Note: Descriptions are shown in the official language in which they were submitted.
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TITLE
A METHOD OF IMPARTING STAIN RESISTANCE TO A
DIFFERENTIALLY DYEABLE TEXTILE SURFACE AND
THE ARTICLE PRODUCED THEREBY
BACKGROUND OF THE INVENTION
Field of the Invention The invention relates to a
continuous method for treating a textile surface made of
differentially dyeable nylon yarns with a stainblocker
composition to impart stain resistance thereto, and to the
article produced thereby.
Description of the Prior Art In the industrial
production of articles having a textile surface thereon, such
as a broadloom carpet or carpet tiles, it is common to treat
such articles with a composition to impart added desirable
properties thereto, such as resistance to staining by a
variety of agents, e.g. foods or beverages. Some especially
troublesome stains are coffee, black tea and red wine.
In the industrial production of such articles it is also
common to use differentially dyeable nylon yarns. By the term
"differentially dyeable" it is meant that the article contains
yarns having at least two different dyeabilities, such as acid
dyeable yarn and cationic ("cat") dyeable yarn. Often a
desired aesthetic effect in a carpet is possible only by
combining yarns of these two different dyeabilities. Both
dyeabilities are available in various dye depths, such as
light, regular, deep and extra deep acid dye and light and
regular cat dye.
Compositions referred to as "stainblockers" are commonly
applied to non-differentially dyeable carpets or carpet tiles
to impart stain resistance.
There is presently available both a continuous process
and a discontinuous, or batch-wise, process for applying a
stainblocker composition to a carpet made of non-
differentially dyeable yarns.
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Continuous Conventional Process The steps of a
conventional process for applying a stainblocker composition
to a textile surface (such as a broadloom carpet) made of non-
differentially dyeable yarns are listed in Figure 3. In the
conventional continuous process a running line of colored
carpet (colored as by dyeing or printing), after rinsing and
suction hydroextraction, is passed through an aqueous liquid
treatment bath containing a stainblocker composition and a
surfactant. The temperature of the bath is in the range from
twenty to sixty degrees Celcius (20 to 60 C). The residence
time of the carpet in the bath is usually not adjusted as an
independent critical parameter but is instead a function of
the speed of the carpet line. After removal from the bath the
carpet passes through a steam chamber wherein it is exposed to
saturated steam for about sixty to ninety (60 to 90) seconds.
Thereafter, conventional finishing steps for the carpet
typically include: a suction hydroextraction operation where
residual liquid is vacuumed from the carpet; a cold water
rinse operation (either by spraying or passing the carpet
through a dip trough); another suction hydroextraction
operation; and a final drying.
Batch-wise Conventional Process The batch-wise process
for applying the stainblocker composition and a surfactant to
a textile surface made of non-differentially dyeable yarns
(such as a broadloom carpet) is termed the "winch/beck"
process. In the batch-wise winch/beck process discrete dyed
carpets are immersed in a vat having a bath including a
stainblocker composition and a surfactant. The temperature of
the bath in the batch-wise winch/beck process is slightly
higher than in the continuous process, in the range from
seventy to seventy-five degrees Celcius (70 to 75 C), and the
residence time in the bath is on the order of twenty minutes.
After removal from the bath, the carpet is subjected to the
conventional finishing steps such as rinsing with cold water
in situ, or after unloading from the hot application bath,
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rinsed by spray bar followed by a vacuum extraction operation
to ensure no residual stainblocker is left.
In both the continuous process and the batch-wise process
the stainblocker composition is preferably of the anionic
functionalized type, and more preferably, of the sulphone
resole type having nonionic functionality.
Tile Production To produce carpet tiles treated with a
stainblocker composition it is common practice first to treat
a broadloom carpet with a stainblocker composition in one of
the manners specified, and after a backing is applied, to cut
the broadloom carpet into pieces of the desired size to form
carpet tiles.
Stainblockers Suitable anionic functionalized type
stainblocker compositions include sulphonated phenol
formaldehyde condensate types, maleic acid anhydride types,
acrylate dispersions and mixtures thereof. Anionic
functionalized type stainblocker compositions should be
present between three weight percent (3 wt%) and five weight
percent (5 wt.%) based on the weight of the nylon carpet
fiber. When anionic functionalized type stainblocker
compositions are used, the pH of the bath must be adjusted to
between 2 and 5.
Examples of commercially available anionic functionalized
type stainblocker compositions are available from E. I. Du
Pont de Nemours and Company, Wilmington, Delaware, under the
trademarks SR 300, SR 400 and SR 500; from Du Pont de Nemours
International S. A., Geneva, Switzerland, under the trademark
NRD 334; from Allied Colloids, Bradford/West Yorkshire, U.K.,
under the trademark Alguard RD; and from Bayer AG, Leverkusen,
Germany, under the trademark Baygard DT.
When sulphone resole type stainblocker compositions with
nonionic functionality are used, they should be present at
between four weight percent (4 wt. %) and six weight percent
(6 wt. %) based on the weight of the nylon carpet fiber, and
the pH must be adjusted to between 6 and 7.5. An example of a
commercially available sulphone resole type stainblocker
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composition with nonionic functionality is available from E.
I. Du Pont de Nemours and Company, Wilmington, Delaware under
the trademark Zelan 8236.
The pH of the treatment bath may be adjusted by known
acid donor additives such as acetic acid, citric acid and
sulfamic acid.
Surfactants A surfactant may be added to the
stainblocker bath separately or may be included as part of the
stainblocker composition. The surfactant may be anionic,
amphoteric or nonionic in nature. Preferably, the surfactant
used will be either an alkylated diphenyl oxide disulfonate
sodium salt, alone or in combination with an alkylnaphtalene
sulfonic acid formaldehyde condensate sodium salt. The
surfactant is generally added to the bath at a rate of between
one (1) and four (4) grams per liter. Suitable surfactants
are available from E. I. Du Pont de Nemours and Company,
Wilmington, Delaware under the trademark Zelan 50; from Dow
Chemical Company, Midland, Michigan, under the trademark
Dowfax 3B2; or from BASF AG, Ludwigshafen, Germany, under the
trademark Primasol NF.
Problem With Conventional Methods for Differentially
Dyeable Textile Surfaces Unfortunately, when either the
continuous process or the batch-wise process is used to apply
a stainblocker composition to a broadloom carpet containing
differentially dyeable yarns the cationic dyestuff "bleeds"
from the cat dyeable yarn into the surrounding stainblocker
treatment bath, resulting in an unacceptable visual color
change.
Low Liquor Method The only publicly known system to
apply a stainblocker composition to a differentially dyeable
carpet is a method known as the "low liquor" method. Using
the "low liquor" method a differentially dyeable carpet may
attain at least a modest degree of stain resistance. In the
"low liquor" method a cold-foamed liquor including a
stainblocker composition and a fluorocarbon material are co-
applied topically to the carpet. Thereafter the carpet is
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dried, without steam or water rinse. In the past, the
stainblocker composition typically utilized was the acrylate
dispersion sold by 3M Corporation under the trademark "FX-
661", while the fluorocarbon material typically utilized was
those sold by 3M Corporation under the trademarks "FC-3611",
"FC-3602" or "FC-1395". However, the low liquor method is
useful only with a carpet having a very low "wet pick-up", on
the order of fifteen to twenty percent (15-20%). Wet pick-up
(wpu) is the ratio of the weight of the liquid picked-up by
the carpet from a treatment bath to the weight of the carpet.
Moreover, with the low liquor method, the stainblocker
composition penetrates into only about the upper twenty-five
percent (25%) of the height of the pile elements of a
differentially dyeable carpet. This depth of stainblocker
penetration is not believed to be sufficient to impart a high
degree of stain resistance.
Accordingly, in view of the foregoing, it is believed
advantageous to provide a process for treating an article
having a textile surface containing differentially dyeable
nylon yarns, such as a broadloom carpet or carpet tiles, to
impart a high degree of stain resistance thereto, while
maintaining good color stability.
SUMMARY OF THE INVENTION
In a first aspect the present invention is directed to a
continuous method for treating an article having a textile
surface made of differentially dyeable nylon yarns with a
stainblocker composition to impart stain resistance thereto.
This method (the "hot shock" method) comprises the sequential
steps of:
(a) dyeing the textile surface of the article with an
acid dyestuff and a cationic dyestuff;
(b) passing the textile surface of the article through a
bath containing a stainblocker composition and a
surfactant, the bath having a temperature in the
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range from seventy to ninety-five degrees Celsius
(70 to 95 C), the textile surface remaining in the
bath for about five (5) to about thirty (30)
seconds;
(c) removing excess water from the textile surface of the
article;
(d) passing the article through an ambient temperature
zone; and
(e) rinsing the textile surface of the article with
water, and thereafter suctioning and drying the
same,
such that substantially the entire textile surface of the
article is coated with a stainblocker composition, whereby the
textile surface has a stain resistance of 9 or higher on the
AATCC Red 40 Stain Scale.
Preferably, the excess water is removed by passing the
textile article through a pair of nip rolls to control the
level of wet pick-up between two hundred and six hundred
percent (200-600%). The textile article preferably remains in
the cooling zone for twenty (20) to one hundred twenty (120)
seconds.
In the instance where the article is a pile surface
structure having a plurality of pile elements, substantially
the entire height of each pile element is coated with the
stainblocker composition whereby the pile surface structure
has a stain resistance of 9 or higher on the AATCC Red 40
Stain Scale.
In this method, if the stainblocker composition is of the
sulphone resole type having nonionic functionality (as is
preferred) the stainblocker composition is present between
four percent (4%) and six percent (6%) based on the weight of
the nylon yarns, and the pH of the stainblocker bath is
between six (6) and seven and one-half (7.5). Alternatively,
if the stainblocker composition is of the anionic
functionalized type, such as that selected from the group
consisting of sulphonated phenol formaldehyde condensate type,
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maleic acid anhydride type, acrylate dispersions and mixtures
thereof, the stainblocker is present between three percent
(3%) and five percent (5%) based on the weight of the nylon
yarns; and the pH of the stainblocker bath is between two (2)
and five (5).
-0-0-0-
In another embodiment the present invention is a method
(the "infra-red" method) of treating articles having a textile
surface (such as broadloom carpets or carpet tiles) with a
stainblocker composition to impart stain resistance thereto.
The textile surface of the articles may be made of either
differentially dyeable nylon yarns or acid-dyeable nylon
yarns.
The textile surface of the article is colored with acid
dyestuffs and cationic dyestuffs (in the case of an article
made of differentially dyeable nylon yarns) or with acid
dyestuffs (in the case of an article made of acid-dyeable
nylon yarns). The coloring may be accomplished either by
dyeing or by screen or spray printing. After coloring, this
embodiment of the method comprises the sequential steps of:
(a) applying a stainblocker composition to the textile
surface of the article, the stainblocker composition
having a temperature from twenty to ninety-five
degrees Celsius (20 to 95 C);
(b) drying the article in a drying zone having a
temperature in the range from seventy-five degrees
Celsius to ninety-five degrees Celsius (75-95 C)
for a time sufficient to allow the stainblocker
composition to react with the nylon yarn in the
textile surface; and
(c) rinsing the textile surface of the article with
water, and thereafter drying the same,
such that substantially the entire textile surface of the
article is coated with a stainblocker composition whereby the
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textile surface has a stain resistance of 9 or higher on the
AATCC Red 40 Stain Scale.
A broadloom carpet (with the backing thereon) may be cut
into pieces to form carpet tiles either before or after it is
colored, or after the final drying step.
When the article is in the form of carpet tiles, the
tiles lay loosely upon and are conveyed by a transport belt
through the stainblocker application. For carpet tiles the
stainblocker composition is applied using a flood process by a
flood applicator. Broadloom carpets may be transported by any
suitable transport mechanism and the stainblocker composition
can be applied by any appropriate application device.
Preferably, the drying zone of step c) uses infra-red
energy to dry the textile article. Preferably, the
temperature of the drying zone is in the range from eighty
degrees Celsius to eighty-five degrees Celsius (80-85 C).
In this method, if the stainblocker composition is of the
sulphone resole type having nonionic functionality (as is
preferred) the stainblocker composition is present between one
and one-half percent (1.5%) and six percent (6%), and more
preferably, between two percent (2%) and three percent (3%),
based on the weight of the nylon yarns. The pH of the
stainblocker bath is between six (6) and seven and one-half
(7.5). Alternatively, if the stainblocker composition is of
the anionic functionalized type, such as that selected from
the group consisting of sulphonated phenol formaldehyde
condensate type, maleic acid anhydride type, acrylate
dispersions and mixtures thereof, the stainblocker is present
between one percent (1%) and five percent (5%) based on the
weight of the nylon yarns; and the pH of the stainblocker bath
is between two (2) and five (5).
-0-0-0-
In another aspect the invention is directed an article
having a textile surface formed from at least two types of
dyeable nylon yarns. At least one type of nylon yarn is
dyeable by an acid dyestuff and at least one other type of
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nylon yarn is dyeable by a cationic dyestuff. In accordance
with the present invention the textile surface of the article
is coated with a stainblocker composition such that the
textile surface has a stain resistance of 9 or higher on the
AATCC Red 40 Stain Scale. In a preferred embodiment the
article takes the form of a pile surface structure wherein the
textile surface is defined by a plurality of upstanding pile
elements formed from the two types of dyeable nylon yarns.
Substantially the entire height of each pile element is coated
with the stainblocker composition.
The dyeable nylon yarns may be bulked continuous
filament yarns or staple spun yarns. The pile elements
may be formed in such a way that each pile element
includes both a nylon yarn dyeable by an acid dyestuff
and a nylon yarn dyeable by a cationic dyestuff.
Alternately, the pile elements may be formed such that at
least some of the pile elements are formed from a nylon
yarn dyeable by an acid dyestuff and at least others of
the pile elements are formed from a nylon yarn dyeable by
a cationic dyestuff.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be more fully understood from the
following detailed description thereof, taken in
connection with the accompanying drawings, which form a
part of this application and in which:
Figure 1 is a side view of a pile surface structure
in accordance with the present invention;
Figures 2A and 2B are respective schematic
representations of the steps of methods for treating an
article having a textile surface with a stainblocker in
accordance with the present invention, wherein the
representation (Figure 2A) of the "hot shock" process of one
embodiment of the present invention extends along the upper
edge of the drawing sheet, while the representation (Figure
2B) of the "infra-red" process of another embodiment of the
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present invention extends along the lower edge of the drawing
sheet; and,
Figure 3 is a block diagram representation of a
conventional method for applying a stainblocker composition to
a textile surface made of non-differentially dyeable yarns;
and
Figures 4A and 4B are respective schematic
representations of the steps of methods for treating an
article having a textile surface with a stainblocker in
accordance with the present invention, wherein the steps of
the "hot shock" process (Figure 4A) of one embodiment of the
present invention extend along the left hand side of the
drawing sheet, while the steps of the "infra-red" process
(Figure 43) of another embodiment of the present invention
extend along the right hand side of the drawing sheet.
DETAILED DESCRIPTION OF THE INVENTION
Throughout the following detailed description similar
reference numerals refer to similar elements in all figures of
the drawings.
The present invention is broadly directed to methods for
applying a stainblocker composition to any article having a
textile surface to impart stain resistance thereto and to
articles produced thereby. The textile surface may be one
that is formed from at least two types of dyeable nylon yarns.
At least one type of nylon yarn is dyeable by acid dyestuffs
and at least one other type of nylon yarn is dyeable by
cationic ("cat") dyestuffs. A textile surface that contains
yarns having at least two different dyeabilities, such as
cationic dyeable yarn and acid dyeable yarn, is termed
"differentially dyeable". Alternatively, the textile surface
may be "acid-dyeable", that is, a surface that is formed only
from nylon yarns that are dyeable using acid dyestuffs.
In accordance with the present invention the textile
surface of the article is coated with a stainblocker
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composition such that the textile surface has a stain
resistance of 9 or higher on the AATCC Red 40 Stain Scale.
The most preferred form of an article 10 in accordance
with the present invention is illustrated in Figure 1. In
Figure 1 the article 10 is embodied by a carpet 10C whose
textile surface 12 is defined by a plurality of upstanding
pile elements 12P. The pile elements 12P extend above a
backing 14. The carpet 10C may be a full broadloom size, or
(once the backing is applied) may be cut into the form of
"carpet tiles". As is appreciated by those in the art,
"carpet tiles" are, in the typical case, generally square
pieces of carpet having dimensions on the order of fifty-by-
fifty centimeters (50 x 50 cm.). Of course, tiles may take
other shapes and exhibit any desired range of sizes.
As the result of treatment of the carpet 10C (in either
broadloom or tile form) with either embodiment to be described
herein, substantially the entire height 12H of each pile
element 12P has a coating 16 of a stainblocker composition
thereon. It should be noted that although in practice the
coating 16 of stainblocker composition would be invisible, for
purposes of illustration the presence of the coating 16 is
represented in Figure 1 by relatively bold lines on the
contours of the pile elements 12P.
Since the textile surface 12 of the carpet 10C
illustrated in Figure 1 is defined by the plurality of
upstanding pile elements 12P, the carpet 10C is hereinafter be
referred to as a "pile surface structure". This nomenclature
serves to distinguish the illustrated pile surface structure
10C from alternative forms of carpet structures in which the
textile surface is defined by a textile fabric. These
alternative forms of carpet structures also lie within the
contemplation of the invention. An example of one such
alternative form of carpet structure is the carpet disclosed
in International Publication WO 97/01665 (Vinod).
The pile elements 12P defining the textile surface of the
pile surface structure 10C may be either cut pile (as
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illustrated in the right hand portion of Figure 1) or loop
pile (as illustrated in the left hand portion of Figure 1).
The pile elements 12P may be produced by any suitable known
carpet forming process, such as tufting, weaving or knitting.
In the case of a differentially dyeable pile surface
structure, each pile element 12P, however produced, may be
comprised entirely of either acid dyeable nylon yarns or cat
dyeable nylon yarns. Alternately, each pile element 12P may
comprise a combination of both acid dyeable nylon yarns or cat
dyeable nylon yarns. The nylon material may be nylon 6,6 or
nylon 6 or any of the various copolymers thereof. The yarn is
either a bulked continuous filament yarn or a staple spun
yarn.
In the case of an acid-dyeable pile surface structure
each pile element 12P in the pile surface structure 10C is
formed only from nylon yarns that are dyeable using acid-dye.
The backing 14 for the pile surface structure 10C may be
implemented using any convenient materials. A preferred
backing construction is a synthetic latex/chalk filler
compound.
-0-0-0-
A first embodiment of the method of the present
invention, termed the "hot shock" process, by which the pile
surface structure 10C (or the textile surface of any article)
is treated with a stainblocker composition will now be
described in connection with the schematic representation of
Figure 2A and the corresponding block diagram representation
of Figure 4A. This embodiment of the process of the present
invention is implemented in a continuous, as opposed to batch-
wise, manner.
After being made using any known carpet-forming process
the undyed pile surface structure 10C is dyed in a dye bath 20
containing both cationic dyestuffs and acid dyestuffs. The
cat dyeable nylon yarns and the acid dyeable nylon yarns that
form the pile elements 12P are each colored by the appropriate
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dyestuff so that both types of yarns may contribute to the
visual aesthetic properties of the pile surface structure 10C.
The process conditions for the dye bath 20 are suitable
for the dyes chosen for use. Some commercially available acid
dyes that may be suitable for use in the dye bath 20 include
those sold by Ciba Specialty Chemicals, Inc., Basel,
Switzerland, under the trademark Tectilon; by DyStar
Textilfarben, Leverkusen, Germany under the trademark Telon;
by Clariant (Switzerland) Ltd., Basel, Switzerland under the
trademark Nylosan; and by Crompton & Knowles, Charlotte, North
Carolina, under the trademark Nylanthren. Some commercially
available cationic dyes that may be suitable for use in the
dye bath 20 include those sold by Ciba Specialty Chemicals,
Inc., Basel, Switzerland, under the trademark Maxilon; by
DyStar Textilfarben, Leverkusen, Germany, under the trademark
Astrazon; by Clariant (Switzerland) Ltd., Basel, Switzerland,
under the trademark Sandocryl; and by Crompton & Knowles,
Charlotte, North Carolina, under the trademark Sevron.
After dyeing, the pile surface structure 10C passes
through a cold water rinsing step 21 and a hydroextraction
step 22 to remove residual dyes and chemicals. Any
conventional arrangement for suctioning liquid from a carpet
may be used to perform the hydroextraction step. Both these
steps are similar to corresponding steps of the continuous
process of the prior art. If dyeing of the pile surface
structure occurs at an earlier time, the pile surface
structure must be prewet (as at the water rinsing step 21) and
the water extracted (as at step 22) before the stainblocker is
applied.
After hydroextraction the pile surface structure 10C
passes through a hot aqueous liquid treatment bath 24
containing a stainblocker composition and a surfactant.
Although the same stainblocker compositions and surfactants as
are used in the conventional continuous process as earlier
described are used in the treatment bath 24, it has been found
that if the temperature of the treatment bath 24 and dwell
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time of the pile surface structure 10C therein are in accord
with the teachings of the present invention bleeding of
cationic dyestuff from the cat dyeable yarn does not occur.
In accordance with the present invention the temperature
of the hot treatment bath 24 is in the range from about
seventy to about ninety-five degrees Celsius (70 to 95 C).
More preferably, the temperature is in the range from about
eighty to about ninety degrees Celsius (80 to 90 C). The
temperature of the hot bath 24 is maintained by direct or
indirect heating with automatic control. A suitable system
useful for the application step 24 is that manufactured under
the name "hot shock applicator" by Eduard Kuesters
Maschinenfabrik GmbH & Co. KG, Krefeld, Germany, comprising a
low volume dip trough and a steam-supplied plate heat
exchanger with electronic temperature control.
The pile surface structure 10C should remain in the bath
24 for a residence time in the range from about five (5) to
about thirty (30) seconds, and more preferably, in the range
from about ten (10) to about fifteen (15) seconds.
As to the stainblocker compositions themselves, sulphone
resole type stainblocker compositions with nonionic
functionality (in the appropriate weight percentages and with
appropriate pH adjustment) are preferred. Anionic
functionalized type stainblocker compositions (also in the
appropriate weight percentages and with appropriate pH
adjustment) may also be used. As earlier discussed the pH of
the treatment bath may be adjusted by known acid donor
additives such as acetic acid, citric acid and sulfamic acid.
Preferred surfactants again include appropriate amounts of an
alkylated diphenyl oxide disulfonate sodium salt, alone or in
combination with an alkylnaphtalene sulfonic acid formaldehyde
condensate sodium salt.
When the stainblocker composition is of the sulphone
resole type having nonionic functionality the stainblocker
composition is present between four percent (4%) and six
percent (6%) based on the weight of the nylon yarns, and the
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pH of the stainblocker bath is between six (6) and seven and
one-half (7.5).
After exiting the hot treatment bath 24 excess water is
removed from the pile surface structure 10C. To this end the
pile surface structure 10C passes through a pair of nip rolls
26. Preferably, the rolls 26 adjust the wet pick-up of the
pile surface structure 10C to between two hundred percent
(200%) and six hundred percent (600%) and more preferably, to
about three hundred percent (300%). The pressure between the
nip rolls 26 may be varied in order to find the optimal wet
pick-up for a given carpet construction and process.
Expedients other than nip rolls may be used to remove the
excess moisture.
Thereafter, the pile surface structure 10C passes through
an ambient temperature zone 28 in which the pile surface
structure 10C cools toward the ambient air temperature.
Preferably, the pile surface structure 10C remains in the
cooling zone 28 for between twenty (20) to one hundred twenty
(120) seconds, and more preferably, between twenty (20) to
forty (40) seconds. It should be noted that in accordance
with this invention the pile surface structure 10C is not
subjected to a steaming step, as in the prior art continuous
process.
After undergoing treatment in the hot bath 24 and cooling
in the air cooling zone the pile surface structure 10C is
subjected to the conventional finishing steps normally used in
the continuous immersion process of the prior art. Such
finishing steps would include a suction operation 30, a cold
water rinse operation 32, and another suction operation 34.
Finally, the pile surface structure 10C is dried in an oven 36
and collected by a take-up roll 38.
EXAMPLES 1-3
Test Methods The following test methods were used in the
Examples 1-3 below to measure carpet samples made according to
the "hot shock" embodiment of the invention as well as control
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samples for stain resistance, color stability and
dyelightfastness.
Kool-Aid Soft Drink Stain Resistance Standard Test
(Standardized AATCC Test Method 175-1991: Red 40 Stain Rating
Scale) This impact tester method simulates a "household
accident" with a spill dropped from table height onto a
carpet.
Staining Agent: The staining agent is a ninety (90) gram
per thousand (1000) cc water solution of cherry-flavored,
sugar-sweetened Kool-Aid soft drink. The solution is
permitted to reach room temperature (22 2 C) before use.
An alternative staining agent is a solution containing 0.1
gram/liter FD&C Food Red 40 dyestuff, one (1) gram/liter
citric acid, and ten (10) gram/liter sugar.
Equipment: A specially designed impact tester is used to
apply the staining agent to the specimens under test. The
impact tester comprises a cylinder (of plastic or glass) that
is 28 cm high with a 6.5 cm inside diameter. A massive piston
nine (9) cm in length weighing four hundred (400) grams is
received on the inside of the cylinder. The piston is made
from a plastic material (PVC or PTFE). The piston is
vertically movable within the cylinder by a bolt fitted to the
piston. The bolt projects through a four (4) mm vertical slot
in the cylinder. A small (seven (7) mm diameter) hole is
drilled through the cylinder two cm from the bottom for
injecting staining agent.
Procedure: Test samples, measuring ten (10) cm square,
are cut from each pile surface structure under test. The
impact tester is centered on each sample and the plastic
piston lifted and fixed in position by the bolt in the slot.
Using a syringe twenty (20) cc of the staining agent is
injected through the small hole over the surface of the
sample. The plastic piston is released and drops freely onto
the carpet sample. The impact corresponds to the impact of a
cup of liquid falling from the table height [eighty (80) cm].
The impact tester is removed and the sample is left,
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undisturbed, in a horizontal position for twenty-four (24 4)
hours. Without damaging the pile, the sample is rinsed
thoroughly with tap water at about twenty degrees Celsius (20
C), centrifuged to remove any excess water and dried in a
forced air oven at maximum of seventy-five degrees Celsius (75
C).
Each sample is evaluated for staining, using the AATCC
Red 40 Stain Scale. According to this scale stains are rated
on a scale of 1 to 10, with "1" designating heavy staining and
"10" designating no staining. A sample receiving a rating of
"9" is considered to have acceptable stain resistance.
Coffee Stain Resistance Standard Test This test is
substantially identical to the Kool-Aid soft drink test,
except that the staining agent is a twenty gram per liter
(20 g/1) solution of an instant coffee (e.g. Nescafe(D
Gold coffee, with no additives such as milk, cream or
sugar) at a temperature of sixty degrees Celsius (60 C).
Color Measurement Color measurements were made using the
international standard color measurement method promulgated by
"Commission Internationale de L'Eclairage" (Paris, France),
(International Society for Illumination/Lighting), ("CIE")
using standard color coordinates of both the CIELAB L*a*b* and
the CIELAB L*C*h color space: "L" designates the lightness
coordinate; "a" designates the red/green coordinate (+a
indicating red, -a indicating green); "b" designates the
yellow/blue coordinate (+b indicating yellow, -b indicating
blue); and "C" designates the chroma coordinate, the
perpendicular distance from the lightness axis (more distance
indicating more chroma).
Dyefastness Dyelightfastness is measured according to
standardized test method DIN 54004 (ISO 105 B02). This method
is based on scale of 1 to 8, according to standardized
"bluescale" of eight different blue wool dyestuffs, dyed on a
wool fabric, which are joint into the light exposure process
together with the test specimen (1-very poor, 8-very high
lightfastness).
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EXAMPLES 1-3 The pile surface structure in Example 1 and
Controls la-1c were a loop construction containing three
different filament yarn types having regular cationic, light
cationic and deep acid dyeabilities. The deep acid dyeable
yarns were dyed green. The regular and light cationic dyeable
yarns were dyed orange in two color steps.
Control la was treated by conventional batch-wise
winch/beck process. Control lb was treated by conventional
continuous application. Control lc is an untreated control
carpet. Example 1 was treated by the method of the present
invention. The temperature of bath was eighty-five degrees
Celsius (85 C), the residence time of the article in the bath
was ten (10) seconds, and the time in the ambient temperature
zone was thirty (30) seconds.
In Example 1 and Controls la-lb the stainblocker
composition was ZELAN 8236 (DuPont) and the surfactant used
was ZELAN 50 (DuPont). The stainblocker composition was
applied at 5.5% of pile weight and pH values were adjusted
with acetic acid. Control la was treated for twenty minutes
at pH 6.8 and at a temperature of 75 C. Control lb was
treated at pH 6.8 and steamed afterwards. The wet pick-up was
400%. Example 1 was treated as described above at a pH of
6.8. Control is was not treated in order to compare color
stability and dyelightfastness.
After treating with the stainblocker composition Example
1 and Controls la-lb were water rinsed, hydroextracted and
dried. After dyeing, Example 1 and Controls la-lb were each
tested for color stability and dyelightfastness by the test
methods described above. The results are reported in Table 1.
As can be seen from Table 1 Example 1 shows smallest
deviation in color saturation (C* values). Also, the
dyelightfastness resulting from each application method was
good.
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TABLE 1
No. L* a* b* C* Dyelightfastness
Control 46.74 -1.09 +10.39 10.45 5-6
la
Control 46.70 -1.44 +13.09 13.17 5-6
lb
Example 46.43 -1.95 +14.74 14.87 5-6
1
Control 46.31 -2.15 +15.78 15.96 6
lc
Example 2 and Controls 2a-2c The pile surface structure
in Example 2 and Controls 2a-2c was a velour construction
containing four different filament nylon yarn types having
regular acid, extra deep acid, regular cationic and light
cationic dyeabilities. The pile surface structure was dyed to
grey and orange colors. The regular acid dyeable yarn was
light gray, the extra deep acid dyeable yarn was dark gray,
the regular cationic dyeable yarn was dark orange, and the
light cationic dyeable yarn was light orange. Example 2 and
Controls 2a-2c were performed exactly as Example 1 and
Controls la-1c. After dyeing, the carpet sample pieces were
each tested for stain resistance using both the Kool-Aid soft
drink stain resistance test and the coffee stain resistance
test. The results are reported in Table 2. The results show
little difference between the samples, also the stain resist
properties of Example 2 are the best overall.
Due to the special fine four component color pattern in
this carpet, a color measurement could not be done, the
samples were only visually compared.
TABLE 2
Kool-Aid Coffee
Control 2a 10 9-10
Control 2b 10 9
Example 2 10 10
Control 2c 1 1
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Example 3 and Controls 3a-3c These examples demonstrated
the application of stainblocker compositions on cationic
dyeable nylon carpets. Example 3 and Controls 3a-3c were
performed exactly as Example 1 and Controls la-1c. In Example
3 and Controls 3a-3c the pile surface structure was a velour
construction of one hundred percent cationic dyeable nylon
yarn. The carpet was orange in color. The samples were each
tested for color stability and dyelightfastness by the test
methods described above. The results are reported in Table 3.
These results demonstrate the small deviation in color
saturation of the hot-shock treated carpet sample piece
(compare Controls 3a, 3b and Example 3 to Control 3c). Also
these results showed improved dyelightfastness of hot shock
treated carpet sample piece Example 3c compared to Examples 3a
and 3b.
TABLE 3
No. L* a* b* C* Dyelight-
fastness
Control 3a 61.97 +34.56 +39.75 52.67 4-5
Control 3b 58.96 +37.78 +47.88 60.99 4-5
Example 3 58.01 +39.75 +48.86 62.99 5-6
Control 3c 57.79 +40.07 +49.78 63.90 5-6
Discussion of Results Example 1 and Example 3 showed the
smallest measured color deviation from the untreated control
samples. Also in Example 2, where only a visual rating was
feasible, the sample treated according to the above-described
method showed the smallest color change from the control
color. In all three examples application of the stainblocker
composition using a bath having a temperature and with dwell
times in accordance with the "hot shock" embodiment of the
present invention resulted in the lowest and still acceptable
color change on the cationic dyeable yarn components. This is
believed to be the first industry applicable method to treat
nylon differential dye carpets with stainblocker chemicals
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without unacceptable color loss on the cationic dyeable yarn.
In all cases good stainbiocking results were received. The
dyelightfastness results were even one-half (1/2) to one (1)
note better than after standard application methods.
-o-0-o-
The "hot shock" process as above described, although
advantageous for use with broadloom carpets, is not
particularly advantageous for use with carpet tiles.
Accordingly, the alternative embodiment, termed the "infra-
red" process, may be used when the pile surface structure is
implemented in the form of either broadloom carpet or carpet
tiles.
The "infra-red" process by which the pile surface
structure (or the textile surface of any article) is described
in connection with the schematic representation of Figure 2B
and the corresponding block diagram representation of Figure
4B. In the infra-red process embodiment of the present
invention the stainblocker composition is also applied in a
continuous, as opposed to batch-wise, manner.
In a typical implementation, after being made using any
known carpet-forming process, an undyed pile surface structure
10C is colored in a color applicator 16A (such as a dye bath).
The color is fixed in a color fixator 16B (such as a steamer).
If the pile surface structure 10C is formed from
differentially dyeable yarns, the dye bath contains a mixture
of both acid dyestuffs and cationic dyestuffs. The acid
dyeable nylon yarns and the cat dyeable nylon yarns that form
the pile elements are each colored by the appropriate dyestuff
so that both types of yarns may contribute to the visual
aesthetic properties of the pile surface structure. On the
other hand, if the pile surface structure 10C is formed only
from acid dyeable yarns, the dye bath contains only acid
dyestuffs and the acid-dyeable nylon yarns that form the pile
elements are appropriately colored by that dyestuff.
The process conditions for the dye bath are suitable for
the dyes chosen for use. Some commercially available acid
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dyes that may be suitable for use in the dye bath include
those sold by Ciba Specialty Chemicals, Inc., Basel,
Switzerland, under the trademark Tectilon; by DyStar
Textilfarben, Leverkusen, Germany under the trademark Telon;
by Clariant (Switzerland) Ltd., Basel, Switzerland under the
trademark Nylosan; and by Yorkshire Chemicals, Leeds, UK,
under the trademark Nylanthren. Some commercially available
cationic dyes that may be suitable for use in the dye bath
include those sold by Ciba Specialty Chemicals, Inc., Basel,
Switzerland, under the trademark Maxilon; by DyStar
Textilfarben, Leverkusen, Germany, under the trademark
Astrazon; by Clariant (Switzerland) Ltd., Basel, Switzerland,
under the trademark Sandocryl; and by Yorkshire Chemicals,
Leeds, UK, under the trademark Sevron. It should be
understood that the dye(s) appropriate for the pile surface
structure 10C may also be applied using either a screen
printing or a spray printing technique.
After
dyeing, if the pile surface structure 10C remains in a
broadloom form it is conveyed through the stainblocker
application process using a suitable guiding devices typically
used in the art. However, it should be understood that it
lies within the contemplation of the invention to cut the
broadloom carpet (assuming that it is provided with a backing)
into tiles before entering the stainblocker application
process. To this end devices for backing and cutting the
carpet are diagrammatically indicated in the dashed-line path
shown in Figure 2B. It also lies within the contemplation of
the invention to cut the broadloom (with backing) into the
form of tiles prior to dyeing. If the pile surface structure
10C is cut into tiles (either before or after coloring) the
tiles are advanced through the stainblocker application
process using any commercially available transport belt
conveyor.
The dyed pile surface structure 10C (in either the
broadloom or the carpet tile form) passes through a cold water
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rinsing step 21 and a hydroextraction step 22 to remove
residual dyes and chemicals. Any conventional arrangement for
suctioning liquid from a carpet may be used to perform the
suctioning step. Both these steps are similar to
corresponding steps of the conventional continuous process.
If coloring of the pile surface structure occurs at an
earlier time, the pile surface structure must be prewet (as at
the water rinsing step 21) and the water extracted (as at step
22) before the stainblocker is applied.
After suctioning the pile surface structure passes
through an application device 24'where a stainblocker
composition (with a surfactant, if used) is applied. In
accordance with this embodiment of the present invention the
temperature of the stainblocker composition is in the range
from about twenty to about ninety-five degrees Celsius (20 to
95 C). More preferably, the temperature is in the range from
about twenty to about twenty-five degrees Celsius (20 to 25
C)
For pile surface structure in the form of carpet tiles
that are lying loosely on the transport belt a suitable system
useful for the application step 24'is a flood applicator such
as that manufactured by Eduard Kuesters Maschinenfabrik GmbH &
Co. KG, Krefeld, Germany ("Kuesters"). By the term "flood
applicator" it is meant that a running line of dyed carpet
tiles is passed through a "gutter" that contains the
stainblocker composition. A calculated amount of stainblocker
composition is applied continuously by the "waterfall/weir"
principle onto the carpet.
For a pile surface structure in the form of a broadloom
carpet held by the guiding device, the stainblocker
composition can be applied by any appropriate application
device, such as: a dip trough (with nip rolls at the delivery
end); a flood applicator; a foam applicator; the device
manufactured by Kuesters and sold under the trademark FLEXNIPTM
name; or, the device manufactured by Kuesters and sold under
the trademark FLUIDYERT`' name.
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The speed of the transport mechanism controls the time
during which the pile surface structure is within the bath.
For broadloom carpet, transport speed in the range from eight
to fifteen (8 to 15) meters per minute is sufficient to keep
the broadloom carpet within the bath for an appropriate period
of time. For carpet tiles, transport speed in the range from
two to five (2 to 5) meters per minute is sufficient to keep
each tile within the bath for an appropriate period of time.
As to the stainblocker compositions themselves, sulphone
resole type stainblocker compositions with nonionic
functionality (in the appropriate weight percentages and with
appropriate pH adjustment) are preferred. Anionic
functionalized type stainblocker compositions (also in the
appropriate weight percentages and with appropriate pH
adjustment) may also be used. As earlier discussed the pH of
the treatment bath may be adjusted by known acid donor
additives such as acetic acid, citric acid and sulfamic acid.
Preferred surfactants again include appropriate amounts of an
alkylated diphenyl oxide disulfonate sodium salt, alone or in
combination with an alkylnaphtalene sulfonic acid formaldehyde
condensate sodium salt.
When the stainblocker composition is of the sulphone
resole type having nonionic functionality the stainblocker
composition is present between one and one-half percent (1.5%)
and six percent (6%) based on the weight of the nylon yarns,
and the pH of the stainblocker bath is between six (6) and
seven and one-half (7.5).
After exiting the applicator 24' the pile surface
structure (either broadloom or tiles) is passed through a
drying zone 28'. Conveniently, the drying zone 28' is defined
within a heating device. The temperature within the drying
zone is in the range from seventy-five degrees Celsius to
ninety-five degrees Celsius (75-95 C). More preferably, the
temperature within the drying zone is in the range from eighty
to eighty-five degrees Celsius (80-85 C).
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In the drying zone 28' the stainblocker composition is
allowed to react with the nylon yarn in the textile surface.
It is while the pile surface structure is heated to the
temperature of the drying zone [i.e., in the range from
seventy-five degrees Celsius to ninety-five degrees Celsius
(75-95 C), and more preferably, in the range from eighty to
eighty-five degrees Celsius (80-85 C)] that the fiber
structure becomes very open and the stainblocker is allowed to
react with the fiber. The pile surface structure should
remain in this temperature environment for a time sufficient
to permit the stainblocker to enter into and react with the
nylon yarn in the textile surface, without the dye bleeding
from the fiber. The time required for the pile surface
structure to reach this temperature depends upon the
temperature of the stainblocker composition bath and the speed
of the pile surface structure through the process. For
typical stainblocker temperatures and transport speeds this
residence time is in the range from about five (5) to about
twenty (20) seconds, and more preferably, in the range from
about ten (10) to about fifteen (15) seconds.
In the preferred instance infra-red energy is used to raise
the temperature of the carpet in the drying zone. Suitable
for use as the heating device within which the drying zone is
defined is an infra-red oven such as that manufactured by
Babcock Textilmaschinen GmbH, Seevetal, Germany; Brueckner
Trockentechnik GmbH and Co., KG, Leonberg, Germany; or
Fleissner GmbH and Co., Egelsbach, Germany.
It should be noted that in accordance with this invention
the pile surface structure is not subjected to a steaming step
where bleeding of cationic dyestuff from the cat dyeable yarn
would occur, as in the conventional continuous process.
After undergoing treatment in the application device 24'
and drying in the heating device 28' the pile surface
structure is subjected to the conventional finishing steps
normally used in the continuous process. Such finishing steps
would include a cold water rinse operation 32 and a suction
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operations 34. A suction operation before the cold rinse
could also be performed. Finally, the pile surface structure
is dried in a drying oven 36 and suitably collected, as by a
take-up roll (in the case of a broadloom carpet) or a
collection bin (in the case of carpet tiles). The take-up or
collection bin is not illustrated in Figure 2B.
If desired, after final drying in the oven 36, a
broadloom carpet may be backed and then cut into tiles of
desired size.
EXAMPLES 4-5
TEST METHODS The same Test Methods as were used in
connection with Examples 1 through 3 were used in the Examples
4 and 5 below to measure carpet samples made according to the
"infra-red" embodiment of the invention as well as control
samples for stain resistance, color stability and
dyelightfastness.
EXAMPLES 4a-4c Examples 4a-4c were performed to
demonstrate the invention on overprinted carpet tiles. The
carpet tiles were made of acid dyeable yarn.
In all of Examples 4a-4c the stainblocker was ZELAN 8236
and the surfactant ZELAN 50. The amount of ZELAN 8236 was
5.0% of pile weight, the wet pickup was 400%. pH values were
adjusted with citric acid to 6.3. The stainblocker
composition was applied by flood process at a temperature of
seventy-six degrees Celsius (76 C). The tiles were cured for
ten (10) seconds at eighty degrees Celsius (80 C) in an
infra-red heater. In all of Examples la-c the residual
moisture after printing was forty percent (40%). Example la
was one hundred percent (100%) overprinted before treating
with the stainblocker composition. Example lb was forty
percent (40%) overprinted and Example is was an un-overprinted
control carpet. After treating the tile sample pieces 4a-4c
were water rinsed, extracted and dried.
After dyeing, the tile sample pieces were each tested for
stainblocker performance (Kool-Aid test: cold rinsed, coffee
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test: after cleaned) by standard test methods. The results
are reported in Table 4.
As can be seen the stainblocker results of Examples 4a,
4b, and 4c were excellent.
TABLE 4
Example No. Kool- Coffee
Aid After
Cold cleaned
rinsed
4a 10 10
4b 10 10
4c 10 9-10
Discussion of Results In all three examples application
of the stainblocker composition using a flood applicator and
an infra-red oven in accordance with the present invention
resulted in all cases in excellent stainblocking results.
Examples 5a-5d Examples 5a-5d were performed to
demonstrate the invention on differentially dyeable nylon
carpets. The carpet in Examples 5a-5d was a loop construction
containing three different filament yarn types having deep
acid, regular cationic, and light cationic dyeabilities. The
carpet was of blue (acid dyeable yarn) and orange (cationic
dyeable yarn) color. Example 5a was treated by conventional
winch/beck process. Example 5b was treated by conventional
continuous application. Example 5c was treated by the infra-
red process of the present invention. Example 5d was an
untreated control carpet.
In all of Examples 5a-5c ZELAN 8236 (DuPont) as
stainblocker and ZELAN 50 (DuPont) as surfactant were used.
In Examples 5a and 5b the amount of ZELAN 8236 was 5.5% and
in Example 5c the amount of ZELAN 8236 was 3.0% of carpet
pile weight. pH values were adjusted with acetic acid.
Example 5a was treated for twenty minutes at pH 6.8 and at a
temperature of seventy-five degrees Celsius (75 C). Example
2b was treated at pH 6.8 and steamed afterwards. The wet
pick-up was 450%. Example 2c was treated as described above
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at a pH of 6.8. Example 2d was treated in order to compare
stainblocking performance, color stability and
dyelightfastnesses.
After treating the carpet sample pieces 5a-5c were water
rinsed, hydroextracted and dried.
After drying, the carpet sample pieces were each tested
for Kool-Aid staining, color stability and dyelightfastness by
the test methods described above. The results are reported in
Table 5.
TABLE 5
Example Kool-Aid C* Dyelightfastness
No.
5a 10 11.12 5-6
5b 10 13.96 5-6
5c 10 15.87 6
5d 1-2 16.44 6
C* value (saturation, the higher the C* value the richer is
the color)
Discussion of Results As can be seen (compare Examples
5a, 5b to Sc and 5a, 5b, 5c to 5d) the infra-red process-
treated carpet sample Sc shows the same excellent
stainblocking results although a smaller amount of
stainblocker has been used. These results (compare Examples
5a, 5b, 5c to 5d) also show smallest deviation in color
saturation (C* values) of carpet specimen 5c. Also, as can be
seen by comparing Examples 5a, 5b and 5c to 5d, the
dyelightfastnesses at all application methods are good.
28
