Note: Descriptions are shown in the official language in which they were submitted.
- 2- 133132~ `
STAIN A~D SCRATCH RESISTANT RESILIENT SURFACE COVERINGS
The present invention relate~ to surface
coverings, and more particularly to surface covering~
which have i~proved scratch and stain resistance.
Background of the Invention
Resilient surface coverings, and in particular
resilient floor coverings, are well known in the art. The
floor coverings which are in wide u6e today are primarily
of vinyl construction and, although they can be
con~tructed to have varying degrees of flexibility, they
are "resilient~ when co~pared to conventional natural
materials, such as ceramic tile. A variety of ~uch
products are commercially available and these products
have proved to exhibit good wear resistance; however, ~uch
coverings are not without certain deficiencies. For
example, although vinyl flooring products have proved to
be durable and stain resistant, they nevertheless tend to
lose their glossy appearance through wear. A high-gloss
appearance for a floor covering is often desired.
Accordingly, the manufacturers of such material~ have long
sought to find improved floor coverings which exhibit good
gloss retention.
One method of providing improved gloss retention
i8 through the application of polyurethane or other wear
layers to vinyl flooring structures. Such materials are
durable and relatively scratch resistant, and they tend to
retain their high-gloss appearance over a longer period of
time than do vinyl-surfaced flooring 3tructures.
~evertheless, ~hese wear layers, and in particular
polyurethane wear layers, also have certain drawbacks.
For example, they are more susceptible to staining. Thu8,
when exposed to common household item~ likely to cause
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stains (~uch as ballpoint pen, lipstick, mustard, shoe
poliæh and the like), polyurethane coating~ tend to be
more easily stained than vinyl coatingæ.
In recent year~, industry has expended
considerable effort to develop new and different types of
coatings, including coatings ba~ed on aminoplast resins.
Such materials include ureas and ~elamine-formaldehyde
resins, such as melamineæ (triaminotriazine6) which have
been ~-alkylated with formaldehyde to provide a
methylolated or partially methylolated melamine. The
methylol group~ are then etherified or partially
etherified to provide a crosslinkable material. Such
coatingæ are generally fairly rigid, and have found wide
use in coatings for automobiles, appli~nces and other
fairly rigid types of surfaces. They have al80 been u~ed
in coatingæ for ~ertain flexible ~ubstrate6 including
paper, paperboard, metal foil~, "Cellophanes"* and the like.
However, Ruch materials have never been ~uccessfully
applied to flooring structureæ, and in particular to vinyl
flooring Btructures or to vinyl flooring structures
comprisin4 polyurethane wear layers.
Accordingly, one objective of the present
invention i~ to provide resilient surface coverings with
protective coatings two-tenthæ of a mil or greater in
thicknesæ which will deform in conjunction with the
fiurface coverings, yet which will provide improved scratch
- and ætain reæistance.
Another objective of the preæent invention is to
provide flooring structure~ comprising composite wear
surfaceæ whereby the wear layer material i~ provided with
an improved scratch and stain-resistant character.
These and other advantageæ of the present
invention will become apparent from the detailed
description of preferred embodiments which follows.
*Trademark
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133~32A
Summary of the Invention
The present invention relates to surface
coverings, and in particular to floor covering~, which
c~mprise polyurethane or ~ther wear layer6 having coatings
which ~omprise a urea aminoplast which i~ at least
partially etherified with alkyl groups comprising 4 to 10
carbon atoms, a vinyl ~odifier re6in, a polyol, ~nd an
acid catalyst. Ihis coating may be formed on ~ release
surface and thermally cured. A ~rosslinkable wear layer
composition, ~uch a~ a polyurethane composition, may then
be cast on the cured layer and crosslinked, and the
composite can then be tran~ferred to a support surface.
Surface ~overings are produced which exhibit surpri6ing
resi~tance to common hou6ehold ~tains, and also improved
8cratch resistAnce.
. The present invention, then, in one aspect,
resides in a resilient surface covering, said covering
compris~ng a resilient support and a crosslinked wear
layer adhered thereto, the upper surface of said wear
layer compr~sing a protective coating derived from a
composition comprising:
j (a) a urea aminoplast,
~b) a vinyl modifier resin,
$ (c) a polyol, and
i (d) -a 6uitable catalyst,
said protective coating having the ability to conform to
the deflections of said wear layer, yet having improved
scratch and stain resistance relative to the untreated
vear layer.
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In another aspect, the present invention resides in
a process for providing a wear surface for a resilient
surface covering, said process comprising the steps of
providinq a release carrler comprising a support
surface and a release coating,
disposing on said release coating a composition
comprising
(a~ a urea aminoplast,
(b) a vinyl modifier resin,
~c) a polyol, and
(d) a suitable catalyst,
at least partially thermally curing said
composition,
disposing a crosslinkable wear layer composition on
said aminoplast layer,
curing said wear layer,
laminating said cured wear layer to a resilient
support structure, and
~ eparating ~aid release carrier from said wear
layer, whereby said surface covering comprises a wear
layer having d protective coating, said protective
coating being flexible, and scratch and stain-resistant
relative to the untreated wear layer.
~ he present invention further provides a
process for forming a resilient surface covering
comprising a wear layer, which comprises applying to a
free surface of the wear layer a composition comprising
(a) a urea aminoplast,
(b) a vinyl modifier resin,
(c) a polyol, and
(d) a catalyst, and forming a protective coating
therefrom, or by applying a protective coating derivable
from such a composition.
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~etailed Description of Preferred Embodiments
In one embodiment, the preRent invention relates
to a resilient surface covering, said covering comprising
a resilient ~upport and a crosslinked wear layer adhered
thereto, the upper ~urface of ~aid wear layer comprising a
protective coating derived from a composition compri~ing
(1) a urea aminoplast, (2) a vinyl modifier resin, (3) a
polyol, and (4) a suitable cataly~t, 6aid protective
coating having the ability to conform to the deflections
of ~aid wear layer, yet having improved ~cratch and ~tain
resistance relative to the untreated wear layer.
In a second embodiment, the present invention
relates to a process for providing a wear ~urface for a
resilient 6urface covering, said process comprising the
steps of providing a release carrier comprising a support
surface and a release coating: disposing on said release
- coating a composition comprising (1) an aminoplast, (2) a
vinyl =odlfier re~in, (3) ~ polyol, and (4) a euitable
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cataly~t; at least partially thermally curing said
composition; disposing a cros~linkable wear layer
composition on said aminoplast layer; curing ~aid wear
layer; laminating said cured wear layer to a resilient
support structure and ~eparating said release carrier
from said wear layer, whereby said urface covering
comprise~ a wear layer having a protective coating, said
protective coating being flexible, and scratch and
Rtain-resistant relative to the untreated wear layer.
The resilient surface coverings which may be
prepared according to the pre~ent invention are related to
~hoce which are presently well-known in the art. Thus,
they may comprise an underlying re3ilient support typical
of those used to prepare vinyl flooring structures.
Supports of this type may be derived fro~ backing
materials, plastisols, foamed plasti~ols, randomly
dispersed vinyl particle~, stencil disposed vinyl
particles, and the like, the selection of such ~aterials
being well within the skill of an ordinary artisan.
The 6urface covering~ will also comprise
compo~ite wear layer compositions. The major portion of
the wear layer will compri~e materials which are pre6ently
well known in the art. Example~ of such materials are
crosslinked wear layers derived from urethanes, acrylated
or methacrylated urethanes, unsaturated polyesters, and
the like, all of which are well known in the art~ These
wear layer~ may be crosslinkable by moisture-curing
techniques, thermally induced free radical curing
techniques, oxidative curing techniques, radiation-curing
techniques, or a combination thereof.
The novelty of the pre~ent invention re~ides in
the pre~ence of a ~econd protective layer on the
conventional wear layer components. This second material
1~31~2~
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i8 derived from urea aminoplast re~in, a polyol, an acid
catalyst and a vinyl modifier resin, and provides a
flexible, yet 6cratch and ~tain-resistant upper surface.
The resin6 which may be u~ed to practice the
pre6ent inven~ion are referred to herein as
~aminoplast6n. With re~pect to melamine-formaldehyde
resins, the~e material~ may be partially or sub~tantially
methylolated, and ~he methylol group~ may be partially or
6ubstantially etherified with methyl, ethyl, propyl,
butyl, pentyl, hexyl, heptyl, octyl, nonyl, and decyl
group~, isomer~ o~ these moietie~, and mixtures thereof:
however, these aminoplast~ preferably will be at least
partially etherified with a relatively long chain alkyl
group having from about 4 to about 10 carbon atoms. These
long-chain portion~ of the aminopla~t a38ist in providing
fle~ibility to the cured vinyl product.
With respect to urea-based resins, many of these
aminopla~ts are commercially available and are ~old, for
example, as "Resimene"* resins by Monsanto Company.
The vinyl modifier resins which will be utilized
will be one of, or a combination of, resins which are
well-known in the art. Examples of such resins are
co-polymer ~olution vinyl re6ins derived from vinyl
chloride and vinyl acetate. Re6ins ~f this type are sold
by ~nion Carbide, and they ~ay or may not contain hydroxyl
or other functionality. One ~uch available reEinis sold under
the trade designation VAGH*. Other~ ~ight include VAGD*,
VROH* nnd VYES* resins. Examples of other resins are
specialty re6ins such as the polyvinyl acetals (eg.,
polyvinylbutyral), either alone or in combination with
polyvinyl alcohol and/or polyvinyl acetate, and polyvinyl
e6ters such a6 polyvinyl acetate. Such materials are
- well-known in the art as being amenable to application
3~ *Trademar~ (each instance).
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l ~31324
from solution; thu~, they are distinguishable from
dispersion grade and general purpose resins which are
essentially in~oluble in most conventional solvents. In
essence, the modifier resins should be suitable to enhance
the flexibility and etrength of the cured compo~ition
without adversely affec~ing the 6tain resistance.
m e polyols which may be u6ed to practice the
present invention are alcohols which comprise two or more
alcohol groups. For example, 1,6-hexanediol,
10 1,4-cyclohexane dimethanol, glycerine, neopentyl glycol,
tripropylene glycol, 1,4-butanediol, trimethylolpropane,
pentaerythritol, and many other polyols or esters of such
polyols, such a~ neopentyl glycol ester and the like, may
be utilized to prac~ice the present invention, ~aid
15 polyols being well-known in the art.
The ncid catalysts which may be used to catalyze
the thermal curing reaction between the vinyl modifier
resin, the aminoplast, the polyol and the wear layer
~urface are al~o well-known in the art. Examples of such
20 cataly~ts are ~ulfonic acids, such as methane-sulfonic
acid and p-toluenesulfonic acid, and other acids such as
citric acia, maleic acid, phthalic acid, etc. The
cataly~ts may be used in the free acid form, but they may
also be stabilized, such as by the use of an amine to
25 neutralize the acid. E~amples of such amines are ammonia,
diisopropanol amine, and 2-amino-2-methyl-1-propanol. The
only restriction i8 that the catalysts must be compatible
m with the other components of the 6ystem. Because these
catalyst~ are all well-Xnown by those skilled in the art,
30 their ~election will be within the capability of an
ordinary artisan.
To practice the pre6ent invention, ~ release
eurface iB provided for the aminoplast composition. For a
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very smooth surface, a polished chrome plate or a relea~e
paper coated with a polyalkylçne material can be used, a
particularly good example of the latter being
polypropylene, such as polypropylene matted by
calendering. For less glossy surfaces, other types of
coated papers or belts may be u~ed, examples of which are
silicone, complexed chromium and methyl cellulose trea~ed
paperc or belt~. The 6election of such materials is well
within the skill of an ordinary arti~an.
On to the release paper is cast a layer of
aminoplast composition. Although the component ratios of
the composition will have sub~tantial variability, the
compoqition will u~ually compris2 from about 4 to 1 part~
of modifier resin for every 1 to 4 parts of the
aminoplast/polyol mixture. Further, the aminoplast/polyol
mi~ture may comprise from about 5 to 1 parts of aminoplaqt
fcr every 1 to 5 parts of polyol. Preferably, however,
there will be from about 3.5 to 1 parts of modifier for
every 1 to 2 parts of aminoplast/polyol having a ratio of
from about 3 to 1 parts of aminoplast for evesy 1 to 3
parts of polyol. ~ually this composition will be
provided in an organic solvent; however, it i8 al~o
pos~ible to apply the compo~ition in aqueous form.
After the aminoplast composition i8 applied to
the relea~e paper, it is dried and at least partially
cured at about 250-F. Although it is poqsible to form the
laminates of the present invention using partially cured
aminoplast layers to ohtain a high quality product, it is
usually preferable to ensure that the aminoplast layer is
fully cured prior to the depo~ition of the urethane layer.
The crosslinkable wear layer coating composition
may be disposed directly on the aminoplast layer after the
aminoplast layer is cured. It is noted, however, that the
artisan may optionally elect to pretreat the ~urface of
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9 133~32~1
the cured aminoplast layer by corona discharge or by
applying a key coat compocition 80 as to promote adhe~ion
between the layers. The latter compositions, which
typically are vinyl lacquers, are in wide use and are
well-known to those skilled in the art. Such compo~itions
often comprise vinyl chloride copolymer solution resin~
such as the VAGH resin describ2d above.
Corona discharge is also well-known in the art
and involves a raising of the surface energy by exposing
the æurface to an electrical arc. The amount of energy
necessary to promote good adhes~on may be readily
deter~ined by standard means. Thu8, the surface tension
of the coating composition may be determined according to
ASTM D 1331 and the surface energy of the surface to be
coated may be determined essentially as described in ASTM
D 2578. The objective is to rais~ the surface energy of
the surface to be coated such that it will be wetted by
the coating composition. Ideally the surface energy
resulting from the corona treatment will be at lea~t about
10 dynes/cm greater than the surface tension of the
coating compo~ition.
qhe thicknes3 of application of the wear layer
composition can vary from about 1 to about 8 ~il~, but
preferably will vary fron about 2.5 to about 4.5 mils.
The composition may be a low solid (e.g. 40~) solution of
~; polyether or polyester-based urethane which is moisture
curable, or it may comprise a 2-component system such as a
polyester comprising hydroxyl functionality combined with
a diisocyanate. Curing of the latter composition occurs
by reaction of the diisocyanate with the hydroxyl groups
of the polyester, a~ well as with moisture in the air.
Alternatively, radiation curable, or combinea radiation
and moisture curable, component~ can be utilized. As with
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the aminopla~t layer, it i8 alBo advisable to en~ure that
the urethane layer is fully cured before lamination to ~he
xesilient surface covering is achieved.
When fully cured materials are prepared and then
laminated to resilient surface covering~, occa~ional poor
adherence of the laminate to the surface covering ha~ been
encountered. As with the aminoplast layer and wear layer,
it has been found desirable to avoid delamination problem3
by providing a key coat between the back (exposed) surface
of the wear layer and the resilient layer with which it is
interfaced. As an alternative, corona discharge treatment
i~ al~o available to facilitate adhesion of the coat~.
The upward facing wear layer i8 interfaced with
the resilient ~upport surface layer, with or without an
intervening key coat or corona discharge treatment, and
the composite material is ~ubjected to heat and pre~sure
to en~ure firm adhesion. The composite material may al~o
be affixed to granular or consolidated stencil vinyl
products in the same manner. After consolidation i8
complete, the release paper i~ ~tripped from the hot
sample to provide a decorative ~urface covering which
exhibit~ good scratch and ~tain re~i~tance. Thu8 ~ the
materials are resistant to staining by household items
~uch as lipstick, mustard, ~hoe polish, food dye and the
like.
~he present invention will be better under~tood
by reference to the exampl2s which follow, said examples
being provided by way of illustration and not limitation.
EXAMPLES ~ -
Example 1
Compocition~ were prepared as ~et out in Table 1
compri~ing each of the indicated components in parts by
weight.
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Table 1
Component 1-1 1-2 1-3 1-4
Xylol 16.0 16.0 20.0 20.0
Vinyl c~loride/vinyl
acetate copolymer
(V~GH* from Union
Carbide) - - 13.6 13.6
W 6 tabilizer("Uvitex"*
OB; 1% in xylol) 1.0 1.0 1.0 1.0
organotin ~tabilizer
("Thermolite 31" from
Metal and Thermit Co.) - - 0.25 0.25
Fluorocarbon 6urfactant
(FC-430* from 3-M
Company; 10% in xylol) 1.0 1.0 0.80 0.80
Methyl i60butyl ketone 18.1718.17 22.07 22.07
Diacetone alcohol 8.0 8.0 8.0 8.0
Isopropyl alcohol 3.6 3.6 3.6 3.6
Aminoplast resin
"Resimene 980" 15.30 - 5.1
"Resimene 915* (from
Monsanto) - 20.4 - 6.8
Cyclohexane dimethanol
(90% in water) 5.1 5.1 1.7 1.7
1,6-He~anediol - - - -
2~
p-Toluenesulfonic acid
(25% in 1:1 xylol/
isopropyl alcohol) 2.9 2.9 0.9 0.9
Vi~cosity, ~2 Zahn*
cup (6econds) 15.0 16.0 - -
~3 Zahn* - - 31 30
Total Solids (%) 29.327.17 27.0 26.42
Ratio of vinyl copolymer
to total melamine plus
diol -- 2:1 2:1
Trademark (each instance).
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Each of a series of polypropylene-coated release
papers was provided with a coating of samples 1-1 through
1-5 at a wet thickness of about 2~5 to 3.5 mils using a
rever~e roll coater. The coated paper was then passed
through a 260F oven such that the coating resided in the
oven for 4 minutes.
A moi~ture-curable polyurethane coating
compo~ition as set out in Table 2 was prepared for
application to the coated relea3e papers.
1~ Table 2
Component Weight (Gram~)
Polyetherdiol (Union Carbide LHT 240*) 40.80
Polyetherdiol (Union Carbide LHT 112*) 14.20
Xylene ~olvent 110.00
15 Toluene solvent 46.00
Dimethyltin dineodecanoate ~atalyst
~"Witco UL-28"*) 0-55
Surfactant (Mon~anto"XA-677 Multiflow"*~ 0.30
Light stabilizer (American Cyanamid UV-5411*) 0.20
These components were charged to a stirred,
nitrogen-purged glass reactor and heated to 70C for one
hour. A~44.90 gram quantity of 4,4'-diisocyanate
dicyclohexylmethane was added dropwi6e over a 30 minute
period of ti~e at a rate sufficient to maintain the
te~perature of the mixture at 70-C. After an additional
two-hour period of stirring and heating at 70C, the
product was cooled.
To each of the aminopla~t coated relea~e papers
wa6 applied a 1 to 2.5 mil wet layer of key coat lacquer
compris~ng 18.54 percent ~y weight of VAGH* resin, 0.37
- percent ~nY~m~lite 31~*, 0.0094 penx~t ~Uvitex OB"* and 81.08
percent methyl ~Qobutyl ketone solvent. The coated sample
was then dried in ambient air or under low heat to remove
the ~olvent. Upon completion of the drying step, each
*~rademark (each instance).
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paper was provided with a 5 to 6.5 mil wet coating of the
moi~ture curable polyurethane material described above.
The coated samples were then pacsed through a 250F oven
to completely dry the sample, the dwell time in the oven
being 7 minutes.
Coatings of camples of 1-6 through 1-9 were
prepared on polypropylene coated paper uRing a ~30 wire
wound rod drawn to obtain coating~ 0.5 mil in thickness
when dried. The samples were then cured at 250~F for five
minutes. Sa~ple 1-6 delaminated completely and was
discarded. The remaining sampleQ were coated with a
moisture-curable polyurethane coating composition as given
above.
The lamination and consolidation steps for
laboratory evaluations involved the use of a 12 inch x 12
inch press to prepare 9 inch ~ 9 inch samples. The top
platen of the press was heated at 310-F whereas the bottom
platen was heated at 300F. ~he dwell time in the pre~s
was 10 seconds at 250 poundQ pressure, followed by 10
seconds at 1,200 pound~ of pre~ure. Following removal of
the ~ample from the press, the release paper was stripped
from the ~ot ~ample.
Both stencil vinyl and gelled vinyl plastisol
resilient support material~ may be used for lamlnation
with the above coatings, and stain resistance wa~
evaluated u~ing ordinary household stain~. Although
sample 1-7 was clearly more susceptible to ~taining than
the other~, all samples showed superior stain resistance
a3 compared to the untreated polyurethane material, and
also ~howed good scratch resistance.
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