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(11) | EP 1 323 878 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Roofing material, roofing roll and method of manufacturing roofing material |
| (57) A roofing material, comprising: a layer (11) of a carrier material, which is provided
on at least one side with at least one bituminous layer (12) of a bituminous material.
The bituminous layer is provided with a profiling with grooves (4) and a foil (13),
which follows the profiling of the bituminous layer. The foil is located on a side
of the bituminous layer facing away from the layer of the carrier material. During
heating, such as, for instance, flaming, foil in parts located between the grooves
melts earlier than foil in the grooves. During heating, the bituminous layer melts
at least partly, as a result of which the grooves at least partly disappear. |
[0002] From practice, a roofing material is known with a layer of a carrier material on which, on at least one side, a layer of a bituminous material is applied. On the bituminous layer, on the side of the roofing material to be adhered to the base, the so-called side with extra coating, a plastic foil, often polyethylene, is applied. The foil prevents the roofing material from adhering in rolled-up condition. The bituminous layer is provided with a profiling by rolling in the plastic foil. The well-known profiling is designed in the form of anti-projections. The anti-projections form local anchorages of the foil, which, during the melting together of the bituminous material and the base on which the roofing has to be arranged, distribute the contraction of foil remainders over the surface of the roofing material.
[0003] The well-known roofing material has the drawback that, when applying the roofing material, the foil will not burn completely. The remainders of the foil then form a net structure, as a result of which a spontaneous flow behavior of the bituminous material is inhibited. A spontaneous flow behavior is of importance to a good and rapid adhesion to the base.
[0004] It is an object of the invention to provide a roofing material that, in use, has a less strong formation of a net structure of foil remainders. To this end, the invention provides a roofing material according to claim 1.
[0005] Because the foil in parts located between the grooves melts earlier than the foil in the grooves, the foil will show no, or at least a less strong, formation of a net structure. Moreover, during heating, the grooves become flown up at least partly through the melting of the bituminous layer, so that the profiling has no permanent character.
[0006] According to a further elaboration of the invention, the foil is stretched in a direction away from the grooves. As a result of the previous melting of the foil outside the grooves, the foil, during heating, will then tend to curl or contract in the direction of the grooves, owing to the stress. The formation of net structure is thus further inhibited, because the foil remainders then form strips that are practically not connected together. Preferably, the foil has a molecular orientation in a direction away from the grooves. During the heating/burning of the foil, the internal stress in the foil, owing to the anisotropic molecular orientation, promotes contraction of the foil in the direction of the grooves, as a result of which unburned or incompletely burned foil will come to lie practically only in the grooves.
[0007] The invention further provides a roofing roll according to claim 11. The invention also provides a method of manufacturing roofing material according to claim 15. With such a method, a roofing material can be manufactured that, in use, shows less net formation of foil than the well-known roofing material.
[0008] It should be noted that both German utility model 84 32 277 and French patent publication 2 544 361 disclose a bituminous burning roll with a bituminous layer provided with a separating foil. The burning roll is provided with a profiling with elevations and recesses, over which the foil extends. The foil then follows the profiling. The profiling forms a grid, in which the elevations form projections in the burning roll. During attachment, foil remains in the grooves, as a result of which, on those spots, the burning roll is not attached to the base. Through the grooves, after the arrangement of the roofing material, a system of channels is formed to discharge gases and vapors.
[0009] Furthermore, European patent publication 0 271 727 discloses a bituminous roofing material and a method for the manufacture thereof. The roofing material comprises a bituminous layer with a profiling in the form of thickenings or projections. On the profiling is located a foil that, in the area of the projections, is covered with a second bituminous layer. Described is that the profiling may be designed as ribs extending in the longitudinal direction. Through the foil, the roofing material becomes more form-stable, so that bitumen, which can flow more rapidly, can also be used. Outside the grooves, the foil is covered by the second layer and will therefore melt less rapidly outside the grooves. Moreover, the foil is used to impart more form stability to the bitumen and precisely prevents the flowing of the bitumen, so that after the arrangement of the roofing material on a roof surface the grooves are still present practically unchanged.
[0011] Further details, aspects and effects of the invention are discussed below with reference to the figures in the drawing.
Fig. 1 diagrammatically shows a perspective view of a strip of an example of a roofing material according to the invention.
Fig. 2 diagrammatically shows a perspective view of a strip of an example of a roofing material according to the invention, after heating the foil.
Fig. 3 diagrammatically shows a cross-section of an example of a roofing material according to the invention.
Fig. 4 diagrammatically shows a cross-section of an example of a roofing material according to the invention after heating.
Fig. 5 diagrammatically shows a perspective view of a roofing roll of an example of a roofing material according to the invention.
Figs. 6-9 diagrammatically shows a perspective view of a roofing material according to the invention in several phases of an example of a method according to the invention.
Fig. 10 diagrammatically shows a perspective view of a profiled roller with which a roofing material is profiled.
Fig. 11 diagrammatically shows an example of a profiling of grooves in a roofing material according to the invention.
Fig. 12 diagrammatically shows an example of a profiling of grooves in a roofing material according to the invention.
Fig. 13 diagrammatically shows an example of a profiling of grooves in a roofing material according to the invention.
[0012] Fig. 1 shows a strip 1 of a roofing material. The strip 1 is built up from a layer 11 of a carrier material, on which a layer 12 of a bituminous material is applied on at least one side. On the other side of the carrier 11 is, as shown, often also located a bituminous layer 14, which, for its part, is finished with a covering layer 15. Applied on the bituminous layer 12 is a plastic foil 13. The bituminous layer 12 is provided with a profiling in the form of substantially parallel grooves 4. The plastic foil 13 follows the surface of the bituminous layer 12, so that the foil 13 also has a groove-shaped profiling. The foil 13 has an anisotropic molecular orientation direction, which is indicated in the figure with arrow A. The orientation direction is preferably substantially parallel to the longitudinal direction of the strip 1.
[0013] In use, the roofing material is laid on a surface to be covered, with the foil 13 facing down. Then the material is heated, for instance by moving a burner along the material from the foil side, which process is also referred to as 'flaming'. Through the heating, the foil 13 melts or burns. The flaming affects the part 51 of foil 13 that is located on the ridges between the grooves earlier or faster than the part 52 of the foil in the grooves 4, in particular because the foil on the ridges melts or burns earlier, which has the result that the foil bursts open on the ridges located between the grooves. Since the profiling is groove-shaped, no net structure will be formed during the heating of the foil. In fact, remainders of the foil will, as shown in Fig. 2, form strips 5, which are practically not connected together. The strips 5 will then largely extend in the grooves 4.
[0014] When flaming, the bituminous layer flows out, so that after application of the roofing material the profiling, i.e. the grooves 4, has disappeared or is at least strongly reduced. The profiling therefore does not result in channels or the like in the attached roofing material. In a roofing material according to the invention, however, after attachment, a structure of channels may be contained that have not been obtained by the grooves 4 and the foil 13.
[0015] In the example shown, the grooves 4 extend in a direction away from a stretching direction, in the example shown this is the anisotropic molecular orientation direction. Through the anisotropic molecular orientation, the plastic foil has an internal stress.
[0016] Such an internal stress develops, for instance during blowing extrusion, when a foil of a polymer material, while the foil still cools and solidifies, is stretched in the longitudinal direction. The chain-shaped polymer molecules are then stretched and solidified in that condition. The stretched condition is a thermodynamically unfavorable condition, since the molecules strive for maximum entropy. The polymer molecules therefore have a tendency to assume a more compact ball. This, however, is prevented by the high viscosity at temperatures below the melting point of the polymer. Only when during the processing of the roofing roll the foil is heated to near and above its melting point, this 'built-in stress' will be released, because the molecules take random positions again. This externally leads to extreme shrinkage in the longitudinal direction of the foil. When the foil tears or melts during heating, the foil tends to contract or curl in the anisotropic molecular orientation direction, as a result of which the internal stress relaxes. Because the orientation direction is away from the grooves, the foil will therefore contract or curl in the direction of the grooves. Through this curling, the net formation is further inhibited.
[0017] The grooves will be located in any direction away from the stretching direction. In the example shown, the grooves do not cross each other and the grooves 4 are transverse to the orientation direction, with the result that the stress is transverse to the grooves as well. Consequently, the foil will strongly curl or contract in the direction of the groove, as a result of which it has a great effect in the prevention of the formation of a net structure.
[0018] The plastic foil may, for instance, be manufactured from polyethylene. The plastic foil may also be manufactured from a material other than polyethylene, such as, for instance, polypropylene foil or web, a combination of polyethylene and polypropylene, other thermoplastic burn-away foils or otherwise. As a result of the method of manufacture, practically all the plastic foils have an anisotropic orientation of the molecules.
[0019] Fig. 3 shows a cross-section of an example of a roofing material according to the invention. The cross-section is transverse to the grooves and substantially parallel to the molecular orientation direction. In the example shown, the grooves 4 have been provided in the bituminous layer 12 after attachment of the foil 13 to the bituminous layer. As a result, the foil in a part located outside the groove is stretched in a direction away from the groove. Consequently, the foil is more stretched in areas 51 located between the grooves 4 more than in the parts 52 located in the grooves. The stress in the areas 51 is indicated in the figure with the arrows B.
[0020] Fig. 4 shows the example of Fig. 3 after (partial) heating of the plastic foil 13. The parts 51 located between the grooves have been melted, as a result of which strips 5 of the foil 13 are formed that extend in a direction transverse to the cross-section. The strips 5 are located in the grooves 4 and are still connected with the bituminous layer with the parts 52 located in the grooves. Through the stress difference, the foil is rolled up on the backs to the grooves 4, and the net formation is further inhibited.
[0021] It should be noted that in the figures the roofing material according to the invention is not shown to scale or in proportion. In particular Fig. 4 shows the operation of the invention, distorted for the sake of clearness. In practice, in the phase of attachment shown in Fig. 4, the foil 13 has nearly completely shrunk away to narrow strips secured to the bitumen, which are located in the grooves in question. The adhesion of the roofing material to the base is then largely determined by the bitumen on the ridges. This bitumen then flows out and finally also fills the grooves. As a result, the remainders of foil are enclosed by the bitumen, or the foil remainders only take up a negligible part of the contact surface between the bitumen and the base, so that the remainders of foil do not appreciably disturb the contact surface.
[0022] Fig. 3 shows the stress gradient along a line perpendicular to the grooves 4. It is also possible to create between parts of the foil located between the grooves a stress gradient that has a component parallel to the groove.
[0023] Fig. 5 shows a roofing roll from a strip 1 of roofing material according to the invention. The foil 13 is located with the molecular orientation direction parallel to a longitudinal direction of the strip, and the grooves 4 are parallel to an axial direction of the roll. In this example, the grooves 4 extend over the full width of the strip 1. Through the grooves 4, the foil can be easily rolled up. Furthermore, the foil 13 prevents radially consecutive layers of the roofing material from sticking together through, for instance, adhesion of the bituminous material of the layer 12.
[0024] The roll may have any desirable dimension and have, for instance, a diameter of a few decimeters. A suitable diameter of the roll ranges, for instance, between 20 and 25 cm. The distance between the grooves may, for instance, be smaller than a few centimeters. An experimentally found suitable value is, for instance, a distance of about 4 mm. The depth (wave height) of a groove may, for instance, be smaller than 1 centimeter. An experimentally found suitable value is a depth of about 0.5-1 mm at a roll thickness of 4 mm. The invention, however, is not limited to the mentioned values.
[0025] Figs. 6-9 illustrate a method of manufacturing a roofing material according to the invention. Fig. 6 shows a carrier 11, which is manufactured from a suitable carrier material, such as, for instance, glass fiber web or synthetic fibers or a combination of these with glass. On the carrier 11 is applied, on at least one side, a layer of bituminous material. In Fig. 7, the roofing material is provided, on the other side as well, with a layer of bituminous material, thinner in this example. On one side of the carrier 11, a first bituminous layer 12 is located, and on the other side, a second bituminous layer 14 is located.
[0026] Subsequently, the first bituminous layer 12 is provided with a plastic foil. Fig. 8 shows the carrier 11 and the bituminous layers 12, 14 with a foil 13 on the first layer 12. Then the bituminous layer is provided with a profiling, such that the foil follows the profiling. The profiling is designed in the form of grooves 4 in the bituminous layer 12, which extend at least partly transversely to the anisotropic molecular orientation direction of the foil. Fig. 9 shows the roofing material after application of the profiling. During the manufacture, the roofing material may also be provided with a covering layer, not shown, of for instance grit, slate, plastic foil, and the like on the second bituminous layer 14.
[0027] The arrangement of grooves may, for instance, be performed with a profiled roller, as shown in Fig. 10. In this figure, the roller 20 is rotatable about an axis 21, as indicated with arrow 22. The roller 20 is provided with profiled portions 23, which extend radially and have a longitudinal direction parallel to the axis 21. In the example shown, the roller with the profiled portions is approximately star-shaped. Differently shaped profiled portions, for instance rectangular strips, are also possible.
[0028] A roll 30 is placed on the other side of the carrier 11 to apply a counterpressure. The roll 30 is rotatable about an axis 31, as a result of which the roofing material is easily transported. It is also possible to apply a counterpressure in another manner, for instance with a non-rotatable, stationary beam or plate or a conveyer belt, or the like.
[0029] When the roofing material is passed between the roller and the roll and the roller rotates, the profiled portions 23 press the foil 13 into the bituminous layer, as a result of which grooves or traces 4 are formed in the bituminous layer 12. The foil 13 follows the form of the bituminous layer 12. When arranging the grooves, the foil is anchored in areas that come to lie in the grooves, while in areas between the grooves a tensile stress and/or extension of the foil may be created.
[0030] The invention is not limited to the example shown. After reading the foregoing, different modifications will be obvious to those skilled in the art. In particular, it is obvious not to design the grooves as parallel grooves that extend over the full width of the strip, but as series of at least two grooves aligned with each other, as shown in Fig. 11, or that are staggered with respect to each other, in which case the grooves of one series may or may not extend between the grooves of the other series, as diagrammatically shown in Figs. 12 and 13. Also, the profiling may be designed with grooves that are inclined at a, possibly small, angle to each other. Moreover, it is obvious not to arrange the grooves perpendicularly to the orientation direction of the foil, but at an acute or obtuse angle to the foil.
1. A roofing material, comprising:
a layer (11) of a carrier material, which is provided on at least one side with
at least one bituminous layer (12) of a bituminous material, which bituminous layer is provided with a profiling that comprises grooves (4) and ridges located between the grooves, which at least one bituminous layer (12), during heating, at least partly melts, as a result of which the grooves (4) at least partly disappear; and
a foil (13), which follows the profiling of the bituminous layer and is located on a side of the bituminous layer (12) facing away from the layer (11) of the carrier material, of which foil (13) parts (51) located between the grooves melt earlier during heating, such as, for instance, flaming, than parts (52) located in the grooves (4).
2. A roofing material according to claim 1, wherein the profiling substantially comprises
grooves that do not intersect each other.
3. A roofing material according to claim 1, wherein the foil (13) is stretched in a stretching
direction (A) away from the grooves (4).
4. A roofing material according to claim 3, wherein the foil (13) has an anisotropic
molecular orientation direction (A) in a direction away from the grooves (4).
5. A roofing material according to any of the preceding claims, wherein the foil (13)
in parts (51) located between the grooves is more stretched in a direction away from
the grooves (4) than parts (52) located on or in the grooves (4).
6. A roofing material according to any of claims 2-4, wherein the stretching direction
(A) is perpendicular to the grooves (4).
7. A roofing material according to any of the preceding claims, wherein the profiling
comprises at least two series of substantially parallel grooves, which series are
staggered with respect to each other.
8. A roofing material according to claim 7, wherein the grooves of one series extend
at least between the grooves of the other series.
9. A roofing material according to any of claims 1-6, wherein the profiling comprises
at least a number of grooves aligned with each other.
10. A roofing material according to any of the preceding claims, wherein the foil is manufactured
from polyethylene and/or polypropylene and/or another thermoplastic burn-away foil.
11. A roofing roll, comprising a rolled-up strip (1) of roofing material according to
any of the preceding claims.
12. A roofing roll according to claim 11, wherein the foil with stretching direction (A)
is parallel to a longitudinal direction of the strip (1).
13. A roofing roll according to claim 11 or 12, wherein the grooves extend substantially
transversely to a longitudinal direction of the strip (1).
14. A roofing roll according to any of claims 11-13, wherein the grooves extend over the
full width of the strip (1).
15. A method of manufacturing roofing material, comprising:
applying a bituminous layer (12) on a layer (13) of a carrier material;
applying a foil (13) on the bituminous layer;
applying a profiling in the bituminous layer, such that the foil follows the profiling, by pressing grooves (4) into the bituminous layer, while, during heating, such as, for instance, flaming, parts (51) of the foil (13) located between the grooves melt earlier than parts (52) of the foil (13) located in the grooves; and the bituminous layer (12) at least partly melts during heating, as a result of which the grooves (4) at least partly disappear.
16. A method according to claim 15, wherein the arrangement of grooves (4) is performed
with a profiled roller (2).