Carrier for bituminous lengths

Description

[0001] This invention relates to a carrier of the type to which felt and so-called non-woven products belong, more particularly, the invention concerns a reinforced carrier for bituminous roofing rolls.

[0002] Carriers for bituminous lengths must show a certain elasticity. By this, values are meant which both longitudinally and transversely are of the order of 30%.

[0003] When the carrier serves as a carrier for bituminous roofing rolls, it is moved through a bitumen mass at a temperature of substantially 180°C. At such a temperature, and given the resistance exerted by the bituminous mass on the felt or non-woven the carrier is made of, the carrier is subjected to a certain elongation. In other words, it may be said that certain longitudinal stresses are built up in the carrier during this operation.

[0004] Bituminous roofing lengths which were placed on a roof, may subsequently, at summer temperatures, become plastic to some extent. Because the bitumen becomes plastic, the carrier tends to return to its original state, which gives the impression that the carrier shrinks. This phenomenon may cause the appearance of problems on the roof.

[0005] It is thus the aim of the invention to achieve a carrier which does not show the above mentioned flaws, or at least reduces them to an acceptable minimum.

[0006] In order to make this possible in accordance with the invention, the carrier shows at its surface reinforcement wires and/or filaments applied by needling.

[0007] In a first embodiment, above said wires or filaments are of mineral origin.

[0008] According to another possible embodiment, above said wires or filaments are glass wires or filaments.

[0009] Still according to the invention, above said wires or filaments, at a tensile strength of 300 N per 5 cm, show an elongation that is not greater than 8%.

[0010] Other details and advantages of the invention will show from the following description of a carrier for bituminous lengths according to the invention. This description is exclusively given as an example and does not limit the invention.

[0011] The reinforced carrier for bituminous lengths according to the invention differ from the existing felt or non-woven carrier by the strong bond between the material it is made of and the wires or filaments applied for strengthening. The wires and/or filaments used here, are applied in the longitudinal direction of the carrier, and this by needling at the surface of the carrier.

[0012] The wires and/or filaments needled at the surface of the carrier have a small elongation after fracture. When E-glass is used, this elongation is of the order of 3.5%.

[0013] By needling the wires or filaments, a good integration of the wires or filaments into the carrier is ensured, so that delamination of the wires or filaments should not be feared. This is a very important feature of the invention. It has already been proposed to provide parallel reinforcement wires in the direction in which the carried must be reinforced, between two layers of felt. An example thereof can be found in the patent application with reference no. W097/18364. As the sole possible connection between the reinforcement wires and the felt, this document refers to a method known as "heat shrinking". When applying such a method, it cannot be ensured that wires will not come loose, or that no delamination of the product will occur.

[0014] It has already been ascertained that upon "thermal movements" of the bituminous roofing roll, the wires and/or filaments, which, as set forth above, are attached to the two layers of the carrier by heat shrinking between two layers of felt or a similar method, cause the appearance of wrinkles between the wires.

[0015] Contrary to the process described in above said reference, the needling at the surface of the carrier, as proposed now, offers the advantage that neither the structure of the wires and/or filaments, nor that of the carrier will be affected. In the carrier according to the invention, for the reinforcement wires and/or filaments applied parallel to each other, 6 glass wires and/or filaments of 68 Tex per 5 cm with a tensile strength of ± 60 cN/Tex and an elongation after fracture of ± 3.5% are used. Obviously, the number of glass wires and/or filaments utilised per 5 cm, as well as their tensile strength, is calulated as a function of the resistance that the carrier undergoes in the finishing to roofing roll.

[0016] According to the invention, on the carrier preferably six glass wires and/or filaments of 68 Tex per 5 cm, each showing a tensile strength of 60 cN/Tex and an elongation after fracture of ± 3.5% are used. It will be clear, that the values indicated just now, are only mentioned by way of example, and that these may be widely altered as a function of the resistance that the finished product must offer.

[0017] The carriers according to the invention and the roofing lengths manufactured with them, will not show the tendency to form "wrinkles", contrary to the products obtained according to the already mentioned patent application WO97/18364. These wrinkles are the consequence of the differing reaction of the two different elements, namely:

a) the glass which is not sensitive to fluctuations of temperature and is little elastic, and

b) the two layers of non-woven between which the glass wires are encased.

[0018] Reinforcement wires needled to the surface of the carrier are integrated into the non-woven. This implies that upon small "longitudinal movements" (longitudinal stresses) which may still occur, the glass wires and/or filaments "sympathise" with the non-woven. Consequently, no "sliding" arises between the glass wires and/or filaments and the non-woven. According to the invention, the glass wires and/or filaments are now needled in such a way to the non-woven, that the intrinsic properties of the glass wires and/or filaments are not spoiled. In this invention, six glass wires and/or filaments per 5 cm are needled parallel to each other onto the non-woven carrier. The glass filaments used in this invention, have a thickness of 68 Tex and a tensile strength of ± 60 cN/Tex and an elongation after fracture of 3.5%. The number of glass wires and/or filaments used per 5 cm, as well as their tensile strength, is of course calculated as a function of the resistance that the carrier undergoes in the finishing to roofing roll.

Claims

1. Carrier of the type to which felt and non-woven materials, so-called non-woven products belong, more particularly reinforced carrier for bituminous roofing rolls, characterised in that, at its surface, it shows reinforcement wires and/or filaments applied by needling.

2. Carrier according to claim 1, characterised in that above said wires or filaments are of mineral origin.

3. Carrier according to claim 1, characterised in that above said wires or filaments are glass wires or filaments.

4. Carrier according to any one of claims 1-3, characterised in that above said wires or filaments show an elongation that is not greater than 8% at a tensile strength of 300 N per 5 cm.