Fabric (woven – knitted – or nonwoven textile or cloth – etc.) – Nonwoven fabric – Including a free metal or alloy constituent
Reexamination Certificate
2001-08-31
2004-10-05
Cole, Elizabeth M. (Department: 1771)
Fabric (woven, knitted, or nonwoven textile or cloth, etc.)
Nonwoven fabric
Including a free metal or alloy constituent
C442S076000, C442S118000, C442S394000, C442S395000, C442S304000, C442S316000, C442S319000, C442S379000, C427S245000, C427S123000, C427S124000, C427S126100
Reexamination Certificate
active
06800573
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of Invention
The present invention relates to a water-vapor-permeable, watertight, and heat-reflecting flat composite, a process for its manufacture, and use thereof.
2. Description of Related Art
Water-vapor-permeable, watertight, and heat-reflecting composites made from a metal layer and a microporous membrane are known in the art. U.S. Pat. No. 5,955,175 describes a textile material produced by metallizing a microporous membrane. The metallization causes a reflection of thermal radiation. The metal forms a discontinuous layer on the surface and on the pore walls of the microporous membrane that are adjacent to the surface. Compared to the size of H
2
O molecules, the pores of the microporous membrane are very large, even in the metallized state, so that the water-vapor permeability of the microporous membrane is maintained even after it is metallized.
Water-vapor-permeable, watertight, and heat-reflecting composites made from a metal layer and a nonporous membrane, or from a nonporous substrate, have not yet been disclosed. In attempting the metallization of a microporous membrane, as described in U.S. Pat. No. 5,955,175, with a nonporous membrane, it is observed that the adhesion between the metal layer and the nonporous membrane is very poor, i.e., that the metal layer peels off even after short use.
SUMMARY OF THE INVENTION
For this reason, it is an object of the present invention to provide a process for manufacturing a water-vapor-permeable, watertight, and heat-reflecting composite from a metal layer and a nonporous substrate, and to provide such a composite that at least reduces the aforementioned disadvantage.
These and other objects are achieved by a process for manufacturing a water-vapor-permeable, watertight, heat-reflecting flat composite comprising a metal layer and a nonporous, water-vapor-permeable, watertight, hydrophilic flat substrate, whereby the metal layer has a surface facing the substrate and a surface facing away from the substrate, and whereby the substrate has a surface facing the metal layer and a surface facing away from the metal layer, comprising at least the following steps:
a) selecting the substrate,
b) pre-cleaning at least one surface of the substrate, and
c) applying the metal layer to the substrate surface facing the metal layer.
The composites made by the process of the invention exhibit adhesion between the metal layer and substrate that passes the Tesa tape test.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
As previously noted, in the case of the known metallized microporous membrane, the pores of this membrane, which are very large compared to H
2
O molecules, ensure its water-vapor permeability. In the metallization of a nonporous water-vapor-permeable and watertight substrate, however, it was to be expected that a continuous metal layer that is no longer water-vapor-permeable is formed on the substrate. This applies all the more, since it is known from the field of packaging films that films can be provided with a thin metal layer that, as described in JP-A-11-279,306, already forms a vapor barrier at a thickness of about 10 nm.
For this reason, it must be considered surprising that, in the form of the process of the invention, a composite made from a metal layer and a nonporous substrate is rendered accessible that is not only heat-reflecting but is also water-vapor-permeable to a significant extent. It must be considered even more surprising that, with the process of the invention, composites can be provided that even under 100% heat reflection exhibit a water-vapor permeability that is only slightly reduced compared to a non-metallized, nonporous substrate.
In a preferred embodiment of the process of the invention, a polyether ester, polyether amide, or polyether urethane film is selected as a substrate in step a). The process of selecting the substrate may include steps for preparing the substrate.
In another preferred embodiment of the invention, the substrate selected in step a) is joined to a textile fabric, such as a woven, nonwoven, or knitted fabric, on the side facing away from the metal layer to be applied in step c).
In another preferred embodiment of the invention, the substrate selected in step a) is joined to a textile fabric, such as a woven, nonwoven, or knitted fabric, on the side facing the metal layer to be applied in step c), the filaments of which are spaced apart. Spacing of the filaments ensures that a portion of the substrate surface is accessible for steps b) and c).
In accordance with the invention, the substrate must be pre-cleaned in step b) prior to applying the metal layer in step c), whereby the pre-cleaning is preferably conducted on the side of the substrate that is to face the metal layer to be applied in step c).
To pre-clean the substrate, a plasma treatment in oxygen has proven suitable for the process of the invention in order to achieve good adhesion between the metal and substrate. For this reason, a plasma treatment is preferably employed in the process of the invention, whereby the plasma treatment is conducted in a vacuum, preferably at a pressure of about 1 mbar to about 0.001 mbar and more preferably at a pressure of about 0.01 mbar to about 0.03 mbar.
Furthermore, for the pre-cleaning of the substrate in the process of the invention, a plasma treatment in a gas containing oxygen is preferred, whereby it is especially preferred to use a mixture of about 10 to about 50% oxygen by volume and about 90 to about 10% nitrogen by volume as the gas containing oxygen. According to the invention, air is highly preferred as the gas containing oxygen, because the use of air results in good pre-cleaning of the substrate after only brief plasma treatment, such that the metal layer to be applied in step c) adheres to the substrate and passes the Tesa tape test.
In the context of the present invention, passing the Tesa tape test means that, when attempting to remove a strip of “Tesa” tape applied to the metal layer of the substrate, either the substrate is lacerated or the “Tesa” tape can be removed without destroying the substrate and without transferring metal with it.
In a preferred embodiment of the process of the invention, the plasma treatment is conducted in air, especially preferably at atmospheric pressure, i.e., as a corona discharge. The advantage of this embodiment is that generation of a vacuum is not required. However, foreign gases, which can be present in the air of the laboratory or production facility, can interfere with the pre-cleaning process.
For this reason, in another especially preferred embodiment of the process of the invention, the plasma treatment is conducted in a mixture of about 10% to about 50% oxygen by volume and about 90% to about 50% nitrogen by volume, or in air, in a vacuum. In this manner, the penetration of foreign gases into the plasma is prevented, thus ensuring that the plasma treatment indeed takes place only in a defined plasma gas.
Preferably, the vacuum is from about 1 mbar to about 0.001 mbar, and especially preferably from about 0.01 mbar to about 0.03 mbar, since a particularly brief pre-treatment is possible in these ranges.
The application of the metal layer in step c) of the process of the invention is preferably performed by physical vapor deposition (PVD). This is a known coating technique and is described in L. Holland, “Vacuum Deposition of Thin Films”, Chapman and Hall, London (1966), for example.
In the process of the invention, the metal layer is preferably applied with a thickness of about 10 nm to about 200 nm, and especially preferably with a thickness of about 30 nm to about 180 nm.
For applying the metal layer in the process of the invention, basically any metal can be used that can be applied using PVD. In the process of the invention, the metal layer applied is preferably Al, Cu, Au, or Ag, or an alloy of AgGe, CuZn, CuSn, CuAg, or CuAgSn, whereby the alloy layers have a higher corrosion resistance than the pure metal layers. The term “metal layers” thus includes alloys.
To protect the metal lay
Kopp Karl W.
Spijkers Jozef C. W.
Van De Ven Henricus J. M.
Cole Elizabeth M.
Oliff & Berridg,e PLC
Sympatex Technologies GmbH
Torres Norca L.
LandOfFree
Water-vapor-permeable, watertight, and heat-reflecting flat... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Water-vapor-permeable, watertight, and heat-reflecting flat..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Water-vapor-permeable, watertight, and heat-reflecting flat... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3270393