CZ20002692A3 - Plastic foil and use thereof - Google Patents

Abstract

Reversibly vapor-permeable plastic films contain pro a water-impermeable barrier layer and, optionally, across the surface stabilizing structure. The closing layer is formed from monolithic, hydrophilic, and vapor-swellable specific, high-permeable plastic films vapor permeability. Films are suitable as thin building coatings, in particular as under-roof layers, inadequately ventilated structures.

Description

Technical field

The present invention relates to a reversible (reversible) vapor-permeable plastic film comprising a water and vapor-resistant, water-impermeable and vapor-permeable barrier layer. In addition, the invention relates to the use of said film as an under-roof layer, as a film used in construction in poorly ventilated structures and as a canvas.

BACKGROUND OF THE INVENTION

In thermally insulating roof structures, it is common to place an under-roof foil on beams and across insulation to prevent the ingress of air or rain or snow water. If such an under-roof foil is to be laid, care should be taken to ensure the air space between the foil and the insulation to ensure roof ventilation and to prevent condensation on the under-foil, which condensation could drip from the foil as water into the insulation and damage its function . If said air gap provides proper ventilation, an under-roof covering made of water and vapor-resistant, waterproof and vapor-impermeable, optionally surface-stabilized plastic film will function essentially without problems.

Due to the increasing demand for thermal insulation, insulation in a thicker layer is now used in the construction industry than before. Therefore, in the case of roof insulation, less space will be available for the above-mentioned ventilation and safety air space between the under-roof foil and the insulation

moreover, there will be a greater temperature difference across the layers of insulation. Due to the short construction time and the rapid occupancy of new buildings, moisture often occurs in the building and must be forced out by strong heating. All of this has resulted in the need for building films, such as under-roof layers, which, in addition to water and vapor resistance and water impermeability, are now also increasingly reversibly vapor permeable.

Suitable plastic films for such an undercoat layer should, as already mentioned, be water and vapor resistant, which means, first and foremost, that the plastic material of such films should not be chemically degradable by water or steam, even after prolonged use with the associated risk of aging. material. Furthermore, these films must be mechanically strong in order to withstand, in principle, the effects of tearing or impact which are unavoidable in the construction environment. To a certain extent, as well as vapor-impermeable plastic film, it must also be able to withstand high water pressure, even during contact with another material (tent effect) or after local contamination, for example with detergents, and finally, to obtain the desired effect, exhibit high vapor permeability.

Plastic films with the above properties will not only be suitable as an undercoat, but in a broad sense they can be used as building foils for poorly ventilated structures, ie in addition to use as a undercoat also as moisture barriers, vapor inhibitors, wind barriers, paired traps and the like.

Moreover, they can be used in very different sectors, their use is limited only by the requirement of ftft ftft ftft ftft ftft ftft ftft ftft ftft ftft ftft ftft ftft ftft ftft ftft ftft ftft ftft ftft ftft ftft ftft ftft ft · ftft ftft simultaneous water impermeability and good vapor permeability. Examples of such uses, without being exhaustive, may include pipe insulation material, a protective layer for wet materials, tent tents for residential tents, army tents or supply tents and the like.

The vapor-permeable and water-impermeable plastic films can be divided into films made of microporous plastic materials and monolithic films. In the former, the vapor transfer is effected by micropores across the film, the pores being formed mechanically or by selecting suitable combinations of materials in the film production, for example by spreading a mixture of incompatible particles to achieve micropores in the particle boundary regions. In the films of monolithic materials, as the name implies, no pores are present. The films are made of special, especially hydrophilic polymers, and the vapor passes through the film through activated diffusion, where the steam dissolves in the material on the surface of the film above which the partial water pressure is gaseous, permeates through the film and desorbed from the exposed surface partial vapor pressure.

The vapor permeability of the microporous material depends on the material thickness and the pore width, but the risk of water penetration also increases with increasing pore width. In the case of monolithic materials, in addition to the thickness of the material, their chemical composition is of particular importance for the vapor permeability, and such materials can to a large extent be made water-safe.

EP-B-169 308 discloses an under-roof layer for the aforementioned purposes, which consists of only a weakly swelling layer 9 9 9 9 9 9 Polyurethane film, coated on one side with a layer of nonwoven, firmly bonded to the polyurethane film.

The layer is designed to protect the underlying structural members and deep spaces against the penetration of melting accumulated snow, rain, dust and soot. For this reason, it is designed to be waterproof, but on the other hand it is also designed to be water permeable to remove the condensation of steam on this layer. Therefore, a vapor permeability of approximately 150-170 g / m ² per 24 hours has been obtained for this under-roof layer which cannot be considered sufficient in view of the thicker layers of thermal insulation currently used and the possible removal of moisture from the building by strong heating. units.

DE-C-34 25 795 discloses an under-roof layer in the form of a water-collecting film of polyester block amides (PEBA) of the hydrophilic type. In this way, the vapor permeability can truly be increased to about 1000 g / m < ^{2 >} per 24 hours, but the foil not exposed by the nonwoven is strongly exposed to mechanical damage at the construction site, which can render it water permeable.

Attempting to combine the advantages of the two known prior art undercoats by placing a hydrophilic PEBA film on a protective layer of nonwoven fabric and establishing a firm bond between the two layers resulted in an unsuitable undercoat as the PEBA film swelled under the effect of water and released briefly from layers of nonwoven fabric.

EP-A-708 212 describes, in an attempt to overcome the above-mentioned problem, a three-layer sub-roof covering, these three, three three, three three, three of water and steam. permeable and waterproof and vapor-resistant layers of nonwoven and film-like boundary layers, interposed between the two layers of nonwoven fabric, which, in addition to being able to withstand water and vapor, should be impermeable to water, but be vapor-permeable. The presence of two nonwoven layers disposed in such a manner is said to secure adhesion between the two layers and the boundary layer so as not to undesirably lose the bond between the two nonwoven layers and the boundary layer. It is stated in the document that the boundary layers are preferably made of a plastic having the desired water-impermeability and vapor-permeability properties; another possible solution is to use a material which is normally impermeable to water and steam but has been rendered appropriately vapor permeable by microperforation. Examples include nonwoven layers of polyethylene, polypropylene and polyester fibers and boundary layers made of water-absorbing, thermoplastic polyurethane, hydrophilic polyether-polyamide block copolymer and water-absorbing polyether ester. The triple layer composition was optionally reinforced with a mesh attached to the boundary layer, for example embedded therein. In this case a vapor permeability of 700-1000 g / m 2 was achieved in 24 hours.

However, in connection with the nonwoven layers, in particular the two nonwoven layers surrounding the vapor-permeable plastic film, it has proved difficult to achieve the release of residual water from the nonwoven layers. In addition, this phenomenon can lead to water permeability if the boundary layer is made of microporous material in the case of local contamination of the under-roof covering which reduces the surface tension for water.

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If the product suffers mechanical damage at the construction site, the failure / leakage occurring will not be immediately apparent due to the nonwoven layers and could subsequently lead to water penetration into the structure.

In view of the above, it is an object of the present invention to provide a reversibly vapor-permeable plastic film for building purposes of the aforementioned kind which, in addition to retaining mechanical force, preventing water penetration and providing better vapor permeability than the previously described under-roofing.

It has now surprisingly been found that certain plastic films which are known to be used as coatings for textile materials are most suitable for achieving the above object of the invention.

SUMMARY OF THE INVENTION

The reversibly vapor-permeable plastic film for building purposes according to the invention is characterized in that the barrier layer is made of a monolithic, hydrophilic and vapor-absorbing and vapor-permeable plastic film with a vapor permeability measured according to DIN 53122 at 38 ° C and 90% relative humidity at thickness. foil 0.15 mm at least 1000 g / m ² per 24 hours.

According to a preferred embodiment, the monolithic, hydrophilic and vapor-permeable and vapor-permeable plastic material without the additive supplied exhibits a tensile strength according to DIN 53 504 of at least 38 MPa, a relative elongation at 9 · · · · · · · · · «* • 9 999 9 9 9 9 9 9 • •· 9 9 · 9 9 9 9 9 9 9 • 9 9 9 9 9 9 9 9 9 9 _ _ ··» · ··· ·· Tensile strength according to DIN 53 504 at least 500% and tear strength according to DIN 53515 at least eokN.m ^-1 .

Said plastic material is preferably a thermoplastic polyurethane material.

Such materials have high tensile strength and elongation at break and are moreover hard to wear, resistant to chemicals and water as well as to UV destruction. The vapor permeability may be adapted by introducing more or less suitable hydrophilic groups into their polymer backbone.

With respect to further control of mechanical properties, including color and UV resistance, as well as vapor permeability, one or more additional thermoplastic polyurethanes may be added to said thermoplastic polyurethane material; first a thermoplastic polyurethane material in a small amount, preferably 0 to 10% by weight and in particular 0 to 5% by weight. % as a main batch containing additives which are conventional in the art, such as finishing aids, UV stabilizers and fillers and white / colored dyes. However, the additives used may also be directly mixed with the first thermoplastic polyurethane material used. All additives used are well known to those skilled in the art of plastic film and therefore need not be commented upon in detail here.

In a particularly preferred embodiment of the invention, the plastic material used for the plastic films of the invention comprises 90 to 100 wt. %, preferably 95 to 100 wt. %, ·· ·· · ·· · 9 · φ · Φ · Φ · Φ · Φ · Φ · ΦΦΦ · ΦΦΦ · ΦΦΦ · ΦΦ · ΦΦΦ ·

And 0 to 10 wt.% And preferably 0 to 5 wt.% Of the first thermoplastic polyurethane material. % of one or more thermoplastic polyurethane materials in combination with conventional additives and optionally fillers, dyes and / or color pigments.

Certain types of thermoplastic polyurethane materials with 5 to 6 times greater vapor permeability than standard thermoplastic polyurethanes are now available on the market.

These improved polyurethanes are sold under the trade names Estane® 58237 and Estane® 58245 (B.F. Goodrich Company,

Cleveland, Ohio); article 58245, according to the manufacturer, has about 50% higher vapor permeability than article 58237, but is made of a somewhat softer material. Both Estane® products are more resistant to water penetration as they are able to withstand a water pressure represented by a column of water over 10 meters in thickness of 25μιη. Both materials are particularly suitable for use in the textile industry, for example as coatings for textiles for sportswear, according to the commercial leaflets of the company. However, nothing has been mentioned or suggested regarding their suitability for construction purposes.

According to a preferred embodiment, the first thermoplastic polyurethane material is Estan® 58237 and / or Estane®58245.

Reversibly vapor-permeable sheets of plastics for building purposes in which the barrier layer is made of other monolithic hydrophilic and vapor-absorbing and vapor-transferring plastics materials, other than those specifically mentioned above, should also be considered as belonging to the area of the invention, ensuring their vapor permeability, meeting the requirements of claim 1.

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The present film of a plastic transferring material has proved to be more suitable as a building film for direct placement on or near the insulating layer compared to the hydrophilic PEBA film of DE-C-3425795.

However, in view of the wider field of application, the plastic film can also be surface-stabilized.

The reinforcement of the non-swellable (vapor-impermeable) barrier foils mechanically by embedding the netting of a suitable material compatible with the foil material is known and the above-described stabilized three-layer system may also, as already mentioned, include netting as additional reinforcement.

However, as is known to the inventors, the reinforcement of the vapor-permeable (swellable) water barrier layer, in particular such a monolithic layer, by embedding the reinforcing / sheet stabilizing structure without simultaneous double-sided protection and / or reinforcing the barrier layer with nonwoven layers is unknown.

Surface stabilization by means of a film, fabric or net laminated to the barrier layer does not appear to be appealing to the skilled person in view of the above discouraging experience of laminating one layer of nonwoven fabric to a hydrophilic PEBA film.

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Surprisingly, however, it has been found that not only is the reinforcement possible by means of a web embedded in the barrier layer of the plastic film according to the invention, wherein the embedded structure is not separated from the barrier layer even after strong water absorption by the barrier layer. The barrier layers have also shown a surprising coherent stability of such forms of stabilizing structures.

In view of the above, the above-mentioned plastic film according to the invention for building purposes is characterized in that the barrier layer is stabilized by means of a surface stabilizing structure for water and vapor permeable but impermeable material.

In such an embodiment, the surface-stabilizing structure is a film, tissue or mesh laminated to the barrier layer.

In another embodiment, the surface-stabilizing structure is a tissue or open mesh of mono- or multi-fiber or chopped fibers embedded in the barrier layer and having meshes of 0.1 to 5 cm.

The film, web or web laminated to the barrier layer may be a known nonwoven material, such as polyethylene, polypropylene, or polyester fibers, or may be a web as described later.

The embedded structure is preferably a web or open mesh with a mesh size of 0.1 to 5 cm. The structure can be made of natural materials (cellulose, cotton, flax) and in this case it is multi-threaded, ie it consists of yarns «·

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0 0 formed from thin fibers; however, it may also be formed of synthetic materials and in this context may be single-stranded or consist of chopped fibers.

The choice of material is not critical to the invention as long as the requirements of the water and steam resistant and vapor-impermeable material that can be surface stabilizing are met; among the preferred synthetic reinforcing materials, mention may be made of high density polyethylene, polypropylene, nylon and polyester. At present, the preferred sheet-stabilizing structure is an open mesh of polypropylene chopped fibers having a mesh size of 0.5 to 1.5 cm.

The thickness of the reversibly vapor permeable plastic film of the invention may vary within relatively wide limits, while balancing the requirements for mechanical strength, vapor permeability, and material cost. The thickness is usually between 0.02 and 0.5 mm and preferably is 0.1 to 0.2 mm.

The vapor permeability of the reversibly vapor transfer plastic film of the invention, measured according to DIN 53122 at 38 ° C and 90% relative humidity at a film thickness of 0.15 mm, is at least 1000 g / (m ² x 24 hours) above. It is preferably more than 1200 g / (m ² x 24 hours) and in particular at least 1400 g / (m ² x 24 hours).

The reversibly vapor-permeable plastic film of the present invention is produced by a method known per se in the art of manufacturing previously known water and vapor-impermeable plastic films, and the details of such manufacture are not important to the invention and need no further explanation.

In the production of the plastic film according to the invention, which has been surface-stabilized by the above-described lamination, the plastic film itself is produced by the process known in the art, as mentioned above, and lamination by film, netting or tissue is also a commonly known method.

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In the manufacture of a plastic film according to the invention, which is surface-stabilized by embedding the netting or fabric into the barrier layer, the reinforcing structure may be placed on the film of the material used as the barrier layer and the structure may either be coated with said material or hot laminated the additional film.

The reversibly vapor-permeable plastic film of the invention has a simple construction, is mechanically resistant and exhibits excellent vapor permeability compared to known underwater vapor transfer and water retention plastic films. In addition, it is transparent, as opposed to undersized films reinforced with a nonwoven fabric on both sides, unless it is surface-stabilized by opaque mesh or film laminated to the barrier layer or unless it is very dark colored to withstand UV radiation. This allows for easy control of the backing insulation and, due to its much smaller surface area, compared to films reinforced on both sides with a nonwoven fabric, it is much less exposed to UV aging than films reinforced with a nonwoven fabric.

The inventive reversibly vapor-permeable plastic sheet can thus be used according to the invention as a building sheet, either as a sheet immediately adjacent to the surface of an insulating material facing the roof, or in a flat-stabilized state as an under-roof layer, a barrier against

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moisture, vapor inhibitor, wind barrier, vapor trap and similar building foil. According to the invention, the inventive flat-stabilized plastic film can also be used as tent fabric for residential tents, army tents or supply tents.

The following example illustrates the invention.

DETAILED DESCRIPTION OF THE INVENTION

Using a known process, a film of 0.075 mm thickness was produced, consisting of 97% by weight of the masterbatch Estane® 58237 and 3% by weight of thermoplastic polyurethane T50019 (supplied by Goodrich), containing known but unspecified additives as finishing agents and UV stabilizers. An open mesh of chopped polypropylene fibers was placed on the film as a 1 cm mesh stabilizing structure, and then a thin melt coating of the same Estane® material was applied.

The vapor permeability (1400 g / m ² x 24 hours) was measured at a temperature of 38 ° C and 90% relative humidity for the obtained 0.15 mm thick film.

Represented by:

Claims (13)

PATENT CLAIMS Use of a reversible vapor transfer plastic film comprising a water and vapor resistant, water impermeable and vapor permeable barrier layer, wherein said barrier layer is made of a monolithic, hydrophilic and swellable vapor-permeable and vapor-transferable plastic material with vapor permeability measured according to DIN 53122 at 38 ° C and 90% relative humidity at a film thickness of 0.15 mm, at least 1000 g / (m ² x 24 hours), as an undercoat layer positioned immediately adjacent the surface of the insulating material facing the roofing. Use of a reversible vapor transferring plastic film according to claim 1, characterized in that the monolithic, hydrophilic and vapor-absorbing and vapor-transferring plastic material without the additives supplied has a tensile strength according to DIN 53504 of at least 38 MPa, an elongation at break according to DIN 53504 of at least 500% and tear resistance according to DIN 53515 of at least SOkN.m ^first Use of a reversibly vapor transferring plastic film according to claim 1 or 2, characterized in that said plastic film comprises 90 to 100% by weight, preferably 95 to 100% by weight, of the first thermoplastic polyurethane material and 0 to 10% by weight, preferably 0 to 5% by weight of one or more of thermoplastic polyurethane materials in combination with additives customary in the art, optionally with fillers, colorants and / or color pigments. Use of a reversible vapor transfer plastic film according to claim 3, characterized in that the first thermoplastic polyurethane material is Estane® 58237 and / or Estane® 58245. Use of a reversibly vapor transferring plastic film according to claims 1 to 4, characterized in that the thickness of said plastic film is 0.02 to 0.5 mm and preferably 0.1 to 0.2 mm. Use of a reversible vapor transfer plastic film according to claims 1 to 5, characterized in that the vapor permeability as defined in claim 1 is more than 1200 g / (m ² x 24 hours) and preferably at least 1400 g / (m ² x 24 hours). A reversibly vapor transferable plastic film comprising a water and vapor-resistant, water-impermeable and vapor-permeable barrier layer, characterized in that the barrier layer is as defined in claims 1 to 6 and further stabilized by a surface stabilizing water and steam structure. resistant to water and steam impermeable material. Plastic film according to claim 7, characterized in that the surface-stabilizing structure is a film, netting or tissue laminated to the barrier layer. Plastic film according to claim 7, characterized in that the surface-stabilizing structure is a tissue or open mesh of one or more fibers or consists of split fibers embedded in the barrier layer and having a mesh size of 0.1 up to 5 cm. 10. The plastic film of claim 9, wherein the surface stabilizing structure embedded in the barrier layer is made of natural or synthetic materials. 11. The plastic film of claim 9, wherein the natural materials are selected from cellulose, cotton and linen, and the synthetic materials are selected from high density polyethylene, polypropylene, nylon, and polyester materials. Use of a reversibly vapor transfer plastic film in combination with a surface stabilizing structure, according to claim 5, as an under-roof layer, a moisture barrier, a steam inhibitor, a wind barrier or a vapor trap in poorly ventilated objects. Use of a reversible vapor transfer plastic film in combination with a surface stabilizing structure according to claim 5 as tent fabrics for residential tents, army tents or supply tents.