Note: Descriptions are shown in the official language in which they were submitted.
CA 02693186 2010-02-17
ALKALINE AND HEAT RESISTANT FOAM COMPOSITE
AND FLOOR UNDERLAYMENT
FIELD OF THE INVENTION
The present invention relates to foam laminates and in particular to foam
laminates for use as a floor underlayment.
BACKGROUND OF THE INVENTION
Many flooring systems in residential and commercial buildings may comprise a
floor supported by wood or steel joists. In some flooring systems the floor
may comprise
a finished floor that is disposed above a subfloor_ In single-family and multi-
family homes
and small commercial buildings, the subfloor may comprise a poured concrete
slab or be
formed from wooden boards or panels that are laid over the joists. In some
apartment
buildings, larger commercial buildings and other steel-frame buildings, the
subfloor may
be a steel deck, precast concrete slabs or panels, or poured concrete.
The finished flooring provides a decorative, aesthetically pleasing floor
surface.
The finished flooring may be wood, such as wood planks, parquet flooring,
laminate
flooring, and wood-block flooring, or a resilient material, such as linoleum,
asphalt tile, or
vinyl or rubber tile or sheet, or carpeting.
Concrete typically comprises a combination of aggregate and a cement binder
having a high water content. In some cases, the concrete may also include
calcium
chloride as a cure agent for accelerating curing of the concrete. After
mixing, the cement
hydrates and eventually hardens into a hard stone-like material. In many
cases, the
concrete retains a high moisture content that may slowly dissipate from within
the
concrete over a period of time. In some cases, concrete may also wick moisture
from the
surrounding environment, such as the ground, into the concrete. Moisture from
within the
concrete may dissipate upwardly through the concrete and- come into contact
with the
floor.
Hardwood flooring and wood in general are hygroscopic materials. Liquid water
and water vapor can enter wood which may cause it to swell and change its
shape and
size, potentially causing bubbling. If and when the water leaves the wood, the
wood can
shrink which may result in warp, the development of small cracks in the
surface of the
wood, twists, bows, or even develop cups or dips within each piece of wood
flooring. In
some cases, cracks in between pieces of wood may open up as the wood dries.
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To help prevent moisture from contacting the finished flooring, it may be
desirable
to place a moisture barrier between the flooring and the subfloor. The
moisture barrier
may comprise a thin layer of film adhered to the surface of the concrete. In
some
applications an underlayment layer comprising a layer of polymeric film and a
layer of
polymeric foam, or a polyethylene film/foam laminate, is provided as an
underlayment
between the concrete subfloor and finish flooring formed of wood- The
underlayment
levels small irregularities in the top surface of the concrete, provides a
small degree of
resiliency to the floor system, and provides a vapor barrier to prevent
moisture emanating
from the concrete subfloor from attacking and deteriorating the finish
flooring.
In addition to potential damage to wood in the flooring, water can also react
with
excess calcium chloride In the concrete. The reaction of water and calcium
chloride is an
exothermic reaction that generates heat that can dissipate into the
underlayment material-
The addition of heat in the polymeric material of either the film or foam
layer can result in
the cleavage of carbon-hydrogen bonds along the polymer chains and the
generation of
free radicals in the polymer. The thus generated free radicals can lead to
further
breakage of carbon bonds and the generation of additional free radicals.
Overtime, these
continued reactions can lead to degradation and failure of the underlayment
material. For
example, one or more portions of the underlayment material may prematurely
fail, such
as the formations of cracks and/or deterioration or delamination of the foam
and film
layers. Such degradation is particularly troublesome in flooring applications
where the
failure may not be easily discernable or easily remedied.
Thus, there exists a need for an improved floor underlayment which provides
the
cushioning, and floor leveling functions of the prior floor underlayments, but
which also is
resistant to degradation caused by excess heat so to avoid the disadvantages
associated
therewith.
BRIEF SUMMARY OF THE INVENTION
Embodiments of the present invention are directed to a composite foam material
that is alkaline and heat resistance. The composite foam material comprises a
foam layer
that having a film layer attached thereto and in which at least one of the
film or foam
layers includes a carbon free radical scavenger agent that is dispersed
therein. The
carbon free radical scavengers neutralize free radicals that are generated in
the
polymeric material (e.g., film or foam layer) and help prevent the degradation
of the foam
composite material. In particular, foam composite materials in accordance with
the
present invention can be used in underlayment applications in which exposure
to heat
can degrade the underlayment. As a result, the durability and useful life of
the composite
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foam material can be extended- In some embodiments of the present invention
provides
a floor underlayment material that overcomes many of the problems discussed
above.
In one particular, composite foam materials in accordance with certain
embodiments of the present invention are able to meet the requirements of SP
Technical
Research Institute of Sweden test method SP-Method 1116 (e.g., a maximum of
50%
reduction of elongation at break following aging under alkaline conditions).
Suitable carbon free radical scavengers for use in the present invention
exhibit a
carbon scavenging activity over a temperature range between about 0 to 700 C,
and in
particular, over a temperature range that is from about 2 to 20 C, and more
particularly
from about 40 to 16 C. Examples of carbon free radical scavengers that can be
used
include hindered amines, quiriones, benzofuranones (lactones), hydroxylamines,
and
phenols, and combinations thereof One particularly, useful hindered amine that
can be
used in the practice of the invention is poly[(6-(1,1,3,3-
tetramethylbutyl)amino]-1,3,5-
triazine-2,4-diyl][(2, 2, 6,6-tetramethyl-4-piperidinyl)imino-1, 6-
hexanediyl[(2, 2,6,6-
tetramethyl-4-piperdinyl)imino]]).
In one embodiment, the present invention provides an underlayment material
that
may be used in a flooring system to help prevent or limit degradation due to
the exposure
of heat or alkaline materials. In one alternative embodiment, the underlayment
material
may be disposed between a subfloor and floor. The presence of the carbon
radical
scavenger in at least one of the foam or film layers helps to prevent the
propagation and
further creation of carbon radicals that result from the cleavage of hydrogen-
carbon
bonds along the polymeric chains comprising the foam and/or film layer, and
therefore
helps to improve the durability of the underlayment material-
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)
Having thus described the invention in general terms, reference will now be
made
to the accompanying drawings, which are not necessarily drawn to scale, and
wherein:
FIG. 1 is a cross-sectional side view of foam composite material in accordance
with one embodiment of the invention;
FIG. 2 is a cross-sectional side view of a foam composite material having a
foam
layer sandwiched between two film layers that is in accordance with one
embodiment of
the invention; and
FIG. 3 is a cross-sectional side view of a flooring system including the foam
composite material of FIG. 1.
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DETAILED DESCRIPTION OF THE INVENTION
The present inventions now will be described more fully hereinafter with
reference
to the accompanying drawings, in which some, but not all embodiments of the
inventions
are shown. Indeed, these inventions may be embodied in many different forms
and
should not be construed as limited to the embodiments set forth herein;
rather, these
embodiments are provided so that this disclosure will satisfy applicable legal
requirements. Like numbers refer to like elements throughout.
Wi h reference to FIG. I a composite foam material is illustrated and broadly
designated by reference number 10. In one embodiment, the composite foam
material 10
comprises a film layer 12 having an inner surface 16 that Is attached to a
foam layer 14,
At least one of the film or foam layers includes a carbon free radical
scavenger agent
dispersed therein. The carbon free radical scavengers help to neutralize free
radicals
that are generated in the polymeric material comprising the foam and film
layers. For
instance, the exposure to sufficient heat can result in the generation of free
radicals along
the polymer chains of the polymeric material comprising the foam and film
layers- If left
unchecked, these thus generated free radicals can react with other carbon
sites on or
near adjacent polymer chains, resulting in breaking of bonds within the
polymer, which in
turn, can lead to a degradation of the foam or film layer- The carbon free
radical
scavengers in the foam or film layers reacts with and neutralizes these
generated free
radicals so the propagation can be reduced or prevented. As a result, the
durability and
useful life of the composite sheet material can be extended.
As discussed in greater detail below, composite sheet materials in accordance
with the present invention are particularly useful in floor underlayment
applications where
the underlayment material is likely to be exposed to heat liberated from the
reaction of
water with calcium chloride. In particular, composite foam materials in
accordance with
certain the present invention are able to meet the requirements of SP
Technical Research
Institute of Sweden test methods SP-Method 1116 Floor underlay of polyethylene
cellular
plastic and SP-Method 0414 Plastics-Accelerated ageing in alkaline
environment, Method
C, the contents of which are both hereby incorporated by reference. For
example,
composite foam materials in accordance with the present invention were first
aged in
accordance with SP-Method 0414 and then the tensile strength and elongation at
break
were evaluated in accordance with SP-1116. Foam composite materials in
accordance
with embodiments of the present invention met the requirements of SP-1 16 (e-
g.. a
maximum of 50% reduction of elongation at break following aging under alkaline
conditions)-
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Suitable carbon free radical scavengers for use in the present invention
exhibit a
carbon scavenging activity over a temperature range between about 0 to 70 C,
and in
particular, over a temperature range that is from about 2 to 20 C, and more
particularly
from about 4 to 16 C. Examples of carbon free radical scavengers that can be
used
include hindered amines, quinones, benzofuranones (lactones), hydroxylamines,
and
phenols, and combinations thereof. One particularly, useful hindered amine
that can be
used in the practice of the invention is poly[(6-[1,1,3,3-
tetramethylbutyl)amino]-1,3,5-
triazine-2,4-diyl][(2,2,6,6-tetramethyl-4-piperidinyl)imino-1,6-
hexanediyl[(2,2,6,6-
tetramethyl-4-piperdinyl)im ino]j).
The amount of the carbon free radical scavenger in any one of the film or
foams
layers is generally from about 0.01 to 2 weight percent, based on the total
weight of the
layer, and in particular, from about 0.1 to 0.5 weight percent, based on the
total weight of
the layer- The carbon radical scavenger can be added during extrusion as a
melt
additive, as is known in the art.
In some embodiments, the composite sheet material may comprise a second film
layer attached to an outer surface of the foam layer to produce a laminate
wherein the
foam layer is disposed between two film layers. In this regard, FIG. 2
illustrates an
embodiment of the invention in which the foam layer 14 is sandwiched between
two film
layers 12a, 12b_ The second film layer may have moisture vapor barrier
properties.
As noted above, the composite foam material is particularly useful as an
underlayment material for use in flooring applications. In this regard, FIG. 3
illustrates a
cross-sectional side view of an exemplary flooring system 20 in which the
underlayment
material 10 is disposed between a subfloor 22 and a finished floor 24. The
finished floor
24 comprises a series of wood or wood laminate planks fitted together at their
edges. In
the illustrated embodiment, the film layer 12 is disposed adjacent to the
subfloor 22 and
the foam layer 14 is disposed adjacent to the finished floor 24_ In some
embodiments,
the foam layer 14 may be disposed adjacent to the subfloor 22.
In one embodiment, the composite sheet material comprises a laminate in which
the foam layer and the film layer are attached to one another. The film and
foam layers
may be attached together in a variety of known ways. Suitable methods of
attaching the
film and foam layers together include, but are not limited to, the application
of an
adhesive including a molten polymer, ultrasonic bonding, heat bonding, and the
like. In
one alternative embodiment, the composite sheet material may be produced by
extruding
a layer of polymeric resin directly onto the foam layer to thereby form a film
layer that is
thermally adhered to the foam layer. In other embodiments, the composite sheet
material
may be produced via heat lamination by feeding a sheet of foam and a sheet of
film
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through a pair of heated rolls that softens and fuses the film layer to a
surface of the foam
layer.
In some embodiments, the film layer comprises a polymeric material having high
moisture barrier properties, such as a water vapor permeability that is less
than about 0.8
grams/day/100 ina at 100 F, 90% relative humidity as measured according to
ASTM
F1249-01. In the embodiment illustrated in FIG. 3, it may be desirable for the
film layer to
comprise a material having high moisture vapor barrier properties so that
moisture vapor
may be substantially prevented from migrating through the film layer and into
the foam
layer- In some embodiments, the film layer may have a water vapor transmission
rate
that is less than about 0.25 grams/day/100 in2 at 100 F, 90% relative
humidity as
measured according to ASTM F1249-01 _ In other embodiments, the film layer may
comprise a polymeric material having low barrier properties, such as a water
vapor
permeability that is greater than about 0.3 grams/day/100 ina at 100 F, 90%
relative
humidity as measured according to ASTM F1249-01. For instance, the film layer
may
have a water vapor transmission rate that is no greater than about 0.25, 0.35,
0.50, or
0.75 gramslday/100 ina at 100 F, 90% relative humidity. In some embodiments,
it may be
desirable for the composite sheet material to have a high water vapor
permeability.
The film layer may include one or more thermoplastic polymers including
polyolefins, polystyrenes, polyurethanes, polyvinyl chlorides, polyesters, and
ionomers
provided that the desired properties of the film layer may be maintained.
Suitable polyolefins for use as the film layer may include LLDPE, low density
polyethylene, high density polyethylene, metallocene catalyzed polyethylene,
polypropylene, and oriented polypropylene, ethylene homo- and co-polymers and
propylene homo- and co-polymers. Ethylene homopolymers include high density
polyethylene ("HDPE") and low density polyethylene ("LDPE"). Ethylene
copolymers
include ethylenelalpha-olefin copolymers ("EAOs"). ethylene/unsaturated ester
copolymers, and ethylene/(meth)acrylic acid. ("Copolymer" as used in this
application
means a polymer derived from two or more types of monomers, and includes
terpolymers, etc.).
EAOs are copolymers of ethylene and one or more alpha-olefins, the copolymer
having ethylene as the majority mole-percentage content. In some embodiments,
the
comonomer includes one or more C3-C20 alpha-olefins, more preferably one or
more C4-
C12 alpha-olefins, and most preferably one or more C4-C6 alpha-olefins-
Particularly
useful alpha-olefins include 1-butene, 1-hexene, 1-octene, and mixtures
thereof.
EAOs include one or more of the following: 1) medium density polyethylene
("MDPE"), for example having a density of from 0.93 to 0.94 g/cm3; 2) linear
medium
density polyethylene ("LMDPE"), for example having a density of from 0.926 to
0.94
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g/cm3; 3) linear low density polyethylene ("LLDPE"), for example having a
density of from
0.915 to 0.930 g1cm3; 4) very-low or ultra-low density polyethylene ("VLDPE"
and
"ULDPE" ), for example having density below 0.915 g/cm3; and 5) homogeneous
EAOs.
Useful EAOs include those having a density of less than about any of the
following:
0.925, 0.922, 0.92, 0.917, 0-915, 0.912, 0.91, 0.907, 0.905, 0.903, 0.9, and
0.898
gramstcubic centimeter. Unless otherwise indicated, all densities herein are
measured
according to ASTM D1505.
The polyethylene polymers may be either heterogeneous or homogeneous. As is
known in the art, heterogeneous polymers have a relatively wide variation in
molecular
weight and composition distribution. Heterogeneous polymers may be prepared
with, for
example, conventional Ziegler Natta catalysts.
On the other hand, homogeneous polymers are typically prepared using
metallocene or other single site-type catalysts. Such single-site catalysts
typically have
only one type of catalytic site, which is believed to be the basis for the
homogeneity of the
polymers resulting from the polymerization. Homogeneous polymers are
structurally
different from heterogeneous polymers in that homogeneous polymers exhibit a
relatively
even sequencing of comonomers within a chain, a mirroring of sequence
distribution in all
chains, and a similarity of length of all chains. As a result, homogeneous
polymers have
relatively narrow molecular weight and composition distributions. Examples of
homogeneous polymers include the metallocene-catalyzed linear homogeneous
ethylene/alpha-olefin copolymer resins available from the Exxon Chemical
Company
(Baytown, Tex.) under the EXACT trademark, linear homogeneous ethylene/alpha-
olefin
copolymer resins available from the Mitsui Petrochemical Corporation under the
TAMER
trademark, and long-chain branched, metallocene-catalyzed homogeneous
ethylene/alpha-olefin copolymer resins available from the Dow Chemical Company
under
the AFFINITY trademark.
Another useful ethylene copolymer is ethylene/unsaturated ester copolymer,
which is the copolymer of ethylene and one or more unsaturated ester monomers-
Useful
unsaturated esters include: 1) vinyl esters of aliphatic carboxylic acids,
where the esters
have from 4 to 12 carbon atoms, and 2) alkyl esters of acrylic or methacrylic
acid
(collectively, "alkyl (meth)acrylate"), where the esters have from 4 to 12
carbon atoms.
Representative examples of the first ("vinyl ester") group of monomers include
vinyl acetate, vinyl propionate, vinyl hexanoate, and vinyl 2-ethylhexanoate.
The vinyl
ester monomer may have from 4 to 8 carbon atoms, from 4 to 6 carbon atoms,
from 4 to
5 carbon atoms, and preferably 4 carbon atoms.
Representative examples of the second ("alkyl (meth)acrylate") group of
monomers include methyl acrylate, ethyl acrylate, isobutyl acrylate. n-butyl
acrylate, hexyl
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acrylate, and 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate,
isobutyl
methacrylate, n-butyl methacrylate, hexyl methacrylate, and 2-ethylhexyl
methacrylate.
The alkyl (meth)acrylate monomer may have from 4 to 8 carbon atoms, from 4 to
6
carbon atoms, and preferably from 4 to 5 carbon atoms.
The unsaturated ester (i.e., vinyl ester or alkyl (meth)acrylate) comonomer
content
of the ethylene/unsaturated ester copolymer may range from about 3 to about 18
weight
%, and from about 8 to about 12 weight %, based on the weight of the
copolymer. Useful
ethylene contents of the ethylene/unsaturated ester copolymer may include the
following
amounts; at least about 82 weight %, at least about 85 weight %, at least
about 88 weight
%, no greater than about 97 weight %, no greater than about 93 weight %, and
no greater
than about 92 weight %, based on the weight of the copolymer.
Representative examples of ethylenetunsaturated ester copolymers may include
ethylene/methyl acrylate, ethylene/methyl methacrylate, ethylene/ethyl
acrylate,
ethylene/ethyl methacrylate, ethylene/butyl acrylate, ethylene/2-ethylhexyl
methacrylate,
and ethylene/vinyl acetate.
Another useful ethylene copolymer is ethylenel(meth)acrylic acid, which is the
copolymer of ethylene and acrylic acid, methacrylic acid, or both.
Useful. propylene copolymer includes propylene/ethylene copolymers (" FPC"),
which are copolymers of propylene and ethylene having a majority weight %
content of
propylene, such as those having an ethylene comonomer content of less than
10%,
preferably less than 6%, and more preferably from about 2% to 6% by weight.
lonomer is a copolymer of ethylene and an ethylenically unsaturated
monocarboxylic acid having the carboxylic acid groups partially neutralized by
a metal
ion, such as sodium or zinc, preferably zinc. Useful ionomers may include
those in which
sufficient metal ion is present to neutralize from about 15% to about 60% of
the acid
groups in the ionomer. The carboxylic acid is preferably "(meth)acrylic acid"-
which
means acrylic acid and/or methacrylic acid. Useful ionomers include those
having at
least 50 weight % and preferably at least 80 weight % ethylene units- Useful
ionomers
also include those having from I to 20 weight percent acid units. Useful
ionomers are
available, for example, from Dupont Corporation (Wilmington, Del_) under the
SURLYN
trademark-
The film layer may have a composition such that any one of the above described
polymers comprises at least about any of the following weight percent values,
30, 40, 45,
50, 55, 60, 65, 70, 75, 80, 85, 90, 95, and 100% by weight of the layer. Film
layer may
have a single layer construction, or may be formed. from multiple layers for
improved
moisture barrier properties. In one embodiment the film layer may be formed
from
substantially the same polymer, such as low density polyethylene, as is used
to form
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foam layer, or from a different polymer which is adhered to the foam layer. In
other
embodiments, the foam layer may be formed from a low density form of a
polymer, while
film layer may be formed from a high density form of the same polymer.
The thickness of the film layer is selected to provide sufficient material to
permit
the formation of the plurality of recesses in the outer surface. The film
layer may have a
thickness of at least about any of the following values: 0.2 mils, 0.5 mils, 1
mils, 1.25 mils,
1.5 mils, 2 mils, 2.5 mils, 3 mils, 5 mils, 10 mils, and 20 mils. The film
layer may have a
thickness ranging from about 0.2 to about 20 mils, more preferably from about
5 to about
mils, and still more preferably about 10 mils. Further, the thickness of the
film layer as
10 a percentage of the total thickness of the underlayment material may range
(in ascending
order of preference) from about 1 to about 50 percent, from about 5 to about
45 percent,
from about 10 to about 45 percent, from about 15 to about 40 percent, from
about 15 to
about 35 percent, and from about 15 to about 30 percent. The film layer may
have a
thickness relative to the thickness of the underlayment material of at least
about any of
15 the following values: 1%, 5%, 10%, 20%, and 30%.
The foam layer may comprise a variety of different foamed polymeric materials
including polyolefins. The foam layer may be crosslinked or non-crosslinked.
In
embodiments, in which the foam is crosslinked, it is generally desirable for
the carbon
radical scavenger to be present only in the film layer. On the other hand, if
the foam is
non-crosslinked the radical scavenger can be present in the foam layer only or
may be
present in both the foam and film layers.
Suitable polyolefins may include polyethylene resins, including polyethylene
homopolymers and copolymers. Useful polyethylene homopolymers include low-
density
polyethylene (LDPE), linear low-density polyethylene (LLDPE), and high-density
polyethylene (HDPE). Polyethylene copolymers may include homogeneous
ethylene/alpha-olefin copolymers, such as metallocene/single-site catalyzed
copolymers
of ethylene and one or more C3 to C,0 alpha-olefin comonomers, or
heterogeneous
Ziegler-Natta catalyzed ethylene/alpha-olefin copolymers. Other ethylene
copolymers
include propylene, higher olefins and carboxylic acids and esters. Various
ethylene
copolymers are used in which the second comonomer is a carboxylic acid or
ester such
as vinyl acetate, acrylic acid, methacrylic acid, methacrylate and ethyl
acrylate. Ethylene
vinyl acetate (EVA) copolymers with vinyl acetate content ranging up to 30%
weight could
be used copolymers, such as homogeneous ethylene/alpha-olefin copolymers,
heterogeneous Ziegler-Natta catalyzed ethylene/alpha-olefin copolymers, and
ethylene
vinyl acetate (EVA) copolymers. Suitable polyolefin resins may also include
polypropylene homopolymers and copolymers.
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The foam layer provides many of the cushioning characteristics of the
underlayment material. The thickness and density of the foam layer may be
selected so
that the underlayment material has the desired cushioning properties. In one
embodiment the foam layer has a density from about 0.5 to 15 pcf, and in
particular, from
about I to 10 pcf.. In other embodiments, the foam layer has a density that is
from about
1.5 to 3.0 pcf, 1-7 to 2.5 pcf, and from 1.9 to 2.2 pcf. The thickness of the
foam layer may
range from about 0.01 to 3 inches, 0.1 to 2.0 inches, and from 0.75 to 1.5
inches. In one
embodiment, the foam layer has a density from about 1.0 to 2.2 pcf and a
thickness
between about 0.1 to 1.5 inches, and in particular, from about 0.1 to 1 inch.
In some embodiments, the foam layer may include a plurality of spaced apart
ribs
that extend at least partially along the length of the foam layer. The ribs
may provide
channels through which a fluid may migrate to the edges of the flooring
system. Floor
underlayment materials having a plurality of ribs are discussed in greater
detail in
commonly assigned U.S. Patent Applications Ser. Nos. 10/716,922 and
10/758,402, the
contents of which are hereby incorporated by reference.
In some embodiments, the film layer may also include one or more additives,
such
as antioxidants, anti-corrosion agents, UV stabilizers, fire retardants, fire
resistants, anti-
bacterial agents, anti-microbial agents, anti-fungal agents, anti-static
agents,
biostabilizers and/or other functional additives depending on the commercial
application
of the laminate.
In a preferred embodiment, the foam layer comprises a crosslinked polyolefin,
such as a crosslinked polyethylene or crosslinked polypropylene, and the film
layer
comprises a polyolefin in which the carbon radical scavenger is dispersed.
The underlayment material may be used in a wide variety of applications
including
flooring applications. As discussed above, the underlayment material may be
used in
finished flooring applications where it may be desirable to prevent water from
accumulating between the floor and the subfloor. Finished floors may include
one or
more of wood planks, parquet flooring, wood laminate flooring, wood-block
flooring, and
plastic flooring, such as vinyl flooring and linoleum flooring. In one
alternative
embodiment the floor may comprise a laminate wood floor including wood
laminates
which are commercially available. In other embodiments, the underlayment
material may
be used in conjunction with other types of flooring systems including linoleum
and tile
floors-
In one embodiment, the floor may comprise wood or laminate planks that are
positioned side-by-side on the underlayment material. In one alternative
embodiment, the
planks may fit together by means of tongue-in-groove arrangement. In some
embodiments, the floor may be a so-called "floating floor."
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The subfloor may include precast or preformed concrete, poured concrete, or
reinforced concrete. In one embodiment, the flooring system comprises a wood
subfloor
in combination with an underlayment material having low barrier properties. In
such an
embodiment, a low barrier underlayment material may help permit the escape of
fluid
from within the flooring system and thereby prevent the accumulation of
moisture
between the wood subfloor and the underlayment material.
The flooring system may be assembled in any known manner. In one
embodiment, the underlayment material is positioned on a concrete subfloor in
a free-
lying manner. The floor may be in the form of strips of wood or laminate
planks. In some
embodiments, the underlayment material may not be adhered to the concrete
subfloor.
In one alternative embodiment, the bottom of the foam layer contacts the top
surface of
concrete subfloor and the outer surface of the film layer may be at least
partially in
contact with the underside of the floor. Planks of laminate wood flooring may
be
positioned on the underlayment material in a free-lying manner. Planks may fit
together
by means of tongue-in-groove arrangement and in some embodiments may be glued
together. The outer surface of the film layer contacts the bottom surface of
laminate
wood flooring.
In some applications it may also be desirable to adhesively laminate the
underlayment material to one or more of the subfloor or the flooring system.
In some embodiments, the underlayment material may only include a foam layer
and the presence of a film layer may be optional. For example, in one
embodiment the
underlayment material may comprise a foam layer comprising a polyolefin
cellular
material in which the carbon radical scavenger has dispersed, and in which a
film layer is
not attached to the foam layer.
The following examples are provided for the purpose of illustration only and
should not be construed as limiting the invention in any way.
EXAMPLES
In the following example, the alkaline and heat resistance of composite foam
materials were investigated by SP Technical Research Institute of Sweden using
SP
standards SP-Method 116 and SP-Method 0414_ Table 1 describes summarizes the
four
samples that were investigated.
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CA 02693186 2010-02-17
TABLE 1: Compositions of SAMPLES 1-4
Density Carbon
Sample Foam layer (Ibs.lft3)/ Film layer 1 Film layer 2 scavenger
No. Composition Thickness Composition Composition (wt ova)
in.
Polyethylene 2.0
Sample (non- lbs.ft3/0.125 -- --
crosslinked) in.
Sample Polyethylene 2.0 -
2 (non- lbs.ft3/0.125 0.1
crosslinked) in.
Sample Polyethylene 2.0
3 (non- lbs.ft3/0.125 polyethylene polyethylene 0.1/layer
crosslinked in_
Sample Polypropylene 3.0 _
4 (crosslinked) Ibs.ft /0.085
in.
Sample 1 comprised a non-crosslinked low density polyethylene foam. No carbon
radical scavenger was added to Sample 1_
Sample 2 comprised a non-crosslinked low density polyethylene foam. The foam
layer included 0.1 wt_ % of poly[(6-[1,1,3,3-tetramethylbutyl)amino]-1,3,5-
triazine-2,4-
diyl][(2, 2,6,6-tetramethyl-4-piperidinyl)imino-1,6-hexanediyl[(2, 2,6,6-
tetramethyh4-
piperdinyl)imino]]) as a carbon radical scavenger, available from Ciba under
the
tradename CHEMISORBC 944. The carbon radical scavenger was added as a melt
additive during extrusion.
Sample 3 comprised a sandwich construction in which a low density polyethylene
foam was sandwiched between a 1 mil thick polyethylene film layer and a 4 mil
thick
polyethylene film layer. The 1 mil film layer was laminated via in-line
lamination using hot
drawn and pressure. The 4 mil film layer was extrusion coated onto the foam
layer. Each
film layer and the foam layer included 0.1 wt. % of polyj(6-j1,1,3,3-
tetramethylbutyl)amino]-1, 3, 5-triazine-2,4-diyl][(2,2, 6, 6-tetramethyl-4-
pipe ridinyl)imino-
1,6-hexanediylj(2,2,6,6-tetramethyl-4-piperdinyl)imino]]) as a carbon radical
scavenger.
Sample 4 comprised crosslinked polypropylene foam. No carbon radical
scavenger was added to Sample 4.
Test specimens of Samples 1-4 were prepared in accordance with ISO 1798
Flexible cellular polymeric materials. The samples were then exposed in
alkaline
environment for 24 weeks at +90o C in accordance with SP-Method 0414. After
exposure, the elongation at break for 5 unexposed and exposed samples for each
of
Samples 1-4. The mean values are provided in Table 2 below.
TABLE 2: Elongation at Break for Samples 1-4
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CA 02693186 2010-02-17
Sample No. Elongation at break before Elongation at break after
a in (%)* aging
Sample 1 77(g) <2*"
Sample 2 599 51(4)
Sample 3 85(5) 65(10)
Sample 4 173(29) 90(11)
*standard deviation in brackets
*' The <2 value is based on the average 4 of the 5 samples tested. The 51'
sample had
an elongation of 29% and was considered an outlier.
From the Table 2 above, it can be seen that Samples 2-3 which include the
carbon radical scavenger fulfill the requirements of SP-Method 1116 and had
less than a
50% reduction in the elongation at break following aging. Sample 1, which did
not include
the scavenger showed significant reductions in the elongation at break after
aging and did
meet the requirements. Sample 4, which is a crosslinked foam that did not
include the
scavenger, also showed significant reductions in elongation at break following
aging.
Many modifications and other embodiments of the inventions set forth herein
will
come to mind to one skilled in the art to which these inventions pertain
having the benefit
of the teachings presented in the foregoing descriptions and the associated
drawings.
Therefore, it is to be understood that the inventions are not to be limited to
the specific
embodiments disclosed and that modifications and other embodiments are
intended to be
included within the scope of the appended claims- Although specific terms are
employed
herein, they are used in a generic and descriptive sense only and not for
purposes of
limitation.
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