Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Reexamination Certificate
2000-05-23
2003-07-08
Ball, Michael W. (Department: 1733)
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
C264S173120, C264S173160
Reexamination Certificate
active
06589379
ABSTRACT:
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH
Not Applicable
REFERENCE TO A MICROFICHE APPENDIX
Not Applicable
1. Technical Field
This invention relates to methods of manufacturing films for incorporation as backing layers in resilient floor coverings, to films made by such methods and to floor coverings incorporating them.
2. Background Art
Resilient floor coverings are well known and are described for example in an article entitled “Floor Materials” in Encyclopedia of Polymer Science and Engineering, Wiley-Interscience, Volume 7 (1987), pages 223-247. Such floor coverings, as described in that article, are composite materials which comprise a transparent or translucent wear (upper) layer, often a decorative (intermediate) layer such as a printed patterned layer, and one or more backing (lower) layers. The composition of each layer in such composite laminate floor coverings is chosen to provide the desired balance of physical properties, both in that layer and in the whole composite laminate. Thus, for example, the properties of all the layers are desirably balanced so as to avoid curl.
The backing layer nearest the wear layer commonly contains one or more colored pigments and is commonly called the face ply. If no intermediate decorative layer is present, then the face ply itself provides the desired decorative appearance of the floor covering. If the floor covering includes a printed patterned layer, then the face ply serves to enhance the appearance of the printed patterned layer as seen through the wear layer. The face ply is often of a bright color, for example white, although it may be of a neutral color such as black. The other backing layers more remote from the wear layer commonly contain carbon black to provide a neutral opaque background behind the face ply. All the backing layers, including the face ply, commonly contain fillers such as calcium carbonate, hydrated aluminum oxide, kaolin or other suitable particulate or fibrous mineral fillers.
Films for incorporation in resilient floor coverings may be made by extrusion of suitable polymer compositions. For example, the backing layers including the face ply may be made by extrusion of polymer compositions based on ethylene/vinyl acetate or ethylene/alkyl acrylate, for example methyl or butyl acrylate, copolymers. It is often desirable to make differently-colored face plies at different times on a single extruder. Steps must therefore be taken to minimize the production of waste film at changeover. The extruder may be stopped, emptied and cleaned, but this is laborious and involves loss of production from the extruder while this is done. Alternatively, the color of the polymer composition fed to the extruder may be changed while the extruder continues to run, and waste film of intermediate color may be collected until the extruder has been flushed. This waste film can be shredded and used (with the addition of carbon black, if desired) for the manufacture of black backing layers. Nevertheless, this procedure requires additional operations to be carried out, and these operations may result in some degradation of properties of the thus recycled polymer composition.
SUMMARY OF THE INVENTION
The present invention provides improved methods of manufacturing a film for incorporation as a backing layer in resilient floor coverings, in particular to a method for manufacturing a film which includes a face ply where loss of production is reduced when the color of a face ply is changed.
The present invention provides in a first aspect a method of manufacturing a film for incorporation as a backing layer in a resilient floor covering characterized in that at least a first and a second polymer composition are extruded to form a film laminate for use as the backing layer.
Preferably where there are two polymer compositions, a first polymer composition and a second polymer composition, the first polymer composition is a colored polymer composition. The second polymer composition may be colored a masking color such as black, iron-oxide red, blue, or any dark masking color.
There may be three polymer layers extruded to form the film. Preferably when there are three polymer compositions, a first, a second and a third polymer composition, the first and/or third polymer compositions are colored polymer compositions and the second layer/composition is of masking color. The second polymer composition may also be a colored polymer composition.
Preferably the second polymer composition of both systems is a “black” polymer composition. “Black” in the context of this specification includes true black, dark red, dark blue, or any color capable of masking the presence of other colors.
When the backing layer is a face ply the color of the colored polymer composition is chosen to provide the face ply color, and it will accordingly be understood that this color may be any color, including black, or including lighter colors such as white, yellow, beige, pale greens or blues, pink.
The invention provides in a second aspect a film suitable for incorporation as a backing layer in a resilient floor covering characterized in that it is a co-extruded laminate of at least two polymer compositions.
Preferably where there are two polymer compositions the film is a co-extruded laminate of (a) a first colored polymer composition and (b) a “black” polymer composition.
Preferably where there are three polymer compositions the film is a co-extruded laminate of (a) a first colored polymer composition, (b) a “black” polymer composition and (c) a third polymer composition.
The invention provides in a third aspect a resilient floor covering comprising a transparent or translucent wear layer and a backing layer characterized in that the backing layer comprises, in sequential order from the wear layer, at least one backing film which is a co-extruded laminate of at least two polymer compositions.
The floor covering may comprise a transparent or translucent wear layer and two (or more) backing layers, or plys. Preferably where there are two polymer compositions the backing layer comprises in sequential order from the wear layer (a) a first backing film which is a co-extruded laminate of (aa) a first colored polymer composition visible as face ply through the wear layer and (ab) a “black” polymer composition, and (b) a second backing film of substantially the same thickness as the first backing film.
The first colored polymer composition (aa) may be of any color, including black. The second backing film (b) may be a co-extruded laminate of (ba) a second colored polymer composition and (bb) a “black” polymer composition. The second colored polymer composition (ba) may be of any color, including black. Layers (aa) and (ba) are preferably of substantially the same thickness, with the consequence that layers (ab) and (bb) are also preferably of substantially the same thickness. The floor covering of the invention preferably additionally comprises a printed patterned layer as decorative layer interposed between the wear layer and the first backing film.
Preferably where there are three polymer compositions the backing layer comprises in sequential order from the wear layer (a) a first backing film which is a co-extruded laminate of (aa) a first colored polymer composition visible as face ply through the wear layer (ab) a “black” polymer composition, and (ac) a third polymer composition.
Preferably a second backing film (b) is provided.
The first colored polymer composition (aa) may be of any color including black. The third polymer composition (ac) may be of any color including black. The second backing film (b) may be a co-extruded laminate of (ba) a second colored polymer composition (bb) a “black” polymer composition and (bc) a third polymer composition. The second colored polymer composition (ba) may be of any color, including black. The third polymer composition (bc) may be of any color including black. Layers (aa) and (ba) are preferably of substantially the same thickness, with the consequence that layers (ab) and (bb) are also preferably of substantially the sam
Gansser-Potts Michael David
Harwood Ivor C.
Jones Keith Melvin
Wilson Gary John
Ball Michael W.
Musser Barbara J.
Pennie & Edmonds LLP
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