it is also necessary to apply a diffusion tight elastic soft joining of for instance EPDM (Ethene Proper Rubber) or solid rubber.
THE PURPOSE WITHTHE INVENTION
The purpose with the invention is to solve the above mentioned problems and to achieve a sealing strip of the in the introduction mentioned type, which:
- is simple to apply and place in right position also in narrow gaps,
- adapts itself also to relatively big gaps and unevenness ,
- does not give a harmful pressure against the surfaces which delimits the gap,
- can be adjusted afterwards,
- can be bent around a corner,
- can be cut in suitable lengths,
- has good heat and sound isolating characteristics,
- is diffusion tight and forms a steam barrier against the room,
- is cheap to manufacture,
- is environmentally friendly.
THE SOLUTION OF THE PROBLEM
These tasks have been solved by a material of such type and /or is provided with an insert, that in compressed state is transversally stiff and in its longitudinal direction is bendable, preferably possible to wind-up, that the sealing strip is provided with a material which delays the expansion and that the sealing strip is openable along one of the thin sides, and that the elastic material is expendable along its entire length.
DESCRIPTION OF THE DRAWINGS
The invention will below be more closely described in connection with a few embodiments and with reference to the enclosed drawings.
Figure 1 shows a horizontal cut through a window mounted within a wall opening and sealed with the sealing strip in accordance with the invention.
Figure 2 and 3 show cuts through the sealing strip in accordance with Figure 1 in compressed closed and in open, expanded state.
Figure 4 and 5 show with analogous cuts compared to Figure 2 and 3 a modified embodiment.
Figure 6 shows schematically a device for manufacturing of the sealing strip in accordance with the invention.
DESCRIPTION OF EMBODIMENTS
The sealing strip in accordance with the invention, in the drawing designated 11, consists in its basic configuration of a compressable, elastic material 12 and a cover surrounding said elastic material, which in its uncompressed, i.e. expanded state has good heat isolating characteristics comprising elimination of air draught/passage. The material should have a cell structure with interconnecting open cells, and may consist of a suitable plastic foam, but may also be a cellulose derivate or similar. The important thing is that the material is so elastic that it can be compressed and regain essentially its original volume when the pressure ceases. The compression can occur in different ways, mechanically by pressing together the strip of plastic foam, e.g. when passing through the press nip between two ools or by vacuum but also for instance by drying a viscose sponge and then letting it expand by the influence of a liquid, which contains a binder which retains the sponge in its expanded state when the solvent in the binder has steamed away.
Depending on which method of compression that has been used, the cover is adapted thereafter. A vacuum compression demands that the cover is hermetically closed, which means that the strip has a limited length, e.g. is measure adapted, while a mechanical compression demands a cover , which can resist the pressure from the compressed material but can be open at the ends. Preferably a shrinking film can be used, which is shrinked with an oversize of the film so that transversal folds are formed, which in shrinked state form transversal reinforcement bands around the compressed strip. It is also possible that an insert 14 in the form of a paper or plastic band or similar stiffens the strip of plastic foam, which can be applied on one or both sides of the paper or plastic band.
If the compressible material consists of a viscose sponge the cover 13 has during transport and assembly only a protecting function. However, generally the cover 13 is after the assembly in a gap 15 between two constructional parts, e.g. a frame 16 or a wall 17, according to Figure 1, opened at least along the end border 19, which is turned against the outside while the end border which is turned against the room remains closed and forms a steam barrier 18 if the material in the cover is diffusion tight. The compression of the elastic sealing strip does not solely have the purpose of reducing the thickness, but by compressing
and impregnating the plastic foam with an adhesive, the sealing strip, will have a certain stiffness perpendicular to its longitudinal direction and at the same time the strip remains bendable in its longitudinal direction so that it can be bent around a frame, and for easier handling also can be winded up for transportation. The adhesive can for instance be a bitumen mass, which when heated is softened so that expansion can occur, while at room temperature the adhesive prevents the compressed sealing strip from expansion.
The cover 13, which can consists of a plastic film, which only to a very limited degree participate in the expansion of the plastic foam, can at least at one end border, preferably at three end borders, be equipped with an inwards folded part, while the fourth end border, which in applied state is turned inwards and which is intended to be opened, lacks said folds. The purpose is to simplify the expansion, which will not be prevented by a "too tight" cover. The opening of the outward turned end side of the sealing strip, can most, simply be done with a knife, but it is also possible that when manufacturing the sealing strip apply, a tear thread or similar in said end side which thread when drawing it opens said end side.
The sealing strip is manufactured in the following way and as illustrated in the shown device in Figure 6. A web of cellular plastic 21 is fed into a tray 22, which is provided with a stirrer 23 and filled with a mass of bitumen for impregnating the web of cellular plastic. The mass of bitumen or other adhesive is preferably in the form of a water dispersion in order to achieve optimal penetration in the cellular plastic material. A suitable dispersion of bitumen comprising about 50 - 70 weights -% bitumen and about 30 - 50 weights -% water. The web of cellular plastic is fed through the tray 22 by conveyors 24, which in several places allow the web of cellular plastic to pass through the press nip of rolls 25 for compression and following expansion of the web of cellular plastic material in order to fill the cellularplastic material with a mass of bitumen. This mass of bitumen has such a temperature, at least 80 degrees Celsius, that the viscosity gives an easy penetration of the mass into the cellular plastic material. The viscosity of the adhesive, bitumen or other adhesive, can also be regulated by addition of a solvent, which is removed in a later step. The temperature of the bitumen is regulated by heating elements 26 applied in the tray 22. The web of cellular plastic material is thereby compressed to a few percent of its initial volume. The web of
cellular plastic is thereafter allowed to expand, whereby it takes up a mass of bitumen through suction, (replacing air which earlier exists in the web). The web of cellular plastic 21 is thereafter again pressed, together in a pressing nip of a roll pair, 27, and is compressed again to a few percent of its earlier volume/thickness. The web of cellular plastic 21 is thereafter allowed to regain its initial volume or essentially its initial volume by expansion. Thereafter the web is fed on a conveyor through a drying means for elimination of the solvent in the mass of bitumen, or another for the purpose suitable adhesive composition, or for fixation of the bitumen or another adhesive composition. The web of cellular plastic is thereafter chilled and preferably treated with talcum in order to eliminate "tackiness". The amount of adhesive is about 20 - 30 weights -% of the weight if the end product. The amount of adhesive is however dependent of the cell structure and of the type of adhesive.
The web of cellular plastic is thereafter fed to a packaging station, where the web 21 of cellular plastic first is compressed between in the embodiment shown two pairs of pressure rolls 28 for compression of the web 21 of cellular plastic. At the same time two plastic films are fed on both side of the web 21 of cellular plastic, which films are welded together by heat welding or by induction welding with the aid of welding tools 21 along the both longitudinal sides of the compressed web of cellular plastic. In one embodiment the compressed web 21 of cellular plastic is divided along its longitudinal axis for production of two parallel webs, whereby the plastic film is also welded between said webs. In suitable mutual distance the compressed web 21 of cellular plastic is welded crosswise to its longitudinal axis by application of heat with the heating tools 32 and is cut to suitable lengths, preferably in pairs, in a cutting station 33. The compressed and in plastic films , packed webs 21 of cellular plastic is thereafter packed and stored berfore distribution.
The web of cellular plastic may consist of plastic of polyurethane, neoprene rubber or polyolefme, such as polyethylene, polypropylene. Different copolymers, such as ethenevinylacetate - copolymer, can also be suitable in order to achieve a sufficient form stable web of cellular plastic. The structure of the cellular plastic can be open or cross- linked. The web of cellular plastic can also on one of its sides have a closed cell structure achieved by a suitable cooling treatment and or heating treatment when producing the
cellular plastic material, The web of cellular plastic can also be integrated with a plastic film on one or several sides if this is desirable in view of handling.
The used adhesive is preferably bitumen or a non-hardening adhesive, such as ethenevinylacetate acrylate, whereby when using an uncoloured adhesive of the mentioned type this adhesive is painted. Otherwise the cellular plastic material can be coloured to achieve a colour effect, as can be desirable when using the sealing strip as dilation joint in house constructions. In such a case the out-turned side of the joining/sealing strip should also be impermeable to allow painting.
The adhesive could also be provided with sodium silicate or aluminium hydroxide in order to improve the fire-retardation. When using sodium silicate 25% of a solution of waterglass in water is added to the adhesive.
The demand on the cellular plastic material is that it shall regain its initial form after compression, but this expansion should not be too fast as one then cannot handle, the sealing strip. The expansion shall after elimination of the plastic film or after opening of the plastic film, to allow expansion, occur within a half to one hour.
The expansion is allowed by lowering the compression pressure, by eliminating or tearing the surrounding plastic film, or by heating up the adhesive in a suitable way to facilitate the expansion. Heating can be achieved with radiation heat, hot air or with another in this connection suitable heating source.
At expansion the plastic film for packaging should be eliminated in order to achieve a better connection/tight adhesion between for instance window frame and wall or between two wall elements .
Compression of the sealing strip after absoφtion of adhesive can also as mentioned occur by application of a vacuum. In such a case a more complicated equipment is needed and the sealing strip must be encased more effectively in a store cover to withstand expansion before use.
The invention is not limited to the above shown and described embodiments but a lot of variations are possible within the scope of the following patent claims.