U.S. patent application number 14/571394 was filed with the patent office on 2016-06-16 for process to produce hygienically clean textile.
The applicant listed for this patent is Washing Systems, LLC. Invention is credited to Ryan Coggeshall, Adam Stein.
Application Number | 20160168780 14/571394 |
Document ID | / |
Family ID | 54937399 |
Filed Date | 2016-06-16 |
United States Patent
Application |
20160168780 |
Kind Code |
A1 |
Coggeshall; Ryan ; et
al. |
June 16, 2016 |
PROCESS TO PRODUCE HYGIENICALLY CLEAN TEXTILE
Abstract
Textiles are hygienically cleaned by subjecting them to a
low-temperature wash, generally less than 140.degree., and
typically about 100.degree. F. Once cleaned, they are subjected to
a low temperature bleaching step at a pH of generally around 9 or
less. The bleaching step is again conducted a low temperature, such
as 140.degree., 100.degree. F. Treated textiles can then be rinsed
and treated to any typical post-washing operations. By conducting
the washing and the bleaching at low temperatures, energy is saved.
Further, maintaining the low temperature and low pH for the
bleaching solution achieves better disinfection and, at the same
time, minimizes damage to the textile.
Inventors: |
Coggeshall; Ryan;
(Washington Township, OH) ; Stein; Adam;
(Cincinnati, OH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Washing Systems, LLC |
Loveland |
OH |
US |
|
|
Family ID: |
54937399 |
Appl. No.: |
14/571394 |
Filed: |
December 16, 2014 |
Current U.S.
Class: |
8/108.1 ;
8/137 |
Current CPC
Class: |
C11D 3/3956 20130101;
C11D 11/0017 20130101; D06L 4/24 20170101; D06L 4/75 20170101 |
International
Class: |
D06L 3/16 20060101
D06L003/16; D06L 3/08 20060101 D06L003/08 |
Claims
1. A method of laundering and bleaching textiles comprising:
washing said textiles at a temperature less than or equal to
140.degree. F. in an alkaline detergent; bleaching said textile in
a chlorine bleach solution at a temperature less than 140.degree.
F.; and wherein said chlorine bleach solution has a pH less than
9.5.
2. The method claimed in claim 1 wherein said textiles are washed
at a temperature of from 85 to 140.degree. F.
3. The method claimed in claim 2 wherein said textiles are washed
at a temperature of 95 to 120.degree. F.
4. The method claimed in claim 1 wherein said textiles are bleached
a temperature of 85 to 140.degree. F.
5. The method claimed in claim 4 wherein said textiles are bleached
a temperature of 95 to 120.degree. F.
6. The method claimed in claim 1 where in a buffer is added to said
chlorine bleach solution to establish a pH, said pH less than
9.5.
7. The method claim and claim 1 wherein an acid is added to said
chlorine bleach solution to lower said pH to less than 9.5.
8. The method claimed in claim 1 wherein said pH is from 7 to
9.5.
9. The method claimed in claim 8 wherein said pH is from 7-8.
10. The method claimed in claim 9 wherein said pH is from 7 to
7.5.
11. The method claimed in claim 1 wherein said chlorine bleach
solution is a hypochlorite solution.
12. The method claimed in claim 11 wherein said hypochlorite is
sodium hypochlorite.
13. The method claimed in claim 1 wherein said chlorine bleach
solution has a concentration of 25 to 500 ppm.
14. A method of bleaching textiles comprising contacting said
textiles with a chlorine bleach solution at a temperature less than
140.degree. F. and a pH less than or equal to 9.5, for a time
effective to bleach said textile.
15. The method claimed in claim 14 wherein said temperature is from
100-120.degree. F. and said pH is from 7 to 9.
16. The method claimed in claim 14 wherein said time is from 4 to
30 minutes.
17. The method claimed in claim 14 wherein said textile is linen.
Description
BACKGROUND OF THE INVENTION
[0001] Hygienic cleanliness of textiles has become an increasingly
important aspect of the laundering process. Presently, much of the
United States and European Union rely on thermal disinfection as
the means to verify that textiles have been properly washed and are
hygienically clean. In the US, the CDC guidelines state that one
way to help achieve hygienic disinfection for hot-water washing is
to wash at 160.degree. F. for a minimum of 25 minutes. The CDC also
states that several studies have demonstrated that lower water
temperatures of 71.degree. F.-77.degree. F. can reduce microbial
contamination when the cycling of the washer, wash chemistry are
controlled.
[0002] Due to production demands, textiles processed through
continuous batch washers (CBW's) do not typically meet the CDC
thermal disinfection requirements of 160.degree. F. for 25 minutes.
In addition, although washing machines are programmed to reach
160.degree. F., many lack a mechanism to verify that 160.degree. F.
is reached and maintained.
[0003] Thermal disinfection has been shown to be insufficient in
killing spore forming bacteria, such as C. diff. C. diff. can
survive extended heating at 160.degree. F. Temperatures of
145-160.degree. F. may actually enhance spore germination of some
aged spores.
[0004] EPA registered sanitizers/disinfectants are sometimes used
in healthcare laundries. When used properly, these
sanitizers/disinfectants have kill claims on certain organisms. The
deficiency in using these sanitizers/disinfectants is that they do
not have kill claims on many organisms present in the healthcare
environment. One such sanitizer/disinfectant has kill claims for
Staphylococcus aureus, Klebsiella pneumonia, Pseudomonas
aeruginosa, methicillin resistant Staphylococcus aureus (MRSA),
Acinetobacter baumannii, Listeria monocytogenes, Ecsherichia coli,
and Salmonella enterica. This sanitizer/disinfectant does not
address other significant problematic organisms, such as C. diff,
Giardia, Legionella, fungi, and molds.
[0005] In commercial laundries, textiles are typically laundered at
elevated temperatures, such as 150.degree. F. under alkaline
conditions. There are certain detergents on the market which permit
the textiles to be laundered at lower temperatures.
[0006] Certain textiles require a bleaching step. This is
particularly required for white textiles such as white linen.
Chlorine-based bleaches, such as sodium hypochlorite, are typically
used. Generally the commercial laundries bleach such textiles at
temperatures about 150.degree. F., similar to the laundering
temperature, and at relatively high pHs, around 10.2 to 10.8. If
the chlorine bleaches are used at lower pHs, the textiles are
damaged by the bleach.
[0007] Also, once a textile is laundered at a high temperature, it
must be brought down to room temperature gradually or wrinkles will
set in. Generally, the temperature of the textiles is lowered by
going through a series of rinsing steps wherein in each step the
temperature of the rinse water is slightly lower than the previous
temperature. This allows the temperature of the textile to be
lowered to room temperature without setting in wrinkles.
[0008] This operation is relatively expensive, requiring a
significant amount of energy to raise the temperature of the
textiles to the effective laundering temperature. It also requires
a great deal of time for step down rinsing.
SUMMARY OF THE INVENTION
[0009] The present invention is premised on the realization that
one can effectively launder and bleach textiles by initially
washing the textile at a low temperature, generally 140.degree. F.
or lower, and subsequently bleaching the textiles, again at a low
temperature of less than 140.degree. F., at a pH less than 9.5,
generally from about 7 to 9. This effectively launders and bleaches
the textile without causing any damage to the textile, which
typically would be expected when bleaching at such a low pH.
[0010] In one embodiment of the present invention, particularly
suitable for laundering hospital linens, the linens are cleaned in
a four zone process, the first zone designed to remove
chlorhexidine also referred to as Hibiclens, wherein a concentrated
high-performance detergent is used, along with a Hibiclens remover,
such as Hibiclear, to remove any chlorhexidine from the fabric,
preventing it from setting in subsequent zones. In the second zone,
the linens are washed, again at a low temperature, generally
140.degree. F. or less, such as 100.degree. F., down to 85.degree.
F. In this zone, a high performance laundry detergent, along with a
concentrated alkali, is added. This zone helps to reduce
microorganism contamination. In the third zone, the textiles become
hygienically clean by treating the textiles with sodium
hypochlorite, a bleach activator, at a pH of less than 9.5,
generally 7 to 9, more particularly 7-8, again at a temperature
less than 140.degree. F., generally 100.degree. F. or less.
Finally, in the fourth zone, the linens are rinsed and the pH
adjusted to about 7. At this stage, softeners can be added if
required.
[0011] The objects and advantages of present invention will be
further appreciated in light of the following detailed description
and brief description of the Figures, in which:
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a graph showing tensile strength of a cotton
fabric after repeated washes; and
[0013] FIG. 2 is a graph showing tensile strength of a 65/35
polyester/cotton blend after repeated washes.
DETAILED DESCRIPTION OF THE INVENTION
[0014] According to the present invention, textiles are laundered
in a manner that ensures destruction of bacteria and other
pathogens to provide hygienically clean textiles. The washing
process will be conducted in typical commercial laundry facilities.
Generally, any commercial laundry equipment can be used in the
process of the present invention. One such typical apparatus is a
tunnel washing apparatus, generally one having at least four
zones.
[0015] The textiles are initially subjected to a low temperature,
low pH laundering. In this first zone, the textiles are treated in
a manner, well-known to remove chlorhexidine, an antimicrobial
agent typically used in hospitals, also referred us to as
Hibiclens. In this process, the textiles are subjected to a wash at
an acid pH to prevent the chlorhexidine from setting. The wash
washing solution can include Hibiclear, a commercially available
product which is designed to facilitate removal of
chlorhexidine.
[0016] This initial zone washing is conducted generally at a lower
temperature, preferably at 140.degree. F. or less, such as 130,
120, 110 and generally about 100.degree. F. The initial wash is
conducted for a time effective to remove any chlorhexidine present
and generally from about 2 to about 8 minutes and generally about 8
minutes. This step is unnecessary for textiles that do not include
chlorhexidine.
[0017] Once the textiles are treated in the initial zone, they pass
to a wash zone, where they are washed using a high-performance, low
temperature laundry detergent, generally a nonionic
surfactant-based detergent at an alkaline pH. This washing step is
conducted at a temperature of 140.degree. to 85.degree. F.,
generally 130.degree. F. to 95.degree. F., 120.degree. F. or less,
110.degree. F. or less and preferably at about 100.degree. F. The
time during which the textiles are treated in the wash zone may
vary, depending upon the materials being laundered. In most
applications, the time is from 6 to about 15 and generally about
12.
[0018] After the laundry passes through the wash zone, the washing
liquid is separated from the textiles. The textiles are then passed
to a third zone, which is a pathogen removal zone or a bleaching
zone. In this zone, the textiles are treated with a bleach
solution, typically sodium hypochlorite at a pH of 6.5 to 9.5,
generally 8 to 6.5 and, in particular, a pH of 7. The pH is
adjusted as needed by the addition of an appropriate water soluble
buffer, such as urea sulfate.
[0019] The concentration of the bleach will be about 5 ounces to 30
ounces per hundred weight textile or 25 to 500 ppm. In addition to
the sodium hypochlorite, a bleach activator is added, such as
Pathfree. This will effectively established the pH within the
desired range. The temperature in this zone will be maintained at
140.degree. F. or less, generally 130.degree. F. or less,
120.degree. F. or less, 110.degree. F. or less and typically at
about 100.degree. F. In addition to sodium hypochlorite, other
suitable bleaches include powdered bleaches such as lithium
hypochlorite, trichloroisocyanuric acid and hypochlorous acid.
[0020] The washing solution in zone three should have a minimum
oxygen reduction potential of 665 MV, which is achieved by
establishing sufficient sodium hypochlorite and an effective pH.
The clothing is subjected to the hypochlorite solution for about 4
to about 30 minutes, which is more than adequate to destroy
potential pathogens on the textile.
[0021] Once the textile has passed through the third zone, it is
rinsed in a fourth zone or a finishing zone. In this zone, which is
optional, any remaining wash chemicals are removed from the
textiles and the pH is adjusted to a proper finish pH of 6-7.
Softener may be added as required by the end-user.
[0022] The present invention has many different advantages. In
particular, all the zones are operated at lower temperatures,
generally around 100.degree. F. This eliminates the need for either
adding or removing energy from the textiles during the laundry
procedure. In addition to effectively cleaning the textiles, they
are disinfected, destroying pathogens utilizing the third zone
which effectively kills the pathogens with the hypochlorite at a
relatively low pH and low temperature. Again, the low temperature
reduces costs because the temperature of the textile does not have
to be adjusted in going from the wash zone to the pathogen
destruction zone.
[0023] Finally, the present invention reduces the damage to the
textiles, as compared to current bleach parameters which operate at
a higher temperature and higher pHs. As shown in FIG. 1, the
tensile strength of cotton is measured after repeated washes,
either under current bleach parameters or the low temperature
bleach parameters as discussed above for zone three. Particularly
after 10 or 25 launderings or washes, the tensile strengths of the
textiles bleached with the bleach parameters of the present
invention are substantially higher than those bleached using
current bleach parameters (i.e. higher temperatures and pHs).
Likewise with the 65/35 polyester cotton blend, similar improved
results are achieved, as shown in FIG. 2.
[0024] In Examples 1 and 2 below, the effectiveness of these wash
parameters reduce known amounts of microorganisms was studied.
Example 1
Objective
[0025] The objective was to evaluate the effectiveness of the
present invention as a means of reducing known amounts of
microorganisms.
[0026] Test Parameters:
[0027] The effect of the present invention on known quantities of
microbes was tested to examine how the different wash parameters
affect the different organisms. One by one inch square swatches of
linen were inoculated. After inoculation the swatches were allowed
to dry for thirty minutes in a sterile petri dish. Upon completion
of the dry time, the swatches were pinned to a mesh net and
subjected to the differing wash parameters.
[0028] Preparation of Inoculum:
[0029] Each organism was grown in trypitic soy broth for
approximately 24 hours at 32.5.degree. C. in a sterile baffled
flask, while shaking on a Thermo Scientific multipurpose orbital
shaker. After the incubation period the suspension was diluted with
tryptic soy broth, to yield a specific absorbance with the Hach DR
2700 spectrophotometer. The adjusted suspension contains
approximately 5.0.times.10.sup.8 CFU/mL.
[0030] Sample identification--Hospital/Hotel linen 70% cotton 30%
polyester 1.0.times.1.0 square swatches.
[0031] Test Organisms-- [0032] Escherichia coli--ATCC #8739 [0033]
Pseudomonas aeruginosa--ATCC #9027 [0034] Staphylococcus
aureus--ATCC #6538 [0035] Klebsialla pneumoniae--ATCC # BAA-1144
[0036] Salmonella enterica subspecies typhimurium--ATCC #13311
[0037] Method--Membrane filtration (sterile eluation 45 mL), total
aerobic plate count
[0038] Wash and Chemistry Tested:
[0039] Classification: Sheets
[0040] Load weight: 100% capacity
TABLE-US-00001 Process 2 oz/cwt Bleach-8 minute contact time
Operation Time Temperature Level Chemical Usage/35 lb *Bleach-Sub
8/1 100 Low Bleach 22 mL 85% urea 4 ml sulfate Rinse 2/1 split High
Rinse 2/1 cold High *Sour-Soft 4/1 cold Low Pinn. A/C 9 mL Pinn.
Sour 0 mL Total Time: 22 Minutes Inoculum Calculated Inoculum
CFU/mL Volume CFU/Swatch Log10/Swatch E. coli 3.0 .times. 10.sup.9
40 .mu.L 1.9 .times. 10.sup.8 8.28 P. aeruginosa 2.0 .times.
10.sup.8 40 .mu.L 8.1 .times. 10.sup.6 6.91 S. aureus 2.0 .times.
10.sup.8 40 .mu.L 8.0 .times. 10.sup.6 6.90 K. pneumoniae 2.0
.times. 10.sup.9 40 .mu.L 8.2 .times. 10.sup.7 7.90 S. typhimurium
3.1 .times. 10.sup.9 40 .mu.L 1.29 .times. 10.sup.8 8.1
[0041] Results:
TABLE-US-00002 Log Reduction Log.sub.10 (calculated Treatments (3
replicates each) CFU/Swatch Survivors CFU/Swatch) E. coli 1-1
<10 <1.0 7.28 E. coli 1-2 <10 <1.0 7.28 E. coli 1-3
<10 <1.0 7.28 P. aeruginosa 1-1 <10 <1.0 5.91 P.
aeruginosa 1-2 <10 <1.0 5.91 P. aeruginosa 1-3 <10 <1.0
5.91 S aureus 1-1 <10 <1.0 5.90 S aureus 1-2 <10 <1.0
5.90 S aureus 1-3 <10 <1.0 5.90 K. pneumoniae 1-1 <10
<1.0 6.90 K. pneumoniae 1-2 <10 <1.0 6.90 K. pneumoniae
1-3 <10 <1.0 6.90 S. typhimurium 1-1 <10 <1.0 7.1 S.
typhimurium 1-2 <10 <1.0 7.1 S. typhimurium 1-3 <10
<1.0 7.1
Example 2
Objective
[0042] The objective was to evaluate the effectiveness of resource
conservation wash parameters as a means of reducing known amounts
of microorganisms.
[0043] Test Parameters:
[0044] The effect of eight separate laundry processes on known
quantities of microbes was tested to examine how the different wash
parameters affect the different organisms. One by one inch square
swatches of linen were inoculated. After inoculation the swatches
were allowed to dry for thirty minutes in a sterile petri dish.
Upon completion of the dry time, the swatches were pinned to a mesh
net and subjected to the differing wash parameters.
[0045] Preparation of Inoculum:
[0046] Each organism was grown in trypitic soy broth for
approximately 24 hours at 32.5.degree. C. in a sterile baffled
flask, while shaking on a Thermo Scientific multipurpose orbital
shaker. After the incubation period the suspension was diluted with
tryptic soy broth, to yield a specific absorbance with the Hach DR
2700 spectrophotometer. The adjusted suspension contains
approximately 5.0.times.10.sup.8 CFU/mL.
[0047] Sample identification--Hospital/Hotel linen 70% cotton 30%
polyester 1.0.times.1.0 square swatches Test organisms-- [0048]
Escherichia coli--ATCC ft 8739 [0049] Pseudomonas aeruginosa--ATCC
#9027 [0050] Staphylococcus aureus--ATCC #6538 [0051] Klebsialla
pneumoniae--ATCC # BAA-1144 [0052] Salmonella enterica subspecies
typhimurium--ATCC ft 13311
[0053] Method--Membrane filtration (sterile eluation 45 mL), total
aerobic plate count
[0054] Wash and Chemistry Tested:
[0055] Formula:
[0056] 2 oz/cwt Bleach and 100.degree. F.
[0057] Classification: Casino/Hotel sheet
[0058] Load weight: 100% capacity
TABLE-US-00003 RC Formula 2 oz/cwt Bleach-8 minute contact time
Operation Time Temperature Level Chemical Usage/Cwt *Bleach-Sub
10/1 100 Low spectrum 0 mL Express 0 mL Bleach pH 6 22 mL Rinse 2/1
split High Rinse 2/1 cold High *Sour-Soft 4/1 cold Low Pinn. A/C 9
mL Pinn. Sour 0 mL Total Time: 22 Minutes Inoculum Calculated
Inoculum CFU/mL Volume CFU/Swatch Log10/Swatch E. coli 3.0 .times.
10.sup.9 40 .mu.L 1.9 .times. 10.sup.8 8.28 P. aeruginosa 2.0
.times. 10.sup.8 40 .mu.L 8.1 .times. 10.sup.6 6.91 S. aureus 2.0
.times. 10.sup.8 40 .mu.L 8.0 .times. 10.sup.6 6.90 K. pneumoniae
2.0 .times. 10.sup.9 40 .mu.L 8.2 .times. 10.sup.7 7.90 S.
typhimurium 3.1 .times. 10.sup.9 40 .mu.L 1.29 .times. 10.sup.8
8.1
[0059] Results:
TABLE-US-00004 Log Reduction Log.sub.10 (calculated Treatments (3
replicates each) CFU/Swatch Survivors CFU/Swatch) E. coli 1-1
<10 <1.0 7.28 E. coli 1-2 <10 <1.0 7.28 E. coli 1-3
<10 <1.0 7.28 P. aeruginosa 1-1 <10 <1.0 5.91 P.
aeruginosa 1-2 <10 <1.0 5.91 P. aeruginosa 1-3 <10 <1.0
5.91 S aureus 1-1 <10 <1.0 5.90 S aureus 1-2 <10 <1.0
5.90 S aureus 1-3 <10 <1.0 5.90 K. pneumoniae 1-1 <10
<1.0 6.90 K. pneumoniae 1-2 <10 <1.0 6.90 K. pneumoniae
1-3 <10 <1.0 6.90 S. typhimurium 1-1 <10 <1.0 7.1 S.
typhimurium 1-2 <10 <1.0 7.1 S. typhimurium 1-3 <10
<1.0 7.1
TABLE-US-00005 RC Formula 2 oz/cwt Bleach-4 minute contact time
Operation Time Temperature Level Chemical Usage/Cwt *Bleach-Sub
10/1 100 Low Bleach pH 6 22 mL Rinse 2/1 split High Rinse 2/1 cold
High *Sour-Soft 4/1 cold Low Pinn. A/C 9 mL Pinn. Sour 0 mL Total
Time: 22 Minutes Inoculum Calculated Inoculum CFU/mL Volume
CFU/Swatch Log10/Swatch E. coli 2.4 .times. 10.sup.9 40 .mu.L 9.6
.times. 10.sup.7 7.98 P. aeruginosa 5.6 .times. 10.sup.8 40 .mu.L
2.2 .times. 10.sup.7 6.34 S. aureus 2.4 .times. 10.sup.9 40 .mu.L
9.6 .times. 10.sup.7 7.98 K. pneumoniae 1.1 .times. 10.sup.9 40
.mu.L 4.3 .times. 10.sup.7 7.60 S. typhimurium 2.4 .times. 10.sup.9
40 .mu.L 9.5 .times. 10.sup.9 7.97
TABLE-US-00006 Log Reduction Log.sub.10 (calculated Treatments (3
replicates each) CFU/Swatch Survivors CFU/Swatch) E. coli 1-1 190
2.27 5.71 E. coli 1-2 212 2.32 5.66 E. coli 1-3 199 2.29 5.69 P.
aeruginosa 1-1 <10 <1.0 5.34 P. aeruginosa 1-2 <10 <1.0
5.34 P. aeruginosa 1-3 <10 <1.0 5.34 S aureus 1-1 <10
<1.0 6.98 S aureus 1-2 <10 <1.0 6.98 S aureus 1-3 <10
<1.0 6.98 K. pneumoniae 1-1 TNTC N/A N/A K. pneumoniae 1-2 TNTC
N/A N/A K. pneumoniae 1-3 TNTC N/A N/A S. typhimurium 1-1 <10
<1.0 6.97 S. typhimurium 1-2 <10 <1.0 6.97 S. typhimurium
1-3 <10 <1.0 6.97
[0060] These examples demonstrate that the process of the present
invention effectively destroys pathogens in textiles. Further this
is accomplished using a low temperature wash and a low temperature
bleach which significantly reduces energy costs, as well as time
required, because there is no need to have the step down cooling to
prevent wrinkles. Thus, the present invention provides not only an
effective method to destroy pathogens and textiles, but at the same
time reduces costs and laundry time. This has been a description
the present invention, however, the invention itself should only be
defined by the appended claims.
* * * * *