U.S. patent application number 09/782036 was filed with the patent office on 2001-10-11 for method for manufacturing a floor covering.
Invention is credited to Basler, Rolf, Geraghty, John Joseph, Hinds, Terence Martin.
Application Number | 20010028127 09/782036 |
Document ID | / |
Family ID | 11041577 |
Filed Date | 2001-10-11 |
United States Patent
Application |
20010028127 |
Kind Code |
A1 |
Hinds, Terence Martin ; et
al. |
October 11, 2001 |
Method for manufacturing a floor covering
Abstract
A method for manufacturing a floor covering involves leading a
glass fiber matt 1 from a supply reel 2 onto a conveyor belt 3. At
a first scattering station 4, a saturation material is scattered
onto the matt 1 to form a scattered layer. The matt 1 is then led
between upper and lower heated belts 10, 11 to gel the scattered
layer. The belts are then passed between a pair of
smoothing/nipping rollers to form a layer of uniform thickness. The
belts are then cooled and the matt 1 with saturation layer applied
is wound for further processing. In an alternative arrangement a
saturation material is scattered directly onto a substrate belt at
the first scattering station 4, a glass fiber matt 26, is applied
over the scattered material and, at a second scattering station 28,
an amount of the saturation material or a different material is
scattered onto the matt 26.
Inventors: |
Hinds, Terence Martin;
(Maynooth, IS) ; Geraghty, John Joseph;
(Celbridge, IS) ; Basler, Rolf; (Mullingar,
IS) |
Correspondence
Address: |
SUGHRUE, MION, ZINN, MACPEAK & SEAS, PLLC
2100 PENNSYLVANIA AVENUE, N.W.
WASHINGTON
DC
20037-3213
US
|
Family ID: |
11041577 |
Appl. No.: |
09/782036 |
Filed: |
February 14, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
09782036 |
Feb 14, 2001 |
|
|
|
09141326 |
Aug 27, 1998 |
|
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Current U.S.
Class: |
264/126 |
Current CPC
Class: |
D06N 3/06 20130101; B29C
43/30 20130101; B29C 43/48 20130101; B29C 2043/483 20130101; D06N
3/0088 20130101 |
Class at
Publication: |
264/126 |
International
Class: |
D04H 001/54 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 27, 1998 |
IE |
970633 |
Claims
1. A method for manufacturing a floor covering comprising the steps
of: scattering powder, granules or pellets of a thermoplastic
material onto a substrate to form a coating; leading the coating
between a pair of belts; applying heat to gel the coating between
the belts; smoothing the gelled coating to provide a layer of
desired thickness; and cooling the layer.
2. A method as claimed in claim 1, wherein the substrate is a fibre
matt material, especially a glass fibre matt material.
3. A method as claimed in claim 2, wherein the fibre matt has less
than 100 g of glass fibre per m.sup.2 of material.
4. A method as claimed in claim 3, wherein the fibre matt has less
than 65 g of glass fibre per m.sup.2 of material.
5. A method as claimed in claim 4, wherein the fibre matt has from
30 to 50 g of glass fibre per m.sup.2 of material.
6. A method as claimed in claim 1 wherein the gelled coating is
smoothed by leading the gelled coating between a nipping means.
7. A method as claimed in claim 6 wherein the nipping means
comprises a pair of nip rollers defining a gap therebetween.
8. A method as claimed in claim 7 including the step of adjusting
the gap between the nip rollers.
9. A method as claimed in claim 1 comprising the steps of:
scattering powder, granules or pellets of thermoplastic material
onto a first substrate to form a first coating; applying a second
substrate over the first coating; scattering powder, granules or
pellets of a thermoplastic material onto the second substrate to
form a second coating; leading the coatings between a pair of
belts; applying heat to gel the coatings between the belts;
smoothing the gelled coatings to provide a layered product of
desired thickness; and cooling the layered product.
10. A method as claimed in claim 9 wherein the first substrate is
defined by a lower of the conveyor belts.
11. A method as claimed in claim 9 wherein the second coating is of
the same material as the first coating.
12. A method as claimed in claim 9 wherein the second coating is of
a different material to the first coating.
13. A method as claimed in claim 9 wherein the first coating is of
a saturation material to form, on heating, a saturation layer.
14. A method as claimed in claim 9 wherein the second coating is of
a basecoat material to form, on heating, a basecoat layer.
15. A method as claimed in claim 1 wherein the thermoplastic
material is scattered to form, on heating, a saturation layer to
receive a basecoat layer.
16. A method as claimed in claim 1 wherein the thermoplastic
material is scattered to form, on heating, a basecoat layer.
17. A method as claimed in claim 16 wherein the basecoat is formed
by a method including the steps of: scattering a basecoat-forming
material onto the saturation layer of the substrate; leading the
substrate between a pair of belts; and applying heat to the belts
to form a basecoat layer on the saturation layer.
18. A method as claimed in claim 1 wherein a substrate is defined
by one of the heating belts.
19. A method as claimed in claim 1 including the steps of:
scattering a first thermoplastic material onto a first belt;
applying a substrate over the thermoplastic material; scattering a
second thermoplastic material onto the substrate; leading the
substrate with the first and second thermoplastic material under a
second belt; and applying heat to the belts to gel the
thermoplastic material to form a backing layer on one face of the
substrate and a saturation or basecoat layer on the other face of
the substrate.
20. A method as claimed in claim 19 wherein the second layer is a
saturation layer and the method includes the steps of: scattering a
third thermoplastics material over the saturation layer; leading
the substrate between a pair of belts; and applying heat to the
belts to gel the third thermoplastic material to form a basecoat
layer on the saturation layer.
21. A method as claimed in claim 1 including the step, after
heating, of leading the substrate over a smoothing roller prior to
cooling, preferably the substrate is supported on one of the belts
as it is led over the smoothing roller, preferably the method
includes the step of heating and/or cooling the substrate as it is
led over the smoothing roller, preferably the substrate is heated
or cooled by heating or cooling the smoothing roller, preferably
the substrate is led over an infeed roller to the smoothing roller,
preferably the substrate is led over an outfeed roller from the
smoothing roller, preferably the substrate is heated or cooled as
it is led over the infeed and/or outfeed rollers.
22. A method as claimed in claim 1 wherein the substrate is cooled,
after gelling, by leading the pair of belts through a cooling
station.
23. A method as claimed in claim 1 wherein the substrate is a
mineral felt.
24. A floor covering whenever manufacturing by a method as claimed
claim 1.
Description
INTRODUCTION
[0001] The invention relates to a method for manufacturing a floor
covering and in particular to a method for manufacturing a
polymeric, for example, a vinyl floor covering.
[0002] In conventional manufacturing processes for cushion vinyl
floor covering, a glassmat tissue or mineral felt is used as the
base carrier material. In a first step in the process, the glassmat
tissue is saturated with a PVC plastisol material which is applied
to the mat using a knife and/or application roller. The plastisol
is then gelled on a hot chrome plated drum to provide a smooth
solid surface.
[0003] A basecoat in the form of a foamable plastisol is applied
using a knife or roller to a coating thickness of typically 300
g/m.sup.2. This basecoat is also gelled on a hot gel drum to
produce a smooth surface which is suitable for printing. A design
is then printed on the gelled basecoat, typically using a
rotogravure method in which a design/coloration is printed using a
sequence of printing cylinders. To provide an embossed finish, one
or more of the cylinders applies an inhibitor in a desired pattern.
The inhibitor inhibits foam expansion.
[0004] A topcoating in the form of a clear PVC plastisol is then
coated on top of the print layer and the topcoating is gelled on a
hot gel drum. The layered product thus formed is then heated in an
oven at typically 190.degree. C. which causes the basecoat foam
layer to expand in all areas except where the inhibitor has been
applied. The PVC plastisol also fuses at this temperature to give a
clear hard resilient surface finish.
[0005] A backing layer in the form of a PVC plastisol is coated
onto the product. The backing may be of a foamable material. If
desired, the surface of the floor covering thus formed may be
toughened by applying a crosslinkable polyurethane or acrylic
lacquer.
[0006] There are a number of problems with such manufacturing
techniques. In particular, there is an ever increasing need to
minimise production and raw material costs, to minimise use of
environmentally unfriendly material while optimising product
quality.
[0007] There is therefore a need for an improved cost effective
method for producing floor covering.
STATEMENTS OF INVENTION
[0008] According to the invention, there is provided a method for
manufacturing a floor covering comprising the steps of:
[0009] scattering powder, granules or pellets of a thermoplastic
material onto a substrate to form a coating;
[0010] leading the coating between a pair of belts;
[0011] applying heat to gel the coating between the belts;
[0012] smoothing the gelled coating to provide a layer of desired
thickness; and
[0013] cooling the layer.
[0014] In a particularly preferred embodiment of the invention, the
substrate is a fibre matt material, especially a glass fibre matt
material. Preferably, the fibre matt has less than 100 g, ideally
less than 65 g and most preferably from 30 to 50 g of glass fibre
per m.sup.2 of material. This material is easily handled in roll
form and provides the required reinforcing strength.
[0015] In an especially preferred embodiment of the invention, the
gelled coating is smoothed by leading the gelled coating between a
nipping means.
[0016] Ideally, for ease of use the nipping means comprises a pair
of nip rollers defining a gap therebetween. Preferably the method
includes the step of adjusting the gap between the nip rollers. In
this way the process is readily tailored to a desired final
product.
[0017] In one embodiment of the invention the method comprises the
steps of:
[0018] scattering powder, granules or pellets of thermoplastic
material onto a first substrate to form a first coating;
[0019] applying a second substrate over the first coating;
[0020] scattering powder, granules or pellets of a thermoplastic
material onto the second substrate to form a second coating;
[0021] leading the coatings between a pair of belts;
[0022] applying heat to gel the coatings between the belts;
[0023] smoothing the gelled coatings to provide a layered product
of desired thickness; and
[0024] cooling the layered product.
[0025] In one case the first substrate is defined by a lower of the
belts. Alternatively or additionally the second substrate is a
fibre matt substrate as defined above.
[0026] For some applications the first and second coatings may be
the same. For example, the coatings may be of a saturation material
to provide a highly efficient saturation layer in which the
substrate matt is impregnated from both sides.
[0027] Alternatively, the coatings may be of a different material.
For example, the first coating may be of a saturation material and
the second coating may be of a basecoat material. The advantage of
such an arrangement is that two layers may be formed in one pass
through the heating section.
[0028] In both cases, if required, the or each coating may be
pre-heated by means of an infra red heater or the like.
[0029] The material may be scattered to form, on heating, a
basecoat layer. The basecoat is preferably a foamable layer,
typically formed using a blowing agent mix of azodicarbonamide and
zinc oxide.
[0030] Preferably, the basecoat is formed by a method including the
steps of:
[0031] scattering a foamable basecoat-forming material onto the
saturation layer of the substrate;
[0032] leading the substrate between a pair of belts; and
[0033] applying heat to the belts to form a basecoat layer on the
saturation layer.
[0034] In one embodiment of the invention, a substrate is defined
by one of especially the lower of the belts.
[0035] Preferably, the method includes the steps of:
[0036] scattering a first thermoplastics material onto a first
belt;
[0037] applying a substrate over the first thermoplastics
material;
[0038] scattering a second thermoplastics material onto the
substrate;
[0039] leading the substrate with the first and second
thermoplastics materials under a second belt; and
[0040] applying heat to the belts to gel the thermoplastics
material to form a backing layer on one face of the substrate and a
saturation or basecoat layer on the other face of the
substrate.
[0041] In one embodiment of the invention, the second layer is a
saturation layer and the method includes the steps of:
[0042] scattering a third thermoplastics material over the
saturation layer;
[0043] leading the substrate between a pair of belts; and
[0044] applying heat to the belts to gel the third thermoplastics
material to form a basecoat layer on the saturation layer.
[0045] Preferably, after heating, the substrate is led over a
smoothing roller prior to cooling. Ideally, one of the belts as it
is led over the smoothing roller.
[0046] In one embodiment of the invention, the method includes the
step of heating and/or cooling the substrate as it is led over the
smoothing roller.
[0047] Preferably, the substrate is heated or cooled by heating or
cooling the smoothing roller.
[0048] In a preferred arrangement, the substrate is led over an
infeed roller to the smoothing roller. Preferably, the substrate is
led over an outfeed roller from the smoothing roller.
[0049] In one embodiment of the invention, the substrate is heated
or cooled as it is led over the infeed and/or outfeed rollers.
[0050] Preferably, the substrate is cooled after gelling by leading
the pair of belts through a cooling station.
[0051] In another embodiment of the invention, the substrate is a
mineral felt. In this case, a saturation layer is typically not
required and a basecoat material is applied directly to the
substrate.
[0052] In this specification basecoat layer refers to the layer
which is subsequently printed. The basecoat is preferably of a
foamable material.
[0053] The invention also provides a floor covering whenever
manufactured by the method of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0054] The invention will be more clearly understood from the
following description thereof, given by way of example only, with
reference to the accompanying drawings, in which:
[0055] FIG. 1 is a diagrammatic side elevational view of apparatus
used in the method of the invention.
[0056] FIG. 2 is a diagrammatic side elevational view of an
apparatus of FIG. 1 used in a method for manufacturing a floor
covering according to the invention in one arrangement of use;
[0057] FIGS. 3 to 5 are cross sectional views of a layered floor
covering product at various stages in the method of FIG. 2;
[0058] FIG. 6 is a diagrammatic side elevational view of the
apparatus of FIG. 1 in another arrangement of use;
[0059] FIGS. 7 to 9 are cross sectional views of a layered floor
covering product at various stages in the method of FIG. 6;
[0060] FIG. 10 is a perspective view of part of the apparatus of
FIG. 1;
[0061] FIG. 11 is a side elevational view of the apparatus of FIG.
10;
[0062] FIG. 12 is a perspective view of another part of the
apparatus of FIG. 1;
[0063] FIG. 13 is a side elevational view of the apparatus of FIG.
12;
[0064] FIG. 14 is a perspective view of a smoothing roller part of
an alternative apparatus; and
[0065] FIG. 15 is a plan view of the apparatus of FIG. 14.
DETAILED DESCRIPTION
[0066] Referring to FIGS. 1 and 2 of the drawings, there is
illustrated an apparatus used in a method for manufacturing a floor
covering according to the invention. A substrate 1, in this case in
the form of a glass fibre matt material having 30 to 50 g/m.sup.2
of glass fibre material is led from a supply reel 2 onto a lower
conveyor belt 3. At a first scattering station 4, a material is
scattered in a curtain 5 onto the glass fibre matt substrate 1 to
form a scattered layer 6.
[0067] The fibre matt substrate 1 with the scattered layer may then
be passed without any further layers being applied between an upper
belt 10 and a lower belt 11 of a thermofixing oven unit 12. The
belt 11 forms a continuation of the belt 3. The oven unit 12 is a
heated low pressure double belt press which applies heat to the
scattered layer 6 and glass fibre matt 1 to bind the non woven
glass matt to the scattered layer 6. In this case the oven unit
comprises a number of upper and lower sections 13, 14. The
operating temperature of each section or groups of sections 13, 14
may be varied.
[0068] After heating, the substrate supported between the upper and
lower belts 10, 11 is led between a pair of nipping rollers 15, 16
to smooth the gelled coating to provide a layer of desired
thickness.
[0069] The gelled layered substrate is then cooled between the pair
of belts at a cooling station 17. The cooling station 17 comprises
a plurality of top and bottom cooling sections 18, 19, the
operating temperature of which may be adjusted in groups or
individually. The layered substrate 30 may then be wound onto a
take-up reel 40.
[0070] Further layers may be scattered onto the gelled substrate by
leading the substrate through the apparatus again as described
above or through another similar apparatus arranged in series.
[0071] Alternatively or additionally, and referring particularly to
FIGS. 6 to 10 at a second substrate applying station 25, a
substrate such as a fibre matt 26 may be applied over the first
scattered layer either before or after heating. One or more further
layers may be formed by scattering a dry blend material onto the
second substrate 26 at a second applying station 28 upstream of the
heating oven 12. In this way, any desired layer structure may be
built up. An infra red heater 27 may be used to heat the first
scattered layer and/or substrate in advance of oven heating and
second scattering.
[0072] In one case, the scattered material forms, on heating, a
saturation layer to receive a basecoat material. Alternatively or
additionally, the material is scattered to form, on heating, a
foamed basecoat layer.
[0073] The basecoat may be formed by scattering a foamable basecoat
material onto the saturation layer of the substrate, and heating
the dry blend to form a foamed basecoat layer.
[0074] Referring particularly to FIGS. 6 to 10 the substrate may be
defined by one of the heating belts 3, 11. In this case, a first
material may be scattered onto the first belt 3, 21 at the first
scattering station 4, a substrate 26 applied over the first coating
and a second coating applied over the substrate 26 from the second
scattering station 28. The substrate with the first and second
scattered layers is then led under the second belt 10 and the
layered product is heated to gel the coatings. For example, a
backing layer may be formed on one face of the substrate and a
saturation or basecoat layer on the other face of the
substrate.
[0075] In another case, the second layer is a saturation layer and
the method includes the steps of scattering a further coating over
the saturation layer and heating the third coating to form a
basecoat layer on the saturation layer.
[0076] The material that is scattered on the substrate may be in
any suitable form such as powder, granules or pellets. A blended
powder may be extruded to produce a fully fused compound which is
then pelletised and in some cases pulverised. Such pellets have the
advantage that they are more easy to control and are less adherent
to the belts generally than powders. Thus, a more controlled
scattering, higher processing speed and a more uniform product may
be achieved. Typically the pellets are from 0.5 to 2 mm diameter,
preferably about 1 mm, and from 1 to 2 mm long, preferably about
1.5 mm. The pulverised particles are generally in the 100 to 500
micron range.
[0077] Preferably the belts are at least coated with a release
material such as a silicone-based material and/or Teflon or the
like material.
[0078] In an alternative or additional arrangement illustrated in
FIGS. 14 and 15 the gelled coating may be smoothed or further
smoothed by leading the substrate supported on the lower belt 11
over a large diameter smoothing roller 20. To optimise the
operation of the smoothing roller 20, the substrate is first led
over an infeed roller 21 on the infeed side and is led over an
outfeed roller 22 at the outfeed side of the smoothing roller
20.
[0079] The substrate may be heated or cooled by circulating a
heating or cooling fluid through the smoothing roller 20.
Similarly, a heating or cooling fluid may be circulated through the
infeed and/or outfeed rollers 21, 22.
EXAMPLE 1
[0080] A glass fibre matt material having 50 g/m.sup.2 of glass
fibre material is used as the substrate.
[0081] A saturation layer forming dry blend of the following
formulation was used. The dry blend may be in the form of a powder
or in the form of granules or the like material.
1 Parts by Weight Suspension Grade PVC 100 Di-2-Ethyl Hexyl
Phthalate 40-60 Butyl Benzyl Phthalate 10-30 Calcium Carbonate
Filler 100-160 Barium/Zinc Stabiliser 2-3
[0082] At a first scattering station, an amount of typically 200
g/m.sup.2 of the saturation dry blend is applied on a substrate
belt. The glass fibre matt is then applied over the scattered
material as described above and at a second scattering station an
amount of typically 200 g/m.sup.2 of the saturation dry blend is
scattered on top of the fibre matt. We have found that by splitting
the saturation material and applying it top and bottom as
described, a matt with a high level of saturation and a smooth
surface finish is achieved. Alternatively, an amount of 350
g/m.sup.2 of the saturation dry blend may be applied to the top of
the fibre matt at only one scattering station.
[0083] The substrate is then passed between heated belts at a
temperature typically in the range of 180.degree. C. to 200.degree.
C. at a residence time in heating of typically one minute.
[0084] The heated layered substrate is passed between nip rollers
and then cooled by passing between a pair of cooling belts which
are maintained at typical process water conditions. The residence
time in cooling is typically one minute.
[0085] A glass fibre matt with a smooth surface top and bottom is
formed in a highly cost efficient manner which may be processed
further using conventional techniques or by passing through the
same oven unit or another similar unit arranged in series.
EXAMPLE 2
[0086] A foamed basecoat material may be applied to a saturated
substrate using the following basecoat dry blend formulation:
2 Parts by Weight Suspension Grade PVC 95-100 Dispersion Grade PVC
0-5 Di-2-Ethyl Hexyl Phthalate 20-50 Butyl Benzyl Phthalate 20-50
Calcium Carbonate Filler 20-80 Barium/Zinc Stabiliser 1.5-3.5
Blowing Agent Mixture 2-4 (Azodicarbonamide/Zinc Oxide) Titanium
dioxide 6-10
[0087] The foamable basecoat material is scattered onto the
saturated substrate at a single scattering station at a rate of
from 250-450 g/m.sup.2 and further processed as described above in
Example 1.
[0088] It will be appreciated that the method is applicable to
producing non directional homogeneous floor covering materials.
[0089] It will also be appreciated that while the invention has
been described particularly in relation to PVC material it may also
be applied to any suitable thermoplastics materials which are
substantially free of PVC.
[0090] Many variations on the specific embodiments of the invention
described will be readily apparent and accordingly the invention is
not limited to the embodiments hereinbefore described which may be
varied in detail.
* * * * *