Note: Descriptions are shown in the official language in which they were submitted.
I
yield of the Invention
The present invention relates to a process for the preparation of a
composite mat having smooth upper and lower faces comprising a mat of fibrous
material encapsulated within a resinous polymeric gel.
Backgro no of reinvention
The process of the present invention is intended for use in the
preparation of vinyl sheet goods as surface coverings and the like,
particularly floor coverings. By virtue of the superior properties of a
product prepared by the present process however, the process has application in
a number of other areas.
Traditionally, vinyl sheet goods for use as floor coverings and the
like have been prepared by coating a backing web or substrate with a liquid
resinous polymeric ccm~osition which is processed into the flooring material.
A useful description of the process appears in United States Patent 3,293,094
to Cairn, Harking, Ehrenfeld and Tallow. Same kind of substrate is neon swerve
during the processing of the liquid resinous composition, and may be integrated
into the final product or stripped away. If the substrate is included in the
final product it will add strength an dimensional stability.
For some years the material most commonly employed for this substrate
was a petrochemical impregnated asbestos fiber mat. However, asbestos has
recently been linked to various health hazards and its continued availability
as a raw material for the asbestos felts useful for -this purpose is
estionable .
Research into various alternative materials which can be employed for
this purpose has been carried out, but most of the materials tested have been
functionally unsuitable. Others, showing marginal technical Seiko so, would
have required extensive and costly changes to process equiF~ent in order
to implement their use.
For reasons of economy, one of the avenues explored was the creation
of a composite mat by impregnating a fibrous mat with the printable resinous
polymeric material itself. While the initial testing on convention machinery
was successful in producing a composite mat with a printable surface, irregular
variations in the thickness of the golfed polymer were encountered. Where
formable plastisol was used, these irregular variations were magnified in
further processing of the material, particularly where such further processing
resulted in incomplete foaming of the plastisol where such irregularities were
located. Further, the opposite surface was often uneven with errant, non-
encapsulated fibers, which would obstruct roper adhesion in flooring uses. An
additional problem encountered was incc~plete interstical filling of the mat.
United States Patent 4,138,521 to Brawn shows a substrate for vinyl
floor coverings which comprises a smooth, non-woven tissue of glass fibers
bonded within a synthetic binder. At least one surface of the substrate
contains a continuous layer of resin at least partially impregnating into the
surface. This reference does not contemplate the us of a formable
plastisol and the process described would not seem to be usable for this
purpose. Since the depth to which the resin impregnates the tissue is not
controlled, wide variations in thickness would be expected when the material
ore foamed. Further, no attempt is made to encapsulate the glass tissue as in
the process of the present invention. Rather, the second surface would be
separately coated with a layer of resin in a repetition of the demonstrated
process. Without some additional teaching with respect to how all voids in the
tissue could be filled, a teaching unnecessary to the use of non-foamed
resins with which the reference is concerned, the process could not be made
applicable to formable plastisols.
I
Summary of the Present Invention
cording to the present invention there is
provided a process for the preparation of a formable
composite mat having a smooth and printable first surface
and a smooth and adorably opposite surface which formable
composite mat may be foamed to a uniform expanded thickness
and which composite mat comprises a fibrous mat encapsulated
within a formable, printable resinous polymeric gel which
process comprises providing a supply of suitable fibrous
mat material; combining a controlled amount of a formable,
liquid resinous polymeric composition with the fibrous mat
material in such a manner that the formable liquid permeates
into and through the interstices of the fibrous material
and coats both surfaces of the fibrous mat, wherein the
formable liquid resinous polymeric composition is capable
of forming a printable resinous polymeric gel at a suitable
temperature, thereby providing a formable liquid resinous
polymeric composition saturated fibrous mat having a uniform
thickness; providing a suitable environment for the gellation
of the formable liquid resinous polymeric composition, the
suitable environment for the gellation of the formable
liquid resinous polymer composition consisting of a heated,
rotary drum at least partially enclosed with a seamless belt;
and maintaining the Embowel liquid saturated fibrous mat
within the suitable environment for a sufficient period of
time to golf the formable liquid resinous polymer composition
to produce a fibrous mat encapsulated within a formable and
printable resinous polymeric gel.
. .
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Brief Description of the Drawings
_~____
The Figure represents, in diagramic form, the process of the present
invention.
Detailed Description of the Present I've lion
.
It has now been fount that a composite mat having a smooth and
printable first surface and a smooth and adorably opposite surface , which
composite mat is suitable for use in vinyl sheet goods such as flooring and the
like, can be prepared employing essentially standard process machinery.
In structure, the composite mat prepared by the process of the
present invention is not substantially different in appearance from the
substrate previously employed. In the structure of that substrate, fibers of
asbestos or another fibrous material normally in the form of a non-woven mat,
are impregnated with a petrochemical. Such a non-w~ven asbestos fiber mat
old be structurally suitable for use in the present invention and might be
preferable but for the present focus of health inquiries. Various other woven
and non-woven fibrous materials may be employed and these might include
fiberglass, polyester, polypropylene, armed, rayon or ox Lyle. In fact, any
natural or man-made organic or inorganic woven or non-woven continuous porous
mat compatible with the plasticizer or other solvent system Gould be employed
in the practice of the present invention. This list would be narrowed
somewhat by process considerations, such as the temperatures to which the
composite material would be subjected in later processing. At present,
however, the preferred material for this purpose would be non oven fiberglass
mat because of its availability, temperature characteristics and cost.
It should be apparent that the fibrous mat material need not be
formed into a mat prior to being combined with a liquid resinous polymeric
composition, as a sufficient quantity of stable fibers to form a mat in situ
could first be mixed into a suitable liquid resinous polymeric composition.
I
Then, the resulting mixture Gould be metered onto a storable substrate or
backing web. This procedure has not yet been implemented commercially because
it would require greater modification of processing emanate, but is intended
to be included within the process as presently descried and defined in the
claims.
The confute of utilizing a preformed mat lies in the fact that it
can be introduced into the process from a supply roll and will simulate the
function of a backing web or substrate. This fibrous mat can be introduce d
into the present process in much the same fashion as the substrate material had
keen introduce d in the process of the prior art. The thickness of the pro-
formed mat of fibrous material will defend to a large extent upon the
particular product to be made and the Particular subsequent use for which it is
intended. Normally such thicknesses are in the range of about seven miss to
about twenty mill, but other thicknesses, especially those creator than
twenty-five miss, may be used in particular circumstance s.
In the figure, the process of the present invention is illustrated
diagrammatically as two). A preformed mat of fibrous material (12) is drawn
from a su~plv, such as a roll of such material (14) illustrated, and conveyed,
as by drive rollers (16), into the process (10). Tension on the supply roll,
and other processing parameters can be used to determine the ratio of the
thicknesses of the plastisol coating on each foe of the mat.
A resinous polymeric composition, of the kind which will form a
printable polymeric gel is then combined with the fibrous material. There is
substantial literature with respect to the formulation of a printable
polymeric gel, and the reader is referred to such literature for the teaching
no ox scary to the formulation of a suitable polymeric composition for any
specific purpose. Such resinous polymeric compositions may be made by well-
known standard and conventional methods and may contain one or more polymer or
oopolv~er of vinyl chloride or other resin.
Other constituents of such resinous polymeric compositions include: a
blowing or foaming agent, such as azodicarbonamide, if a blink or foaming
agent is desired; various aloe lerator/stabilizers or catalysts such as dibasic
lead phthalate, zinc octet, zinc oxide, lead octet, dibasic lead phosphate,
etc., various light and/or heat stabile us and metallic soaps; plasticizers
as ductile phthalate, bottle bouncily phthalate, dibutyl subacute, etc.; coloring
agents and pigments, such as titanium dioxide; solvents and delineates, such as
methyl ethyl kiter, mineral spirits, etc.; fillers, such as clay and
limestone; and many other conventional and well-known additives and improvement
agents.
Although a polymer or copolymer of vinyl chloride in the form of a
plastisol is the referred and typical synthetic resin to be incorporated into
the resinous polymer ocmFosition, many other resins are equally applicable, not
only in plastiso~ form but also in organosol, latex or solvent form. The
specific resin and its particular form of use, do not relate to the essence of
the inventive cone pi and many other suitable resins are set forth in the prior
art.
The resinous polymeric composition is also preferably a dispersion of
a synthetic resin in a liquid medium, since the viscosity of the resin system
must be few enough to permit the resin to be prosody into and through the
fibrous material. Suitable viscosities for the resin system would be from
about five hundred cycles per second (500 cups) to about twenty-five thousand
cycles per second (25,000 cups), with viscosities in the range of fifteen
hundred cycles For second (1500 cups) to five thousand cycles per second (5000
cups) being preferred. The dispersion medium can be a plasticizer in the case
of a plastisol, or water in the case of an aqueous latex, or it can be an
organic solvent in the case of an organosol. Excellent results are obtained
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with a dispersion of a synthetic resin in a plastic or as a plastisol and such
form is the Preferred and typical form for the application of the present
invention.
A few preferred and typical plastic us useful in forming such
plastisols are dibutvl socket, dioctvl subacute, ductile adipate, didecyl
adipate, ductile a late, dibutyl phthalate, dip privily phthalate, ductile
phthalate, diabetics ethyl phthalate, tricresyl phosphate, ~ctyl diphenyl
phosphate, dipropylene glvcol dikenzoate, bottle bouncily subacute, dikenzyl
subacute, dibenzyl phthalate and bottle bouncily phthalate.
It is also to be appreciated that, although plastisols will be used
to further describe the invention and in the Example which follows, such is not
intended to exclude the use of organosols or aqueous latexes which are also
utilizable.
Also, azodicarbonamide is indicated herein as the preferred and
typical blowing or foaming agent to he included in the resinous polymeric
composition when blowing or foaming is desired or required, and is employed in
the Example which follows. however, many other similar blowing or foaming
agents are also applicable and within the principle of the present invention.
The specific blowing or foaming agent which is employed will be determined by
such considerations as cost, availability and physical properties of the
desired finished product. A number of aloe twill blowing or foaming agents are
well-known to the prior art. All that is required in the practice of the
present invention is that the blowing or foaming agent remain unrequited during
the process of golfing the resinous polymeric composition. For most resin
systems, gellation will occur at an elevated temperature, and the blowing or
foaming agent must have a deoomFosition temperature which is sufficiently high
that it will not be activated or decomposed prematurely during the golfing
process. It might also be noted that the blowing or foaming agent must also
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remain unrequited during any other preliminary steps, such as heating or
mechanical embossing, or the like.
In a similar way, Mooney other aloe aerators, initiators, catalysts,
viscosity improvers, light and heat stabilizers, dyes, pigments, plasticizers,
antioxidant, fillers, bacteriostats and bacterioci~es, and many other
additives may be included in the resinous polymeric composition. The specific
nature and the particular physical and chemical properties and characteristics
of the various constituents of the resinous polymeric composition should not be
seen as limiting the nature of the present invention, and further elaboration
of such additives is believed Anne ox scary. The use of these various classes of
additives as well as specific compounds for specific purposes, is well known to
the art.
In the illustrated embodiment, a resinous polymeric composition (18)
contained in reservoir (20) is introduced across the width of the moving pro-
formed mat (12). This material may be deposited by gravity flaw, if the
reservoir is properly located, or by some kind of pumping action. as necessary.
A suitable amount of this deposited resinous polymeric composition (22) is
allowed to accumulate uniformly across the width of the preformed mat (12),
and this deposited resinous composition (22) is then metered by some means,
such as by drawing the preformed mat (12) between the combination of a
doctoring blade (24) and pressure roller (26), as illustrated. This operation
results in a uniform layer of the viscous liquid resinous polymeric composition
(28) being deposited on the fibrous mat (12).
One the liquid resinous polymeric composition (28) and fibrous mat
(12) have teen prepared in such a manner, they are conveyed into a thermal
environment suitable for golfing the liquid polymeric composition. One
apparatus suitable for the creation of such an environment is shown as (30) in
Fig. 1, and comprises a rotating heated drum (32), at least one pressure roller
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(34), a surrounding belt (36), and several tensioning rollers (38).
In the precut ox of the present invention, the Lydia resinous polyp
metric composition (28) and fibrous mat (17~ are brought into intimate contact
with the outer surf ox of the notating heated drum (32). Preferably, this is
done at a point where a pressure roller (34) and the drum (32) create a nip
~40) into which the fibrous mat (28) is drawn by the rotation of the drum, as
indicated by the arrow (42). The effect of this nip (40) prevents the unwanted
inclusion of air pockets which may result in voids and thus damage the finished
product. The drum is preferably crated with a suitable release agent and
maintained at a temperature suitable for golfing the liquid Plastisol.
Throughout the reside ox period, lye., that period of time during which the
liquid resinous polymeric composition (28) and fibrous mat (12) remain in
thermal contact with the outer surface of the rotating heated drum (32), a
sufficient quantity of heat is transferred to transform the resinous
camFosition from a liquid to a gel.
It should be noted that this period of temperature transfer is
critical for several reasons. First, the temperature of the rotating drum
cannot be too great or the liquid resinous composition will edge molten and
adhere to the drum. Yet the temperature must not be too GUY or the residence
time required for the thermal transfer no ox scary to effect gellation will not
be achieved at necessary operating speeds. Uniformity of thermal transfer and
isolation of the thermal environment is greatly assisted by the presence of the
surrounding belt I Belts of a similar apron ox have been employed with
processing equipment of this kind previously, but the purpose for such use was
to maintain a suitable tension during lamination of dissimilar materials.
In the present invention, the use of such a belt may serve as a molding
functionality as well. Applicants are not aware of the employment of such a
belt in contact with a liquid resinous polymeric composition, nor are they
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aware of the previous use of a belt wide enough for use in the preparation of
vinyl sheet goods such as floor coverings. While it was useful to keep the
belt employed in the process herein described in tension, it also assisted in
creating a uniform thermal environment suitable for the efficient heat transfer
neon scary to eel the liquid resinous polymeric composition by en~elGping the
saturated mat during the residence period in thermal contact with the heated
drum.
Allure pressure rollers (44) may be employed to assist in
maintaining the no ox scary contact between the fibrous mat I and the heated
drum (32). In addition, such rollers, if utiliæd, assist in maintaining a
uniform thickness and help to insure consolidation of errant fibers within the
polymeric gel.
After the resinous polymeric composition gels to produce a printable
gel, which no encapsulates the fibrous mat, the fibrous mat encapsulated
within the printable polymeric gel (46) is drawn off the heated drum (32) and
it is useful to pass the encapsulated mat (46) over one or more chill rollers
(48) to reduce the temperature of the product.
The cooled, encapsulated mat may be further processed immediately
after preparation, as by rotogravure printing and heating to chemically emboss
the polymeric gel in a manner well known to the art. However, in general and
in the diagrammatic process illustrated here, the cooled, encapsulated mat is
taken up in a storage roll (50) for later use.
It should ye apparent to those skilled in the art that a suitable
thermal environment can be created in other ways, and various alternatives acme
to mind. In this regard, a fibrous mat can be conveyed through a reservoir of
suitable resinous polymeric composition and then squeezed by suitable nip
rollers to provide a suitable saturated mat. To provide an environment for
gellation of the resinous polymeric composition this saturated mat could then
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be drawn through a thermal environment, such as an oven, preferably a vertical
oven where the effects of gravity ma be avoided. Pairs of pressure rollers
could be provided on each side of the saturated fibrous mat during its trawl
as no ox scary to assist in consolidating and collaborating the celled product.
An elaborate embodiment of such an alternative would include the use of two
endless belts of the kind described above which would be used to encase the
saturated mat, one covering each foe , during the period of thermal transfer.
The present invention is shown more clearly in the following
illustrative example.
Example
A non-woven g]ass-fiber mat was obtained oammercially and processed
according to the steps of the present invention. The mat employed weighed
approximately fifty grams For square meter (50 g/m2) of which approximately
twenty Perle nut (20~) represented the weight of urea-formaldehyde which
impregnated the fiber mat as a binder. The individual glass fibers varied from
approximately eight microns to approximately thirteen microns in thickness and
from about one and two-tenths ox ntimeters (1.2 cam.) to abut two and five-
tenths ox ntimeters (2.5 cam.) in length. The mat itself was a wet laid
fiberglass tissue available commercially from the Johns-Manville Corporation
and marketed under the trademark "Duraglass."
From a supply roll holding approximately eight thousand square yards
of the fibrous material, a one hundred and forty-seven inch wide web was taken
into the prove so at a rate of twenty inches For second (on inset This
fibrous material was coated with a formable and printable resinous polymeric
composition in the form of a plastisol, the composition of which is set out in
Table I below. This Plastisol was fed by gravity from a reservoir and
dispensed across the width of the fibrous mat. The mat was then drawn through
a slit-llke opening of t~enty-five thousandths of an inch (0.025")
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Jo hod by the combination of a doctor blade and a pressure roller. This
combination is effective both in metering the amount of plastisol added and in
promoting saturation of the fibrous mat by Helen to forte the plastisol into
and through the interstices of the fibrous mat.
TABnr~
parts per hundred parts
of resin
_
Vinyl Chloride Dispersion Resin
(coon 123 - BY Goodrich Chemical Group) 66
Vinyl Chloride Extender Resin
(Gccdvear M 70L*- Goodyear Chemical Kiwi 34
Primary Plasticizer
(Plasticizer Sly -
Monsanto Polymer Products Company, Inc.) 44
Secondary Plasticizer
(Plasticizer S452 -
Monsanto polymer Products Company, Ionic if
Calcium Carbonate Filler
(Passaic White B - RYE. Carroll Co.) 80
Blowing Agent
(Azodicarbonamide & Zinc Oxide) 5
Cell S illusory
~-103 - Air Products & Chemicals, Inc.)
Viscosity Depressant
(Hanukkah POW - Diamond-Shamrock Chemical Company) 1.5
Delineate *
(Aromatic 150 - Sun Chemical Co.) 2
The thus-saturated fibrous material mat was then conveyed into
contact on the foe of an oil-filled, heated, rotary drum supplied by the
Olbrich Company and commonly employed in the manufacture of vinyl sheet goods.
or this kind of use such a drum is preferably coated with a release agent, and
the drum employed here was coated with a silicone release agent available
ocmm~rcially from the Moray Chemical Company under the trademark "Bavsilone."
*trade mark
, . -:
I,
For the purpose of the present process this equipment had been fitted with a
thirteen foot-wide endless belt similar in design to the narrow pressure belts
commonly employed in pre~arinq laminates with this equipment. The belt
employed in this instance, however, was specially manufactured by the Globe
Albany Division of Albany International, Northern America, located in sulfa
New York and had its entire working foe , i.e., that face which would be in
contact with liquid plastisol saturated fibrous mat, with a layer of silicone
rubber having a thickness of one hundred and twenty miss. to prevent adhesion
of the plastisol.
This endless belt passed over a pressure roller set in contact with
the surface of the heated drum and the liquid plastisol-saturated fibrous mat
was conveyed into the nip formed between the knelt and the drum. Tension on the
endless belt thereafter kept the plastisol saturated mat in intimate contact
with the drum during its rotation.
The oil-filled drum employed was maintained at a constant temperature
of 140C. throughout the process of the present invention in a manner well
known to the art. In addition, the drum was rotated at a speed of four and
eighty-five one hundredths revolutions per minute (4.R5 rev/min)O During the
residence period, lye., that period during which the plastisol saturated mat is
in thermal contact with the drum, the temperature of the plastisol was brought
to a level where gellation of this plastisol c~nposition would occur, somewhere
from approximately 110C. to 140C., and was maintained at that level.
Residence time within this enviror~nent was approximately nine seconds and was
sufficient to gel this plastisol material.
The gel-encapsulated fibrous mat thus formed was taken off the drum
and passed through a series of three chill rollers maintained at a temperature
of 25 & . before king taken up by a storage roll.
On inspection, thy gel-encapsulated fibrous mat was of generally
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uniform thickness and had a smooth and printable first surface and a smooth and
adorably opposite Syria . In addition, the product showed little or no
evidence of voids and no errant fibers were detectable.
Other features, advantages and specific embodiments of this invention
will become readily apparent to those exercising ordinary skill in the art
after reading the foregoing disclosures. These specific embodiments are within
the scope of the claimed subject matter unless otherwise expressly indicated to
the contrary. Moreover, while specific embodiments of this invention have been
described in considerable detail, variations and modifications of these
embodiments can be effected without departing from the spirit and score of this
invention as disclosed and claimed.
