Stock material or miscellaneous articles – Composite – Of aldehyde or ketone condensation product
Reexamination Certificate
1999-08-13
2003-11-04
Kiliman, Leszek (Department: 1773)
Stock material or miscellaneous articles
Composite
Of aldehyde or ketone condensation product
C428S526000, C428S530000, C428S537500, C428S542200
Reexamination Certificate
active
06641926
ABSTRACT:
TECHNICAL FIELD
The present invention relates generally to the manufacture of laminated products such as may be used for flooring, counter tops, table tops, and wall panels, and more specifically to systems and methods for manufacturing such products to include a liquid resistant film and another laminate material providing a desired balancing characteristic to the laminated product.
BACKGROUND
The ability to replicate natural materials has substantially improved over the years. For example, decorative laminates have replaced natural materials in the construction of furniture, cabinets, counter tops, flooring and other surfaces. In each of these applications, a decorative surface may be applied to a core layer or substrate, namely, plywood, particle board, chipboard, hardboard, wood waste, medium density fiberboard, high density fiberboard, inert mineral board, sheet rock, plaster board and other substances. The core layer or substrate may also be made of Alternate Substrate Materials (ASM). Such ASM may include non-wood cores or substrates, such as synthetic or non-cellulose substrate material, for example, recycled plastic substrates, ABS/PC, nylon, PVC, or the like. However, a core or substrate is not included with all laminate products.
Often, a backing layer is secured to the opposite side of the substrate to balance the movement of the decorative surface or provide other benefits. It is well known in the art that traditional high pressure laminates expand or contract with an increase or decrease in the environmental humidity. Moreover, it is also known that prolonged exposure of the flooring composite, made of laminates bound to a wood-based substrate, to liquids, for example water, such as by flooding through the sub-floor, adversely effects not only traditionally constructed laminates, but also the substrate, such as by causing swelling, peaking or blistering.
Generally the decorative surface of a laminate composite, such as a laminate flooring, is designed as shown in
FIG. 1. A
high pressure laminate
10
may be comprised of a thin aluminum oxide incorporated overlay sheet
11
impregnated with a protective substance, such as melamine resin, which provides color fastness, hardness, chemical resistance, and also resistance to brief exposure to water. The high pressure laminate
10
may employ a decorative sheet
12
disposed under overlay sheet
11
, which may be a melamine treated sheet, and sheets
13
and
14
of kraft paper impregnated with phenolic resin disposed below the decorative sheet.
Traditionally, the backing layer is similarly designed. As shown in
FIG. 1
, the backing layer of a decorative high pressure laminate
10
may comprise two sheets
16
and
17
of kraft paper impregnated with phenolic resin disposed below substrate
15
, and a balancing layer
18
of an overlay paper impregnated with a protective substance disposed below the kraft paper sheets
16
and
17
to balance the overlay sheet
11
of the decorative side. In flooring laminates such protective substance may be a melamine resin. Typically both the backing layer and the decorative layer are bonded to substrate
15
by using a suitable adhesive.
As those of ordinary skill in the art will appreciate, the decorative and backing layers discussed above are purely exemplary and not intended to limit the description of the present invention to the above discussed structures.
After installation, such as by gluing several pieces of laminate flooring together at the seams, the decorative laminate is subject to a different environment than the backer laminate. That is, the exposed decorative laminate experiences temperature and humidity fluctuations of the room environment. In contrast, the backer laminate, is exposed to temperature and moisture changes of the sub-floor over which the laminate flooring is applied. Moreover, prolonged exposure of the backer laminate to liquids, for example water, such as by moisture penetration through the sub-floor, adversely effects not only the backer laminate but also the substrate. The traditional flooring panels are, however, not designed or otherwise properly adapted to compensate for the difference between the environments to which the decorative and backer laminates are exposed.
One inventive solution to prevent the penetration of moisture, such as water vapor or humidity into the backer layer, is to use a layer that is liquid impermeable, such as a styrenemaleic anhydride copolymer layer, at the bottom of the backing layer to substantially prevent the penetration of moisture, such as water, in liquid form. This inventive solution is disclosed in detail in the above referenced U.S. Patent Application, entitled “LAMINATE”.
Although the incorporation of the liquid impermeable layer into the backer of the laminate flooring in accordance with a preferred embodiment of U.S. Patent Application, entitled “LAMINATE” provides a significant improvement in the resistance of the entire composite to standing water, the sensitivity of the decorative laminate to conditions of low humidity has been discovered to increase, as in the preferred embodiment disclosed therein the melamine balancing layer
18
in the backer laminate is replaced with a liquid impermeable layer. Thus, the movement of the melamine layer
11
of the decorative side in conditions of low humidity may cause the flooring panel to warp without resistance as the liquid impermeable layer does not inflict an equal and opposite shrinkage and thus the lateral edges of the panel point in an upward direction (positive warpage). Such positive warpage of the flooring panel is visually obtrusive and often times necessitates replacement of the entire floor. The backer laminate as described in the preferred embodiment in the above referenced U.S. Patent Application, entitled “LAMINATE”, is comprised of the liquid impermeable layer positioned at an exterior surface of one of several phenolic resin impregnated kraft paper sheets. The melamine treated balancing sheet is not incorporated into the backer laminate described in the preferred embodiment of the above referenced U.S. Patent Application entitled “LAMINATE” as a sufficient bond may not be achieved between the liquid impermeable layer and the melamine layer. Attempts have been made to balance and/or counteract the humidity driven movement of the decorative laminate by increasing the number and weight of the phenolic resin impregnated kraft paper sheets in the backer laminate to yield a strong backer. However, such efforts did not provide a backer strong enough to balance the movement of the decorative laminate when two or more melamine treated sheets were used in the decorative laminate to improve wear resistance.
In the preferred embodiment of the above referenced U.S. Patent Application, entitled “LAMINATE EMPLOYING LIQUID RESISTANT FILM AND TWO SIDED SHEET” a method of incorporating a melamine treated balancing sheet in the backer laminate is described. In the preferred embodiment of the above referenced application, a layer of phenolic resin may be inserted between the liquid impermeable layer and the melamine layer so that both the liquid impermeable layer and the melamine layer may be used in the same laminate to provide the desired liquid impermeable and balancing characteristics. However, in order to properly balance a composite having a particular characteristic material associated with the exterior of the top or decorative laminate, it may be desirable to have the balancing layer close to the bottom exterior of the backer laminate. Thus, when a laminate flooring has a melamine impregnated overlay layer as a top exterior surface of the decorative side, it may be desired to have a balancing layer of melamine close to the bottom exterior of the laminate in order to properly balance the top overlay layer. However, as in the preferred embodiment of the above referenced patent application, entitled “LAMINATE EMPLOYING LIQUID RESISTANT FILM AND TWO SIDED SHEET”, the balancing layer is not adjacent to the liquid impermeable layer as a layer of a third substa
Lay Timothy J.
Malina Jerry L.
Marshall Donald Murray
Stolarski Victoria Lynn
Williams Joel Lane
Fulbright & Jaworski L.L.P.
Kiliman Leszek
Premark RWP Holdings Inc.
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