EP1566476B1 - dimensinnally stable web for roofing membranes - Google Patents

Abstract

A ply of polyester non-woven, which has been consolidated but contains no other reinforcement, has a latent shrinkage force of 2 to 20 N/5 cm to oppose stretching or other deformation during subsequent operations involving heat, e.g. coating with PVC or bitumen or welding into position. Consolidation can be by mechanical or hydrodynamic needle punching or thermal bonding. An independent claim is also included for the process of making such a non-woven from spun-bonded polyester filament non-woven by applying a binder, drying and then drawing above the crystallization temperature, e.g. above 130 to 140 [deg]C. The latent retraction force is tailored to suit the deformation forces likely to be subsequently encountered.

Description

The invention relates to a liner based on a polyester fleece, which can be processed as such or in combination with other fabrics to a bitumen roofing membrane or geomembrane, a process for their preparation and made therefrom intermediate or end products namely composites and bitumen roofing membranes and geomembranes.

Inserts for bitumen roofing membranes or geomembranes generally consist of a textile fabric such. As a consolidated nonwoven fabric of synthetic fibers, usually in conjunction with one or more layers of other or even the same fabrics.

These deposits are bituminised, often on one side with slate or provided with a foil. The resulting end product, ie the roofing membrane or geomembrane has a considerable weight, which is often in the order of 2.5 to 6 kilos / m ² .

During further processing, which often take place at temperatures up to about 200 ° C, act on the deposits a variety of forces, such. B. tensile forces when the insert passed through a bitumen bath and pulled out of this bath again. The insert lengthens.

Furthermore, forces occur, which act on the web when it is under its own load, for. B. during transport from one device to another device, sag. Again, a lengthening occurs. This and other forces thus cause a deformation of the insert, ie a delay, and in the insert, a latent tension builds up, which is released in the next treatment step, in which a warming takes place in a low-voltage or de-energized state, and shrinking the Deposit leads.

This is particularly disadvantageous z. B. when laying the roofing membrane when working with heat. The train gets more or less the delay back, shrinks and enters it. But it is also possible that the already laid train z. B. by sunlight and the associated increase in temperature begins to shrink. This leads to the formation of bumps such as wave formation. And if the tracks were not laid or not enough overlapping, it comes to leaks, since the shrinkage exposed areas in the roof covering can be caused by the moisture, dust and the like can penetrate.

Furthermore, even if shrinkage does not result in exposed areas, since the overlap itself was adequately sized, problems may arise as shrinkage of the receding web removes the slate coverage of the underlying sites, as it were. This implies that the exposed areas of the slate are exposed to the weather conditions, which leads to premature or rapid aging, which leads to premature embrittlement, which again creates places through which dust and moisture in particular can penetrate.

Although it has been attempted to improve the dimensional stability of the deposits and also the bitumen roofing or geomembrane by the deposits with threads, layers, mesh fabrics u. Like. Reinforced in particular by inserting Glasgelegen or longitudinal threads of glass. Such fabrics are z. B. in the EP 0 572 891 B1 described.

However, these measures complicate the manufacture of the inserts by one or more further process steps. In addition, the reinforcements must be made separately, often in complicated and expensive process steps. Also, the dimensional stability through the incorporation of reinforcements can not be guaranteed in many cases to complete satisfaction.

So it may be z. Example happen that arise in reinforcement with glass fibers by failure of individual threads or by tearing of threads places that are not or less well reinforced, so that it can come under tensile stress at these points to form waves.

In such processes, there is the danger that reproducible products with consistent, good quality can be produced only with difficulty over a long period of time and that rejects are frequently produced.

Therefore, reinforced inserts not only have a number of technical disadvantages, but are also more expensive and complicated to manufacture. Thus, there is still a need for improved deposits, which are particularly suitable for bitumen roofing or waterproofing membranes, as well as improved processes for their preparation, which do not have disadvantages mentioned above or only to a reduced extent.

The object of the invention is therefore to provide an insert which does not have the abovementioned disadvantages and which is particularly suitable for the production of roofing and waterproofing membranes, which is free from reinforcements, is simple and economical to produce and which leads to end products which have high thermal dimensional stability.

This object is achieved by a liner which is suitable as a liner for roofing and waterproofing membranes, comprising a reinforcement-free, solidified polyester filament non-woven, which is bonded with a binder and has a latent shrinking force, which the delay forces in the subsequent, in the heat counteracts occurring in the manufacture of composites, wherein the shrinkage force is 2N / 5cm - 20N / 5cm.

Preferably, the nonwoven is mechanically consolidated by needling.

Also very suitable are hydrodynamically or thermally consolidated nonwovens.

Preferably, the shrinkage force is equal to the sum of the drafting forces. An advantageous range for the shrinkage force is 6 N / 5 cm to 10. However, the shrinkage force may also have higher or lower values if necessary.

The fleece of a polyethylene terephthalate filament fleece is preferred.

Another object of the invention is a process for producing a non-reinforcing polyester filament nonwoven insert which is suitable as a liner for roofing and waterproofing membranes, which is characterized in that by the spunbond process produces a polyester filament nonwoven, solidifies the resulting nonwoven fabric, provides a binder, dried in a dryer and stretched in a downstream of the dryer drafting device to an extent that the nonwoven fabric has a shrinking force, which counteracts the delay forces that occur in the subsequent, taking place in the heat treatments.

Preferably, the shrinkage force is equal to the delay forces. An advantageous range for the shrinkage force is 6N / 5 cm to 10N / 5 cm.

Preferably, a polyethylene terephthalate filament nonwoven fabric is used.

It is advantageous to needlepunch the fleece several times, in particular 2 or 3 times.

The needled web can also be consolidated with a calender with an embossing calender, especially with heated calenders.

Further objects of the invention are composites, roofing membranes and geomembranes containing deposits described above.

The basis weight of the fleece is within the usual range and can be varied depending on the application. For bonding the nonwovens, customary binders are used, preferably in the form of 5-25% strength aqueous dispersions.

The fleece provided with the binder is then dried. Directly downstream of the drying is a drafting system, in which the nonwoven is stretched, namely at a temperature which is still above the crystallization temperature of the polyester used. The temperature of the nonwovens should therefore not fall below this temperature before the shrinkage force is built up, preferably this temperature is 130 ° - 140 ° C.

The amount of draft in the drafting equipment depends on the desired latent shrinkage force that is to be built up. This can be adjusted individually to the wishes of the customer.

By stretching in the drafting system according to the invention, the nonwoven fabric is given a shrinking force which remains latent in the nonwoven and is released again when the nonwoven insert is subjected to heat during further processing operations. Then this shrinking force counteracts the delay forces and lifts them completely or at least largely. Such delay forces occur z. Example, when the fleece is pulled through a hot Bitumenbad or when the still hot bituminierte fleece on further transport has the opportunity to sag. The own weight exerts a delay force.

The laying of roofing membranes can, for. B. done by mechanical attachment in the cold state. Of importance, however, is laying according to the welding process.

Since shrink-free provided with a liner roofing membranes are accessible by the invention, it does not shrink even with sunlight and the associated heating, so that the initially described disadvantages do not occur, there are thus no vacancies between the joints and no places with the slate support removed.

Under composite materials in the context of the invention are to be understood multilayer textile and technical sheet, such fabrics with coating, roofing and waterproofing membranes, floor coverings, z. As those with a PVC coating, and bitumen roofing and waterproofing membranes and the like.

The size of the shrinking forces, which is to be imparted to the nonwoven according to the invention, can be determined in a simple manner by a few preliminary tests; it is the sum of the stretching forces acting on the insert until the final product is finished. In this way it is possible to produce a tailor-made product according to the wishes of the end user.

The inserts according to the invention can be produced simply and economically. They are because of the elimination of reinforcements such as glass fibers, glass mesh fabrics or glass shelves particularly cost-effective.

Claims (14)

1. An intermediate layer which is suitable as an intermediate layer for roofing and sealing membranes, comprising a reinforcement-free, bonded non-woven of polyester filaments which is bound by a binder and which has a latent shrinkage force which counteracts the distortion forces which arise in the subsequent treatment operations during the manufacture of composite materials which take place under heat, the shrinkage force being 2 N/5 cm to 20 N/5 cm.
2. The intermediate layer according to claim 1, characterized in that the non-woven is bonded mechanically by means of needles.
3. The intermediate layer according to claim 1 or 2, characterized in that the non-woven is bonded hydrodynamically.
4. The intermediate layer according to claim 1, characterized in that the non-woven is bonded thermally.
5. The intermediate layer according to at least one of claims 1 to 4, characterized in that the shrinkage force is equal to the distortion forces.
6. The intermediate layer according to at least one of claims 1 to 5, characterized in that the shrinkage force is 6 N/5 cm to 10 N/5 cm.
7. The intermediate layer according to at least one of claims 1 to 6, characterized in that the non-woven is a non-woven of polyethylene terephthalate filaments.
8. A method for producing a reinforcement-free non-woven intermediate layer of polyester filaments which is suitable as an intermediate layer for roofing and sealing membranes, characterized in that a non-woven of polyester filaments is produced by the spun-bond method, the non-woven obtained in this way is bonded, is provided with a binder, is dried in a dryer and is stretched on a stretching unit positioned downstream of a dryer to an extent such that the non-woven has a shrinkage force which counteracts the distortion forces which arise in the subsequent treatment operations which take place under heat, the shrinkage force being in a range from 2 N/5 cm to 20 N/5 cm.
9. The method according to claim 8, characterized in that the shrinkage force is equal to the distortion forces.
10. The method according to claim 8 or 9, characterized in that shrinkage force is in a range from 6 N/5 cm to 10 N/5 cm.
11. The method according to at least one of claims 9 and 10, characterized in that the non-woven of polyester filaments is a non-woven of polyethylene terephthalate.
12. The method according to at least one of claims 8 to 12, characterized in that for bonding the non-woven is needle-punched and passed through a calender.
13. Composite materials containing intermediate layers which are suitable as an intermediate layer for roofing and sealing membranes comprising a reinforcement-free, bonded non-woven of polyester filaments which is bound by a binder and which has a latent shrinkage force which counteracts the distortion forces which arise in the subsequent treatment operations during the manufacture of composite materials which take place under heat, the shrinkage force being 2 N/5 cm to 20 N/5 cm.
14. Roofing or sealing membranes containing intermediate layers according to any one of claims 1 to 12.