Title of Invention

A METHOD FOR SUSTAINING THE BIOCIDAL ACTIVITY OF HALOGENATED POLYSTYRENE HYDANTOIN BEADS

Abstract The invention discloses a method for sustaining the biocidal activity of halogenated polystyrene hydantoin beads, comprising: incorporating a composition comprising at least one oxidative halogen containing compound into water being treated with halogenated polystyrene hydantoin beads to provide treated water suitable for drinking, wherein the composition provides a free halogen concentration from about 0.1 ppm to about 10 ppm in the water, the concentration being sufficient to maintain the biocidal activity of the halogenated polystyrene hydantoin beads.
Full Text This application is divided out of the Indian Patent application no.
00581/KOL/2004
FIELD OF THE INVENTION
The invention is related to water purification systems, including systems
employing polymers having pendant heterocyclic amine groups, such as polystyrene •
having pendant hydantoin and halogenated hydantoin groups, and to the compositions and
methods for maintaining the polymers in a biocidally active state.
BACKGROUND OF THE INVENTION
Heterocyclic N-halamine groups are known to have biocidal properties that can be
put to use in water purification. Heterocyclic N-halamine groups that are attached to a •
polystyrene polymer are described in U.S. Patent No. 5,490,983. A crosslinked
polystyrene polymer having similar pendant heterocyclic N-halamine groups is described
in U.S. Patent No. 6,548,054. The crosslinked version of the polystyrene polymer is
typically provided in beads that do not have the problems associated with a powder. The
beads are available from Vanson HaloSource of Redmond, WA. A representative '
heterocyclic amine group described in both of these patents is a hydantoin group. When '
the hydantoin group has a chlorine or bromine atom bonded to one or both of the
hydantoin nitrogen atoms, the hydantoin is biocidal. Worley et al. '054 describe methods
for the creation of the biocidal halogenated polystyrene hydantoin (HPSH) polymer from
the non-biocidal polystyrene hydantoin (PSH) polymer using a variety of free chlorine
sources (for example, sodium hypochlorite, calcium hypochlorite, sodium •
dichloroisocyanurate). Over time however, the biocidal HPSH polymer reverts to nonbiocidal PSH polymer as a result of depletion of the halogen atoms due to contact
with the biodemand. PSH polymer, however, has the ability to be recharged or
rehalogenated with a halogen to restore its antimicrobial properties.
Worley et al. '054 describe recharging PSH polymer once the polymer has lost its
biocidal efficacy by halogenating the PSH polymer using concentrated solutions of •
industrial strength liquid bleach and bromine. It has been determined that the levels of -
halogen in solution according to Worley et al. '054 are of such high concentration that
when used in-situ in a water treatment device, the subsequent purified water is rendered
undrinkable and requires considerable post-treatment to remove the excess halogen to
render the purified water drinkable.

One of the drawbacks of using HPSH polymer in water filters is that once the
halogen is consumed from the HPSH polymer, the halogen must be either replaced by
recharging the halogen-depleted PSH polymer, or the entire mass of PSH polymer must '
be discarded and replaced with fresh HPSH polymer. Until now, there was no practical
alternative to either recharging or replacing the PSH polymer in a water treatment system.
Replacing halogen-depleted PSH polymer with fresh HPSH polymer raises the capital and
operating costs of the water treatment system. Recharging PSH polymer that has lost
biocidal efficacy requires that the water treatment system be taken out of service. Off-line
recharging of PSH polymer to HPSH polymer creates considerable down-time and system '
complexity.
Another short-coming of HPSH polymers is the drop in biocidal efficacy during
use. As halogen is consumed from the HPSH polymer, the biocidal efficacy of the HPSH
polymer drops below commonly required biocidal performance standards, such as the
United States Environmental Protection Agency (EPA) purifier standards of 6 log
removal of Klebsiella, and 4 log removal of poliovirus. While the drop in biocidal -
efficiency is expected as halogen is consumed by the biodemand, the speed at which this
reduced effectiveness occurs creates several difficulties for the practical application of the
HPSH polymer in applications, such as a water filter in the home or as an emergency
water supply. Product designers and engineers wishing to apply HPSH polymer
technology to commercial products must either increase the initial amount of HPSH
polymer to achieve the desired performance life of the product or add complexity to the .
system by allowing for off-line rehalogenation of the PSH polymer.
Accordingly, there is a need to provide methods and the means to maintain
constantly or for a prolonged period of time, a biocidally effective halogen charge on
polymers having pendant heterocyclic N-halamine groups without adversely affecting
water quality, and without the need to recharge or replace the halogen depleted PSH
polymer. The present invention fulfills this need and has further related advantages.
SUMMARY OF THE INVENTION
In accordance with the present invention, the need for replacing the halogen-
depleted charge of HPSH polymer with new HPSH polymer or taking a water treatment
system off-line for recharging, is avoided by providing a low concentration of halogen in
the water that is to be treated that is sufficient to maintain the HPSH polymer at an ,

effective biocidally active state. Ideally, the concentration is sufficient to maintain the
HPSH polymer biocidal, yet not so high as to render the treated water undrinkable due to
high concentrations of halogen. In this manner, the HPSH polymer is constantly
maintained at an effective biocidal level, thus eliminating replacement or recharging.
However, one of the difficulties of implementing this new solution is in achieving a
prolonged low concentration of free halogen in water to bond with the heterocyclic '
amines to render them biocidal, yet not have the halogen concentration so high as to
adversely effect water potability.
Up until now, commercially available solid sources of halogens are designed for
use in an emergency to provide drinking water and/or for pool and spa sanitizing.
Examples of solid halogen sources include calcium hypochlorite tablets for municipal
drinking water system disinfection, bromine tablets for pool and spa sanitation, and
sodium dichloroisocyanurate tablets for disaster relief/emergency water treatment.
However, these commercially available sources of halogens elute free halogens at
concentrations far greater than would be accepted by consumers for drinking water.
Worley etal. '983 and '054 does not mention or indicate the halogen concentration in
water required to maintain a biocidally active state of the HPSH polymer that would still
be low enough so that the water is suitable for use as potable water. Furthermore, no
mention of a means for continuously maintaining or least prolonging the biocidally active
state of HPSH polymer is described. Worley et al. '983 only describe the regeneration of
non-halogenated precursor cyclic amine polymers in filters.
In accordance with the present invention of prolonging the biocidally active state
of polymers having pendant heterocyclic amine groups, the present invention provides
methods and the means to maintain continuously or for a prolonged period of time a low
concentration of free halogen in water to maintain or prolong the effective halogen
loading on polymers having pendant heterocyclic amines. The present invention avoids
the need to recharge the polymers after they have become biocidally ineffective and also
avoids the need to take a water purification system off-line for recharging biocidally
ineffective polymers. With the use of the present invention, the polymers having pendant
heterocyclic amine groups are maintained biocidally effective constantly or for at least
prolonged periods of time. The present invention treats the polymers having pendant
heterocyclic amine groups with low concentrations of free halogen in water while the
polymer is still biocidally effective. Free halogen refers to the halogen in water that is

available to bond with a nitrogen atom on a heterocyclic amine. The present invention
provides halogens to bond with nitrogen atoms on the heterocyclic amine groups,
simultaneously while halogens are being depleted from the heterocyclic amine groups by
the biodemand, so that the polymer with pendant heterocyclic amines is not rendered
biocidally ineffective. Thus, the need to recharge the polymer from a biocidally
ineffective state is avoided. It is to be appreciated that the heterocyclic amine groups may
have halogen depleted sites.
In one embodiment of the invention, an article is designed and manufactured to
provide free halogen at low concentrations for prolonged periods of time for use in water
treatment systems employing polymers having pendant heterocyclic N-halamines, such as
hydantoin moieties. The article according to the present invention can elute free halogen
into a flowing water stream that then contacts the polymer with pendant heterocyclic
N-halamines to maintain an effective halogen loading of the polymer so that the polymer
achieves a continuous or at the veiy least a prolonged period of biocidal activity without
the need to replace the entire mass of halogen-depleted polymer and without the need to
take the system off-line for recharging the biocidally ineffective halogen-depleted
polymer. The article according to the invention allows for on-line, in-situ halogenation of
the biocidally effective polymer during the period when the polymer is biocidally active.
The article achieves maintenance of the effective halogen loading on the polymer by
releasing a low level dose of halogen into flowing water to create a solution having a total
free chlorine concentration in the range of about 0.1 ppm to about 3 ppm and/or a total
free bromine concentration in the range of about 0.2 ppm to about 4 ppm. The lower
limit of these ranges is still effective to produce a biocidally active polymer having
pendant hydantoin groups. The higher limit of these ranges still produces a biocidally
active polymer having pendant hydantoin groups, but is not so high as to render water
nonpotable. "Nonpotable", "not suitable for drinking", or "undrinkable" refers to water
having chlorine or bromine or both chlorine and bromine at a concentration such that a
majority of a population would avoid drinking the water if the population has an abundant
alternate water supply. The water with the low concentration of free halogen within these
ranges is then made to contact the polymer with pendant heterocyclic N-halamine groups,
continuously or intermittently.
In one embodiment, the article of the invention is a solid, monolithic tablet that
elutes chlorine or bromine within predetermined limits into untreated flowing water that

is subsequently exposed to a biocidally active polymer having pendant heterocyclic N- ;
halamine groups. The method and article according to the invention achieve the constant
or prolonged biocidally active state of polymers having pendant heterocyclic N-halamines
by replacing the halogens that are constantly being depleted by the biodemand. This is in
direct contrast to Worley et al. '983 and '054 that only recharges the polymer after the
polymer has been depleted of halogen, that has rendered the polymer biocidally
ineffective. With the article according to the invention, the biocidally active state of any ;
polymer having pendant heterocyclic N-halamine groups can be maintained continuously
or at the very least for a prolonged period of time as compared with the prior art that only
recharges the polymer after the polymer has been rendered biocidally inactive.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The foregoing aspects and many of the attendant advantages of this invention will ,■
become more readily appreciated as the same become better understood by reference to
the following detailed description, when taken in conjunction with the accompanying
drawings, wherein:
FIGURE 1 is a schematic illustration of a system for measuring the concentrations
of halogen in water flowing past an article made according to the present invention;
FIGURE 2 is a schematic illustration of a representative water purification system ,
incorporating an article made according to the present invention;
FIGURE 3 is a graph illustrating the chlorine concentrations produced by articles
made according to the present invention as plotted against cumulative water flow;
FIGURE 4 is a graph illustrating the poliovirus LRV for both the control and the
challenge system plotted against cumulative water flow; and
FIGURE 5 is a graph illustrating the chlorine concentration produced by an article ,
according to the present invention as plotted against cumulative water flow.
DETAILED DESCRIPTION OF THE PREFERT The present invention is related to methods and the means for maintaining a
prolonged biocidally active state for polymers having pendant heterocyclic N-halamine
groups. Specifically, one embodiment of the present invention provides an article for ,
maintaining a continuous long-term level of biocidal efficacy for water treatment devices

that employ hydantoinylated polymers, such as PSH polymer, HPSH polymer, and/or a
mixture of PSH polymer and HPSH polymer.
The article according to the present invention elutes low concentrations of free
halogen into the water that is to be treated by a water treatment device that includes
HPSH polymer. One representative article of the invention is a solid phase composition
including at least a source of chlorine, bromine, or both chlorine and bromine. The article
is provided as a monolithic composition, meaning the article has no layers of differing
compositions or, stated another way, the article is substantially homogeneous with regard >
to composition. The article according to the invention has been designed and
manufactured in a manner as set forth below to elute free halogen at the desirable
predetermined concentration into water.
It is believed the predetermined concentration of free halogen eluted by the article
is attributable, at least in part, to the method of its manufacture that includes taking into
consideration the article's size, shape, density and its components. The article according ,
to the present invention produces a total free chlorine concentration in the range of about
0.1 ppm to about 10 ppm, and preferably in the range of about 0.1 ppm to about 3 ppm
and/or a total bromine concentration in the range of about 0.1 ppm to about 10 ppm, and
preferably in the range of about 0.2 ppm to about 4 ppm in a flowing water stream
averaging from about 10 ml/min. to about 3 liter/min, and preferably from about 10
ml/min to about 250 ml/min, averaged over a total flow of about 10 liters to about ,
150 liters. However, it is to be appreciated that the article according to the invention can
produce chlorine or bromine or both chlorine and bromine for much larger total volumes
of water flow. The low concentration of chlorine and/or bromine in water by itself is
insufficient to achieve the 4-log and 6-log removal standards required by the EPA.
However, this low concentration of chlorine and/or bromine when supplied in the
untreated water is sufficient to sustain a HPSH polymer at a biocidally effective level that ,
is able to achieve the required 4-log and 6-log removal rate.
One embodiment for making the article includes reconstituting commercially
available compounds by either crushing the commercial products into a powder or
obtaining powdered versions of the compounds. The powder or powders can be passed
through sieves of various sizes to obtain the appropriate sized grains. The powder or
powders can be combined, optionally with one or more other sources of chlorine or
bromine or adjuvants, in predetermined amounts, and fully mixed together. The mixture

is compressed by any commercial tablet manufacturing apparatus to achieve an article of
a certain density, size, or shape. Depending on the amount of compaction, the size,
shape, or density of the article, the concentrations of chlorine or bromine or both eluted
from the article, can be affected. For example, the article according to the invention can
have a density that is in the range of from about 1.4 grams per cubic centimeter to about 4
grams per cubic centimeter.
The article according to the invention includes one or more compounds capable of
releasing chlorine and/or bromine at predetermined low concentrations in flowing or
stagnant water that is determined by the design of the article, including the article's
solubility, density, erosion rate, ratio of volume to surface area, and optionally, the
amount and/or type of binders and tableting aides. Low when referring to the
concentration of a halogen in water means about 0.1 ppm by weight to about 3 ppm by
weight chlorine and about 0.2 ppm by weight to about 4 ppm by weight bromine.
Depending on the desired level of free halogen required to maintain a biocidally active
HSPH polymer, one or more of the variable factors mentioned herein can be adjusted.
Optional adjuvants, tableting and compaction aides include calcium phosphate, dicalcium
phosphate, tricalcium phosphate, sodium bicarbonate, a polyfluorinated polymer, lactose,
a fatty acid, a wax, calcium stearate, magnesium stearate, talc, starch, calcium carbonate,
sucrose, glucose, mannitol, sorbitol, bentonite, carboxymethylcellulose, methylcellulose,
hydroxethylcellulose, hydroxypropylcellulose, sodium metaphosphate, magnesium oxide,
polytetrafluoroethylene (TEFLON®7), polyfluorinated polymers, phosphate buffers,
sodium based phosphate buffers, dibasic sodium phosphate, monobasic sodium
phosphate, tribasic sodium phosphate, sodium hexametaphosphate, potassium based
phosphate buffers, dibasic potassium phosphate, monobasic potassium phosphate, or any
combinations. The tableting and compaction aides are preferably selected to be
compatible with the source of halogen. Sources of chlorine and bromine can include, but
are not limited to the following.
1. A halohydantoin, including but not limited to l,3,dichloro-5,5-
dimethylhydantoin l,3,dibromodimethylhydantoin, l-chloro-3-bromo-5,5-
dimethylhydantoin or l-bromo-3-chloro-5,5-dimethylhydantoin;
2. A chlorinated isocyanurate or a metal salt of a chlorinated isocyanurate,
including but not limited to trichloroisocyanuric acid, dichloroisocyanuric acid, potassium

trichloroisocyanurate, sodium trichloroisocyanurate, potassium dichloroisocyanurate or
sodium dichloroisocyanurate;
3. A N-halooxazolidinone, including but not limited to 3-chloro-2,2-dialkyl-
4,4-dimethyl-1,3 -oxazolidinone, 3 -chloro-4,4-dimethyl-2-oxazolidinone, 3 -bromo-4,4-
dimethyl-2-oxazolidinone, 3-chloro-4-ethyl-4-methyl-2-oxazolidinone, 3-bromo-4-ethyl- '
4-methyl-2-oxazolidinone, 3-chloro-4-methyl-2-oxazolidinone, 3-bromo-4-methyl-2-
oxazolidinone, or 3-chloro-2-oxazolidinone, or 3-bromo-2-oxazolidinone;
4. A NjN'-dihaloimidazolidinone, including but not limited to 1,3-dichloro-
4,4,5,5-tetramethyl-2-imidazolidinone, l,3-dibromo-4,4,5,5-tetramethyl-2-
imidazolidinone, l-bromo-3-chloro-4,4,5,5-tetramethyl-2- imidazolidinone, 1,3-dichlor-
2,2,5,5-tetramethyl-4- imidazolidinone, l,3-dibromo-2,2,5,5-tetramethyl-4- '
imidazolidinone, or l-bromo-3-chloro-2,2,5,5-tetramethyl-4- imidazolidinone;
5. A N-halosuccinimide, including but not limited to N-chlorosuccinimide or
N-bromosuccinimide;
6. A N-halomelamine, including but not limited to trichloromelamine;
7. A N-haloglycoluril, including but not limited to tetrachloroglycoluril
tetrachlorodimethylglycoluril, tetrabromoglycoluril or tetrabromodimethylglycoluril;
8. A sulfonhalamide, including but not limited to sodium
p-toluenesulfonchloramide (chloramine T), p-toluenesulfondichloramide (dichloramine
T), sodium benzenesulfonchloramide (chloramine B), p-sulfondichloramidobenzoic acid,
N-chloro-N-methyl-p-toluenesulfonamide, sodium p-toluenesulfonbromamide
(bromoamine T), p-toluenesulfondibromoamide (dibromamine T), sodium
benzenesulfonbromoamide (bromamine B), p-sulfondibromamidobenzoic acid or N- '
bromo-N-methyl-p-toluenesulfonamide;

9. A cyclic N-halamine, including but not limited to l,3,5-trichloro-2,4-
dioxohexahydrotriazine, l,3,5-tribromo-2,4-dioxohexahydrotriazine, l-chloro-2,2,6,6-
tetramethylpiperidine, l-bromo-2,2,6,6-tetramethylpiperidine, 1,4-dichloro-2,2,5,5-
tetramethyl-3,6-piperazinedione, l,4-dibromo-2,2,5,5-tetramethyl-3,6-piperazinedione,
l-chloro-2,2,6,6-tetramethyl-4-piperidone or l-bromo-2,2,6,6-tetramethyl-4-piperidone;
10. An acyclic N-halamine, including but not limited to
N,N'-dichloroazodicarbonamidine (Chloroazodin) or N,N'-dibromoazodicarbonamidine;
11. A solid metal salt of hypochlorous acid, including but not limited to
calcium hypochlorite or lithium hypochlorite;

12. A metal salt of hypobromous acid, including but not limited to calcium
hypobromite, sodium hypobromite, lithium hypobromite, or potassium hypobromite;
13. A bromide salt, including but not limited to sodium bromide, lithium
bromide, or potassium bromide;
14. A chloride salt, including but not limited to sodium chloride, lithium
chloride, or potassium chloride; f
15. Sodium hypochlorite;
16. A metal salt of oxychlorosene, including but not limited to sodium
oxychlorosene.
The grain size, tablet dimensions, density, and relative percentages of halogen
source to other potential materials in the article are adjusted based on the desired level of
halogen needed for the particular water purification system employing the HPSH ,
polymer. The hydraulic characteristics of the water purification system can also be taken
into account. Tests can be easily conducted to achieve the desired concentrations of
halogen for each particular water purification system to determine the proper amounts of
the chlorine and or bromine source compounds, as well as the size, shape, density, and
surface area of the article.
For one particular embodiment of a water purification system, the following ratios ,
provided the desired halogen concentrations. The list is not exhaustive and it is to be
appreciated that ratios can deviate from the following depending on the chosen water
purification system and the other variable factors affecting the article. All ratios are given
as weight ratios. For an article comprising trichloromelamine and magnesium oxide, the
ratio of the respective compounds is about 1:1. For an article comprising
dichlorodimethylhydantoin, sodium metaphosphate and polytetrafluoroethylene ,
(TEFLON®7), the ratio of the respective compounds is about 2:2:1. For an article
comprising calcium hypochlorite and polytetrafluoroethylene (TEFLON®7), the ratio of
the compounds is about 1:3. For an article comprising sodium dichloroisocyanurate,
calcium phosphate dibasic, and polytetrafluoroethylene (TEFLON®7), the ratio of the
respective compounds is about 1:1:2. For an article comprising sodium
trichloroisocyanurate, sodium metaphosphate, and polytetrafluoroethylene (TEFLON®7), ,
the ratio of the respective compounds is about 2:1:4.
In one embodiment, a composition comprising trichloromelamine, a buffer and
sodium bicarbonate, is provided. The composition can be compressed into a tablet that

provides chlorine in the range of about 0.1 to about 3 ppm in a flowing water stream. The
buffer can include sodium based phosphate buffers or potassium based phosphate buffers.
Sodium based phosphate buffers include dibasic sodium phosphate, monobasic sodium
phosphate, tribasic sodium phosphate, and sodium hexametaphosphate. The potassium
based phosphate buffers include dibasic potassium phosphate and monobasic potassium
phosphate. For an article comprising trichloromelamine, a buffer and sodium
bicarbonate, the amounts of the respective compounds are the following:
trichloromelamine is about 25% to about 85% by weight, buffer is about 1% to about
50% by weight, and sodium bicarbonate is about 0.5% to about 33% by weight. In one
embodiment, an article comprising trichloromelamine, sodium hexametaphosphate and
sodium bicarbonate the ratio of the respective compounds is about 2:1:0.2.
Suitable polymers that can be used in combination with the article of the
invention, include any polymer that can be rendered biocidal on contact with water to be
treated that includes free halogen at a concentration generated by the article. For
example, polymers having heterocyclic amine groups that can be halogenated with the
article of the invention. One representative heterocyclic amine group is a hydantoin
moiety. Hydantoins along with several other heterocyclic amine groups and the polymers
incorporating these compounds are described in U.S. Patent Nos. 5,490,983 and
6,548,054; and U.S. Published Application No. 10/400,165, all of which are incorporated
herein by reference.
In another aspect, the invention provides a method for sustaining the biocidal
efficacy of polymers having pendant heterocyclic N-halamines. The method relies on a
water purification device having two compartments, one respectively for an article of the
invention, and the other for a polymer having pendant heterocyclic N-halamines. The
compartments are in communication with each other such that water to be treated passes
into and out of the first compartment with an article and is then directed to flow into and
out of the second compartment with the polymer having pendant heterocyclic N-
halamines. The polymer is situated downstream from an article according to the
invention. The polymer is located in the compartment that has a water inlet and outlet.
The polymer is situated such that the water contacts the polymer before exiting through
the water outlet. A second compartment is provided for an article made in accordance
with the invention. The second compartment for the article likewise has a water inlet and
outlet. The second compartment is also configured in a manner that induces water to

contact the article before the water exits the compartment. The second compartment
containing the article is situated such that water to be treated entering the device contacts
the second compartment containing the article before contacting the compartment '
containing the polymer. The water outlet from the article compartment is connected to
the water inlet to the polymer compartment. The water purification system may
incorporate any other type of filters before or after the article compartment or the polymer
compartment. For example, a ceramic filter may be located ahead of the article
compartment. Other filters, such as activated carbon filters may also be used. Untreated
water or water to be treated, meaning water that has not contacted the polymer, is allowed '
to enter the article compartment through the water inlet where contact is made with the
article. In contacting the article, free chlorine or bromine or both chlorine and bromine
are eluted into the water at the concentrations described herein. The halogenated water
leaves the article compartment through the water outlet, and enters the polymer
compartment through the polymer compartment water inlet. While the halogen is being
depleted by the biodemand, the HPSH polymer within the polymer compartment is '
halogenated by the water. The article according to the invention provides free chlorine or
bromine or both chlorine and bromine into the water at specified predetermined
concentrations. A further advantage of the article made in accordance with the present
invention is the minimal effect on the pH of the water flowing over the article. A small
pH increase or pH decrease in the water that passes over the article may be noticed
however. A change of about plus or minus one pH unit may sometimes be realized
between the water before the article and the water after the article.
FIGURE 1 illustrates a representative experimental apparatus used in the
determination of free halogen in water from articles made in accordance with the present
invention. The experimental apparatus includes a water feed tank 100. The water feed
tank 100 contains water that is either untreated or, alternatively, can include municipally
treated water. However, municipally "treated" water is considered untreated for purposes •
of this application, if the water is not treated by passing over a heterocyclic N-halamine
polymer. The water feed tank 100 is connected to the suction side of the water feed
pump 104. The line 102 connects the water feed tank to the suction side of the water feed
pump 104. The water feed pump 104 pumps water through a control valve 106. The
control valve 106 meters the amount of water that is pumped by the water feed pump 104
to two chambers 126 and 128. The water from the control valve 106 flows through the •

line 108. The water from line 108 flows into branch line 112 and branch line 114.
Branch line 112 feeds a metered amount of water into the chamber 126 having a polymer
compartment 116 but without an article compartment. The compartment 116 is filled
with PSH polymer or HPSH polymer beads 130. The chamber 126 is used as the control. '
Branch line 114 feeds a metered amount of water into the chamber 128 with a polymer
compartment 120 and also including an article compartment 118. Compartment 120 is
filled with PSH polymer or HPSH polymer beads 132. Compartment 118 includes a
replaceable article 134, such as a tablet, made in accordance with the invention. By
introducing different articles into the article compartment 118 ahead of the polymer
compartment 120, a side-by-side comparison can be made of the levels of halogen '
loading of the polymer downstream of the article compared with a control sample of the
polymer that is not exposed to water containing low concentrations of halogen. The
concentration of halogen, in the water streams 122 and 124 that exit the chambers 126
and 128 are measured analytically. As can now be more readily understood from the
description provided, practical applications for the use of HPSH polymer in water
purification systems are made possible by the invention.
Referring to FIGURE 2, a gravity feed water purification system having an article
for the constant halogenation of HPSH polymer according to the invention is illustrated.
The system includes an upper chamber 200 and a lower chamber 202 separated by a
horizontal dividing wall 204. The upper chamber 200 contains a flow-through ceramic
filter 206 that is connected to a conduit 208 for channeling water from the ceramic
filter 206 to the lower chamber 202. The conduit 208 discharges through the dividing '
wall 204 into an article compartment 210 located in the bottom chamber 202. The article
compartment 210 is connected at the conduit outlet 218 so that water exiting the ceramic
filter 206 enters and passes through the article compartment 210. The article
compartment has an outlet for water leading to the inlet 222 to a polymer
compartment 212. The polymer compartment 212 contains the HPSH polymer
beads 224. The water purification cartridge described in US Patent Application '
No. 10/676,730, filed on October 1, 2003, can be used in the water purification system of
FIGURE 2. The water purification cartridge of US Patent Application No. 10/676,730
describes a filter having compartments that can be used to contain an article of the present '
invention and to contain HPSH polymer. US Patent Application No. 10/676,730 is
incorporated herein by reference.

Untreated water deposited into the upper chamber 200 rises to a level such that the
water flows through the ceramic filter 206 and the article compartment 210 before
entering the polymer compartment 212. On passing through the article compartment 210,
the untreated water contacts the article 220 where the article releases chlorine into the
water at the concentrations predetermined to sustain the biocidal efficacy of the HPSH -
beads, but does not render the water unsuitable for drinking. The water containing the
predetermined concentrations of halogen further contacts the HPSH polymer beads 224 in
the polymer compartment 212. In this manner, the article 220 in compartment 210 is able
to maintain the HPSH polymer beads 224 at a biocidally effective level. Treated
water 214 exits the polymer compartment 212 from the polymer compartment outlet 226
and accumulates in the lower chamber 202. Water drawn from the lower chamber 202 '
through faucet 216 is both treated and suitable for drinking. It can be understood that the
method according to the invention includes contacting untreated water with a plurality of
N-halohydantoin functionalized beads having biocidal activity for a time sufficient to
provide water suitable for drinking, wherein the untreated water comprises a contaminant
and a halogen. On contact with a contaminant in the water, at least a portion of the
plurality of N-halohydantoin functionalized beads are converted to hydantoin •
functionalized beads to provide an inactive contaminant, while at the same time at least a
portion of the hydantoin functionalized beads are converted to N-halohydantoin
functionalized beads on contact with the halogen in the untreated water.
As the following examples demonstrate, a low halogen concentration in water
made to contact PSH/HPSH polymer beads can create and maintain a halogen loading on
the PSH/HPSH polymer sufficient for the polymer to maintain continuous biocidal •
activity to meet EPA standards, without having to be recharged. The concentrations of
chlorine provided by representative examples of articles made in accordance with the
invention are illustrated in FIGURE 3. The chlorine concentrations shown in FIGURE 3
are within the concentration range of about 0.1 ppm (weight) to about 3 ppm (weight)
required to constantly sustain halogenated polystyrene beads having pendant hydantoin
groups biocidally effective, but without effecting water potability. FIGURE 3 shows a •
variety of elution profiles for a halogen from an article made in accordance with the
invention. Representative halogen elution rate profiles include, but are not limited to a
substantially constant profile, a rapid increase profile, a rapid decrease profile, a gradual
increase profile, a gradual decrease profile, or a sinusoidal profile.

EXAMPLE 1 ',
SUSTAINING BIOCIDAL EFFICACY OF HPSH BEADS WITH DILUTED BLEACH
Two beds arranged as shown in FIGURE 1, each containing 20 g of chlorinated
HPSH beads (16.9% wt/wt of C1+ (C1+ is the chlorine attached to a nitrogen on the
hydantoin available for the biodemand)) and confirmed to be of a biocidal state achieving
a 4-log reduction value (LRV) in poliovirus and a 6-LRV in Klebsiella terrigena (as
determined using the methods described in the USEPA Guide Standard and Protocol for ■
Testing Microbiological Purifiers: Report of Task Force, 1987), were challenged with
feed water having the characteristics of 1,500 mg/L total dissolved solids as sea salts,
10 mg/L of total organic carbon as humic acid, and a pH of 9.0 adjusted using NaOH and
HC1. Each bed was continuously challenged at 60 ml/min. One bed was designated the
control and continuously challenged only with the feed water. The other bed was
continuously challenged with feed water that was adjusted to 2 ppm free chlorine (as ,
measured by N,N-diethylphenylenediamine (DPD) reagent using HACH Corp. Method
8021) using dilute sodium hypochlorite (i.e., bleach). After treating the beds with 140 L
of the respective feed waters to the two beds, the weight percentage of chlorine (measured
as C1+) of the polymers in the beds was determined using an iodometric/fhiosulfate
titration of 1-gram of weighted crushed polymer. The polymer of the control bed was
measured at 15.9% by weight chlorine, while the polymer of the test bed increased to a .
chlorine weight percentage of 17.2%. The chlorine concentration in the water is plotted
as a function of cumulative water flow in FIGURE 3.
EXAMPLE 2
SUSTAINING BIOCIDAL EFFICACY OF HPSH BEADS WITH
TRICHLOROMELAMINE AND MAGNESIUM OXIDE TABLET
A commercially available gravity feed ceramic drinking water system as shown in
FIGURE 2 (Doulton Berkefeld) was used along with a 20 gram cartridge of HPSH
polymer (having 16% C1+ wt/wt) attached to the outlet of the ceramic filter. The system
was challenged with feed water having the characteristics of 1,500 mg/L total dissolved
solids as sea salts, 10 mg/L of total organic carbon as humic acid, and a pH of 9.0
adjusted using NaOH and HC1. The system was allowed to run daily at 10 liters per day
at an average flow rate of 10 ml/min using chlorine-free tap water and challenged weekly
using the above challenge water until the poliovirus log reduction dropped below a
complete kill of 4-LRV (as determined using the methods described in the USEPA Guide

Standard and Protocol for Testing Microbiological Purifiers: Report of Task Force,
1987). Prior to the introduction of an article that releases a low-level of free chlorine, the "
polio virus LRV was measured at 1.36-LRV. A compressed tablet of '/2-inch diameter and
having a mass of 800 mg (Parr Pellet Press, Parr Instruments Co.) and a density of
1.9895 g/cc of well mixed powdered trichloromelamine and magnesium oxide in a ratio
of 1:1 by weight, was placed in situ above the inlet to the cartridge containing the
PSH/HPSH polymer. Samples of the water coming into contact with the compressed
tablet were taken prior to entering the cartridge and contained 0.30 ppm of free chlorine
(as measured by N,N-diethylphenylenediamine (DPD) reagent using HACH Corp. .
Method 8021). The following week's challenge measured a poliovirus LRV at 4.26-LRV.
The chlorine concentration in the water is plotted as a function of cumulative water flow
in FIGURE 3.
For examples 3-8, the sustainability of biocidal activity is demonstrated using
PSH polymer (0% wt/wt of C1+) to avoid die need of testing the LRV during each
example. It was found that any level of biocidal activity of HPSH polymer can be
sustained as long as the halogen loading on a PSH polymer is found to increase.
Furthermore, the residual halogen level in the water remained within the ranges
acceptable for drinking. A tablet that was found to both increase the weight percent of
halogen in PSH polymer and also maintain.the residual level of halogen within the ranges
acceptable for drinking demonstrates a suitable formulation for a tablet according to the
invention. The increase in the halogen weight percent represents the sustaining rate for
the tablet for each of the examples.
EXAMPLE 3
ACTIVATING BIOCIDAL EFFICACY OF PSH BEADS WITH
TRICHLOROMELAMINE TABLET
Two beds, each containing 22 g of PSH polymer in bead form (0% wt/wt of C1+) '
arranged as shown in FIGURE 1, were challenged with municipally treated drinking
water that was processed through an activated carbon block commonly sold into retail
markets for the removal of chlorine taste and odor. The water contained less than
0.02 ppm of free chlorine and had a hardness of 0.07 ppm (as total CaC03 using HACH
hardness method 8030). One bed was designated the control and continuously challenged
only with the feed water. The other bed was continuously challenged with feed water that ■'
flowed over a solid /4-inch diameter, 550 mg, compressed tablet of compacted powdered

trichloromelamine (Parr Pellet Press, Parr Instruments Co.) having a density of
1.3678 g/cc. The feed water after the pellet contained 0.10 ppm to about 0.30 ppm of free
chlorine (as measured by N,N-diethylphenylenediamine (DPD) reagent using HACH .'
Corp. Method 8021) and hardness as CaCO3 was measured at 3.06- 3.44 ppm. After
treating the bed for 40 L of the respective feed waters at an average flow rate of
10 ml/min, the weight percentage of chlorine determined through iodometric/thiosulfate
titration in the control bed was measured at 0.0% wt/wt, while the test bed increased to a
chlorine weight percentage of 0.07%. The chlorine concentration in the water is plotted as
a function of cumulative water flow in FIGURE 3.
EXAMPLE 4
ACTIVATING BIOCIDAL EFFICACY OF PSH BEADS WITH
DICHLORODIMETHYLHYDANTOIN, SODIUM METAPHOSPHATE AND TEFLON
7 TABLET
Two beds each containing 1.65 g of PSH polymer in bead form (0% wt/wt of C1+)
arranged as shown in FIGURE 1 were challenged with municipally treated drinking water ;
that was processed through an activated carbon block commonly sold into retail markets
for the removal of chlorine taste and odor. The water contained less than 0.02 ppm of
free chlorine and had a hardness of 0.07'ppm (as total CaC03 using HACH hardness
method 8030). One bed was designated the control and continuously challenged only
with the feed water. The other bed was continuously challenged with feed water that
flowed over a solid, !4-inch diameter, 240 mg compressed tablet (Pan- Pellet Press, Pan- ;
Instruments Co.) having a density of 2.388 g/cc of well mixed powdered
dichlorodimethylhydantoin, sodium metaphosphate, and TEFLON 7® (DuPont) at a ratio
of 2:2:1 by weight. The feed water after the pellet contained 1.10 ppm to 1.82 ppm of
free chlorine (as measured by N,N-diethylphenylenediamine (DPD) reagent using HACH
Corp. Method 8021) and hardness as CaC03 was measured at 0.16-3.26 ppm. After
treating the bed for 13 L of the respective feed waters at an average flow rate of 222 ml ;
per minute, the weight percentage of chlorine determined through iodometric/thiosulfate
titration in the control bed measured 0.0% wt/wt, while the test bed increased to a
chlorine weight percentage of 0.20%. The chlorine concentration in the water is plotted
as a function of cumulative water flow in FIGURE 3.

EXAMPLE 5
ACTIVATING BIOCIDAL EFFICACY OF PSH BEADS WITH CALCIUM
HYPOCHLORITE AND TEFLON 7 TABLET
Two beds each containing 2.05 g of PSH polymer in the form of beads (0% wt/wt •
of C1+) arranged as shown in FIGURE 1 were challenged with municipally treated
drinking water that was processed through an activated carbon block commonly sold into
retail markets for the removal of chlorine taste and odor. The waters contained less than
0.02 ppm of free chlorine and had a hardness of 0.07 ppm (as total CaC03 using HACH
hardness method 8030). One bed was designated the control and continuously challenged
only with the feed water. The other bed was continuously challenged with feed water that -
flowed over a solid, '/4-inch diameter, 400 mg compressed tablet (Parr Pellet Press, Parr
Instruments Co.) having a density of 3.980 g/cc of well mixed powdered of calcium
hypochlorite and TEFLON 7® (DuPont) at a ratio of 1:3 by weight. The feed water after
the pellet contained 0.11 to 0.80 ppm of free chlorine (as measured by N,N-
diethylphenylenediamine (DPD) reagent using HACH Corp. Method 8021) and hardness
as CaC03 was measured at 2.51-3.12 ppm. After treating the bed for 45 L of the ,
respective feed waters at an average flow rate of 250 ml per minute, the weight
percentage of chlorine determined by iodometric/thiosulfate titration in the control bed
measured 0.0% wt/wt, while the test bed increased to a chlorine weight percentage of
0.60%. The chlorine concentration in the water is plotted as a function of cumulative
water flow in FIGURE 3.
EXAMPLE 6
ACTIVATING BIOCIDAL EFFICACY OF PSH BEADS WITH SODIUM
DICHLOROISOCYANURATE, CALCIUM PHOSPHATE AND TEFLON 7 TABLET
Two beds each containing 2.0 g of PSH polymer in bead form (0% wt/wt of C1+)
arranged as shown in FIGURE 1 were challenged with municipally treated drinking water
that was processed through an activated carbon block commonly sold into retail markets
for the removal of chlorine taste and odor. The water contained less than 0.02 ppm of .
free chlorine and had a hardness of 0.07 ppm (as total CaC03 using HACH hardness
method 8030). One bed was designated the control and continuously challenged only
with the feed water. The other bed was continuously challenged with feed water that
flowed over a solid, 'A-inch diameter, 200 mg compressed tablet (Parr Pellet Press, Pan-
Instruments Co.) having a density of 1.990 g/cc of well mixed powdered sodium

dichloroisocyanurate, calcium phosphate dibasic and TEFLON 7® (DuPont) in a ratio of
1:1:2 by weight. The feed water after the pellet contained 0.91 to 3.4ppm of free
chlorine (as measured by N,N-diethylphenylenediamine (DPD) reagent using HACH
Corp. Method 8021) and hardness as CaC03 was measured at 0.76-2.97 ppm. After
treating the beds with 44 L of the respective feed water at a flow rate of 222 ml per
minute, the weight percentage of chlorine by iodometric/thiosulfate titration in the control
bed measured 0.0% wt/wt, while the test bed increased to a chlorine weight percentage of
0.30%. The chlorine concentration in the water is plotted as a function of cumulative
water flow in FIGURE 3.
EXAMPLE 7
ACTIVATING BIOCIDAL EFFICACY OF PSH BEADS WITH
TRICHLOROISOCYANURATE, SODIUM METAPHOSPHATE AND TEFLON 7
Two beds each containing 2.09 g of PSH polymer in bead form (0% wt/wt of C1+)
arranged as shown in FIGURE 1 were challenged with municipally treated drinking water
that was processed through an activated carbon block commonly sold into retail markets
for the removal of chlorine taste and odor. The water contained less than 0.02 ppm of
free chlorine and had a hardness of 0.07 ppm (as total CaC03 using HACH hardness ,
method 8030). One bed was designated the control and continuously challenged only
with the feed water. The other bed was continuously challenged with feed water that
flowed over a solid, '/4-inch diameter, 200 nig, compressed tablet (Parr Pellet Press, Parr
Instruments Co.) having a density of 1.990 g/cc of well mixed powdered sodium
trichloroisocyanurate, sodium metaphosphate and TEFLON 7® (DuPont) at a ratio of
1:0.5:2 by weight. The feed water after the pellet contained 0.30 to 0.76 ppm of free
chlorine (as measured by N,N-diethylphenylenediamine (DPD) reagent using HACH
Corp. Method 8021) and hardness as CaC03 was measured at 1.59-3.16 ppm. After
treating the beds with 34 L of the respective feed water at an average flow rate of 180 ml
per minute, the weight percentage of chlorine by iodometric/thiosulfate titration in the
control bed measured 0.0% wt/wt, while the test bed increased to a chlorine weight
percentage of 0.30%. The chlorine concentration in the water is plotted as a function of
cumulative water flow in FIGURE 3.

EXAMPLE 8
ACTIVATING BIOCIDAL EFFICACY OF PSH BEADS WITH DIBROMO-5,5-
DIMETHYLHYDANTOIN TABLET
Two beds each containing 2.00 g of PSPI polymer in bead form (0% wt/wt of C1+)
arranged as shown in FIGURE 1 were challenged with municipally treated drinking water
that was processed through an activated carbon block commonly sold into retail markets
for the removal of chlorine taste and odor. The water contained less than 0.02 ppm of
free chlorine and had a hardness of 0.07 ppm (as total CaC03 using HACH hardness
method 8030). One bed was designated the control and continuously challenged only
with the feed water. The other bed was continuously challenged with feed water that
flowed over a solid, '/4-inch diameter, 200 mg, tablet (Parr Pellet Press, Parr Instruments
Co.) having a density of 1.990 g/cc composed of commercially available nuggets of
dibromo-5,5-dimethylhydantoin (ALBROM100, Albemarle Corp.) crushed and
reconstituted to have the parameters above. The feed water after the pellet contained 0.62
to 4.13 ppm of total bromine (as measured by N,N-diethylphenylenediamine (DPD)
reagent using HACH Corp. Method 8021) and hardness as CaC03 was measured at
0.70-1.93 ppm. After treating the bed for 46 L of the respective feed waters at an average
flow rate of 192 ml per minute, the weight percentage of bromine (Br+) determined by
iodometric/thiosulfate titration in the control bed measured 0.0% wt/wt, while the test bed
increased to a bromine weight percentage of 1.20%.
EXAMPLE 9
SUSTAINING BIOCIDAL EFFICACY OF HPSH BEADS WITH
TRICHLOROMELAMINE, SODIUM FIEXAMETAPHOSPHATE AND SODIUM
BICARBONATE TABLET
Two commercially available gravity feed ceramic drinking water systems as
shown in FIGURE 2 (Doulton Berkefeld) were used along with a 20 gram cartridge of
HPSH polymer (having 14% C1+ wt/wt) attached to the outlet of the ceramic filter. The
systems were challenged with feed water having the characteristics of 1,500 mg/L total
dissolved solids as sea salts, 10 mg/L of total organic carbon as humic acid, and a pH of
9.0 adjusted using NaOH and HC1. The systems were allowed to run daily at 10 to
20 liters per day at an average flow rate of 15 ml/min using chlorine-free tap water and
challenged periodically using the above challenge water to measure poliovirus log
reduction as determined using the methods described in the USEPA Guide Standard and

Protocol for Testing Microbiological Purifiers: Report of Task Force, 1987. One unit
was designated as the control while the other unit contained a compressed tablet of '
'/2-inch diameter and having a mass of 550 mg (Parr Pellet Press, Pan- Instruments Co.)
and a density of 1.52 g/cc of well mixed powdered trichloromelamine, sodium
hexametaphosphate and sodium bicarbonate in a ratio of 2:1:0.20 by weight, placed in
situ above the inlet to the cartridge containing the PSH/HPSH polymer. The above tablet
dissolved within and was replaced with a fresh tablet after 70L, 140L, 210L, 280L, 350L,
and 420L had passed through the system. The control unit showed a drop in poliovirus
LRV from above 4 to 3.5 at 280 liters. The drop in poliovirus LRV continued down to
2.5 LRV by 351L. The challenge unit containing the in-situ compressed tablet, on the
other hand, continued to show a greater than 4 LRV through 420L. The poliovirus LRV
for both the control and challenge system is plotted as a function of total water through
the system in FIGURE 4. Samples of the water coming into contact with the compressed
tablet system and control system were taken after the PSH/HPSH bead bed and contained
0.05 to 0.36 ppm of free chlorine (as measured by N,N-diethylphenylenediamine (DPD)
reagent using HACH Corp. Method 8021). The chlorine concentration in the water
leaving the PSH/HSPH bead beds for both the control and challenge systems is plotted as
a function of cumulative water flow in FIGURE 5.
It can be seen from the above examples that using low concentrations of chlorine
and/or bromine can halogenate HPSH polymers to a level sufficient to be effective
biocides.
While the preferred embodiment of the invention has been illustrated and
described, it will be appreciated that various changes can be made therein without
departing from the spirit and scope of the invention.

WE CLAIM:
1. A method for sustaining the biocidal activity of halogenated polystyrene
hydantoin beads, comprising: incorporating a composition comprising at least one
oxidative halogen containing compound such as herein described into water being
treated with halogenated polystyrene hydantoin beads to provide treated water
suitable for drinking, wherein the composition provides a free halogen concentra-
tion from about 0.1 ppm to about 10 ppm in the water, the concentration being
sufficient to maintain the biocidal activity of the halogenated polystyrene hy-
dantoin beads.
2. The method as claimed in claim 1, wherein halogenated polystyrene
hydantoin beads comprise chlorinated polystyrene hydantoin beads.
3. The method as claimed in claim 1, wherein halogenated polystyrene
hydantoin beads comprise brominated polystyrene hydantoin beads.

4. The method as claimed in claim 1, wherein the halogen concentration is
about 0.1 ppm to about 4 ppm.
5. The method as claimed in claim 1, wherein the water to be treated is
continuously supplied to the beads.
6. A method for halogenating a polymer having pendant heterocyclic
N-halamine groups, comprising: flowing water from a first compartment
containing a composition comprising at least one oxidative halogen containing
compound such as herein described to a second compartment containing a
polymer having pendant heterocyclic N-halamine groups; wherein the

composition provides a free halogen concentration from about 0.1 ppm to about
10 ppm in said flowing water.
7. The method as claimed in claim 6, wherein the composition generates a
concentration of free oxidative halogen sufficient to sustain the biocidal activity
of halogenated polystyrene hydantoin beads.
8. The method as claimed in claim 7, wherein the concentration of free
halogen is from about 0.1 ppm to about 4 ppm.
9. The method as claimed in claim 6, wherein the polymer having pendant
heterocyclic N-halamine groups comprises N-halohydantoinyl groups.
10. The method as claimed in claim 6, wherein the halogen is chlorine.
11. The method as claimed in claim 6, wherein the halogen is bromine.


The invention discloses a method for sustaining the biocidal activity of
halogenated polystyrene hydantoin beads, comprising: incorporating a
composition comprising at least one oxidative halogen containing compound into
water being treated with halogenated polystyrene hydantoin beads to provide
treated water suitable for drinking, wherein the composition provides a free
halogen concentration from about 0.1 ppm to about 10 ppm in the water, the
concentration being sufficient to maintain the biocidal activity of the halogenated
polystyrene hydantoin beads.

Documents:

00920-kol-2006-abstract.pdf

00920-kol-2006-assignment.pdf

00920-kol-2006-claims.pdf

00920-kol-2006-correspondence others-1.1.pdf

00920-kol-2006-correspondence others.pdf

00920-kol-2006-correspondence-1.2.pdf

00920-kol-2006-correspondence-1.3.pdf

00920-kol-2006-description(complete).pdf

00920-kol-2006-drawings.pdf

00920-kol-2006-form-1.pdf

00920-kol-2006-form-18.pdf

00920-kol-2006-form-2.pdf

00920-kol-2006-form-3.pdf

00920-kol-2006-general power of authority.pdf

00920-kol-2006-priority document.pdf

920-kol-2006-assignment.pdf

920-kol-2006-correspondence.pdf

920-kol-2006-examination report.pdf

920-kol-2006-form 18.pdf

920-kol-2006-form 3.pdf

920-kol-2006-form 5.pdf

920-KOL-2006-FORM-27-1.pdf

920-KOL-2006-FORM-27.pdf

920-kol-2006-gpa.pdf

920-kol-2006-granted-abstract.pdf

920-kol-2006-granted-claims.pdf

920-kol-2006-granted-description (complete).pdf

920-kol-2006-granted-drawings.pdf

920-kol-2006-granted-form 1.pdf

920-kol-2006-granted-form 2.pdf

920-kol-2006-granted-specification.pdf

920-KOL-2006-OTHER PATENT DOCUMENT.pdf

920-kol-2006-others.pdf

920-kol-2006-reply to examination report.pdf

abstract-00920-kol-2006.jpg


Patent Number 246639
Indian Patent Application Number 920/KOL/2006
PG Journal Number 10/2011
Publication Date 11-Mar-2011
Grant Date 08-Mar-2011
Date of Filing 11-Sep-2006
Name of Patentee VANSON HALOSOURCE, INC.
Applicant Address 14716 NORTHEAST 87th STREET, REDMOND, WASHINGTON 98052
Inventors:
# Inventor's Name Inventor's Address
1 BRIDGES MICHAEL A 1565 GRAND AVENUE, SEATTLE, WASHINGTON 98122
2 CHEN TAN-YUAN 5300 SOMERSET DRIVE, SOUTHEAST BELLEVUE, WASHINGTON 98006
3 NICHOLS EVERETT J 22204 92ND AVENUE WEST EDMONDS, WASHINGTON 98020
4 WILLIAMS JEFFREY F 3013 MEINHOLD ROAD, LANGLEY, WASHINGTON 98260
5 MCCLURE STEVEN 2632 50TH AVENUE SOUTHWEST SEATTLE, WASHINGTON 98116
6 WETHERBEE JERRY 536 OLYMPUS BOULEVARD PORT LUDLOW, WASHINGTON 98365
7 KAWAI HIROYUKI 845 8TH AVENUE SOUTH KIRKLAND, WASHINGTON 98033
PCT International Classification Number A61F13/49
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 60/507,735 2003-10-01 U.S.A.