DE2009844A1 - Cover film - Google Patents

Description

"Cover film"

The invention relates to a cover film made from a bitumen-elastomer mixture.

The properties of elastomer mixtures with different Additives and especially bitumen are known. A bitumen-elastomer mixture can be considered:

- as tempered bitumen, if the elastomer content of the mixture is low or

- as reinforced rubber, if this content is high.

Known cover films are either from one or the other made from the other category.

In the former, there is a product, its properties are similar to those of bitumen foils: low elasticity, plasticity, flowing under the action of a

109820/2081

Tension. Welding or gluing with bitumen is possible. It is used wherever conventional Sealing materials in film form for sealing roofs o. The like. Use.

In the second! "All there are rubber sheets with this one Material's own properties: elasticity, high modulus of elasticity, no or only very little flow. Of the Use of these foils in the sealing sector requires Special glue, while welding or gluing with molten bitumen in the conventional way does not is possible.

The invention is based on the object of creating a cover film which has the good properties of both known Categories united in themselves.

The invention is based on the knowledge that some elastomers in a certain mixing ratio with bitumen result in a product which, according to its properties, belongs to the "second of the two categories mentioned above." appears. In film form, this product has the mechanical properties of rubber films, while on the other hand it does is meltable and can be welded or glued to bitumen, as is the case with fabric or felt reinforced Bitumen in film form is common, which is used in a conventional manner for sealing roofs or the like.

1038 2 0/2081

In this way, multi-layer covers are obtained, in which the bituminized felt layers are replaced by means of elastic foils, although the conventional bitumen is retained as an adhesive layer.

These foils can be used just like reinforced bitumen foils

weld with the welding torch. J

These panels have the properties of rubber covers on, i.e. an excellent elasticity, while in bituminous materials the plasticity the salient feature is.

To date, these foils have properties that are unknown in the field of sealing due to their elasticity Properties taking into account the fact that they can still be welded or glued to bitumen.

A cover sheet according to the invention consists of the following

Mixture: I.

A. Petroleum bitumen obtained by direct distillation with a penetration depth of 20 to 50 0 mm at 25 ° G, but preferably with a penetration depth of 8 0 to 22 0 mm. This product must not contain more than 5 % volatile substances at 273 ° for a period of 5 hours.

B. An elastomer of the so-called block polymer group, for example of the polystyrene-polybutadiene-polystyrene type or polystyrene-polyisoprene-polystyrene.

Such a mixture with inert materials such as talc, chalk, Asbestos o. The like. Be reinforced to make the material more economical.

These foils can be made of glass canvas o. be equipped.

The ratio of 1: B is determined as follows:

If the ratio of the mixtures B: A is less than 6%: 9 ^%, the degree of compensation of the bitumen is not high enough so that the cover films obtained have too low a melting point and too weak an elasticity is not comparable to that of a rubber sheet.

If the mixture ratio B: A is more than 30 % : 70 % , the product can no longer be melted with the welding torch and can no longer be welded; in addition, the adhesion to bitumen is not very great.

The invention thus relates to the production of cover films from the following mixture for sealing surfaces

109820/2081

6 to 30 % of mixture B to 94 to 70% of mixture A.

The optimal mixing ratio is 10 to 22 % of B.

Additions and reinforcements used in these foils can be different, with the rest of the so-called Fillerization techniques (techniques dites de fillerization) are known.

Example 1:

A mixture consisting of:

Bitumen with a penetration depth of 8 0 to

10 0 mm at 25 ° 0 82 %

Block polymer of the polystyrene-polybutadiene type

Polystyrene 18%

Mixing takes place at 210 ° until dissolution. I.

20 parts of calcium carbonate are added to 80 parts of this mixture added as reinforcement.

The melted mixture is used to make foils according to the usual process used for the preparation of bituainated Felting with glass canvas reinforcement is applied.

109820/2081

These are used, for example, to seal roofs Foils can be welded or glued to bitumen like conventional bituminized felt. About that in addition, they have the properties of rubber films, namely:

100% elasticity with 100% elongation, Elongation at break: over 500%.

Example 2:

A mixture consisting of:

Bitumen with a penetration depth of

18 0 to 200 mm at 25 ° C 87 %

Block polymer (according to example 1) 13%

The manufacturing process corresponds to that of Example 1, the films obtained have somewhat different mechanical properties, but without the elastic properties as well as the weldability by means of a welding torch and the adhesiveness with molten bitumen affect.

10982 0/2081

Claims (3)

Claims Covering film made of a bitumen-elastomer mixture, characterized by a mixture of 94 to 70 % of a petroleum bitumen obtained by direct distillation with a penetration depth of 8 0 to 22 0 ma. At 25 ⁰ O and a proportion of less than 5 % volatile substances at 273 ° 0 for a period of 5 hours and 6 to 30 % of an elastomer belonging to the group of block polymers and soluble in the bitumen. 2. Covering film according to claim 1, characterized in that the elastomer belongs to the group of block polymers, such as for example, polystyrene-polyisoprene-polystyrene or polystyrene-polybutadiene-polystyrene. 3. Cover film according to claim 1 or 2, characterized by a fabric reinforcement. Dr.- Gr / zo Jooß Dipl.-Ing. Gramm patent attorneys 109820/2081