Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Cellular products or processes of preparing a cellular...
Reexamination Certificate
2001-09-14
2004-01-06
Aftergut, Jeff H. (Department: 1733)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Cellular products or processes of preparing a cellular...
C156S082000
Reexamination Certificate
active
06673849
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention describes composites comprising a polyurethane foam core and an outer layer of a textile material. Suitable polyurethane foam cores for the composite materials of the present invention comprise hydrophilic polyester-polyurethane foam materials. These composite materials can be used for the production of vehicle interior trim parts.
One important application of polyester-polyurethane foamed materials is the splitting of long blocks of block foamed material to form strip material, followed by further processing to produce composite materials suitable for use as interior trim parts in vehicles after lamination with textiles or sheeting materials.
Composite materials for vehicle trim are understood to mean textile-laminated PUR foamed materials such as, for example, seat or seat back upholstered supports.
It is predominantly textile-laminated strip material which forms the uppermost layer of upholstery in these areas. The textile-laminated strip material, after being cut and sewn to the seat or seat back support, is converted to the finished fitted part by upholstering it (mostly by hand hitherto) to the rest of the seat or seat back construction.
In addition to upholstering by hand, there is also a technique for the foam-backing of prefabricated seat and seat back supports or of other upholstery parts, such as, for example, head rests or arm rests, in a foam mold using a costly processing technique.
However, apart from manufacturing advantages, this results in specific disadvantages for parts “enveloped” by the climatic environment of the seat, such as, for example, seat and seat back supports. This is due to the lamination of vacuum-tight sheeting, which thus mostly exerts a diffusion-inhibiting effect, on to the back of textile-laminated strip material; but which is necessary due to the production technique employed. Alternatively, this technique results at least in the use of strip material which is particularly impermeable to air for the lamination operation.
If the strip material which is used according to the invention is of sufficient thickness, this disadvantage can also be compensated for, at least in part, by the moisture absorption behavior of the layer of foamed material which remains in the sandwich lamination (i.e., from the top side of the textile to the underside of the sheeting).
In sandwich laminations for customary upholstering by hand, however, the back of the strip is simply laminated to a wide-meshed knitted fabric which facilitates diffusion.
Apart from adhesive lamination, flame-lamination is a technique which has proved to be a particularly inexpensive. Flame lamination is, however, an efficient technique for joining strip materials made of flexible foamed materials to textiles and sheeting.
In a flame-lamination technique, foamed material strips are joined to textile strip material, in a continuous process at, for example, operating speeds within the range from 15 to 40 m/minute. This process comprises melting the surface of the foamed material by flaming (i.e., burning) it with a gas flame burner bar immediately before the textile strip is supplied. In addition to melting processes on the PUR matrix, decomposition reactions also occur on the surface. Immediately after being brought together, the textile and foamed material strips are pressed together by, for example, being passed between pairs of rotating rollers of the flame-laminating installation. After pressing, the melt which is formed on the surface of the foamed material has to form a relatively continuous bond.
Previously, these requirements have been fulfilled significantly better by ester-PUR foamed materials than by ether-PUR foamed materials, since during the laminating process the ether-PUR foamed materials form a melt which is considerably less viscous. Additionally, in comparison to ester-PUR foamed materials, the said melt shows a delayed viscosity build-up on cooling, which causes distinctly lower bond strength in the lamination process.
However, ether-PUR foamed materials possess properties which, in practice, make them highly suitable for use as upholstery materials. These include, for example, a significantly higher permeability to air at a comparable bulk density, and a considerably higher level of elasticity.
Ester-PUR foamed materials have a comparatively pronounced thermoplastic character, thus improving their capacity for flame-laminating. In addition, ester-PUR foamed materials with sufficiently open cell structure exhibit appreciable moisture absorption properties, and enable an improved seat climate, and thus, are expected to result in an increased level of seat comfort in one or the other upholstery situation.
Like polyester-PUR flexible foamed materials, polyether-PUR flexible foamed materials are preferably produced in a single-stage (“one shot”) process. Details of the chemistry and process technology are given, for example, in the Kunststoff-Handbuch, Volume VII, Carl Hanser-Verlag Munich/Vienna, 3rd Edition (1993), on pages 193-220. This process results in block foamed materials (for further processing) which exhibit unsatisfactory hydrophilic properties, even when they are mainly of an open-cell character. Therefore, there have been numerous attempts aimed at improving this behavior by post-treating the foamed material matrix or by foaming it in conjunction with various different types of additives (see, for example, DE-A 2,207,356 and DE-A 2,207,361). These attempts have only achieved moderate success at considerable cost.
The object of the present invention was thus to provide polyurethane foamed materials which exhibit good hydrophilic properties and which are suitable for the production of composite materials which are particularly suitable for vehicle interior trim.
It has surprisingly been found that polyester-PUR foamed materials, which have been produced by replacing part of the polyester polyols in the formulations by polyether polyols which have a degree of ethoxylation greater than 30% by weight, achieve this object particularly well.
SUMMARY OF THE INVENTION
The present invention relates to a composite comprising a polyurethane core and at least one outer layer wherein the polyurethane core comprises hydrophilic polyester-polyurethane foamed materials. Suitable polyester-polyurethane foams materials comprise the reaction product of:
(a) at least one polyisocyanate, with
(b) at least one polyester polyol containing at least two hydroxyl groups and having an average molecular weight of more than 700 to 10,000,
(c) at least one ethoxylated polyether polyol containing at least two hydroxyl groups, having a molecular weight of more than 700 and a functionality of from 2 to 6, and having a degree of ethoxylation greater than 30% by weight, based on 100% by weight of alkoxylation, and
(d) optionally, at least one compound containing at least two active hydrogen atoms and having an average molecular weight within the range of from 32 to 700, and
(e) catalysts, water and/or foaming agents, and
(f) optionally, adjuvant substances and additives.
These composite materials are particularly suitable to be used as vehicle interior trim.
The present invention also relates to a process for the production of these composite materials, and particularly to a continuous process for the production of a flame-laminated composite of textile and foamed material.
The degree of ethoxylation of the polyether polyols which are used is usually greater than 30% by weight, and is preferably between 50 and 95% by weight. Trimethylolpropane derived polyether polyols, and/or polyether polyols which are derived from glycerol, preferably highly ethoxylated polyether polyols which are derived from glycerol, are usually employed (e.g. VP PU41WB01, a trifunctional polyether polyol commercially available from Bayer AG).
The content of highly ethoxylated polyether polyols present in the polyol mixture is usually between 2 and 50% by weight, based on the combined weight of components b), c) and d).
Suitable polyester polyols can be produced by the condensa
Baatz Günther
Herzog Klaus-Peter
Aftergut Jeff H.
Bayer Aktiengesellschaft
Brown N. Denise
Gil Joseph C.
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