Patent Application
20060051558
The invention relates to a multilayer film that is water-tight and water vapor permeable for use in home or other building construction, for instance for sealing in particular in the roof area during home construction, with a water vapor permeable base layer made of a first plastic material and with at least one water vapor permeability-controlling second layer that is coupled to the base layer and that is made of a second plastic material, the use of such a multilayer film as an adhesive tape and/or vapor barrier and/or facade film and/or on-roof film, as well as to a system made of such a multilayer film and a multilayer film designed as an adhesive tape and to a method for producing such a multilayer film.
In general because of increasing environmentally focused methods used in home construction and home renovation, it is becoming increasingly important to seal the roof area, in particular beneath the roof and/or on the roof and/or the facade area so that it is water-tight and water vapor permeable in order to create a pleasant and healthy living climate while still preventing rain water from penetrating. While laying and gluing film for this it is therefore very important that no open areas occur in the seal due to warping in the films in the area of joints between the strips of film. Furthermore, care must be taken that the water vapor permeability of the materials used is high enough that condensation does not occur under these films. The problems cited above occur in particular with conventional seals in which films/adhesive tapes are used that cannot flexibly compensate warping and joint openings up to a certain degree and that have incorrect water vapor permeability (water vapor permeability that is too low or too high). Furthermore, with all of the aforesaid requirements it must be assured that the materials used have adequate strength and mechanical stability, particularly in home construction. In addition, a film/adhesive tape should be as simple and cost-effective to produce as possible with reproducible product properties.
Normally films made of plastic material, e.g. appropriate polymer films, are blown or cast as monolayer or multilayer films. Typical methods are described in the literature, for instance by K. R. Osborn and W. A. Jenkins, Plastic Films: Technology and Packaging Applications, Technomic Publishing Co., Inc., Lancaster, Pa. 1992. Although properties of such films such as tensile strength and extensibility are varied in wide ranges for instance by appropriate selection of film thickness or polymer used, water vapor permeability cannot be appropriately adjusted as desired and is too low for certain uses, as described in the foregoing and e.g. also when such films are used for food packagings. In addition, strength and mechanical stability are not provided in all circumstances. Furthermore, known film materials are expensive and complex to produce. It is difficult to reproducibly adjust the product properties of such films.
U.S. Pat. No. 6,540,949 describes a method for producing bi-oriented polyethylene films with high water vapor permeability. In it, a water vapor permeable base film made of a first plastic material is coated with one or a plurality of very thin water vapor permeability-controlling film layers that are no more than approx. 0.0038 mm thick. The degree of water vapor permeability is thus determined using the water vapor permeability of the base layer and the thickness of the water vapor permeability-controlling film layer or layers. Since the thickness of the water vapor permeability-controlling film layer or layers is very low, however, this thickness and thus the resulting water vapor permeability of the embodied multilayer film cannot be precisely controlled. In addition, since the base film has a microporous structure due to the addition of fillers and the thickness of the additional water vapor permeability-controlling film layer or layers is very thin, the multilayer films produced in this manner do not in all circumstances have satisfactory tensile strength, mechanical stability, and extensibility. However, if the film layers described in the cited US patent are made thicker, the water vapor permeability then decreases so that it is about the same as that of conventional films if the base film has a thickness of approximately 0.05 mm.
Known from Offenlegungsschrift DE 101 16 477 A1 is a roof lining web that is water-tight and open to vapor diffusion and that is made of a complex composite that has at least three layers and that is based on thermoplastics with a vapor-permeable interior layer made of a porous substrate, a vapor-permeable but liquid-impermeable middle layer made of porous film, and a vapor-permeable but liquid-impermeable embossed and perforated film that has a three-dimensionally structured surface. An additional interlaid scrim layer arranged on the interior side of the roof is provided in order to assure mechanical sturdiness. The roof lining web is not extensible.
Offenlegungsschrift DE 198 19 085 A1 describes a water-tight and water vapor permeable flat material made of a microporous film and a water-tight membrane that uses relatively expensive materials and whose product properties must be adjusted via the layer thicknesses used for the film and/or the membrane. An additional reinforcing layer is provided for ensuring high stability.
Utility model DE 297 00 987 describes a diffusion-permeable under-roof membrane made of a composite with at least three layers and with exterior non-woven layers and an interior microporous film layer without holes.
In general multilayer films based on microporous films have the disadvantage that they are not water-tight for low surface tension water. Such low surface tension water, that is, water with a reduced surface tension, can occur for instance when pollutants in the roof region mix with rain water. Low surface tension water does not form drops or tends not to form drops. Low surface tension water in the sense of the foregoing and in the sense of the following specification and the claims shall be defined as water with a surface tension of 0.04 N/m to 0.045 N/m, for instance soapy water produced by the addition of rinse agents or washing agents, such as surfactants, to distilled water.
It is the object of the present invention to provide a multilayer film that is water-tight and water vapor permeable, in particular for sealing in the roof area during home construction, that overcomes the disadvantages of the films in the prior art, in particular to provide a multilayer film that offers very good mechanical stability and that can be produced simply, cost effectively, and with reproducible product properties, whereby the water vapor permeability is adjustable. In addition, a corresponding production method for such a multilayer film should be provided.
Furthermore, the inventive multilayer film should have particularly high water vapor permeability and high resistivity to mechanical loads, such as tensile loads, and high extensibility.
The inventive multilayer film is designed water-tight and water vapor permeable and has high mechanical stability. It is in particular for sealing in the roof area during home construction. The inventive multilayer film has a water vapor permeable, water-tight base layer made of a first plastic material and at least one water vapor permeability-controlling second layer that is coupled to the base layer and that is made of a second plastic material. In accordance with the invention, the base layer is water-tight for low surface tension water. Furthermore, the multilayer film is inventively extensible and tear-resistant. The water vapor permeability-controlling second layer is provided with macroscopic holes, the arrangement of which removes a defined surface area from the second plastic material so that the water vapor permeability of the multilayer film is adjusted. The more plastic material removed, the greater the water vapor permeability. The inventive combination of the base layer that is water-tight for low surface tension water and the at least one water vapor permeability-controlling second layer, whereby the multilayer film can be extensible and can have a certain tear resistance, and whereby this second layer is provided with macroscopic holes, the arrangement of which removes a defined surface area from the material of the second layer, makes it possible to provide in a particularly cost-effective manner a mechanically loadable and stable multilayer film that is water-tight and water vapor permeable and in which the water vapor permeability can be adjusted in a simple manner. In particular providing holes is substantially easier and more reproducible than for instance adjusting the thickness of a very thin additional coating, whereby the number, size, and position of the inventively provided holes in the second layer, comprising the second plastic material, makes it particularly easy to adjust the appropriate water vapor permeability. In particular the mechanical load carrying ability can be adjusted as desired using the different thickness selected for the second layer, depending on the use for the multilayer film, without this affecting the water vapor permeability.
In accordance with one preferred embodiment, the inventive tear-resistant multilayer film has a tear-resistance in accordance with DIN 53504 of greater than 3 N/mm2, preferably greater than 5 N/mm2, more preferably greater than 7 N/mm2, particularly preferably greater than 9 N/mm2, very particularly preferably greater than 11 N/mm2 or greater than 13 N/mm2, or most particularly preferably greater than 15 N/mm2.
The macroscopic holes can preferably be round, oval, square, rectangular, rhomboidal, or of a different shape, whereby the arrangement can be provided very dense, in rows and columns, or distributed evenly across the surface area and/or arranged randomly.
The diameter of the macroscopic holes is preferably in a range from 0.1 mm to 100 mm, preferably from 0.2 mm to 50 mm, more preferably from 0.4 mm to 20 mm, particularly preferably from 0.5 mm to 8 mm, and most preferably from 0.6 mm to 6 mm. This is the diameter in the case of round macroscopic holes or the largest diameter in the case of oval macroscopic holes or it is the edge length in the case of polygonal macroscopic holes.
The water vapor permeability of the first plastic material is preferably greater than the water vapor permeability of the second plastic material. This means the water vapor permeability of the multilayer film can be adjusted in a particularly simple manner since it is thus particularly simple to change the number, size, and position of the inventively provided holes in the second layer, comprising the second plastic material, and thus, in combination with the greater water vapor permeability of the first plastic material, rendering the overall water vapor permeability of the inventive multilayer film adjustable.
It can also be preferred that the water vapor permeability of the first plastic material is greater than the water vapor permeability or the overall water vapor permeability of the inventive multilayer film. This results simply from the fact that the inventive multilayer film is provided with at least two layers (the base layer and the at least one second layer).
Water vapor permeability is measured in accordance with DIN 53122-1, Part 1, gravimetric method (August 2001) at 23° C. and at a relative humidity of 85% in the vaporization space (climate D), whereby the base layer is oriented to the vaporization space and the second layer is oriented to the absorption space.
The base layer preferably has a water vapor permeability in the range of at least 0.5 g/(m2*d) to 100 g/(m2*d), preferably 0.75 g/(m2*d) to 50 g/(m2*d), more preferably 1.0 g/(m2*d) to 40 g/(m2*d), particularly preferably 1.5 g/(m2*d) to 35 g/(m2*d), very particularly preferably 2.0 g/(m2*d) to 30 g/(m2*d) or 2.5 g/(m2*d) to 25 g/(m2*d), or most preferably 3.0 g/(m2*d) to 20 g/(m2*d).
The plastic material of the second layer preferably has a water vapor permeability of at least greater than 0.1 g/(m2*d), preferably greater than 0.3 g/(m2*d), more preferably greater than 1.0 g/(m2*d), particularly preferably greater than 5 g/(m2*d), very particularly preferably greater than 10 g/(m2*d) or greater than 20 g/(m2*d), or most preferably greater than 30 g/(m2*d). Most particularly preferable is a water vapor permeability of no more than 100 g/(m2*d), preferably of no more than 50 g/(m2*d), and particularly preferably of 40 g/(m2*d).
The inventive multilayer film preferably has a water vapor permeability in the range of at least 0.5 g/(m2*d) to 90 g/(m2*d), preferably 1.0 g/(m2*d) to 70 g/(m2*d), more preferably 1.5 g/(m2*d) to 50 g/(m2*d), particularly preferably 2.0 g/(m2*d) to 30 g/(m2*d), very particularly preferably 2.5 g/(m2*d) to 25 g/(m2*d) or 3.0 g/(m2*d) to 20 g/(m2*d), or most preferably 5.0 g/(m2*d) to 15 g/(m2*d).
In one preferred embodiment, the inventive multilayer film is adaptive to moisture only to a limited extent. If water vapor permeability WDD2 is measured using DIN 53122-1, Part 1, at 23° C. and a relative humidity of 50% rel. hum. in the evaporation space (for instance a well ventilated environmental testing space) and compared to water vapor permeability WDD1 in accordance with DIN 53122-1, Part 1, gravimetric method (August 2001) at 23° C. and a relative humidity of 85% in the evaporation space (climate D), the ratio WDD1/WDD2 is less than 15, preferably less than 10, more preferably less than 8, particularly preferably less than 6, very particularly preferably less than 4, and most preferably less than 2.
In another preferred embodiment, the inventive multilayer film is adaptive to moisture only to a limited extent with respect to the properties at high humidity. If water vapor permeability WDD3 is measured using DIN 12572, test conditions C (information on behavior of materials at high humidity) and compared to water vapor permeability WDD1 in accordance with DIN 53122-1, Part 1, gravimetric method (August 2001) at 23° C. and a relative humidity of 85% in the evaporation space (climate D), the ratio WDD3/WDD1 is less than 12, preferably less than 6, more preferably less than 4, particularly preferably less than 3, very particularly preferably less than 2, and most preferably less than 1.5.
In accordance with the invention, the base layer of the inventive multilayer film is preferably extensible in a first direction, preferably a production direction, and the holes of the second layer are arranged such that the second layer is also extensible in the first direction, whereby the extensibility starting from the unextended condition is at least 20%, preferably at least 35%, particularly preferably at least 100%, and most preferably at least 200%. The extensibility can preferably occur using appropriate selection of the first and/or second plastic material, whereby the extensibility of this layer is especially to be assured by the size and position of the holes of the second layer. In general, the “production direction” is the direction in which a web of the multilayer film is produced during the production process. The web can preferably be wound onto a corresponding roller. Because of the extensibility in at least a first direction, the inventive multilayer film preferably offers particularly secure and leak-free layability, in particular in the area of joints. Warping also occurs less frequently because of this, or even not at all, and can thus be compensated.
Particularly preferably, the base layer is also extensible in a second direction perpendicular to the first direction and the holes of the second layer are arranged such that the second layer is also extensible in the second direction, whereby the extensibility starting from the unextended condition is at least 20%, preferably at least 35%, particularly preferably at least 100%, and most preferably at least 200%. In this case as well the extensibility can be additionally enhanced or obtained using appropriate material selection, as described in the foregoing. The extensibility in the second direction should in general mean that the multilayer film is inventively particularly preferably extensible perpendicular to the first direction as well, whereby naturally extensibility at oblique angles to the first direction and the second direction will occur in practice.
In one preferred embodiment, the multilayer film is also still water-tight with respect to low surface tension water even during and after extension in a direction that is longitudinal and/or transverse to the production direction. The film is preferably also still water-tight with respect to low surface tension water even during an extension of at least 20% in at least one direction, and is particularly preferably still water-tight with respect to low surface tension water even during an extension of at least 50% in at least one direction.
In accordance with one preferred embodiment, the first plastic material is a water vapor permeable material or a polyolefin material made of polyethylene, e.g. a polyethylene which is or has properties of LDPE (low density polyethylene), MDPE (medium density polyethylene), HDPE (high density polyethylene), or LLDPE (linear low density polyethylene), polypropylene, or a copolymer comprising ethylene or propylene or butylene or butadiene or isoprene or a combination thereof, and the plastic material contains a material for enhancing the water vapor permeability, preferably made of polyvinyl alcohol, polyvinyl pyrrolidone, acrylic acid homopolymers, acrylic acid copolymers, cellulose fibers, polyurethanes, polyesters, in particular polyurethanes and polyesters based on polyether polyols, (for instance PTMEG and PPO), polyester polyols, or made of minerals, particularly preferably calcium carbonate or styrene or a mixture of calcium carbonate and styrene. The water vapor permeability of the base layer is thus adjusted using the at least one material for enhancing the water vapor permeability.
In accordance with another preferred embodiment, the second plastic material is a polyolefin material, e.g. made of polyethylene, e.g. a polyethylene which is or has properties of LDPE (low density polyethylene), MDPE (medium density polyethylene), HDPE (high density polyethylene), or LLDPE (linear low density polyethylene), polypropylene, or a copolymer comprising ethylene or propylene or a combination thereof.
It is inventively preferred that the base layer and the at least one additional second layer are coupled to one another with an interposing coupling layer, wherein the coupling layer comprises a contact adhesive, preferably adhesive or a hot melt adhesive, reactive adhesive (for instance 2-component polyurethane adhesive), or a polyolefin material, preferably comprising polyethylene which is or has properties of LDPE (low density polyethylene), MDPE (medium density polyethylene), HDPE (high density polyethylene), or LLDPE (linear low density polyethylene), polypropylene, or a copolymer comprising ethylene or propylene or a combination thereof. The base layer and the second layer can preferably also be coupled using heat-melting, for instance by flaming, thermolamination, or thermocalendering.
In one particularly preferred variant, the coupling layer is a water vapor permeable material, in particular a water vapor permeable plastic material, preferably a polyolefin material made of polyethylene, e.g. a polyethylene which is or has properties of LDPE (Low Density Polyethylene), MDPE (Medium Density Polyethylene), HDPE (High Density Polyethylene) or LLDPE (Linear Low Density Polyethylene), polypropylene, or comprising a copolymer comprising ethylene or propylene or butylene or butadiene or isoprene or a combination thereof, and the plastic material of the coupling layer contains at least one material for enhancing water vapor permeability, preferably made of polyvinyl alcohol, polyvinyl pyrrolidone, acrylic acid homopolymers, acrylic acid copolymers, cellulose fibers, polyurethanes, polyesters, in particular polyurethanes and polyesters based on polyether polyols (for instance PTMEG and PPO), polyester polyols, or made of minerals, particularly preferably calcium carbonate, or polystyrene, or a mixture of calcium carbonate and polystyrene.
This inventively preferred design offers a variable option for adjusting the appropriate product parameters with relatively simple and cost-effective producibility of the inventive multilayer film.
In accordance with one preferred embodiment of the inventive multilayer film, the coupling layer has a thickness between 0.0001 mm and 0.1 mm, preferably between 0.0005 mm and 0.05 mm, and particularly preferably between 0.001 mm and 0.03 mm, and the coupling layer can also preferably be provided with holes that are arranged flush with the holes of the second layer or the coupling layer preferably extends across the entire surface between the base layer and the second layer. However, the coupling layer, or the material of the coupling layer, can also be distributed, in particular applied, in points or strips across the entire surface. Thus, with simple producibility, further enhanced very good coupling, and thus mechanical stability of the individual layers of the inventive multilayer film, can be attained.
Particularly preferred is an embodiment of the inventive multilayer film in which the inventive multilayer film has a contact adhesive coating, preferably made of adhesive or a hot melt adhesive, on at least one of the surfaces, preferably on the base layer and/or on the at least one second layer. When the width of such a multilayer film is appropriately selected, this embodiment makes it possible to assure either direct gluing, and thus simpler handling, of such a multilayer film, or to employ a multilayer film preferably thus designed inventively as an adhesive tape for sealing joints, whereby the inventive adjustability of the water vapor permeability avoids formation of condensation in the area of the edges to be glued, which is not possible with conventional adhesive tapes from the prior art, especially film adhesive tapes. The preferred given flexibility and/or extensibility of the inventive multilayer film is particularly advantageous since warping is avoided and gaps in the joint area cannot occur or can be compensated.
In order to assure very good mechanical stability of the inventive multilayer film, in accordance with one preferred embodiment of the invention the base layer has a thickness of at least 0.005 mm, preferably of at least 0.01 mm, more preferably of at least 0.03 mm, particularly preferably of at least 0.06 mm, even more preferably of at least 0.09 mm, and most preferably of at least 0.15 mm.
For assuring mechanical stability, in accordance with one preferred embodiment the second layer has a thickness of at least 0.002 mm, preferably of at least 0.005 mm, particularly preferably of at least 0.01 mm or 0.02 mm, even more preferably of at least 0.04 mm, and most preferably of at least 0.08 mm.
In one preferred embodiment, the multilayer film has a thickness of at least 0.03 mm, preferably at least 0.05 mm, particularly preferably at least 0.075 mm or 0.1 mm, even more preferably at least 0.15 mm, and most preferably at least 0.2 mm.
Particularly preferred is one embodiment of the inventive multilayer film that has a water vapor permeability-controlling third layer that is provided with holes, the arrangement of which removes a defined surface area so that the water vapor permeability of the multilayer film is adjusted. With regard to this third layer, all of the statements made in the foregoing regarding the arrangement, design, and coupling of the second layer apply, and it should also be mentioned that the holes of the second layer can preferably be in registry with the holes of the third layer, and that the third layer can be arranged on the side of the base layer that opposes the second layer. However, there can also be the option of using a suitable intermediate layer to attach in a coupled manner the third layer to the second layer. The third layer can also correspondingly be provided with a contact adhesive coating described in the foregoing.
In order to be able to adjust the water vapor permeability of the inventive multilayer film across a particularly large area, the defined removed surface area of the second layer (and/or also of the third layer, if any) is no more than 80%, preferably no more than 60%, particularly preferably no more than 40%, or most preferably no more than 30%. Preferably the minimum value of the defined removed surface area of the second layer (and/or also of the third layer, if any) is 1%.
The multilayer film is suitable for use as a film for sealing in home or other building construction without additional reinforcements. However, in one preferred embodiment for sealing with particularly high mechanical stability, the inventive multilayer film can be further reinforced. Suitable reinforcements can be: one reinforcing layer or a plurality of reinforcing layers made of laminated non-woven fabrics, woven fabrics, or interlaid scrims. The reinforcing layer or layers can be worked in as intermediate layer or layers and/or can be laminated on at least one exterior side.
In accordance with one preferred embodiment, the inventive multilayer film can have a width in a range from 400 mm to 5000 mm, preferably in a range of 500 mm to 4200 mm, even more preferably in a range of 600 mm to 3000 mm, particularly preferably in a range of 800 mm to 2500 mm, and most preferably in a range of 900 mm to 2000 mm. Thus application preferably as film for sealing in the roof area during home construction is covered.
The inventive multilayer film can preferably also have a width in a range of 30 mm to 400 mm, preferably in a range of 40 mm to 350 mm, and particularly preferably in a range of 60 mm to 250 mm, i.e. the inventive multilayer film can also essentially be used as a tape-like film, in particular as an adhesive assembly tape for sealing and/or gluing joints when sealing in the roof area during home construction.
The multilayer film can preferably be made flame-retardant. For this purpose, the plastic material of the base layer and/or of the second layer and/or of the coupling layer can be provided with flame-retardant additives such as for instance antimony compounds or phosphorus compounds.
In accordance with one preferred embodiment, the inventive multilayer film can be made light and UV stable. For this purpose, the plastic material of the base layer and/or of the second layer and/or of the coupling layer can be provided with light and/or UV light stabilizers for instance based on inorganic compounds such as zinc oxide or carbon black or on organic compounds such as for instance from the HALS (hindered amine light stabilizers) group.
In accordance with one preferred embodiment, the inventive multilayer film can be rendered antistatic. For this, the plastic material of the base layer and/or of the second layer and/or of the coupling layer can be provided with antistatic agents, for instance based on alkyl amines or amides.
The multi-layer film described in the foregoing can be inventively used as adhesive tape, in particular for sealing in the roof area during home construction.
The multilayer film described in the foregoing can inventively be used as a vapor barrier, in particular for sealing in the roof area during home construction.
The multilayer film described in the foregoing can inventively be used as on-roof film and/or facade film, in particular for sealing in the roof area and/or wall area during home construction.
In accordance with the invention, a system can also be provided that comprises the multilayer film described in the foregoing and an adhesive tape that comprises the multilayer film described in the foregoing. Such a system offers the special advantage that the multilayer film and the associated adhesive tape made of the corresponding multilayer film have the same or at least largely the same product properties, in particular with respect to mechanical stability, extensibility, and water vapor permeability, so that each time it is used it is possible to obtain optimum sealing with such a system.
The inventive method for producing a multilayer film that is water-tight and water vapor permeable, in particular for sealing in the roof area during home construction, in particular a multilayer film with the properties described in the foregoing, whereby the water vapor permeability of the multilayer film is adjusted, is characterized by the following steps:
Preferably a water vapor permeability-controlling third layer is coupled to the base layer, whereby the third layer is provided in advance with holes, the arrangement of which removes a defined surface area of this third layer.
The coupling step preferably occurs using heat-melting, particularly preferably using flaming, or preferably using thermolamination or preferably using thermocalendering. The inventive multilayer film is described in more detail in the following using an exemplary embodiment and the attached drawings.
a is a top view of a preferred embodiment of the inventive multilayer film in its unextended condition; and
b is a top view of an embodiment of the inventive multilayer film in
a is a top view of the inventive multilayer film, wherein the second layer 2 provided with the holes 3 is shown in the unextended condition. In accordance with
The inventive multilayer film is relatively simple and inexpensive to produce and offers adjustable water vapor permeability, water-tightness even for low surface tension water, and very good mechanical stability.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2004 043 010.1 | Sep 2004 | DE | national |
| 10 2005 038 863.9 | Aug 2005 | DE | national |
