Note: Descriptions are shown in the official language in which they were submitted.
1046869
Decorative cushioned vinyl floor coverings are now~
produced on a very large scale. They comprise a decorative
cushioned vinyl layer carried on a substrate. The decorative
cushioned vinyl layer generally comprises a layer of foamed
vinyl polymer covered by a non-foamed wear resistant layer,
the foamed layer or the wear resistant layer or both together
giving a decorative effect to the product. Such products are
made by spreading a layer of foamable composition over the
substrate and then foaming it. This layer may be deliberately
embossed or caused to foam in such a manner as to give an
embossed effect but wherever it is desired that the final
foamed layer should be of uniform thi~kness it is absolutely
vital that the substrate and/or foamable layer should be of
uniform thickness before foaming. For instance in a typical
foaming operation the depth of the foamable layer increases
fivefold upon foaming and so minor non-uniformity that is
hardly visible before foaming may, after foaming fivefold,
result in gross surface imperfections.
Accordingly, in practice, most methods of making
decorative cushioned vinyl floor coverings involve the use
of a substrate that is as flat and as smooth as possible.
Typical substrates that come into consideration are
discussed on page 3 of British Patent Specification No.1,069,998.
In practice the substrate most widely used is wet laid asbestos
felt, that is to say an asbestos felt formed by draining water
and binder
out of a layer of a slurry of asbestos fibres/in water. The
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production and use of asbestos felt constitutes a serious
health hazard and also asbestos is expensive.- Despite---------
these disadvantages no alternative substrate has gained
widespread acceptance.
Numerous suggestions for alternative substrates
have of course been made in the literature and some are
mentioned in Specification ~,069,998. Examples of such
other substrates are woven fabrics and non-woven fabrics.
For instance in British Specification No.1,206,584 a non-
woven fabric of glass tissue is said to be preferred even
though it is not used in the Examples of that Specifi-
cation. However none of these alternative suggestions
seem to have achieved wide acceptance. This is probably
because woven fabrics, or even substrates based on a
parallel thread construction, tend to be costly and also
both woven and non-woven fabrics and tissues made by the
most common methods tend to have surface irregularities
which are sufficiently great as to be unacceptable as a
basis for a decorative cushioned vinyl floor covering. m e
example a normal glass tissue will generally have an
unacceptably rough surface and its thickness will generally
vary from point to point to an unacceptable extent.
- We have now found remarkably that it is possible to
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replace the conventional wet laid asbestos felt with a
substrate based on a particular form of glass tissue
without detrimentally affecting the stability and surface
appearance of the final product but avoidi~g the cost and
health disadvantages arising from the use of asbestos.
According to the invention a substrate for a
decorative cushioned vinyl floor covering comprises a smooth
non-woven tissue having a substantially uniform thickness
of from 0-13 to 0-76 mm and weighing from 30 to 150 g/m2
and comprising glass fibres 5 to 15 microns in diameter
bonded with from 10 to 30% by weight based on the total
weight of tissue of a synthetic binder and which has at
' least on one surface a continuous layer of a resin
impregnated at least partially into that surface. A
decorative cushio~ed vinyl floor covering according to the
invention comprises such a substrate and, on the continuous
layer Or resin or on one of these layers, a wear resistant
de¢orative cushioned vinyl layer.
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The non-woven tissue usually consists solely of the
synthetic binder and the glass fibres.
The tissue must be smooth and of substantially
uniform thickness in order that any surface irregularities
in it are so minute that even when they are magnified as
a result of foaming the foamable layer that is subsequently
applied an acceptable smooth result is achieved.
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A One way of measuring smoothness is by using a Talysurf
Instrument (manufactured by Rank Taylor Hobson Ltd.). In this
method, a 15 centimetre length of the material is mounted on a
motorised traversing table, and a diamond tipped probe is used to
follow the surface irregularities of the tissue. From a scan of
the surface, variations in surface smoothness can be determined.
Variations in surface smoothness are apparent in the glass fibre
tissues commercially available and are often introduced by the
method of manufacture of the tissue. After the tissue is coated
with a continuous layer of resin the variation in surface smooth-
ness of the glass tissue may be masked since it is often coated
hot and cooled under constraint. However on heating an apparently
smooth coated tissue under the conditions encountered in the
manufacture of decorative cushioned vinyl floorcovering, an
initially irregular glass tissue will again resume its irregular
shape, causing the coated substrate to have an unacceptable un-
dulating surface. Thus a commercially available air laid glass
tissue i8 coated, the coatings smoothed and the coated tissue
cooled down while under constraint. The variation in surface
smoothness, measured by the Talysurf Instrument at this stage
is + 0.04 mm. The coated tissue is then re-heated under the con-
ditions to be encountered in manufacture of a cushioned vinyl
floorcovering and cooled down in contact with a smooth glass
plate without constraint. The variation in surface s othness
of the re-heated substrate measured as before is now + 0.12 mm.
~' In the invention, the variation in smoothness of the
i', coated tissue measured in this manner is preferably + 0.06 mm.
~ and more preferably less than + O.03 mm. at least on the surface
; that is to carry the decorative cushioned vinyl layer.
When one holds up to the light many normal glass tissues
one can see variations in thickness and/or density and such
tissues are not of substantially uniform thickness. In the
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invention it is preferred that the thickness of the tissue should
at all places be within + 15%, and preferably + 10% of the chosen
thickness and it is also preferred that the weight per unit area
of the tissue should in all places be within + 15% and pre-
ferably within + 10% of the chosen weight.
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It is particularly preferred that the thickness in all
places should be within + 5% of the chosen thickness
and the weight should be within + 5% of the chosen weight,
and in particular the weight should be
within + 2% of the chosen values. Preferably
variations in weight are not more than + 3, and preferably
not more than + 1 gjm2 and ~referably the variations in
thickness are not more-than +oO-02 mm.
The weight of the tissue is preferably from 30 to
100 g/m2 and preferably it is from 0-25 to 0-5 mm thick.
composition
The amount of resin/applied to it to form the continuous
layer on either or both of its surfaces is normally within
the range 300 to 1D00 g/m2.
Particularly good results are obtained in t`he
invention when the tissue weighs from 50 to 60 g/m2 and
carries from 15 to 20X binder. These and other particularly
preferred tissues are made by a wet laying technique, whereas
many glass fibre tissues are made by an air laying technique.
The glass fibres from which the tissue is formed
preferably have a diameter of 10 to 13 microns. m e fibres
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may be continuous fibres that have been broken into lengths
of several centimetres or relatively short fibres, e.g. of
2 centimetres or less.
The preferred tissues of the invention having the
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optimum smoothness, weights, deviations, fibre diameters and
binder contents are commercially available although most glass
tissues commercially available do not have these properties.
The binders used in the tissue may be conventional,
for instance they may be based on acrylic resins, polyvinyl
alcohol or urea formaldehyde resins.
The substrate must include the prescribed continuous
layer of resin on at least one surface, namely the surface
that is to carry the decorative cushioned layer. The resin
is generally a vinyl chloride resin. The layer may be a
preformed layer that is calendered onto the tissue or it - -
may be formed on the tissue from a plastisol. If it is
formed from a plastisol then this plastisol may be spread
as a layer direct onto the tissue or may be spread first
on a release paper, the tissue then being embedded in the -~
layer of plastisol. Either way the plastisol is then
gelled. However, the layer is formed it must be at least
partially impregnated through the tissue from the surface on
which it is applied in order that it bonds securely to the
tissue. Thus, the tissue may have the continuous layer of
resin on one surface and this resin fully impregnates the
tissue from that surface through part of the thickness of the
tissue, but often the tissue will be wholly impregnated with
resinous material, this material either extendin~ all the way
through from a continuous layer on one surface or resinous
material from continuous layers on each surface merging with
one another within the thickness of the tissue. When, as is often
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preferred, there is a continuous layer on each surface it
is generally preferred that each layer shall contain from
150 to 400 g/m2 of resin composition.
One preferred method of forming the substrate from
the tissue comprises coating the glass tissue first on one
side with from 100 to 700, preferably 300 to 500, g/m2 of
a polyvinyl chloride plastisol having a viscosity of 250 to
350 poise and comprising 100 parts PVC, 50 to 100 parts
plasticiser, O to 200 parts filler and pigments, 1 to 5
parts stabiliser and O to 10 parts diluent. Conditions
of application, which may conveniently be by a knife on roller, or
coater,
! knife on jacket, / should be such that only partial
penetration of the tissue, i.e. 20 to 80% of the depth,
and preferably 50% of the depth, occurs. The coated
tissue is then cured by passing it either around a heated
drum or through a hot air oven at 150 to 200C. The
reverse side of the coated material is then coated with
a plastisol of sufficient mobility to penetrate the
tissue sufficiently to contact the previously applied coating
~ through the tissue. m e amount of this coating is
generally from 100 to 500 g/m2, preferably 200 to 400 g/m2.
The plastiæol may be of the same general formulation as
given above but often it is preferred that it should be
slightly less viscous, for instance having a viscosity of
150 to 250 poise.
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Another method of applying the continuous layers
involves coating a plastisol having a viscosity of 150 to
onto a releasing substrate
250 poise and of the general formulation given above/to
form a layer of 100 to 500, preferably 200 to 400 g/m2.
The glass tissue is laid into the wet plastisol and the
assembly cured by passage through a hot air oven at 150 to
200C. ~A plastisol coat, for example of a plastisol
having a viscosity of 100 to 200 poise, is then applied
at a weight of 100 to 400, preferably 150 to 300 g/m2 to
the opposite surface of the tissue and is then cured.
In each of these methods,if desi~ed,the second
coat can be applied to the tissue by a tandem coating
technique before the first coating has been dried and
cured.
In another method,instead of either, but usually instead of
the first, plastisol coating the tissue is calender coated
with a film of 200 to 600 and preferably 300 to 500 g/m2
of a vinyl chloride composition, usually at a temperature
of 150 to 200C.
In any of these coating operations it may in some
instances be desirable to improve the smoothness of the
surface layer by passing it through a facing nip.
The final substrate can easily be made to have a
smoothness, as measured by the Bendsten surface smoothness
tester using an overpressure of 150 mm water gauge, of 500 ml/min.
and below, for instance below 400 ml/min.
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This compares vary fa~ourably with con~entional asbestos
-felts which are in fact often rougher than this. For
instance a typical coated felt at present being used
commercially has a smoothness of 600 ml/min. by this test.
The Bendsten surface smoothness tester is ~anufactured by
H.E. Mesmer.
m e coated substrate normally weighs from 300 to
1200 g/m2 preferably 600 to 1000 g/m2.
A decorative Gushioned ~inyl surface can be of
uniform thickness, the decoration then being due to it
having a uniform or patterned colour, but preferably it
also has a profiled structure. Such a structure may be
made by, for example, printing differing amounts of
foamable composition, and optionally also non-foamable
¦ 15 composition, and then heating the printed product to
cause foaming and to gel the composition, for example
as described in U.S. Specification No.2,920,977. In
another method a foamable composition may be applied
uniformly and material printed on to it, or printed
initially underneath it, to cause preferential foaming
either in the printed or in the non-printed areas upon
~ubsequent heating, for example a~ described in British
Patent Specification No.1,069,998. A wear layer may be
applied before or after foaming. m e wear layer may be
transparent, and thus a multi-coloured pattern printed
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~ ln or on the ioamable layer before or after ioamlng, or on A unl~orm
non-i'oamed layer over that i'oamable layer, will be vlslble through the
wear layer.
Throughout thi~ Speciiication all reierence to vinyl chloride
polymers and PVC are intended to embrace not only polyvinyl chloride
homopolymer but al~o copolymers oi vinyl chlorlde with, ior instance,
vlnyl acetate. All visco~lties are measured by a Brookileld Viscometer
HAT model uslng ~pindle number 6 at 20 r.p.m. and at 25 &.
If deslred a foamable layer can be applled also to the backing
oi the substrate ~o as to give a resilient underlay.
In the iollowlng Examples in every instance the glass iibre
tissue used was that which is supplled by Glaswerk Schuller GmbH under
A thelr de~ignatlon OR50N. Thl~ welghS 51 g/m and 19% of thl~ welght
18 urea iormaldehyde resin whlch i8 impregnated into the tis~ue, the ~-
remainder being gla~ iibre~ which are a~out 13 microns in diameter.
The tissue is a wet laid tl~ue havlng a variatlon in weight over 30
sample~ o~ 100 cm each oi about - 2.2 g/m . The tissue i~ 0.46 mm
thlck as mea~ured by the WIRA Carpet Thlckness Tester under the conditions
as lald down by BS 4051:1972 , but only using one sample ~or each
measurement, with a range in thlckne~ mea~ured at 25 places along a
30 metre roll, oi - 0.02 mm. In the iollowlng
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1046869
Examples the first resin coating and the decorative foamable
layer are always applied onto the smoother of the surfaces !
ExamPle 1
The glass fibre tissue is coated by a knife on a
roller coater, with Plastisol A, applied at 500 g/m2
Plastisol ~ Parts
PVC 1 00
Dioctyl phthalate 100
Whiting 190
TiO2 10
Thiotin heat stabiliser
Viscosity of the plastisol, as measured at 25C
HAT model
with a Brookfield/viscometer, using spindle number 6 at
20 r.p.m, is 295 poise.
(Although a variety of PVC resins may be used,in a
A preferred Example 67 parts Vestolit E8001 and ~3 parts Vinnol
~65V PVC resins are used, these being supplied by Chemische Werke
Huls AG and Wacker-Chemie Gmbh respectively.)
The coated glass tissue is then cured by passage
through an air circulation oven, situated immediately after
the knife and roller coater, at 180C with a dwell time of
150 seconds, and, after leaving the oven, is "faced" by
passage through a smooth rollered nip, before being rolled
up- .
The material is then taken to the front of the
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coating line and re-coated on the second side by a knife
on roller coater with Plastisol B, applied at 300 g/m2.
Plastisol B Parts
PVC (e.g. as in 100
Plastisol A)
Dioctyl phthalate 90
Whiting 190
TiO2 10
Thiotin heat stabiliser
Viscosity depressant 5
(e.g. Nopco 5221/L)
White spirit -8
Viscosity of the plastisol, measured as Plastisol A,
- is 240 poise. ("Nopcd'is a Trade Mark of the Diamond ShamrocX
Chemical Co.)
The æecond coat of PVC plastisol is cured by passage
through an air circulation oven in the same manner as the
first coat, is "faced" and finally rolled up to give a sub-
strate weighin~ about 850 g/m2 and having a smoothness of
350-360 Bendsten units.
Exam~le 2
` 20A A release paper (for example Multikas ~type 446,
; supplied by Wiggins Teape) is coated by knife on roller
coater with Plastisol C, applied at 400 g/m2.
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Plastisol C Parts
PVC (e.g. as in Plastisol A) 100
Dioctyl phthalate 67
Whiting 125
TiO2 25
Thiotin heat stabiliser
Viscosity Depressant 5
White Spirit 8
Viscosity of the plastisol, measured at 25C with a
HAT model
Brookfield/viscometer, using spindle number 6 at 20 r.p.m.,
is 295 poise.
Immediately after the coater, the glass tissue is
laid into the wet coating using a laminating roll working
at low pressure to press the glass tissue into intimate
contact with the wet coating.
The laminate i8 then passed through an air cir-
culation oven at 180C for 150 seconds in order to cure
thé plastisol, faced whilst still hot by passage through
a smooth rollered nip and rolled up, when cool, prior to
further processing into a floor co~ering or other surface
co~ering material, whilst still attached to the release
paper.
amPle 3
As an extension of method of manufacture of
Example 2, a further coat of Plastisol D, application
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weight 200 g/m2, is applied to the glass tissue side of
the cured laminate by knife on roller coating, the plastisol
being cured in an air circulation oven at 180C for 150
seconds and then faced while still hot by passage through
a hot smooth rollered nip.
Plastisol D Parts
PVC 100
Dioctyl phthalate 70
Whiting 90
TiO2 10
m iotin heat stabiliser
- Nopco 5221/L 5
White Spirit 8
Viscosity o* the plastisol measured as quoted in
Example 2, is 150 poise. (The PVC may be 60 parts Quirvil~
~A 268 and 40 parts Corvic XP60/68 from Rumianca SpA and I.C.I.
respectively.)
After being cooled, the glass tissue reinforced
vinyl layer is removed from the release paper substrate
prior to further processing.
ExamPle 4
: The glass tissue is calender coated with the
following formulation, at 400 g/m2.
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Parts
PVC 100
Dioctyl phthalate ~3
Ground limestone 125
TiO2 12
Ba/Cd liquid stabiliser 3
Hydrogenated castor oil 1-5
Stearic Acid
A (The PVC may be Scon~5300, from Vinyl Products.)
Calender roll temperatures of 170C to 180C are
used.
The coated glass tissue is re-coated on the glass
side, by Plastisol D, applied at 300 g/m2 by knife on
roller coater. Following coating, the composite is cured
by passage through an air circulation oven at 180C with a
dwell time of150 seconds, faced whilst hot by passage
through a smooth rollered nip, cooled down and rolled up
prior to use in further processes.
ExamPle 5
- The reinforced vinyl layer from Example 1 is coated
on the side initially coated with 500 g/m2 Plastisol A, by
reverse roll coater with 200 g/m of a chemically foamable
PVC plastisol such as any of the foamable compositions
described in British Patent Specification No.1,069,998.
The viscosity of the piastisol, measured with a
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Brookfield HAT model viscometer at 25C, using a number 6
spindle at 20 r.p.m., is 20 poise.
The coating is fused at 160C, a temperature at which
the coating can be gelled without decomposing the blowing
agent, by passage through an air circulation oven.
- The coated material is printed using solvent based
inks on a gravure printing press, some of the inks optionally
containing an inhibiting agent for the foaming reaction
(following the teaching of British Patent 1,069,998 and British
Patent 1,069,999) if texture is required in the end product.
The printing material is then overcoated by reverse
roll coater using a plastisol, which cures to a hard trans- .. -
parent wear layer film, giving protection to the print layer
in the fin~shed product.
The viscosity of this plastisol, measured as quoted
in Example 1, is 20 poise. The application weight is 160 g/m2.
After application of this plastisol, the material is
passed through an air circulation oven at 200C to cure the
, coating and to cause.foaming to occur. After leaving the hot
air circulation oven, the material is cooled down before being
rolled up. The finished product weighed approximately 1200
g/m and had a thickness, in non-debossed areas, of 0.045 inches.
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